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AnesthesiologyAnesthesiology
Glen T. Porter, MDGlen T. Porter, MD
Francis B. Quinn, MDFrancis B. Quinn, MD
University of Texas Medical BranchUniversity of Texas Medical Branch
Galveston, TexasGalveston, Texas
June 2004June 2004
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HistoryHistory15401540 ValeriusValerius CordusCordus synthesizes ethersynthesizes ether
1842 Dr. Crawford Long (Georgia) first1842 Dr. Crawford Long (Georgia) firstuses inhaled ether to anesthetize patientuses inhaled ether to anesthetize patient
for surgeryfor surgery1845 Dr. Horace Wells attempts to1845 Dr. Horace Wells attempts todemonstrate use of Nitrous oxide indemonstrate use of Nitrous oxide insurgerysurgery
1846 William Morton (dentist) uses ether1846 William Morton (dentist) uses etheranesthesia at Massachusetts Generalanesthesia at Massachusetts GeneralHospital (soon to become the etherHospital (soon to become the etherdome). Dr. John Warren removes a neckdome). Dr. John Warren removes a neckmass.mass.
1846 Nitrous oxide used for anesthesia1846 Nitrous oxide used for anesthesia
1847 Dr. James Simpson introduces1847 Dr. James Simpson introducesChloroform anesthesiaChloroform anesthesia
1853 Queen Victoria undergoes1853 Queen Victoria undergoesanesthesia performed by Dr. John Snowanesthesia performed by Dr. John Snow
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HistoryHistory
Crawford Long
Horace Wells W. Thomas Morton
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HistoryHistory
1878 Endotracheal tube invented1878 Endotracheal tube invented
1885 Halstead introduces nerve1885 Halstead introduces nerveblock anesthesia with cocaineblock anesthesia with cocaine
1934 Sodium thiopentone (IV1934 Sodium thiopentone (IV
anesthesia)anesthesia)1934 Curare1934 Curare
1940s clinical use of muscle1940s clinical use of muscle
relaxantsrelaxants1950s Introduction of1950s Introduction of flourinatedflourinatedinhalational anesthetic agentsinhalational anesthetic agents
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Stages of AnesthesiaStages of Anesthesia
Stage I (analgesia stage)Stage I (analgesia stage) Conscious and rationalConscious and rational
Perception of pain is diminishedPerception of pain is diminished
Stage II (delirium stage)Stage II (delirium stage) UnconsciousUnconscious
Body responds reflexively and irrationallyBody responds reflexively and irrationally
Breath holding, pupils dilatedBreath holding, pupils dilated Muscle tone intactMuscle tone intact
Stage III (surgical anesthesia)Stage III (surgical anesthesia) Increasing degrees of muscular relaxationIncreasing degrees of muscular relaxation
Unable to protect airwayUnable to protect airwayStage IV (medullary depression)Stage IV (medullary depression) Depression of cardiovascular and respiratoryDepression of cardiovascular and respiratory
centerscenters
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Inhalational AnesthesiaInhalational Anesthesia
Effect is mediated by concentration of agentEffect is mediated by concentration of agent
present in the nervous systempresent in the nervous system
Each agents anesthesia effect mediated byEach agents anesthesia effect mediated bysolubility, metabolism, alveolar ventilation,solubility, metabolism, alveolar ventilation,
cardiac output, potencycardiac output, potencyMinimum Alveolar Concentration (MAC) is aMinimum Alveolar Concentration (MAC) is ameasure of relative potencymeasure of relative potency
MAC=amount of an agent in which 50% ofMAC=amount of an agent in which 50% ofpatients do not move with surgical stimulus.patients do not move with surgical stimulus.
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Nitrous OxideNitrous Oxide
Discovered 1776 by David PriestlyDiscovered 1776 by David Priestly
Largely recreational use until mid 1800sLargely recreational use until mid 1800sColorless, tasteless, odorlessColorless, tasteless, odorless
Low potency (MAC=105%)Low potency (MAC=105%)
Usually used with additional agent to achieveUsually used with additional agent to achievesurgical anesthesiasurgical anesthesia
Weak anestheticWeak anesthetic
Powerful analgesicPowerful analgesic
Poor solubility (rapid onset/offset time)Poor solubility (rapid onset/offset time)
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Nitrous OxideNitrous Oxide
Systemic effectsSystemic effects
Mild myocardial depression (usually innocuous)Mild myocardial depression (usually innocuous)
Severe cardiac depression with underlyingSevere cardiac depression with underlying
hemodynamic compromisehemodynamic compromise
No effect on respiration/neuromuscular junctionNo effect on respiration/neuromuscular junction
Side effectsSide effects Blood:gasBlood:gas partition coefficient of nitrous oxide is 34partition coefficient of nitrous oxide is 34
times greater than that of nitrogen.times greater than that of nitrogen.
Second gas effectSecond gas effectPressure changes in airPressure changes in air--filled spacesfilled spaces
Prolonged exposure can result in megaloblastic orProlonged exposure can result in megaloblastic or
aplastic anemia, Baplastic anemia, B--12 deficiency (inhibits methionine12 deficiency (inhibits methionine
synthetase)synthetase)
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Nitrous oxideNitrous oxide
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HalothaneHalothane
Synthesized by Suckling in 1956Synthesized by Suckling in 1956
First of the fluorinated anestheticsFirst of the fluorinated anestheticsDistinctive aroma, nonDistinctive aroma, non--flammable, highlyflammable, highly
potent (MAC=0.75%)potent (MAC=0.75%)Poor analgesic propertiesPoor analgesic properties
Very soluble in blood/fatty tissues withVery soluble in blood/fatty tissues withpotential for longer offset timepotential for longer offset time
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HalothaneHalothane
Systemic EffectsSystemic Effects Reduces/eliminates sympathetic response (includingReduces/eliminates sympathetic response (including
baroresponsebaroresponse)) Depresses respiratory drive. Respiration is rapid, shallow, andDepresses respiratory drive. Respiration is rapid, shallow, and
unvaried predisposing to atelectasisunvaried predisposing to atelectasis
Decreases airway reflexesDecreases airway reflexes
Decreases myocardial contractility and heart rate resulting inDecreases myocardial contractility and heart rate resulting indecreased cardiac output and hypotensiondecreased cardiac output and hypotension
Myocardial sensitization to exogenousMyocardial sensitization to exogenous catecholeminescatecholemines
Side EffectsSide Effects HepatitisHepatitisThought to be mediated by allergic response to byproductsThought to be mediated by allergic response to byproducts
Malignant hyperthermiaMalignant hyperthermia
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EnfluraneEnfluraneIntroduced in 1972Introduced in 1972
Stable, nonflammable, pungent odorStable, nonflammable, pungent odor
MAC=1.68%MAC=1.68%
Systemic effectsSystemic effects Respiratory drive depressed (more than halothane), hypoxemiaRespiratory drive depressed (more than halothane), hypoxemia
response bluntedresponse blunted
Depresses cardiac contractility and heart rate more thanDepresses cardiac contractility and heart rate more than
HalothaneHalothane Less sensitization of myocytes to exogenous catecholaminesLess sensitization of myocytes to exogenous catecholamines
Metabolism 1/10Metabolism 1/10thth that of Halothanethat of Halothaneless hepatotoxicless hepatotoxic
Rare cases of fluoride toxicity (hyperthyroid, rifampin)Rare cases of fluoride toxicity (hyperthyroid, rifampin)
Nephrogenic diabetes insipidusNephrogenic diabetes insipidusSide effectsSide effects Similar to other fluorinated agentsSimilar to other fluorinated agents
Epileptiform EEG at deep levelsEpileptiform EEG at deep levels
Avoid in patients with seizureAvoid in patients with seizure d/od/o
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IsofluraneIsoflurane
NonflammableNonflammable
Properties similar to Halothane andProperties similar to Halothane andEnfluraneEnflurane
Pungent odorPungent odorLess soluble than Halothane/Enflurane,Less soluble than Halothane/Enflurane,
more rapid induction/recoverymore rapid induction/recoveryMAC=1.3%MAC=1.3%
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SevofluraneSevoflurane
Fluorinated ether compoundFluorinated ether compound
Similar properties to other fluorinatedSimilar properties to other fluorinatedagentsagents
Mild respiratory/cardiac depressionMild respiratory/cardiac depression
NotNot bronchoirritantbronchoirritant
Rapid onset/offset secondary to low lipidRapid onset/offset secondary to low lipid
solubilitysolubilityAs enflurane, may cause renal and hepaticAs enflurane, may cause renal and hepatic
side effectsside effects
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DesfluraneDesflurane
Newer agentNewer agent
Low blood and lipid solubility with rapidLow blood and lipid solubility with rapidonset/offsetonset/offset
High incidence ofHigh incidence of bronchoirritationbronchoirritation withwithcough, laryngeal spasm, breath holdingcough, laryngeal spasm, breath holding
Minimal metabolism resulting in few sideMinimal metabolism resulting in few sideeffectseffects
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Intravenous Anesthetic AgentsIntravenous Anesthetic Agents
Barbiturates/otherBarbiturates/other
ThiopentalThiopentalEtomidateEtomidate
KetamineKetaminePropofolPropofol
BenzodiazepinesBenzodiazepines
Narcotic agonists (Narcotic agonists (opiodsopiods)/antagonists)/antagonists
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ThiopentalThiopental
Barbiturate with alkaline formulation. May causeBarbiturate with alkaline formulation. May causesevere complications if extravasation orsevere complications if extravasation orintraarterial injection occurs.intraarterial injection occurs.
Unconsciousness within 10Unconsciousness within 10--15 seconds15 seconds
Depresses neuronal activityDepresses neuronal activitymay decrease ICPmay decrease ICPPoor analgesicPoor analgesic
Varied effect on cardiovascular systemVaried effect on cardiovascular system
Decreased ventilatory drive, short period ofDecreased ventilatory drive, short period ofapnea after bolusapnea after bolus
Short duration secondary to rapid redistributionShort duration secondary to rapid redistribution
Metabolized in liverMetabolized in liver
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Thiopental distributionThiopental distribution
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EtomidateEtomidate
Onset, elimination, ability to produceOnset, elimination, ability to produce
unconsciousness similar to Thiopentalunconsciousness similar to ThiopentalShort duration of action secondary to rapidShort duration of action secondary to rapidredistributionredistribution
Less cardiopulmonary depressionLess cardiopulmonary depression
Can cause local pain and myoclonicCan cause local pain and myoclonic
movements with injectionmovements with injectionCortisol suppression and AddisonianCortisol suppression and Addisoniancrises reported in debilitation patientscrises reported in debilitation patients
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KetamineKetamine
Similar in structure to PCPSimilar in structure to PCP
Dissociative anesthesia,Dissociative anesthesia,
intense analgesia, amnesiaintense analgesia, amnesiaSlow nystagmus with eyes openSlow nystagmus with eyes open
Systemic effects similar to sympathetic stimulationSystemic effects similar to sympathetic stimulation
Respiratory function not depressed, airway protectionRespiratory function not depressed, airway protectionnot effectednot effected
Rapid onset, lasts 10Rapid onset, lasts 10--15 minutes15 minutes
Side effect is unpleasant dreams/hallucinations duringSide effect is unpleasant dreams/hallucinations duringemergence. Benzodiazepines shown to decrease this.emergence. Benzodiazepines shown to decrease this.
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PropofolPropofol
Substituted phenolSubstituted phenol
Rapid onset, short duration (metabolized)Rapid onset, short duration (metabolized)Dilates peripheral vasculature leading toDilates peripheral vasculature leading to
decreased blood pressuredecreased blood pressuremay be significantmay be significant
in patients with blunted sympathetic responsein patients with blunted sympathetic response
Short period of apnea after administrationShort period of apnea after administration
Venous irritationVenous irritation
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BenzodiazepinesBenzodiazepines
Good for amnesia/sedationGood for amnesia/sedationvia potentiation atvia potentiation atGABA receptorsGABA receptors
Diazepam onset 2Diazepam onset 2--3 minutes (IV), Lorazepam3 minutes (IV), Lorazepam(Ativan) onset 10(Ativan) onset 10--15 minutes, both have long15 minutes, both have longhalfhalf--life (Diazepam (Valium)
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Narcotic agonists/antagonistsNarcotic agonists/antagonists
Analgesia,Analgesia, dpresseddpressed sensorium,sensorium,
respiratory depressionrespiratory depressionEffects are doseEffects are dose--relatedrelated
Minimal cardiovascular effects, thoughMinimal cardiovascular effects, thoughvasodilatory effects can be serious invasodilatory effects can be serious inpatients with hypovolemiapatients with hypovolemia
Side effects include bradycardia (doesntSide effects include bradycardia (doesntusually effect output),usually effect output), n/vn/v, chest wall, chest wallrigidity, seizure activity, decrease GIrigidity, seizure activity, decrease GI
motilitymotility
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NarcoticsNarcotics
Several receptorsSeveral receptorsMuMu: analgesia, respiratory depression, euphoria,: analgesia, respiratory depression, euphoria,
dependancedependanceKappa: spinal analgesia, sedation, meiosisKappa: spinal analgesia, sedation, meiosis
Omega: hallucinations, dysphoria, tachycardiaOmega: hallucinations, dysphoria, tachycardia
Meperidine, Morphine, Fentanyl, Sufentanil,Meperidine, Morphine, Fentanyl, Sufentanil,RemifentanilRemifentanil
Nalorphine: agonist/antagonistNalorphine: agonist/antagonistless analgesia,less analgesia,
less respiratory depressionless respiratory depressionNaloxone: reverses analgesia/respiratoryNaloxone: reverses analgesia/respiratorydepression (30 minutes)depression (30 minutes)
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Muscle RelaxantsMuscle Relaxants
Used clinically since 1940s. 1960s led toUsed clinically since 1940s. 1960s led to
the balanced anesthesia concept.the balanced anesthesia concept.Important to provide motionImportant to provide motion--free surgicalfree surgical
fieldfieldWork at neuromuscular junctionWork at neuromuscular junction
Nondepolarizing vs. DepolarizingNondepolarizing vs. Depolarizing
Competitive inhibition of endplate nicotinicCompetitive inhibition of endplate nicotinic
receptor vs. receptor binding withreceptor vs. receptor binding with
depolarizationdepolarization
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Paralytic agentsParalytic agents----AnatomyAnatomy
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Neuromuscular junctionNeuromuscular junction
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DepolarizationDepolarization
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Nondepolarizing AgentsNondepolarizing Agents
Bind to and competitively inhibit endBind to and competitively inhibit end--plateplatenicotinic receptorsnicotinic receptors
IntermediateIntermediate--acting (15acting (15--60 minutes)60 minutes)Atracurium, vecuronium, mivacuriumAtracurium, vecuronium, mivacurium
Relatively independent of renal function for clearanceRelatively independent of renal function for clearance
Less circulatory effectLess circulatory effectLongLong--acting (>60 minutes)acting (>60 minutes)Pancuronium, metocurine, dPancuronium, metocurine, d--tubocurarine, gallaminetubocurarine, gallamine
More hemodynamic effectsMore hemodynamic effectsTubocurarine blocks autonomic ganglia, may causeTubocurarine blocks autonomic ganglia, may cause
mast cell degranulationmast cell degranulation
Pancuronium inhibits vagal and muscarinic receptorsPancuronium inhibits vagal and muscarinic receptorsand produces tachycardiaand produces tachycardia
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Reversal of Muscle RelaxationReversal of Muscle Relaxation
Effect is reversed when the ratio of ACh atEffect is reversed when the ratio of ACh at
the NMJ is increasedthe NMJ is increasedNeostigmine, edrophonium, acetylcholineNeostigmine, edrophonium, acetylcholine(anticholinesterases)(anticholinesterases)
Reversal agents can cause bradycardia byReversal agents can cause bradycardia bystimulation of heartstimulation of heart muscarinicmuscarinic receptorsreceptors
PreadministrationPreadministration of muscarinic blockersof muscarinic blockersare effective in avoiding this side effectare effective in avoiding this side effect(atropine, glycopyrrolate)(atropine, glycopyrrolate)
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Depolarizing Muscle RelaxantsDepolarizing Muscle Relaxants
Bind to and depolarize endBind to and depolarize end--plate ACh nicotinic receptorsplate ACh nicotinic receptors
The depolarization continues as long as receptor isThe depolarization continues as long as receptor is
occupiedoccupiedTypically short duration of effect as drug isTypically short duration of effect as drug is hydrolysedhydrolysed bybyplasma cholinesterasesplasma cholinesterases
Patients with abnormal cholinesterase are at risk forPatients with abnormal cholinesterase are at risk forprolonged paralysisprolonged paralysis
Sustained depolarization produces transientSustained depolarization produces transient fasiculationsfasiculations
which can result in postoperative myalgias andwhich can result in postoperative myalgias andextravasation of potassium in patients with damagedextravasation of potassium in patients with damagedmyocytes. Prior administration of lowmyocytes. Prior administration of low--dose nondose non--depolarizing paralytic can attenuate incidencedepolarizing paralytic can attenuate incidence
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SuccinylcholineSuccinylcholine
Only depolarizing paralytic used clinicallyOnly depolarizing paralytic used clinically
Sinus bradycardia, junctionalSinus bradycardia, junctional arhythmiasarhythmias,,even sinus arrest can followeven sinus arrest can followadministrationadministrationlikely secondary tolikely secondary to
muscarinic receptors on heart (blockedmuscarinic receptors on heart (blockedwith atropine)with atropine)
Increased intraocular pressure, intragastricIncreased intraocular pressure, intragastricpressure, trismus reported.pressure, trismus reported.
Malignant hyperthermiaMalignant hyperthermia
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RapidRapid--Sequence InductionSequence Induction
PreoxygenationPreoxygenation
AnesthesiaAnesthesia--inducing drugs (barbiturates,inducing drugs (barbiturates,benzodiazepines,benzodiazepines, opiodsopiods, etomidate,, etomidate,
ketamine, or propofol)ketamine, or propofol)
SuccinylcholineSuccinylcholine
IntubationIntubation
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Local AnestheticsLocal Anesthetics
Reversibly inhibit the generation and conductionReversibly inhibit the generation and conductionof impulses from a particular area of the bodyof impulses from a particular area of the body
Effect is secondary to conduction blockade byEffect is secondary to conduction blockade bydecreasing permeability of nerve membranes todecreasing permeability of nerve membranes tosodiumsodium
Binds to sodium channel and blocks itBinds to sodium channel and blocks itAll but cocaine are vasodilators and thereforeAll but cocaine are vasodilators and thereforeusually are mixed with epinephrineusually are mixed with epinephrine
Ester/Amide family of drugsEster/Amide family of drugsEsters metabolized by plasma cholinesterase,Esters metabolized by plasma cholinesterase,amides metabolized by liver pamides metabolized by liver p--450 system450 system
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Local AnestheticsLocal Anesthetics
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Local AnestheticsLocal Anesthetics
Lipophilic/hydrophilic endsLipophilic/hydrophilic ends
NonNon--ionized form crosses membranesionized form crosses membranesmore readilymore readily
Drugs have less effect in acidic environmentDrugs have less effect in acidic environment
(infection)(infection)
Addition of HCO3 to acidic preparations mayAddition of HCO3 to acidic preparations may
increase potency and decrease painincrease potency and decrease pain
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Local AnestheticsLocal Anesthetics
Local Anesthetic InjectionLocal Anesthetic Injection
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Local Anesthetic InjectionLocal Anesthetic Injection
The TargetThe Target
L l h i i j i O l i
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Local anesthetic injectionLocal anesthetic injection -- OtologicOtologic
L l h iL l th ti I lI t l
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Local anestheticLocal anesthetic -- IntranasalIntranasal
L l A h iL l A th i M illM ill
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Local AnesthesiaLocal Anesthesia -- MaxillaMaxilla
Local AnesthesiaLocal Anesthesia --
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Local AnesthesiaLocal Anesthesia
MandibleMandible
N t diti l A th iN t diti l A th i
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Nontraditional AnesthesiaNontraditional AnesthesiaAcupunctureAcupuncture Acupuncture with electrical stimulation gave 50Acupuncture with electrical stimulation gave 50--65% decrease in65% decrease in
opiodopiod use, decreased PCA use time, and decreased N/V afteruse, decreased PCA use time, and decreased N/V afterintraabdominal surgery (Wang, 1997,intraabdominal surgery (Wang, 1997, HamzaHamza, 1999,, 1999, KotaniKotani, 2001), 2001)
Decreased N/V after tonsillectomy in adults (NIH consensus,Decreased N/V after tonsillectomy in adults (NIH consensus,1998)1998)
Pain control antagonized by naloxone (Pain control antagonized by naloxone (SjolundSjolund, 1979), 1979)
Thought to stimulate large nerve fibers which changes painThought to stimulate large nerve fibers which changes painperception in the spinal cord transmitted by small fibers.perception in the spinal cord transmitted by small fibers.
Endorphins also increased.Endorphins also increased.AcupressureAcupressure
TENS (transcutaneous electrical nerve stimulation)TENS (transcutaneous electrical nerve stimulation) 1010--30% reduction in post30% reduction in post--op pain and needop pain and need
for analgesics (Tyler, 1982)for analgesics (Tyler, 1982)CapsiacinCapsiacin
HypnosisHypnosis
Tidbits, oddsTidbits, odds
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db ts, odds,
& ends& endsMalampattiMalampatti
classificationclassification
ThyromentalThyromental distancedistance
Grading the intubationGrading the intubation
viewviewSP systemSP system
Closed systemClosed systemanesthesiaanesthesia6.5cm
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AnesthesiologyAnesthesiology
Glen T. Porter, MDGlen T. Porter, MD
Francis B. Quinn, MDFrancis B. Quinn, MD
University of Texas Medical BranchUniversity of Texas Medical BranchGalveston, TexasGalveston, Texas