General Surgery MCQ.docx

8/16/2019 General Surgery MCQ.docx

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weight, an increase in total body water, and a decrease in body fat.

. "he hormonal alterations that follow operation and in2ury fa+or acceleratedgluconeogenesis. "his new glucose is consumed by which of the followingtissues?A. Central ner+ous system.!. Skeletal muscle.C. !one.#. 3idney.$. "issue in the healing wound.

Answer% A#$

#&SC'SS&()% Glucose is produced in increased amounts to satisfy the fuelre4uirements of the healing wound. &n addition, ner+e tissue and the renalmedulla also utili5e this substrate. Skeletal muscle primarily utili5es fattyacids, and bone utili5es mineral substrate.

6. Cytokines are endogenous signals that stimulate%A. ocal cell proliferation within the wound.!. "he central ner+ous system to initiate fe+er.C. "he production of /acute-phase proteins.0#. 7ypoferremia.$. Septic shock.Answer%A!C#

#&SC'SS&()% Although cytokines e*ert primarily autocrine and paracrineeffects, they may also cause systemic effects.

8. "he characteristic changes that follow a ma2or operation or moderate to


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se+ere in2ury do not include the following%A. 7ypermetabolism.!. 9e+er.C. "achypnea.#. 7yperphagia.$. )egati+e nitrogen balance.Answer% #

#&SC'SS&()% "he characteristic metabolic response to in2ury includeshypermetabolism, fe+er, accelerated gluconeogenesis, and increased

proteolysis :creating a negati+e nitrogen balance;. 9ood intake is generally

impossible because of abdominal in2ury or ileus.


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intermittent cardiac output measurements.!. Continuous cardiac output monitoring by the thermodilution methodre4uires continuous infusion of fluid in2ectate at a constant rate andtemperature.C. "he ma2or ad+antage of the 9ick method o+er the thermodilution methodof calculating cardiac output is that it is nonin+asi+e, re4uiring only thedetermination of o*ygen consumption by respiratory gas analysis.#. "he techni4ue of thoracic electrical bioimpedance utili5es sensors todetermine stroke +olume by detecting changes in resistance to a small,applied alternating current.Answer% A#

#&SC'SS&()% arious techni4ues are a+ailable to measure cardiac outputcontinuously. "he ad+antages of continuous cardiac output monitoring, ascompared with intermittent methods, are :1; pre+iously undetected e+entsmay be unmasked@ : ; more prompt recognition of ad+erse e+ents may beachie+ed@ and : ; earlier therapeutic inter+ention may be possible.Continuous cardiac output monitoring using the thermodilution methodappears to be as accurate as the /standard0 intermittent bolus method, but it

does not re4uire fluid in2ectates. &n this method, a modified pulmonary arterycatheter incorporating a thermal filament heats blood in the right +entricle at

pulsed inter+als, and a distal thermistor detects the temperature change,which can be related mathematically to cardiac output. "he 9ick methodcombines respiratory gas analysis with o*imetery to determine o*ygenconsumption : :o+erdot;( ; and to estimate mi*ed +enous and arterialo*ygen content differences, respecti+ely. Cardiac output :C(; is thendetermined from the formula% C( :o+erdot;( B C:a-+;( D 1EF :o+erdot;( B Sa( - S+( ; D :7b; D :1. H; D 1EF. "horacic electrical

bioimpedance is a techni4ue by which the resistance to a small-amplitudealternating current :i.e., the impedance; is measured using +arious electrodes."he impedance change induced by each cardiac e2ection is a function of thestroke +olume, which then can be used to calculate the cardiac output.


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I.


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to +olume and pressor therapy.!. "he presence of hyperglycemia and hypotension may suggest thediagnosis of shock due to adrenocortical insufficiency.C. 7ydrocortisone does not interfere with the serum cortisol assay and should

be gi+en to hemodynamically unstable patients suspected of ha+inghypoadrenal shock.#. "he rapid adrenocorticotropic hormone :AC"7; stimulation test should be

performed to help establish the diagnosis of acute adrenocorticalinsufficiency.Answer% A#

#&SC'SS&()% Shock due to acute adrenocortical insufficiency is relati+elyuncommon but must be considered when shock refractory to +olumereplacement and pressor therapy is present. 7ypoglycemia may be present.Jatients with high metabolic stress may e*hibit adrenal insufficiency onlyunder conditions of se+ere stress@ thus, a history of adrenal insufficiency orsteroid dependency need not be elicited.


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treatment.#. Se+ere head in2ury, spinal cord in2ury, and high spinal anesthesia may allcause neurogenic shock.Answer% C

#&SC'SS&()% )eurogenic shock occurs when se+ere head in2ury, spinalcord in2ury, or pharmacologic sympathetic blockade leads to sympatheticdener+ation and loss of +asomotor tone. !oth arteriolar and +enous +esselsdilate, causing reduced systemic +ascular resistance and a great increase in+enous capacitance. "he patientKs e*tremities appear warm and dry, incontrast to those of a patient in cardiogenic or hypo+olemic shock.

"achycardia is fre4uently obser+ed, though the classic description ofneurogenic shock includes bradycardia and hypotension. olumeadministration to fill the e*panded intra+ascular compartment is the mainstayof treatment. "he use of alpha-adrenergic agonist is infre4uently necessary totreat neurogenic shock.

11. "rue statements regarding eicosanoids include which of the following?

A. Jrostaglandins and thrombo*anes are synthesi5ed +ia the cyclo-o*ygenase pathway.!. "he +asoconstricting, platelet-aggregating, and bronchoconstricting effectsof thrombo*ane A are balanced by the actions of prostacyclin, which

produces the opposite effects.C. eukotriene synthesis is inhibited by the action of nonsteroidal anti-inflammatory drugs :)SAs;.#. "he principal prostaglandins ha+e a short circulation half-life and e*ertmost of their effects locally.Answer% A!#

#&SC'SS&()% "he eicosanoids are a group of compounds arising from themetabolism of arachidonic acid. "he prostaglandins and thrombo*anes are


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synthesi5ed +ia the cyclo-o*ygenase pathway@ thus, their synthesis is blocked by )SAs. eukotrienes, on the other hand, are synthesi5ed +ia thelipo*ygenase pathway. Jrostacyclin, produced largely by +ascularendothelium, inhibits platelet aggregation and causes +asodilatation as wellas bronchodilatation. &ts effects are balanced by those of thrombo*ane A ,which is produced by platelets and also local actions, including plateletaggregation, +asoconstriction, and bronchoconstriction. "he leukotrienes alsoha+e pulmonary and hemodynamic effects and may be in+ol+ed in the

physiologic responses associated with anaphylactic and septic shock.

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multiple organ dysfunction syndrome. &n such cases, #:o+erdot;( crit may be increased, although the therapeutic benefit of trying to achie+e/supranormal0 o*ygen deli+ery has not been firmly established.

1 . All of the following may be useful in the treatment of cardiogenic shocke*cept%A. #obutamine.!. Sodium nitroprusside.C. Jneumatic antishock garment.#. &ntra-aortic balloon pump.

Answer% C

#&SC'SS&()% Cardiogenic shock occurs when the heart fails to generateade4uate cardiac output to maintain tissue perfusion. &ntrinsic causes such asmyocardial dysfunction secondary to coronary artery disease, or e*trinsiccauses such as pulmonary embolism, tension pneumothora*, and pericardialtamponade, may produce cardiogenic shock. Jrinciples of treatment ofcardiogenic shock are aimed at optimi5ing preload, cardiac contractility, and

afterload. Jreload is usually ade4uate or high in cardiogenic shock.#obutamine is a useful inotropic agent, particularly when filling pressures arehigh, because of its mild +asodilatory effect, as well as its effect to enhancecardiac contractility. Afterload-reducing agents, such as sodium nitroprusside,may be beneficial in cardiogenic shock in the setting of ele+ated filling

pressures, low cardiac output, and ele+ated systemic +ascular resistance.Cardiac output may impro+e with use of afterload-reducing agents bydecreasing myocardial wall tension and optimi5ing the myocardial o*ygensupply-demand ratio. "he intra-aortic balloon pump :&A!J;, by pro+idingdiastolic augmentation, reducing left +entricular afterload, and reducingmyocardial o*ygen consumption, is sometimes useful in the treatment ofcardiogenic shock. "he &A!J is especially useful in lowLcardiac output

postcardiotomy patients, in patients awaiting re+asculari5ation, and in


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patients with acute myocardial infarction complicated by mitral insufficiencyor +entricular septal defect. "he pneumatic antishock garment :JASG;, whichcauses an increase in systemic +ascular resistance, is contraindicated incardiogenic shock.

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A. "he /two-hit0 model proposes that secondary M(#S may be producedwhen e+en a relati+ely minor second insult reacti+ates, in a more amplifiedform, the systemic inflammatory response that was primed by an initial insultto the host.!. "he systemic inflammatory response syndrome :S& S;, shock due tosepsis or S& S, and M(#S may be regarded as a continuum of illnessse+erity.C. Jrolonged stimulation or acti+ation of 3upffer cells in the li+er is thoughtto be a critical factor in the sustained, uncontrolled release of inflammatorymediators.#. "he incidence of M(#S in intensi+e care units has decreased owing to

increased awareness, pre+ention, and treatment of the syndrome.Answer% A!C

#&SC'SS&()% M(#S is part of a clinical continuum that begins with thesystemic inflammatory response syndrome, which is the hostKs stress responseto any ma2or insult such as in2ury or infection. M(#S may de+elop as aresult of the initial insult, but more commonly, it de+elops following a secondor subse4uent insult to the host. "he two-hit theory holds that the systemic

inflammatory response is amplified following the second hit, such asnosocomial pneumonia, leading to e*aggerated, persistent release ofinflammatory mediators that contribute to the pathogenesis of M(#S. "heli+er appears to be a pi+otal organ in the progression and outcome of M(#S,

partly because of the acti+ation and prolonged stimulation of the 3upffercells, which comprise the ma2ority of the bodyKs macrophage population.Macrophages are known to play a critical role in the elaboration of numerousinflammatory mediators. #espite ad+ances in critical care and in theunderstanding of the pathogenesis of M(#S, the incidence of M(#Scontinues to increase without a significant impro+ement in outcome.

1>. All of the following statements about hemorrhagic shock are true e*cept%


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A. 9ollowing hemorrhagic shock, there is an initial interstitial fluid +olumecontraction.!. #opamine, or a similar inotropic agent, should be gi+en immediately forresuscitation from hemorrhagic shock, to increase cardiac output and impro+eo*ygen deli+ery to hypoperfused tissues.C. "he use of colloid solutions or hypertonic saline solutions iscontraindicated for treatment of hemorrhagic shock.#. &n hemorrhagic shock, a narrowed pulse pressure is commonly seen beforea fall in systolic blood pressure.Answer% !C

#&SC'SS&()% 7emorrhagic shock is associated with a contraction of theinterstitial fluid compartment because of precapillary +asoconstriction andreabsorption of interstitial fluid into the +ascular compartment alonghydrostatic pressure gradients. Systolic hypotension may not be e+ident inhemorrhagic shock until at least EN or more of blood +olume ise*sanguinated. A decrease in the pulse pressure :the difference betweensystolic and diastolic pressures; may be obser+ed with losses of 18N to ENof blood +olume. "reatment of hemorrhagic shock includes intra+ascular

fluid administration and definiti+e control of the source of the hemorrhage.&notropic agents should not be started before +olume resuscitation but may beadded to impro+e o*ygen deli+ery to hypo*ic tissues if +olumeadministration alone does not produce resuscitati+e goals. Colloid orhypertonic saline solutions are not contraindicated in the treatment ofhemorrhagic shock@ howe+er, definiti+e e+idence that such solutions are

better than standard crystalloid solutions is lacking.

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surface, a pulmonary capillary wedge pressure of 18 mm. 7g, and a systemic+ascular resistance inde* :S &; of IEE dynes-secB:cm 8-m ; is ahemodynamic profile consistent with septic shock.C. An increase in S+( in septic patients may be e*plained by the finding ofanatomic arterio+enous shunts.#. esults of human trials employing antimediator therapy, such asantiendoto*in antibodies, & -1 receptor antagonist, and tumor necrosis factor:")9; antibodies, ha+e confirmed animal studies that demonstrate asignificant impro+ement in sur+i+al with the use of such agents.Answer% A!

#&SC'SS&()% Shock due to sepsis or S& S fre4uently manifests as ahyperdynamic cardio+ascular response, consisting of an ele+ated C& and adecreased S or S &. (ccasionally, myocardial depression may be seen,characteri5ed by increased +entricular +olumes and decreased e2ectionfractions. A circulating myocardial depressant factor, possibly ")9, may beresponsible for the cardiac dysfunction in such instances. "he cause of theincreased S+( fre4uently obser+ed in septic patients is unclear, but it may

be secondary to bioenergetic failure, metabolic downregulation, or

microcirculatory maldistribution leading to physiologic shunting. "rueanatomic arterio+enous shunting has not been demonstrated in humans inseptic shock. "reatment of septic shock consists of appropriate antibiotic useand supporti+e therapy. $*perimental antimediator therapies ha+e not beenencouraging thus far in human clinical trials, despite the promising resultsfrom many animal studies.

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C. "he deleterious effects of o*idants include lipid pero*idation and cellmembrane damage, o*idati+e damage to #)A, and inhibition of adenosinetriphosphate :A"J; synthesis.#. "he mechanism of ischemia-reperfusion in2ury in+ol+ed the catalytic

production of supero*ide anion :( O; by the en5yme *anthine o*idase.Answer% A!C#

#&SC'SS&()% (*idants are reacti+e o*ygen metabolites that ha+e both physiologic and pathophysiologic roles. As potent o*idi5ing agents, o*idantsare in+ol+ed in cytochrome J 68ELmediated o*idations, for e*ample. &n

pathophysiologic processes associated with inflammation, in2ury, and

infection, o*idants may be generated by acti+ated neutrophils and inischemia-reperfusion in2ury. #uring ischemia, the en5yme *anthine o*idaseaccumulates.


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the de+elopment of M(#S by the mechanism of bacterial translocation.#. As compared with parenteral nutrition, enteral nutrition is associated witha reduction in septic morbidity.Answer% !C#

#&SC'SS&()% "he gut has a +ital role in the pathophysiology of shock. "hesplanchnic circulation is +ery +ulnerable to the circulatory redistribution thatoccurs in shock, thus, gut ischemia may occur early in the +arious shocksyndromes. Gut in2ury, as a result of ischemia or reperfusion in2ury, leads todisruption in the intestinal mucosal barrier and increased gut permeability."ranslocation of enteric flora or bacterial to*ins across the gut wall may then

occur, resulting in amplification of the systemic inflammatory response andthe de+elopment of multiple organ dysfunction. Gut dysfunction, therefore,may perpetuate the inflammatory process. arious methods ha+e been tried tomodulate the deleterious effects of gut dysfunction. Selecti+edecontamination of the digesti+e tract by oral antibiotics has been shown toreduce the incidence of nosocomial pneumonias, but no impro+ement inmortality has been demonstrated thus far with this contro+ersial techni4ue.$arly enteral nutrition probably has the biggest impact on the preser+ation of

gut architecture and function.


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Answer% A

#&SC'SS&()% Acute symptomatic hyponatremia is characteri5ed by centralner+ous system signs of increased intracranial pressure. Changes in blood

pressure and pulse are secondary to increased intracranial pressure. &n theabsence of hypo+olemia, asymptomatic patients may be treated by restrictionof water intake@ howe+er, in such patients, hyponatremia should be partiallycorrected by parenteral sodium administration. apid correction, particularlyto hypernatremia, may lead to central pontine myelinolysis. (liguric renalfailure may rapidly de+elop in se+ere hyponatremia.

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A. "he total e*tracellular fluid +olume represents 6EN of the body weight.!. "he plasma +olume constitutes one fourth of the total e*tracellular fluid+olume.C. Jotassium is the principal cation in e*tracellular fluid.#. "he protein content of the plasma produces a lower concentration ofcations than in the interstitial fluid.$. "he interstitial fluid e4uilibrates slowly with the other body compartments.Answer% !

#&SC'SS&()% "he total e*tracellular fluid +olume represents EN of bodyweight. "he plasma +olume is appro*imately 8N of body weight. Sodium is

the principal cation. "he Gibbs-#onan e4uilibrium e4uation e*plains thehigher total concentration of cations in plasma. $*cept for 2oint fluid andcerebrospinal fluid, the ma2ority of the interstitial fluid e*ists as a rapidlye4uilibrating component.

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which can lead to +olume depletion. &nsulin therapy and the correction of the patientKs associated acidosis produce mo+ement of potassium ions into theintracellular compartment.

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#&SC'SS&()% An ele+ated anion gap may be produced by lactic acidosisfrom shock or by retention of inorganic acids from uremia. actated ingerKssolution rapidly corrects the lactic acidosis from hypo+olemia, as lactate iscon+erted to bicarbonate with hepatic reperfusion. !icarbonate loss fromdiarrhea and /dilutional acidosis0 are nonLanion gap types of metabolicacidosis.

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#. Se+erely hypercalcemic patients e*hibit the signs of e*tracellular fluid+olume deficit.$. 'rinary calcium e*cretion may be increased by +igorous +olume repletion.Answer% A#$

#&SC'SS&()% Markedly ele+ated serum calcium le+els produce polydipsia, polyuria, and thirst. igorous +olume repletion and saline diuresis correct thee*tracellular fluid +olume deficit and promote the urinary e*cretion ofcalcium. Metastatic breast cancer is the most common cause ofhypercalcemia, from bony metastasis. "he calcitonin effect on calcium isdiminished with repeat administrations.

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infection after ma2or electi+e surgery?A. Age o+er >E years.!. Chronic malnutrition.C. Controlled diabetes mellitus.#. ong-term steroid use.$. &nfection at a remote body site.Answer% C

#&SC'SS&()% Controlled diabetes mellitus has been shown repeatedly notto be associated with increased likelihood of incisional infection pro+idedone a+oids operations on body parts that may be ischemic or neuropathic.

'ncontrolled diabetes mellitus, such as ketoacidosis, is associated with adramatic increase in surgical infection. "he other parameters notedPage o+er >E, chronic malnutrition, regular steroid use, and an infection at a remote

body sitePare well-recogni5ed ad+erse predicti+e factors and are identifiedin tables within the chapter.

1. E years.Answer% !

#&SC'SS&()% Clinical e+idence of congesti+e heart failure in a patient withI.8 gm. per dl. hemoglobin concentration is a misleading sign. $+idence ofcongesti+e failure is ordinarily a ma2or risk factor, but in this particular

patient the anemia lends itself to correction by preoperati+e transfusion with


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packed red blood cells, and often it is found that congesti+e failure and theassociated increased risks disappear when the hemoglobin concentration isreturned to the 1 gm. per dl. or higher ratio. All other factors are o+ert signsof increased likelihood of a postoperati+e cardiac e+ent, the most ominous

being a myocardial infarction 6 months preoperati+ely or the presence of aharsh aortic systolic murmur suggesting the presence of aortic stenosis. Ageo+er >E years and the presence of premature atrial or +entricular contractionson the electrocardiogram are less strong determinants of a postoperati+ecardiac complication.

. ank the clinical scenarios in order of greatest likelihood of serious postoperati+e pulmonary complications.A. "ransabdominal hysterectomy in an obese woman that re4uires hours ofanesthesia time.!. ight middle lobectomy for bronchogenic cancer in a =8-year-old smoker.C. agotomy and pyloroplasty for chronic duodenal ulcer disease in a 8E-year-old who had chest film findings of old, healed tuberculosis.#. ight hemicolectomy in an obese =E-year-old smoker.

$. Modified radical mastectomy in a 8I-year-old woman who is obese.Answer% !#CA$

#&SC'SS&()% &f one considers the constellation of risk factors for pulmonary complications that is pro+ided in tabular form in theaccompanying chapter, one should readily recogni5e !, right middlelobectomy for bronchogenic cancer in a =8-year-old smoker, as the highestrisk of a clinical situation for the likelihood of serious pulmonarycomplications. "he ne*t in rank may be properly debated between answer #and answer C. #, right hemicolectomy, is 2udged to ha+e somewhat greaterlikelihood of complications since the patient is older, smokes, and is obese,although the procedure may be done through a trans+erse or lower abdominalincision. C, +agotomy and pyloroplasty, is +iewed as being somewhat less


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serious since it is an upper abdominal operation on an electi+e basis in a 8E-year-old whose only abnormalities include old, healed tuberculosis on a chestfilm. A +ery low risk of pulmonary complication should follow atransabdominal hysterectomy done through a lower abdominal incision in awoman whose only risk factors are obesity and a -hour anesthesia time. "helowest risk probably resides with the younger patient undergoing modifiedradical mastectomy, whose only risk factor is obesity. "his is particularly truesince this operation is conducted on the surface of the body, is associatedwith relati+ely little postoperati+e pain, and pro+ides free and unrestrictedrespiratory function.

. ank the following laboratory tests and procedures in terms of theirrelati+e +alue to a =8-year-old woman who is to undergo electi+e resection ofa sigmoid cancer.A. Carcinoembryonic antigen :C$A;.!. !lood urea nitrogen :!');.C. $lectrocardiogram :$CG;.#. 7emoglobin concentration :7gb;.

$. Serum creatinine :Cr;.9. Arterial blood o*ygen tension :Ja( ; on room air.G. Serum sodium concentration :)a ;.Answer% C#9$!AG

#&SC'SS&()% "he most important test by far is the electrocardiogram, withits capacity to indicate signs of occult heart disease. "he second mostimportant e+aluation is the hemoglobin concentration, which in this patientmay show an anemia related to chronic alimentary tract blood loss that wouldre4uire correction prior to safe induction of a general anesthetic. Arterial

blood gases +ary from indi+idual to indi+idual depending primarily onsmoking habits and age. Accordingly, each older person should ha+e a resting

baseline determination prior to operation. Serum creatinine may show


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e+idence of occult renal disease and is substantially more useful than bloodurea nitrogen, which is more +ulnerable to transient +olume changes.Carcinoembryonic antigen is important to know in many patients with cancerwith respect to postoperati+e follow-up since in some cases it may be an earlyherald of recurrent disease. 7owe+er, it has little to do with the patientKs

preoperati+e assessment in terms of risk and preparation for an electi+eoperation. "he presence of li+er metastases, for e*ample, can be disco+eredwith significant accuracy by palpation at the time of operation, and anele+ated carcinoembryonic antigen in no set of circumstances would lead oneto withhold colon resection with its relief of potential obstruction and

bleeding. 9inally, serum sodium concentration in a =8-year-old woman who

is admitted electi+ely for resection of the colon is always normal and would be of least +alue among these tests.

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plasma can be used for factor replacement, and the platelets and white cellscan be used for patients deficient in these components. "he use of whole

blood to replace acute blood loss is associated with lower diseasetransmission rates than the use of packed red blood cells, fresh fro5en plasma,and platelets, each from a different donor.

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blood cells based on currently a+ailable data?A. apid, acute blood loss with unstable +ital signs but no a+ailablehematocrit or hemoglobin determination.!. Symptomatic anemia% orthostatic hypotension, se+ere tachycardia :greaterthan 1 E beats per minute;, e+idence of myocardial ischemia, includingangina.C. "o increase wound healing.#. A hematocrit of =N in an otherwise stable, asymptomatic patient.Answer% A!

#&SC'SS&()% Currently accepted guidelines for the transfusion of packed

red blood cells include acute ongoing blood loss, as might occur in an in2ured patient, and the de+elopment of symptomatic anemia with manifestations ofdecreased tissue perfusion related to decreased o*ygen-carrying capacity ofthe blood. "his includes situations in which the patient is unable tocompensate for a decreased o*ygen-carrying capacity by the usualmechanisms, such as increased cardiac output. Such patients de+elopmyocardial dysfunction if an e*cessi+e demand is placed on the heart. "he

patient should be transfused with packed red blood cells, which afford added

o*ygen-carrying capacity. "his decreases the workload on the myocardiumwhile pro+iding the necessary o*ygen-deli+ery capability. "he use of packedred blood cells to impro+e wound healing or to impro+e the patientKs sense ofwell-being is highly 4uestionable. )o data support such a practice. &n general,the use of a transfusion trigger such as a hematocrit of EN or hemoglobin of1E gm. per dl. constitutes a 4uestionable indication for transfusion. &f a

patient is asymptomatic and stable and has no risk of myocardial ischemia, packed red blood cell transfusion should not be gi+en based solely or predominantly on a numerical +alue such as a hematocrit of IN.

>. "he transfusion of fresh fro5en plasma :99J; is indicated for which of thefollowing reasons?


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A. olume replacement.!. As a nutritional supplement.C. Specific coagulation factor deficiency with an abnormal prothrombin time:J"; andBor an abnormal acti+ated partial thromboplastin time :AJ"";.#. 9or the correction of abnormal J" secondary to warfarin therapy, +itamin3 deficiency, or li+er disease.Answer% C#

#&SC'SS&()% "he use of 99J as a +olume e*pander is not indicated. "hereare currently se+eral preparations :both crystalloid and colloid; that aree4ually effecti+e and do not carry the infectious and other risks associated

with the use of 99J. "he use of 99J as a /nutritional0 supplement is to becondemned. Jatients with specific deficiencies of coagulation factorsgenerally benefit greatly from the infusion of 99J. &n cases of specific factordeficiency, other preparations may be more appropriate, but 99J is generallyimmediately a+ailable and is effecti+e in most patients. Jatients recei+ingwarfarin therapy, those who ha+e +itamin 3 deficiency, and those with li+erdysfunction ha+e abnormalities of the +itamin 3Ldependent factors &&, &&,& , and , as well as protein C and protein S.

I. &n patients recei+ing massi+e blood transfusion for acute blood loss,which of the following isBare correct?A. Jacked red blood cells and crystalloid solution should be infused to restoreo*ygen-carrying capacity and intra+ascular +olume.!. "wo units of 99J should be gi+en with e+ery 8 units of packed red bloodcells in most cases.C. A /si* pack0 of platelets should be administered with e+ery 1E units of

packed red blood cells in most cases.#. (ne to two ampules of sodium bicarbonate should be administered withe+ery 8 units of packed red blood cells to a+oid acidosis.$. (ne ampule of calcium chloride should be administered with e+ery 8 units


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of packed red blood cells to a+oid hypocalcemia.Answer% A

#&SC'SS&()% Jatients who are suffering from acute blood loss re4uirecrystalloid resuscitation as the initial maneu+er to restore intra+ascular+olume and re-establish +ital signs. &f to liters of crystalloid solution isinade4uate to restore intra+ascular +olume status, packed red blood cellsshould be infused as soon as possible. "here is no role for /prophylacticinfusion0 of 99J, platelets, bicarbonate, or calcium to patients recei+ingmassi+e blood transfusion. &f specific indications e*ist patients should recei+ethese supplemental components. &n particular, patients who ha+e abnormal

coagulation tests and ha+e ongoing bleeding should recei+e 99J. Jatientswho ha+e depressed platelet counts along with clinical e+idence of oo5ing:micro+ascular bleeding; benefit from platelet infusion. Sodium bicarbonateis not necessary, since most patients who recei+e blood transfusion ultimatelyde+elop alkalosis from the citrate contained in stored red blood cells. "he useof calcium chloride is usually unnecessary unless the patient has depressedli+er function, ongoing prolonged shock associated with hypothermia, or,rarely, when the infusion of blood proceeds at a rate e*ceeding 1 to units

e+ery 8 minutes.

H. 7emostasis and the cessation of bleeding re4uire which of the following processes?A. Adherence of platelets to e*posed subendothelial glycoproteins andcollagen with subse4uent aggregation of platelets and formation of ahemostatic plug.!. &nteraction of tissue factor with factor && circulating in the plasma.C. "he production of thrombin +ia the coagulation cascade with con+ersionof fibrinogen to fibrin.#. Cross-linking of fibrin by factor &&&.Answer% A!C#


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#&SC'SS&()% 7emostasis re4uires the interaction of platelets with thee*posed subendothelial structures at the site of in2ury followed byaggregation of more platelets in that area. &nteractions between endothelialcell and subendothelial tissue factor with factor && acti+ate the coagulationcascade. "he end product is large amounts of thrombin that cataly5e thecon+ersion of fibrinogen into fibrin. 9ibrin thus formed is cross-linked byfactor &&& to form a stable clot that incorporates the platelet plug and fibrinthrombus into a stable clot.

6E.


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61. "he e+aluation of a patient scheduled for electi+e surgery should alwaysinclude the following as tests of hemostasis and coagulation%A. 7istory and physical e*amination.!. Complete blood count :C!C;, including platelet count.C. Jrothrombin time :J"; and acti+ated partial thromboplastin time :AJ"";.#. Studies of platelet aggregation with adenosine diphosphate :A#J; andepinephrine.Answer% A

#&SC'SS&()% "he e+aluation of most patients scheduled for electi+esurgery who do not ha+e a history of significant bleeding disorders is

somewhat contro+ersial. An ade4uate history and physical e*aminationscreen out most patients with bleeding problems. 9or patients who arescheduled to undergo a ma2or surgical procedure, it is ad+isable to obtain aC!C and platelet count, as well as a J" and AJ"" le+el. "his detects a largenumber of bleeding disorders but does not rule out all possible causes of

perioperati+e bleeding. Studies of platelet aggregation are indicated only for patients who are suspected of ha+ing 4ualitati+e defects of platelet function:e.g., +on


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#&SC'SS&()% "he incidence of both 7& and hepatitis transmitted +ia blood transfusions has been steadily decreasing since the 1HIEs. "his isrelated to impro+ed methods for detection and increased awareness ofsurrogate markers of disease. "he currently a+ailable techni4ues for thedetection of 7& are highly effecti+e, pro+ided the donor is not in the/window0 before the formation of specific antibody. "he surrogate markersfor hepatitis C, as well as the specific assays for the organism, are nowsufficiently refined to allow the detection of a large percentage of hepatitis Cinfection in donated blood. Screening for hepatitis ! surface antigen haseffecti+ely eliminated the transmission of hepatitis ! through blood products

in most cases. CM is the most commonly transmitted infectious agent in blood. Since a large percentage of the population carry the +irus, routinescreening is not performed for this organism@ howe+er, se+erelycompromised patients such as those undergoing transplantation shouldrecei+e CM -negati+e blood products.

6 . "he most common cause of fatal transfusion reactions is%

A. An allergic reaction.!. An anaphylactoid reaction.C. A clerical error.#. An acute bacterial infection transmitted in blood.Answer% C

#&SC'SS&()% "he most common cause of fatalities related to transfusionreactions result from A!(-incompatible transfusion related to clerical error.Most such reactions occur if a type ( person recei+es type A red cells owingto a clerical error that occurs either at the time the blood sample was drawn,during processing in the laboratory, or at the time a unit is administered. "heimportance of e*tremely careful labeling, transfer, and handling of specimensand of cross-matched blood products cannot be o+eremphasi5ed. Allergic and


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other reactions are common but rarely fatal. "he transmission of bacterialorganisms :e.g., Staphylococcus aureus; has been reported especially with

platelet concentrates maintained at or near room temperature. 9ortunately,such reactions are rare.

66.


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following findings identify the patient at risk?A.


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Answer% !#

#&SC'SS&()% !iochemical e+idence of essential fatty acid deficiency mayoccur as early as > to 1E days following initiation of fat-free parenteralnutrition. "he decrease in arachidonic acid in plasma and the appearance ofthe abnormal eicosatrienoic acid may yield the earliest indication of

prostaglandin deficiency@ it is not absolute. #ecreased intraocular pressure,another early indication of prostaglandin deficiency, may appear as soon as >days following initiation of fat-free parenteral nutrition.


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nutrition, especially if not carried out safely, can result in significantmortality. "he most common of the se+ere complications of enteral nutritionresult from the gastrostomy, or tube feedings into the stomach. Suddenchanges in gastric motility, such as those associated with sepsis, may result inaspiration. )asoenteric or nasoduodenal tubes help pre+ent this complication,as does shutting off enteral feedings between the hours of 11 J.M. and > A.M.&t is also essential to keep the patientKs head ele+ated E degrees. Alsonecessary is the use of e*treme care when initiating enteral nutrition. &fhypertonic material is gi+en into the stomach, one can increase osmolalityfollowed by an increase in +olume. &f, howe+er, the material is gi+en into thesmall bowel, +olume must be increased first and then tonicity, with the

e*pectation that osmolality greater than 6EE or 8EE m(sm per liter may ne+er be achie+ed without pro+oking se+ere diarrhea. &f care is not taken with theinitiation of enteral nutrition, massi+e diarrhea may result, including fluidloss, the absorption of enormous amounts of carbohydrate into the circulationwith inade4uate fluid to support it, and the de+elopment of hyperosmolar,nonketotic coma. Alternati+ely, se+ere unremitting diarrhea may result innecrosis of the intestinal wall, the appearance of pneumatosis cystoidesintestinalis, and, finally, perforation and death. All of these complications

may be pre+ented by 2udicious use of enteral nutrition with the same care oneuses for parenteral nutrition.

6I. &t has been suggested that enterocyte-specific fuels be utili5ed for all patients recei+ing parenteral nutrition. "heoretically, the benefits of suchfuels include%A. Glutamine increases gut mucosal protein content and wall thickness.!. !utyrate increases 2e2unal mucosal protein content and wall thickness.C. "he short-chain fatty acidsPbutyrate, propionate, and acetatePare usefulin supporting ileal mucosal protein content and thickness.#. "he use of glutamine-enriched solutions for parenteral nutrition for

patients with chemotherapy to*icity or radiation enteritis is without ha5ards.


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Answer% )()$ &S $)"& $ T " '$

#&SC'SS&()% "he use of enterocyte-specific fuels is part of a new and potentially e*citing phase of /nutritional pharmacology0 in parenteralnutrition@ howe+er, e*citing as the research may be, the use of such fuels is

by no means acceptable for indiscriminate use at present. "hough somestudies ha+e shown that the pro+ision of glutamine in amounts up to N instandard parenteral nutrition solutions increases both 2e2unal and ilealmucosal protein content, cell wall thickness, and #)A content, this has not

been the case in all studies, and this reported effect seems +ery dependent one*perimental design. &n many of the studies that ha+e shown such an effect,

N glutamine has been used to replace +irtually all nonessential amino acids, probably initiating a deficiency state. "he beneficial effects seen withglutamine are far less impressi+e than those seen with epidermal growthfactor, for e*ample, and disappear entirely when a different e*perimentaldesign is used in which N glutamine is added to an ade4uate amino acidformulation in which glutamine does not replace nonessential amino acids

but is added to them. )onetheless, the use of enterocyte-specific fuels,specifically glutamine, is potentially e*citing and should be carefully

in+estigated. More striking are the results that follow massi+e bowelresection, radiation enteritis, and chemotherapy to*icity. Glutamine may helpthe small bowel regenerate more 4uickly, enabling more rapid use of thesmall bowel for nutrition. &t should be pointed out, howe+er, that glutamine isa fuel utili5ed by many tumors and, thus, one runs the risk of stimulating thegrowth of the tumor with e*cessi+e glutamine. "he short-chain fatty acids,

produced from bacterial fermentation of soluble pectin, may be useful in boththe maintenance of colonocyte-specific nutrition and, in the case of butyrate,ileal enterocyte nutrition.

6H. $ssential amino acids ha+e been ad+ocated as standard therapy for renalfailure.


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A. &ncreased sur+i+al from acute renal failure has been reported with bothessential and nonessential amino acid therapy of patients in renal failure.!. $ssential amino acids retard the rise of blood urea nitrogen :!');secondary to decreased urea appearance.C. $ssential amino acids and hypertonic de*trose are a con+enient form oftherapy for hyperkalemia.#. $ssential amino acids decrease !') and creatinine to the same degree assolutions containing e*cessi+e nonessential amino acids.Answer% !C

#&SC'SS&()% $ssential amino acids and hypertonic de*trose, as opposed to

hypertonic de*trose alone, was reported by Abel and co-workers to beassociated with a decreased mortality rate in mostly surgical patients withacute tubular necrosis. "he most significant impro+ement in mortality, ascompared with the control group recei+ing hypertonic de*trose, was among

patients who re4uired dialysis :i.e., the more se+erely affected patients;.Another group responding fa+orably to treatment includes patients withnonoliguric renal failure whose need for dialysis is not clearly established."he effect of essential amino acids in pre+enting a rise in !'), as well as its

beneficial effect in pre+enting hyperkalemia, may ob+iate dialysis in such patients.


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hepatitis.!. )itrogen balance is achie+ed in such patients with amounts of 6E gm. ofamino acids per 6 hours.C. "he use of IE to 1EE gm. of such solutions is associated with hepaticencephalopathy.#. &n some studies of surgical patients, impro+ements in mortality ha+e beenreported.Answer% #

DISCUSSION: The use of modi ed amino acid solutions is based on the falseneurotransmitter hypothesis of the cause of hepatic coma. Accordin to thishypothesis! the imbalance bet"een aromatic and branched#chain amino acids in

plasma results in abnormally hi h le$els of the to%ic aromatic amino acids in the

brain! thus pro$o&in hepatic encephalopathy. The use of modified amino acidmi*tures, with glucose as the calorie base, has been associated in a number of studies with impro+ement in encephalopathy. Meta-analysis has concludedthat the use of such solutions is indicated as therapy for hepaticencephalopathy but has been proposed only for hepatic encephalopathycomplicating acute e*acerbation of chronic li+er disease. Although there are afew anecdotal reports of beneficial effects on hepatic encephalopathy of acutefulminant hepatitis, the use of such a solution has not been ad+ocated, butsuch a modified solution is tolerated better than standard amino acid mi*turesin patients re4uiring "J). &n some studies, particularly in complicatedsurgical cases, the use of a highLbranched-chain, lowLaromatic amino acidsolution has been associated with lower mortality. "hese statements are trueonly for studies in which the modified solutions are gi+en with hypertonicglucose as a calorie base. Studies in which lipid was the pri ncipal caloriesource ha$e not re$ealed such impro$ements in mortality. In recent studies! i$inan aromatic amino acid'de cient! branched#chain amino acid'enriched solution topatients about to under o resection of the li$er has pro$ed particularly e(cacious ina roup of patients "ith cirrhosis! decreasin morbidity and sho"in a trend to"arddecreased mortality.


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81. &n the nutritional support of patients with cancer, which of the followingstatements isBare true?A. )utritional support benefits the patientKs lean body mass but does notenable the tumor to grow.!. &n e*perimental animals, the growth of implanted tumors is directly

proportional to the amount of calories and protein supplied.C. Jrospecti+e randomi5ed trials of nutritional support utili5ingchemotherapy and radiation therapy ha+e re+ealed benefits to patientsrecei+ing total parenteral nutrition.#. Studies of nutritional support for patients with cancer about to undergosurgery re+ealed decreased morbidity and mortality, especially morbidity

from sepsis.Answer% !

#&SC'SS&()% "he problem with the patient with cancer is a +ery +e*ingone. Clearly, one of the metabolic effects of cancer, cache*ia, affects patientsin the last 4uartile of their disease and makes such patients intolerant ofchemotherapy, radiation therapy, and, in many cases, operati+e procedures."otal parenteral nutrition :"J); has been proposed as a means of re+ersing

cache*ia and enabling patients to better tolerate surgery, chemotherapy, andradiation therapy. &n e*perimental animals, it is clear that the pro+ision ofcalories and protein, especially in e*cessi+e amounts, is associated with themore rapid growth of tumors and decreased sur+i+al, especially in the groupthat is o+erfed in the e*treme. "here is also e+idence suggesting thato+erfeeding, or at least "J), may result in increased growth :or at leastchange cell kinetics; in patients who are o+ernourished with "J). (f therandomi5ed prospecti+e trials that ha+e been carried out, no trial utili5ingchemotherapy or radiation therapy has re+ealed a sur+i+al ad+antage for

patients recei+ing "J). &ndeed, in ShambergerKs study, there is a suggestionthat the tumor-free inter+al following treatment of lymphoma may be shorterin patients recei+ing "J). &n patients undergoing surgery, howe+er,especially those who are se+erely malnourished :as recently re+ealed in the


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A study; or in patients with ma2or procedures such as esophagogastrectomy:as in MullerKs study;, e+idence suggests that "J) is beneficial. &n a latefollow-up in MullerKs study, there was no apparent increase in recurrence, andthe sur+i+al rate was the same, despite much higher mortality in the non-"J)group. "his suggests that any impro+ed sur+i+al following operation mayha+e been offset by an increased late recurrence rate, although it is difficult toreach this conclusion. &n summary, for patients with cancer "J) probablynourishes the tumor as well as the host. )onetheless, in se+erelymalnourished patients pro+ision of "J) from 8 to 1E days preoperati+elymay increase sur+i+al and decrease morbidity. (+erfeeding must be a+oided.9uture studies will undoubtedly re+eal that there are certain nutrients that

tumors re4uire, which probably should be best a+oided.

8 . Glucose o+erload results in increased C( production.


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under which Askana5iKs patients were studied, these were a group of septic,depleted patients who were taken from almost no nutritional support to acaloric supply of . 8 times their caloric re4uirement, most of the caloriesconsisting of glucose. Suffice it to say that, in patients with impairedrespiratory function, one should measure C( and, when C( issignificantly ele+ated and appears to interfere with weaning, decrease theamount of glucose calories and increase the amount of fat. &f one measures or estimates calorie re4uirements and does not o+erfeed, lipid can be utili5ed for 8N of the caloric re4uirement and glucose for the remainder, without muchfear of e*cessi+e C( production.

8 . 7epatic abnormalities ha+e been noted in adults since the beginning ofhyperalimentation.


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appears to be largely +acuoli5ation with increased storage of triglycerides.7epatic steatosis is almost always associated with an o+erload of glucose.ecent studies in e*perimental animals ha+e suggested that the portal insulin-glucagon ratio, which is ele+ated under these circumstances, may be causallyrelated to hepatic steatosis. &nsulin is the leading storage en5yme and isresponsible for lipogenesis. "he presence of insulin inhibits lipolysis.Glucagon, on the other hand, results in the mobili5ation of hepatic lipid. "heli+er /sees0 the portal +ein insulin-glucagon ratio. $*cesses of insulin elicited

by hypertonic de*trose increase lipid deposition in the li+er, whereasglucagon, which is elicited by certain amino acids, results in the mobili5ationof hepatic lipid.

86.


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cholecystitis :infection, sepsis, gangrene of the gallbladder; are morecommon in diabetics, a decision-analysis study has shown that prophylacticcholecystectomy cannot be 2ustified since the risk of morbidity andBormortality from the cholecystectomy procedure is as great as that ofcomplications or death from acute cholecystitis. Jatients who becomesymptomatic should be promptly prepared and should undergo electi+echolecystectomy, because an emergency operation in these patients withcomorbid conditions, especially coronary artery disease, has substantialadded mortality associated with it. "here is no causal relationship betweendiabetes and pancreatic cancer.

88. &ntensi+e insulin therapy%A. Jre+ents the aggressi+e de+elopment of atherosclerosis in diabetic

patients.!. &s not associated with unawareness of hypoglycemia.C. &mpro+es peripheral neuropathy.#. &mpro+es established retinopathy and nephropathy.$. &s indicated in all patients with nonLinsulin-dependent diabetes mellitus

:)#M;.Answer% C

#&SC'SS&()% &ntensi+e insulin therapy is indicated in patients with #Mwho can acti+ely participate in their own management and the attainment ofthe goals set for their blood glucose and glycosylated hemoglobin :7gA1 c;le+els. !ecause the main complication of intensi+e therapy is iatrogenichypoglycemia, this mode of treatment is not indicated for patients with

)#M, who often ha+e coe*isting medical conditions such as coronaryartery disease and who tolerate hypoglycemia poorly. "here is little or noe+idence that macro+ascular disease is affected by intensi+e insulin therapy,and the added weight gain and hyperinsulinemia associated with the therapymay worsen atherosclerosis. 'nawareness of hypoglycemia is directly related


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to a recent hypoglycemia episode, so patients treated intensi+ely are oftenunaware of the problem. &ntensi+e therapy does not impro+e establishedretinopathy or nephropathy but slows or pre+ents progression of thesecomplications@ howe+er, better glucose control may impro+e peripheralneuropathy.

8=.


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A. "he surgical procedure.!. "he length of the surgical procedure.C. "he anesthetic techni4ue :e.g., general, regional;.#. "he length of anesthesia.$. All of the abo+e.Answer% A

#&SC'SS&()% "he planned surgical procedure is the ma2or determiningfactor in assessing an indi+idual patientKs risk for perioperati+e complicationsand in deciding which anesthetic techni4ue will be most appropriate. Goodcommunication between the surgeon and the anesthesiologist is +ital, as the

surgeon knows better than anyone else the e*tent of the operation and thelength of time it will re4uire.

8I.


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!. "o pro+ide optimal surgical conditions.C. "o optimi5e +entilator support.#. "o pro+ide sedation.Answer% A!C

#&SC'SS&()% Muscle rela*ants are administered to facilitate endotrachealintubation, to pro+ide the surgeon with optimal working conditions duringanesthesia, and to optimi5e mechanical +entilator support in some patients."hey do not produce analgesia, sedation, or amnesia. "herefore, muscle

paralysis should not be performed without sedation or general anesthesia.

=E. ocal anesthetics%A. &nhibit transmission of ner+e impulses by increasing sodium membrane

permeability and the displacement of ioni5ed calcium.!. Are classified as amides or esters.C. Jroduce peripheral +asodilation.#. Are weak acids.Answer% !C

#&SC'SS&()% ocal anesthetics act within the ner+e membrane, where theyinhibit transmission of ner+e impulses by reducing sodium membrane

permeability and the displacement of ioni5ed calcium. All local anestheticsconsist of a hydrophilic region and a hydrophobic region separated by analkyl chain. "he bond of the alkyl chain is either an ester or an amide, andthese drugs are classified based on this bond. All local anesthetics e*ceptcocaine produce +asodilatation and are weak bases.

=1. Absolute indications for a double-lumen endotracheal tube duringthoracic surgery are%A. Massi+e hemorrhage from one lung.


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!. 'nilateral lung infection.C. 9acilitation of surgical e*posure.#. 'nilateral bronchopulmonary la+age.$. All of the abo+e.Answer% A!#

#&SC'SS&()% "he absolute indications for a double-lumen tube are for the purposes of protecting one lung from the other. "hese indications include+entilation with a bronchopleural fistula, massi+e hemorrhage from one lung,

pulmonary air cyst resection, unilateral lung infection, and unilateral bronchopulmonary la+age. elati+e indications include facilitation of surgical

e*posure, for pneumonectomy, upper lobectomy, and thoracic aneurysmrepair.

= . #eterminants of cerebral blood flow include%A. Jreoperati+e neurologic dysfunction.!. Arterial C( tension.C. Arterial ( tension.

#. Systemic arterial pressure.$. All of the abo+e.Answer% !C#

#&SC'SS&()% #eterminants of cerebral blood flow include arterial C( and ( tensions, systemic arterial pressure, and temperature. (ther factorsthat may affect cerebral blood flow and intracranial pressure are head

position, 2ugular +enous obstruction, and positi+e end-e*piratory pressure.

= . #ischarge criteria following ambulatory surgery include%A. Ability to eat solid food.!. Stable +ital signs.


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C. Ability to ambulate.#. Ability to ha+e protecti+e airway refle*es.Answer% !C#

#&SC'SS&()% #ischarge criteria following ambulatory surgery include the patientKs being fully awake and oriented, the ability to ha+e protecti+e airwayrefle*es, stable +ital signs, ade4uate hydration with the ability to hold downoral intake, the ability to ambulate, and ade4uate pain control. All patientsmust ha+e a competent person with them to transport themPand ideally tostay with them on the first postoperati+e night.

=6. Ad+antages of patient-controlled analgesia :JCA; include%A. &mmediate medication deli+ery.!. ess contact with nursing staff.C. apid onset of analgesia.#. Jatient control o+er pain medication.$. All of the abo+e.Answer% AC#

#&SC'SS&()% Ad+antages of JCA are immediate medication deli+ery, rapidonset of analgesia, and patient control o+er pain medication. #isad+antagesof JCA are less contact with nursing staff and patientsK fears that they couldinad+ertently administer an o+erdose or possibly become addicted to theopioid.

=8. Ad+antages of epidural analgesia include%A. $arlier mobili5ation after surgery.!. $arlier return of bowel function.C. Shorter hospitali5ations.#. #ecreased stress response to surgery.


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$. All of the abo+e.Answer% $

#&SC'SS&()% $pidural analgesia include e*cellent pain relief, decreasedsedation with more rapid reco+ery to presurgical le+els of consciousness,earlier mobili5ation after surgery with increased ability to co-operate withrespiratory therapy and physical therapy. 9ollowing +ascular surgery epiduralanalgesia may also impro+e graft flow through mild sympathetic blockade.$arlier return of bowel function, decreased stress response, shorterhospitali5ations, and decreased morbidity ha+e all been associated withepidural analgesia.

==. 3etorolac%A. &s a nonsteroidal anti-inflammatory drug :)SA appro+ed forintra+enous, intramuscular, and oral administration.!. Can be used indefinitely for postoperati+e analgesia.C. Can cause renal dysfunction.#. May decrease surgical blood loss.

Answer% AC

#&SC'SS&()% 3etorolac tromethamine, an )SA, is appro+ed by the 9#Afor intra+enous, intramuscular, and oral administration. "he agent is aneffecti+e analgesic with minimal side effects@ howe+er, ketorolac, like all

)SAs, can enhance surgical bleeding and cause renal and plateletdysfunction. Additionally, it is recommended that ketorolac should not beused for more than 8 consecuti+e days.

=>. 9actors that decrease collagen synthesis include all of the followinge*cept%A. Jrotein depletion.


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called myofibroblasts, which, as their name implies, ha+e histologiccharacteristics of fibroblasts and smooth muscle cells. "he acti+ity of thesecells, and therefore wound contraction, can be influenced by topicalapplication of smooth muscle inhibitors such as thiphenamil. &nhibitors ofmicrotubule formation in myofibroblasts, such as colchicine and +inblastine,also inhibit wound contraction under e*perimental conditions.Glucocorticoids and )SAs do not affect the wound contraction process.

=H.


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C. &ncreased production of "G9-b.#. )o collagen deposition.$. Minimal angiogenesis.Answer% A$

#&SC'SS&()% "he ability of a fetus to heal without scar formation dependson its gestational age at the time of in2ury and the si5e of the wound defect. &ngeneral, linear incisions heal without scar until late in gestation, wherease*cisional wounds heal with scar at an earlier gestational age. "he profiles offetal proteoglycans, collagens, and growth factors are different from those inadult wounds. "he less differentiated state of fetal skin is probably an

important characteristic responsible for scarless repair. "here is minimalinflammation and angiogenesis in fetal wounds. 9etal wounds arecharacteri5ed by high le+els of hyaluronic acid and its stimulator:s; withmore rapid, highly organi5ed collagen deposition. "he roles of peptidegrowth factors such as "G9-b and basic fibroblast growth factor are less

prominent in fetal than in adult wound healing. An understanding of scarlesstissue repair has possible clinical applications in the modulation of adultfibrotic diseases and abnormal scar-forming conditions.

>1.


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wound. &n contrast, depletion of monocytes and macrophages causes a se+erealteration in wound healing with poor dUbridement, delayed fibroblast

proliferation, and inade4uate angiogenesis. Jlatelets carry a cadre of biologically acti+e substances that are important for wound repair, including peptide growth factors like platelet-deri+ed growth factor :J#G9; and "G9- b. 9ibroblasts are the principal cell for matri* synthesis and deposition.Myofibroblasts are important for wound contraction in open defects but ha+elittle if any role in clean, incisional wounds.

> .


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C. aminin.#. 7yaluronic acid.$. Collagen type & .Answer% A!C

#&SC'SS&()% Cell adhesion glycoproteins such as fibronectin, +itronectin,laminin, and tenascin pro+ide a /railroad track0 to facilitate epithelial andmesenchymal cell migration o+er the wound matri*. 7yaluronic acid is aglycosaminoglycan, and collagen type & is a protein that is a crucialcomponent of basement membrane.

>6.


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A. !ecause of its thickness, the tensile strength of a healing wound on theeyelid is much less than one on the thick skin of the back.!. !y days, the e*perimental burst strength of skin is minimal sincecollagen has been formed in the wound but has not yet cross-linked.C.


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which is important for collagen synthesis. &n high enough concentration, proline analogs pre+ent collagen formation with minimal effects onnoncollagenase protein synthesis.

>>


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mo+ement across cell membranes?a.


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"ransport +esicles that bud off the Golgi network carry both material to besecreted from the cell and protein destined to become components of the

plasma membrane. "hese +esicles can fuse with the plasma membrane in a process termed e*ocytosis. esicular transport to the cell surface can bedi+ided into two components, constituti+e and regulated secretion. egulatedsecretion occurs in cells secreting digesti+e en5ymes, hormones and otherregulatory molecules, and neurotransmitters. &n regulated secretion, thematerial to be secreted is sorted in a storage +esicle or granule@ fusion withthe plasma membrane in e*ocytosis then takes place in response to e*ternalstimulation. egulated secretion is triggered in most cases by a hormone orneurotransmitter. "he ensuing process is termed stimulus-secretion coupling.

&n most cases the coupling in+ol+es an increase in cytoplasmic concentrationof Ca , but may also in+ol+e generation of diacylglycerol or production ofcyclic AMJ which acti+ate kinases or phosphatases.

IE


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followed by membrane fusion and a pinching off. As opposed to endocytosis,this process does not in+ol+e the membrane protein, clathrin, but rather actin.A physiologically rele+ant site of phagocytosis is the thyroid gland, wherethyroid follicular cells phagocytose and digest thyroglobulin from the lumenof the thyroid follicle, thereby releasing the thyroid hormones, thyro*inetriiodothyronine.

I1 A striking feature of li+ing cells is a marked difference between thecomposition of the cytosol and the e*tracellular milieu. M, a 1E,EEE-fold gradient. Such none4uilibrium ion


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distributions are e+en more remarkable in light of the fact that the plasmamembrane is, to +arying degrees, leaky to ions such as sodium, potassiumand calcium. "he plasma membrane is leaky to a +ariety of substances, but ite*hibits an astonishing ability to discriminate or select one substance o+eranother. "his selecti+ity relates to not only ions but also for organiccompounds such as glucose. 9inally, the selecti+ity of biologic membranescan be altered drastically as a result of regulatory or signaling processes thatoccur within the cell.

I


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I


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Answer% b, c

Most transport proteins appear to function as carriers, rather than channels.&mportant distinctions can be made between types of carrier proteins on the

basis of transport kinetics. "wo primary types can be distinctly identified based on carrier-type and channel-type mechanisms. "he most importantdifference between the channel mechanism and the carrier mechanism is therole in the transport e+ent played by conformational changes in themembrane protein. "he channel is depicted as ha+ing two states, closed andopen, so that it operates like a switch. &n contrast, carrier transport isen+isioned as re4uiring a cycle of conformational changes. "he transport of

one molecule of substrate re4uires one complete cycle of the protein. &n achannel mechanism, binding sites within the open pore are e4ually accessiblefrom either side of the membrane, whereas in a carrier mechanism, the

binding site is a+ailable only one side of the membrane at any instant.

I=


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co+alent attachment of the carbo*yl end of the amino acid to the end of thet )A in a process using A"J. Jrotein synthesis occurs by the formation of a

peptide bond between the carbo*yl terminal of the growing peptide chain andthe free amino acid of deacti+ated amino acid t )A. "his e+ent does notoccur in free solution, but within ribosomes. ibosomes are proteinsynthesi5ing machines that bring all of the necessary components together inthe correct se4uence and spacial orientation. Jrotein synthesis consumes agreat deal of energy because four high-energy phosphate bonds must be splitto make each peptide bond. Complete synthesis of a single protein takes Eseconds to a few minutes, but multiple ribosomes can initiate translation and

be mo+ing down the m )A molecules simultaneously, thus increasing the

rate of protein synthesis.

I> Cell regulation can be thought of as the effector side of cellcommunication. Most commonly cell regulation occurs by means ofe*tracellular chemical messengers.


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response to acti+ation of adenylate cyclased. cAMJ is the only cyclic nucleotide acti+e as an intracellular messenger Answer% a, b

"he prototypic intracellular messenger is cAMJ. "o function as a mediator,the concentration of cAMJ must change rapidly. &n resting cells, cAMJ iscontinuously being degraded by a specific en5yme, cAMJ phosphodiesterase.cAMJ le+els can increase 1E-fold or more within seconds of receptor bindingthrough acti+ation of adenylate cyclase. cAMJ acts as an allosteric regulator,and most, if not all, of its actions are mediated by acti+ation of cAMJ-dependent protein kinase A. cAMJ is not the only cyclic nucleotide acti+e as

an intracellular messenger. Most animal cells also produce cGMJ.&ntracellular calcium ions also ser+e as second messengers in a large numberof cells.

HE "he acti+ities of the cytoskeleton is dependent on which of the followingtypes of filaments?a. Microtubules

b. &ntermediate filaments

c. Actin filamentsd. )one of the abo+eAnswer% a, b, c

"he cytoskeleton is a collection of filamentous protein structures that allowcells to assume and maintain a +ariety of shapes, to produce directedmo+ement of organelles within the cell, and to affect mo+ement of the entirecell relati+e to other cells. "hese multiple acti+ities depend upon three maintypes of filaments% actin filaments, intermediate filaments, and microtubules.

H1 &ntracellular organelles in+ol+ed with protein synthesis include%a. Mitochondria

b. $ndoplasmic reticulum


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c. Golgi comple*d. ysosomesAnswer% b, c

Mitochondria are the ma2or source of energy production in eukaryotic cells."he endoplasmic reticulum is the network of interconnected membranesforming closed +esicles, tubules, and saccules. "he endoplasmic reticulumhas a number of functions and is primarily in+ol+ed in the synthesis of

proteins and lipids. Ad2acent to the rough endoplasmic reticulum andfunctionally in+ol+ed in the sorting and package of secreted protein is theGolgi comple*. ysosomes are membrane-limited organelles containing acid

hydrolytic en5ymes that degrade polymers such as proteins, carbohydrates,and nucleic acids.

H An important step in protein synthesis is transcription.


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transcription are known as heterogeneous nuclear )A because of their largesi5e +ariation. "hese primary transcripts are then processed to form m )A.)A splicing accounts for mature )A being much shorter than nuclear)A. Moreo+er, alternati+e splicing can lead to the production of differentm )A molecules and in some cases different proteins from the same gene.m )A is e*ported from the nucleus only after processing is complete.

H "here are two properties of the cell necessary to maintain none4uilibriumcellular composition@ the first is selecti+ity and the second is energycon+ersion.


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transport of a second species such as protons, calcium, amino acids, orglucose.

H6


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Answer% a, b, c

Channel blockade is an important mechanism of action for to*ins and sometherapeutic agents. "he deadly to*in of the puffer fish, tetrodoto*in, acts by

blocking the )a channels that are responsible for the conduction of ner+eimpulse. "he diuretic, amiloride, acts by blocking the )a channels thatinhabit the apical membrane of the epithelial cells of the distal nephron.ocal anesthetics such *ylocaine also act by blocking ion channels.

H= Most hormone receptors are locali5ed on the cell membrane and transducehormone binding into altered le+els of intracellular messengers. A limited

number of intracellular receptors do e*ist.


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undergoes a conformational change, termed acti+ation. "his allowscytoplasmic receptors to mo+e into the nucleus and bind to #)A. eceptorsalready in the nucleus increase their affinity for #)A. &n the case ofglucocorticoid receptors and probably others of this class, the inacti+ereceptor is associated with another protein, the heat-shock protein. "hey

block the #)A-binding domain of the receptor. Acti+ation in+ol+es thedissociation of the inhibitor protein.

H> Altering the amino acid profile in total parenteral nutrition solutions can be of benefit in certain conditions.


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with li+er failure with solutions enriched in branch chain amino acids anddeficient in aromatic amino acids results in impro+ed tolerance toadministration of protein and clinical impro+ement in encephalopathic states.Glutamine-enriched "J) partially attenuates +illous atrophy and may beuseful in treatment of short gut syndrome.

HI 'nder certain circumstances, the gut may become a source of sepsis andser+e as the motor of systemic inflammatory response syndrome. Microbialtranslocation is the process by which microorganisms migrate across themucosal barrier to in+ade the host.


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b. 'nder-nutrition may compromise the patientVs a+ailable defensemechanismsc. )utritional support is an immediate priority for the trauma patientd. 9ifty percent of non-nitrogen caloric re4uirements should be pro+ided inthe form of fatAnswer% b

Metabolic response to in2ury results in increased energy e*penditure. &fenergy intake is less than e*penditure, o*idation of body fat stores anderosion of lean body mass will occur with resultant loss of weight.


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d. !ody protein is a +aluable storage form of energyAnswer% b, c

"he body contains fuel reser+es which it can mobili5e and utili5e duringtimes of star+ation or stress. !y far the greatest energy component is fat,which is calorically dense since it pro+ides about H caloriesBgram. !ody

protein comprises the ne*t largest mass of utili5able energy, but amino acidsyield only about 6 kcalBgram. 'nlike fat reser+es, body protein is not astorage form of energy but rather ser+es as a structural functional componentof the body@ loss of body protein, if se+ere, is associated with functionalconse4uences. Glycogen stored in muscle and li+er and free glucose ha+e a

tri+ial caloric +alue of less than 1EEE kcal for a >E kg male.1E1 to 1E days. $nteral nutrition is always the preferredroute of feeding cancer patients if the G& tract is functional. "here are se+eral

benefits of using the bowel lumen for nutrient deli+ery. "he trophic effects of


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enteral feeding on small bowel mucosa ha+e been well described. "heintegrity of the mucosal lining is maintained and it may pro+ide an effecti+e

barrier to intraluminal enteric organisms which might otherwise translocateinto the systemic circulation. Atrophic changes may be seen in the intestinalepithelium after se+eral days of bowel rest@ this atrophy is not re+ersed bycurrently a+ailable total parenteral nutrition solutions. 1E


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some form of enteral nutrition b. A nutritional re imen consistin of supplementallutamine! ro"th hormone! and a modi ed hi h carbohydrate! lo" fat diet may bebene cial in this patient c. The re imen described abo$e may decrease the cost ofcare d. T N needs "ill increase after discontinuation of ro"th hormone Ans"er: a!b! c rior to the a$ailability of T N! most patients de$elopin short bo"el syndrome

from either sur ery or catastrophic e$ent died. In selected patients! ho"e$er! "ithresidual small intestine 4at least +9 inches5! post#resectional hyperplasia mayde$elop "ith time such that they can tolerate enteral feeds. ;ecent studies ha$edemonstrated the re7uirement for T N could be decreased or e$en eliminated inpatients "ith short# ut syndrome by pro$idin a nutritional re imen consistin ofsupplemental lutamine! ro"th hormone! and a modi ed hi h carbohydrate! lo"fat diet. There "as a mar&ed impro$ement in absorption of nutrients "ith thiscombin

on of therapy and a decrease in stool output. In addition! T N re7uirements "erereduced by similar alterations are obser$ed in serum incle$els. The administration of iron to the infected host! especially early into thedisease! is contraindicated! ho"e$er! because increased serum iron concentrationsmay impair resistance. Unli&e iron and inc! copper le$els enerally rise! and theincreased plasma concentrations can be ascribed almost entirely to the le$els of theceruloplasmin produced by the li$er. +1- A +?#year#old patient in$ol$ed in anautomobile accident is paraly ed "ith multiple peripheral e%tremity [email protected] support is instituted "ith a transnasal feedin catheter. 3hich of thefollo"in statement4s5 is6are true concernin the patient s mana ement8 a. )eedininto the stomach results in stimulation of the biliary6pancreatic a%is "hich isprobably trophic for small bo"el b. /astric secretions "ill dilute the feedin s

increasin the ris& of diarrhea c. The ma@or ris& in this patient is tracheobronchialaspiration d. lacement of the feedin catheter throu h the pylorus into the rstportion of the duodenum reduces the ris& of re ur itation and aspiration Ans"er: a!c! d The use of transnasal feedin catheters for intra astric feedin or for duodenalintubation are popular ad@uncts for pro$idin nutritional support by the enteralroute. The stomach is easily accessed by passa e of a soft ,e%ible feedin tube.Intra astric feedin pro$ides se$eral ad$anta es for the patient. The stomach hasthe capacity and reser$oir for bolus feedin s. )eedin into the stomach results in


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stimulation of the biliary6pancreatic a%is "hich is probably trophic for the smallbo"el. /astric secretions "ill ha$e a dilutional e0ect on the osmolarity of the

feedin s! reducin the ris& of diarrhea. The ma@or ris& of intra astric feedin is theregurgitation of gastric contents resulting in aspiration into the

tracheobronchial tree. "his risk is highest in patients who ha+e an alteredsensorium or who are paraly5ed. "he placement of the feeding tube throughthe pylorus into the fourth portion of the duodenum reduces the risk ofregurgitation and aspiration of feeding formulas. 1E> Although "J) hasma2or beneficial effects to the patient and specific organ systems, "J) has adownside which is related to intestinal disuse.


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e "he nona4ueous portion of total body mass is made up of bones, tendons,and mineral mass as well as adipose tissue. "he a4ueous component containsthe body cell mass which is made up of skeletal muscle, intraabdominal andintrathoracic organs, skin, and circulating blood cells. Also contributing to thea4ueous portion is the interstitial fluid and intra+ascular +olume. 1EH 9attyacids are a ma2or energy source for the body.


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described with in2ury. Se+ere infection is often associated with ahypercatabolic state that initiates marked changes in interorgan glutaminemetabolism. "his process results in accelerated muscle proteolysis and netskeletal muscle glutamine release. "he bulk of glutamine is taken up by theli+er at the e*pense of the gut. &t appears that sepsis can impair gutmetabolism of glutamine. 9at is a ma2or fuel o*idi5ed in infected patients,and increased metabolism of lipids from peripheral fat stores is especially

prominent during a period of inade4uate nutritional support. 111


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accentuated by the catabolic disease states. "his results in a negati+e nitrogen balance in which the amount of nitrogen taken in by the patient is e*ceeded by the amount of nitrogen lost in the urine, stool, skin, wounds, and fistuladrainage. 11


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infected patient. "he e*tent of this increase is related to the se+erity of theinfection, with peak ele+ations reaching 8EN to =EN abo+e normal. &f the

patientVs metabolic rate is already ele+ated to a ma*imal e*tent because ofse+ere in2ury, no further increase will be obser+ed. &n patients with only aslightly accelerated rate of o*ygen consumption, the presence of infectionwill cause a rise in metabolic rate added to the pree*isting state. A portion ofthe increase in metabolism may be ascribed to increase in reaction rateassociated with fe+er. Calculations suggest that the metabolic rate increases1EN to 1 N for each ele+ation of 1YC in central temperature. 116&nterleukin-= is recogni5ed as the cytokine primarily responsible for thealteration in hepatic protein synthesis recogni5ed as the acute phase response.


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statement:s; isBare true concerning necessary changes to be made in hisnutritional management? a. Carbohydrate load should be reduced in the faceof respiratory failure b. &n patients with renal failure, protein intake should bediminished c. #uring hemodialysis protein intake should be limited to thesame e*tent d. &n patients with hepatic failure, carbohydrate load should beincreased Answer% a, b "he most se+ere complication of sepsis is multiplesystem organ dysfunction syndrome, which may result in death. "hede+elopment of organ failure re4uires changes in the nutritional re4uirementsand creates special feeding problems. A problem associated with systemicinfection is o*ygenation and elimination of carbon dio*ide. Most of theenteral and parenteral formulas used to pro+ide nutritional support for

critically ill patients contain large amounts of carbohydrate, which generatelarge amounts of carbon dio*ide following o*ygenation. Such a large C(load may worsen pulmonary function or may delay weaning from therespirator. &f this factor becomes a problem, the carbohydrate load should bereduced to 8EN of metabolic re4uirements and fat emulsion administered to

pro+ide additional calories.


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concerning the role of glutamine in total parenteral nutrition? a. Glutamine isan essential amino acid b. Glutamine appears to be of primary benefit incritical illness c. Glutamine is included in most standard "J) solutions d.Glutamine is the primary energy source for intestinal mucosal cells of thesmall bowel and colon Answer% b Glutamine is the most studied gut-specificnutrient. Glutamine has been classified as a nonessential or nutritionallydispensable amino acid since glutamine can be synthesi5ed in ade4uate4uantities from other amino acids and precursors. Glutamine is not includedin most nutritional formulas and has been eliminated from "J) solutions

because of its relati+e instability and short half life compared to other aminoacids. N of total amino acids;. Se+eral recent studies, howe+er,ha+e demonstrated that glutamine may be an essential amino acid duringcritical illness, particularly as it relates to supporting the metabolicre4uirements of the intestinal mucosa. "hese studies demonstrate that dietaryglutamine is not re4uired during states of health but appears to be beneficialwhen glutamine depletion is se+ere andBor when intestinal mucosa isdamaged by insults such as chemotherapy or radiation therapy. "he addition

of glutamine to enteral diet reduces the incidence of gut translocation butthese impro+ements are dependent upon the amount of supplementalglutamine and the type of insult studied. Glutamine-enriched "J) partiallyattenuates +illous atrophy that de+elops during parenteral nutrition. "he useof intra+enous glutamine in patients appears to be safe and effecti+e in itsability to maintain muscle glutamine stores and impro+e nitrogen balance. &ncontrast to glutamine, short chain fatty acids are primary energy source forcolonocytes. 11>


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composition is a ma2or determinant of the metabolic responses obser+edduring surgical illness. Jost-traumatic nitrogen e*cretion is directly related tothe si5e of the body protein mass. A strong relationship between proteindepletion and postoperati+e complications has been demonstrated innonseptic, nonimmunocompromised patients undergoing electi+e ma2orgastrointestinal surgery. Jrotein-depleted patients ha+e significantly lower

preoperati+e respiratory muscle strength and +ital capacity, increasedincidence of postoperati+e pneumonia, and longer postoperati+e hospital stay.&mpaired wound healing and respiratory, hepatic, and muscle function in

protein-depleted patients awaiting surgery has also been reported. Many ofthe changes in the metabolic responses to surgical illnesses that occur with

aging can be attributed to alterations in body composition and to long-standing patterns of physical acti+ity. 9at mass tends to increase with age andmuscle mass tends to decrease. oss of strength that accompanies immobility,star+ation and acute surgical illness may ha+e marked functionalconse4uences. 9urthermore, the pre+alence of cardio+ascular and pulmonarydiseases increase with age. "hus, the deli+ery of o*ygen to tissues may beimpaired in the elderly. 9inally, obser+ed differences in metabolic responsesof men and women generally reflect differences in body composition. ean

body mass is lower in women than in men@ and this difference is thought toaccount for the net loss of nitrogen after ma2or electi+e abdominal surgerygenerally being lower in women than in men. 11I &n contrast to a patientundergoing an electi+e operation, which of the following statement:s; isBaretrue concerning a patient who has suffered a multiple trauma? a. !asalmetabolic rates are similar b. "he patient is highly sensiti+e to insulin c.'tili5ation of the amino acids, glutamine and alanine, is similar to theircomposition in skeletal muscle d. 9at and protein stores are rapidly depletedAnswer% b, d "he degree of hypermetabolism is generally related to these+erity of in2ury. Jatients with long-bone fractures ha+e a 18L 8N increasein metabolic rate, whereas metabolic rates in patients with multiple in2uriesincreases by 8EN. "hese metabolic rates in trauma patients are contrastedwith those in postoperati+e patients, who rarely increase their !M by more


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than 1EL18N following operation. Studies ha+e shown that unin2ured+olunteers are able to dispose of e*ogenous glucose load much more readilythan in2ured patients. (ther studies ha+e demonstrated a failure to suppresshepatic glucose production in trauma patients during glucose loading orinsulin infusion. "hus, profound insulin resistance occurs in in2ured patients.Skeletal muscle is the ma2or source of nitrogen that is lost in the urinefollowing e*tensi+e in2ury. Although it is recogni5ed that amino acids arereleased by muscle in increased 4uantities following in2uries, it has only beenrecently appreciated that the composition of amino acid reflu* does notreflect the composition of muscle protein. "he release is skewed towardsglutamine and alanine, each of which comprise about one-third of the total

amino acids released by skeletal muscle. "o support hypermetabolism, storedtriglyceride is mobili5ed at an accelerated rate. Although mobili5ation anduse of free fatty acids are accelerated in in2ured sub2ects, if unfed, se+erelyin2ured patients rapidly deplete their fat and protein stores. 11H A 6>-year-old

patient undergoing a complicated laparotomy for bowel obstruction de+elopsa postoperati+e enterocutaneous fistula.


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patients with fistulas. Second, if spontaneous closure of the fistula does notoccur, patients are better prepared for operati+e inter+ention because of thenutritional support they ha+e recei+ed. 9inally, certain fistulas are associatedwith a lower rate of spontaneous closure than others and should be treatedmore aggressi+ely surgically after a defined period of nutritional support:unless closure occurs;. 1 E Appropriate guidelines for the use of "J) incancer patients include% a. ong-term "J) in patients with rapid progressi+etumor growth unresponsi+e to other therapy b. Mildly malnourished patientsundergoing surgery for a curable cancer c. Jreoperati+ely administered "J)

prior to surgery or other therapy in patients with se+ere malnutrition d.Jatients in whom treatment to*icity precludes the use of enteral nutrition

Answer% c, d As a general rule, the most important factor to consider whenmaking decisions about the use of "J) in patients with cancer is the responseof the tumor to antineoplastic therapy. Appropriate guidelines would includethe following% Short-term "J) is indicated in se+erely malnourished patientsor in those in whom gastrointestinal or other to*icities preclude ade4uateenteral intake for se+en days or a longer period. "J) is not indicated in wellnourished or mildly malnourished patients undergoing therapy or surgerywho would be e*pected to be able to resume ade4uate nutrition in

appro*imately se+en days. ong-term "J) is indicated in patients in whomtreatment associated to*icities preclude the use of enteral nutrition andrepresent the primary impediment to the restoration of performance status."hese patients should be e*pected to be responding to anti-tumor therapy.ong-term "J) is not indicated with rapidly progressi+e tumor growth whichis unresponsi+e to such therapy. 1 1 E kg male, a+erage resting energyconsumption is almost 18EE kcalBday d. Similar increases in energye*penditures are associated with electi+e surgery and trauma or thermalin2ury Answer% a, c !asal energy re4uirements are measured with the sub2ect


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at rest when no e*ternal work is being done@ the energy is used mainly fortransport and synthetic work within cells. A surprisingly small percentage :X8N; of this energy is spent on cardiac output and the work of breathing innormal sub2ects. &n contrast, the work of breathing in indi+iduals with chronicobstructi+e lung disease or in patients on a +entilator may account for 18L EN of caloric e*penditure. "he a+erage resting post-absorpti+e >E kg maleconsumes about 18EE kcalBday. $nergy needs increase as se+erity of illnessincreases. "he e*penditure of kcal is only minimally increased after electi+esurgery. "he

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