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Fluids & Electrolytes and Nutrition. Srinivas H Reddy, MD Trauma & Surgical Critical Care Jacobi Medical Center. Fluids & Electrolytes. “ The recognition and management of fluid, electrolyte, and related acid-base problems are common challenges on the surgical service. ”. - PowerPoint PPT Presentation
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Fluids & Fluids & Electrolytes and Electrolytes and
NutritionNutritionSrinivas H Reddy, MDSrinivas H Reddy, MD
Trauma & Surgical Critical CareTrauma & Surgical Critical CareJacobi Medical CenterJacobi Medical Center
Fluids & Fluids & ElectrolytesElectrolytes
““The recognition and The recognition and management of fluid, management of fluid,
electrolyte, and related electrolyte, and related acid-base problems are acid-base problems are common challenges on common challenges on the surgical service.”the surgical service.”
Lawrence, P F, Essentials of General Surgery, 4th ed., 2005
GoalsGoalsReview concept of total body fluidsReview concept of total body fluids
Review types of crystalloids and colloidsReview types of crystalloids and colloids
Review electrolyte disturbances & their Review electrolyte disturbances & their treatment strategiestreatment strategies
Review acid-base disturbancesReview acid-base disturbances
67% 33%
8%
25%
Na-K
ATPase
Na+/K+ ATPaseActively pumps 3 Na+ out of cell and 2K+ inside cell
Energy from ATP
Regulated by
Insulin
Aldosterone
Starling’s ForcesStarling’s Forces
Cations and Anions in Body Cations and Anions in Body FluidsFluids
Serum OsmolalitySerum Osmolality
==
[2 x Na] + [BUN/2.8] + [Gluc/18][2 x Na] + [BUN/2.8] + [Gluc/18]
Osmolality Osmolality = = CONCENTRATIONCONCENTRATION
Tonicity Tonicity = ONCOTIC = ONCOTIC PRESSURE FORCE ON PRESSURE FORCE ON WATERWATER
Antidiuretic hormone (ADH, Vasopressin)Antidiuretic hormone (ADH, Vasopressin)Stimulates kidney to resorb water from collecting ductsStimulates kidney to resorb water from collecting ductsCauses systemic vasoconstrictionCauses systemic vasoconstrictionStimulates thirst centerStimulates thirst center
AldosteroneAldosteroneStimulates NaStimulates Na++ (& water) absorption and K (& water) absorption and K++ loss along loss along the DCTthe DCTSimilar action on distal colonSimilar action on distal colon
Natriuretic peptides (ANP and BNP)Natriuretic peptides (ANP and BNP)Reduce thirst and block the release of ADH and Reduce thirst and block the release of ADH and aldosterone aldosterone
Primary Regulatory Primary Regulatory HormonesHormones
Renin-Angiotensin-Aldosterone Renin-Angiotensin-Aldosterone SystemSystem
Renin-Angiotensin-Aldosterone Renin-Angiotensin-Aldosterone SystemSystem
Na-K
ATPase
67% 33%
8%
25%
GI Fluid & Electrolyte GI Fluid & Electrolyte LossesLosses
SourceSource Volume Volume (ml)(ml)
Na Na (mEq/L)(mEq/L)
Cl Cl (mEq/L)(mEq/L)
K K (mEq/L)(mEq/L)
HCO3 HCO3 (mEq/L)(mEq/L)
H H (mEq/L)(mEq/L)
StomachStomach1000-4200
20-120 130 10-15 30-100
DuodenuDuodenumm
100-2000 110 115 15 10
IleumIleum1000-3000
80-150 60-100 10-15 30-50
ColonColon 500-1700 120 90 25 45
BileBile 500-1000 140 100 5 25
PancreasPancreas 500-1000 140 30 5 115
Lactated Ringers / Lactated Ringers / Normal SalineNormal Saline
Normal Saline Normal Saline (NS)(NS)
Does not contain Does not contain calcium, may be used calcium, may be used to carry PRBC to carry PRBC transfusiontransfusion
Hyperchloremic Hyperchloremic metabolic acidosis metabolic acidosis after aggressive after aggressive resuscitationresuscitation
pH = 5.5pH = 5.5
Lactated Ringers (LR)Lactated Ringers (LR)
Sydney RingerSydney Ringer’’s frog s frog hearts (London 1882)hearts (London 1882)Alexis Hartman pediatric Alexis Hartman pediatric cholera, added cholera, added bicarbonate (US 1930bicarbonate (US 1930’’s)s)Lactate -> Pyruvate -> Lactate -> Pyruvate -> BicarbonateBicarbonateLactic Acidosis?Lactic Acidosis?Immunosuppressive Immunosuppressive effect on WBCeffect on WBC’’s?s?Calcium precipitates with Calcium precipitates with citrate in PRBC citrate in PRBC transfusiontransfusionpH=6.5pH=6.5
Maintenance Maintenance FluidsFluids
Formula per dayFormula per day
100mL/kg/d x first 100mL/kg/d x first 10kg10kg
50mL/kg/d x next 10kg50mL/kg/d x next 10kg
25mL/kg/d x each addl 25mL/kg/d x each addl kgkg
Formula per hourFormula per hour
4mL/kg/hr x first 10kg4mL/kg/hr x first 10kg
2mL/kg/hr x next 10kg2mL/kg/hr x next 10kg
1mL/kg/hr x each addl 1mL/kg/hr x each addl kgkg
““4-2-1 Rule - per hr”4-2-1 Rule - per hr”
Maintenance Maintenance ElectrolytesElectrolytes
SodiumSodium
1-2 mEq/kg/day1-2 mEq/kg/day
ChlorideChloride
1-2 mEq/kg/day1-2 mEq/kg/day
PotassiumPotassium
0.5-1 mEq/kg/day0.5-1 mEq/kg/day
CalciumCalcium
800 - 1200 mg/d800 - 1200 mg/d
MagnesiumMagnesium
300 - 400 mg/d300 - 400 mg/d
PhosphorusPhosphorus
800 - 1200 mg/d800 - 1200 mg/d
Normal Serum Normal Serum ElectrolytesElectrolytes
CationsCations
Sodium (mEq/L)Sodium (mEq/L) 135 - 145135 - 145
Potassium (mEq/L) Potassium (mEq/L) 3.5 - 4.5 3.5 - 4.5
Calcium (mg/dL) Calcium (mg/dL) 4.0 - 5.5 4.0 - 5.5
MagnesiumMagnesium (mEq/L) (mEq/L) 1.5 - 2.5 1.5 - 2.5
AnionsAnions
Chloride (mEq/L) Chloride (mEq/L) 95 - 105 95 - 105
COCO22 (mmol/L) (mmol/L) 24 - 30 24 - 30
Phosphate (mg/dL)Phosphate (mg/dL) 2.5 - 4.5 2.5 - 4.5
Fluid StatusFluid Status
[Na]
ECV
low normal high
160
140
120
140
GI loss
SIADHHypothyroid
Cortisol CHFCirrhosis
NaHCO3
3% NaClSeawater
DIInsensible
GI lossRenal lossOsmotic
Composition of IV Fluid Composition of IV Fluid SolutionsSolutions
SolutionSolution NaNa++ ClCl-- KK++ CaCa+2+2 HCO3HCO3- - GlucGluc
PlasmaPlasma 141141 103103 4-54-5 55 2626 0 0
NSNS 154154 154154 00 00 00 00
LRLR 130130 109109 44 33 2828 00
D5WD5W 00 00 00 00 00 50g 50g
D5 1/2NS+20KClD5 1/2NS+20KCl 7777 7777 2020 00 00 50g 50g
Serum Osmolality = [2 x Na] + [BUN/2.8] + [glucose/18]
Replacement Fluid Replacement Fluid StrategiesStrategies
SweatSweat: D: D55¼NS + 5mEq KCl¼NS + 5mEq KCl
GastricGastric: D: D55½NS + 20mEq KCl½NS + 20mEq KCl
Biliary/PancreaticBiliary/Pancreatic: LR: LR
Small BowelSmall Bowel: LR: LR
ColonColon: LR: LR
33rdrd space losses space losses: LR: LR
ResuscitationResuscitationCrystalloids first, initial bolus 20mL/kg Crystalloids first, initial bolus 20mL/kg (1-2L), may be repeated, usually NS or (1-2L), may be repeated, usually NS or LRLR
If they have transient response, give If they have transient response, give additional fluidsadditional fluids
Once 3-4 liters of crystalloid has been Once 3-4 liters of crystalloid has been given consider bloodgiven consider blood
Current recommendations in Current recommendations in hemorrhagic shock from trauma, hemorrhagic shock from trauma, transfuse 1:1 PRBC:FFP (previously, and transfuse 1:1 PRBC:FFP (previously, and for other bleeds 3:1 ratio)for other bleeds 3:1 ratio)
Fluid PearlsResuscitation – isotonic fluid (LR or NS), no dextrose, if ongoing losses consider using colloid
Post-op – LR or NS until pt euvolemic, then switch to maintenance
Bolus – isotonic fluid, no dextrose
Mobilization – movement of fluid from 3rd space into intravascular space
Indicators of Successful Indicators of Successful ResuscitationResuscitation
PULSE PULSE <100 - 120 bpm<100 - 120 bpm
URINE OUTPUTURINE OUTPUTChild >1.0 ml/kg/hrChild >1.0 ml/kg/hrAdult >0.5 ml/kg/hrAdult >0.5 ml/kg/hr
Clearance of Clearance of LACTATELACTATE
Resolution of Resolution of BASE DEFICITBASE DEFICIT
BLOOD PRESSURE BLOOD PRESSURE is a is a POORPOOR INDICATOR!INDICATOR!
HypovolemiaAcute volume loss
TachycardiaHypotensionDecreased UOChanges in mental status
Gradual volume lossLoss of skin turgor, dry mucus membranesThirst
Low CVP
Hemoconcentration (Hct rise)
BUN:Cr ( >20:1)
Metabolic acidosis due to hypoperfusion
HypervolemiaLarge UO
Pitting edema
JVD
Crackles on lung auscultation
Hypoxia
CXR – cephalization of vessels, pulmonary edema
HyponatremiaSerum Na+ < 130mEq/L
Sx- nausea, emesis, weakness, altered MS, seizure
May be hypovolemic, euvolemic, or hypervolemic
TxFluid restrictionReplete with Normal SalineFor severe hyponatremia <120-125mEq/L and/or mental status changes, use Hypertonic SalineRemember: do NOT correct faster than 0.5 mEq/L/hr to avoid central pontine myelinolysis
Causes of Hyponatremia
HypovolemicCauses – Na+ and water are lost and replaced with hypotonic solutions
Renal – salt wasting nephropathyGI – diarrhea, vomiting, fistulasSkin – excessive sweating3rd spacing – ascites, peritonitis, pancreatitis, burnsHypoaldosteronism
EuvolemicCauses – SIADH, psychogenic polydipsia
HypervolemicCauses - renal failure, nephrotic synd, CHF, cirrhosis
HypernatremiaSerum Na+ > 145
Sx – altered level of consciousness, seizure, coma, signs of dehydration
Causes – DI, hyperosmolar diuresis, EtOH (suppresses ADH)
Tx calculate Free Water DeficitFWD = 0.6 x wt (kg) x (measured Na+ - 140) / 140Replace first ½ in 24hrs, then 2nd ½ in next 24 hrsNo faster than 10mEq/day to avoid cerebral edemaUse D5W, ½ NS, or ¼ NS
HypokalemiaK+ < 3.5
Sx – fatigue, weakness, ileus, N/V, arrhythmia, rhabdomylosis, flaccid paralysis, resp compromise EKG changes - long QT, depressed ST,
low T waves, U waves
Causes – vomiting, NGT drainage, diarrhea, high output enteric/pancreatic fistula, hyperaldosteronism, loop diuretics
Tx – replete 10 mEq KCl for every 0.1 below 4.0, oral or IV not more than 10-20mEq/hr, if persistent hypokalemia, may also need Mg 2+ replacement, also available K phos or K acetate
Hyperkalemia• K+ > 5.0
• Sx – weakness, N/V, abdominal cramping, diarrhea, arrhythmias EKG – peaked T waves, prolonged PR,
widened QRS, V-fib, diastolic cardiac arrest
• Causes – iatrogenic, renal failure, acidosis, hemolysis, crush injury, reperfusion injury
• Tx
Treatment of Hyperkalemia
• Cardiac monitoring, EKG
• If EKG changes, give Calcium gluconate or chloride (stabilizes cardiac membrane) CaCl : CaGluc = 3 : 1 elemental calcium
• Dextrose and Insulin
• Bicarbonate
• Albuterol
• Kayexalate
• Renal Replacement Therapy (Dialysis)
Hypocalcemia• Ca2+ < 8.5
• Sx – parasthesias, muscle spasms, tetany, seizures, Chvostek, Trousseau– EKG – prolonged QT, can progress to
complete heart block or V-fib
• Causes – pancreatitis, tumor lysis syndrome, blood transfusion, renal failure, thyroid or parathyroid surgery, diet deficient in Vit D or Ca, inability to absorb fat-soluble vitamins
• Tx – chronic hypocalcemia give supplemental oral calcium & vitamin D, and for symptomatic hypocalcemia, give IV calcium ± PO calcium/vit D
Hypercalcemia
• Ca2+ > 10.5
• Sx – stones, moans, groans, psychologic overtones
• Causes – ‘CHIMPANZEES’
• Tx – – Identify and treat cause– Severe/symptomatic hypercalcemia, treat
with IVF, diuretics (saline diuresis)– Bisphosphonates, if due to release of Ca2+
from bone
Acid / BaseAcid / Base
7.4
BE = 0HCO3 = 24
RespiratoryAcidosis
MetabolicAcidosis
MetabolicAlkalosis
RespiratoryAlkalosis
Acid-Base DisturbancesAcid-Base Disturbances
Mechanisms Regulating Mechanisms Regulating
Acid-Base BalanceAcid-Base Balance• Chemical buffers in cells and ECFChemical buffers in cells and ECF
– Instanteous actionInstanteous action– Combine acids or bases added to the Combine acids or bases added to the
system to prevent marked changes in pHsystem to prevent marked changes in pH
• Respiratory SystemRespiratory System– Minutes to hours in actionMinutes to hours in action– Controls CO2 concentration in ECF by Controls CO2 concentration in ECF by
changes in rate and depth of respirationchanges in rate and depth of respiration
• KidneysKidneys– Hours to days in actionHours to days in action– Increases or decreases amount of Increases or decreases amount of
NaHCO3 in ECFNaHCO3 in ECF
Buffer Mechanisms of pH Buffer Mechanisms of pH ControlControl
• Buffer system consists of a weak acid and Buffer system consists of a weak acid and its anionits anion
• Three major buffering systemsThree major buffering systems::1.1. Protein buffer systemProtein buffer system
• Amino acidAmino acid• HH++ are buffered by hemoglobin buffer are buffered by hemoglobin buffer
system system 2.2. Carbonic acid-bicarbonateCarbonic acid-bicarbonate
• Buffer changes caused by organic Buffer changes caused by organic and fixed acidsand fixed acids
3.3. PhosphatePhosphate• Buffer pH in the ICFBuffer pH in the ICF
Relationship between PRelationship between PCO2CO2 and and Plasma pHPlasma pH
Central Role of Carbonic Acid-Central Role of Carbonic Acid-Bicarbonate Buffer System in Bicarbonate Buffer System in
Regulation of Plasma pHRegulation of Plasma pH
Central Role of Carbonic Acid-Central Role of Carbonic Acid-Bicarbonate Buffer System in Bicarbonate Buffer System in
Regulation of Plasma pHRegulation of Plasma pH
ABG RulesABG Rules
• Rule #1: increase or decrease in Rule #1: increase or decrease in PaCOPaCO22 of 10 mm Hgof 10 mm Hg, is associated with a , is associated with a reciprocal decrease or increase of reciprocal decrease or increase of 0.08 0.08 pHpH
• Rule #2: increase or decrease in Rule #2: increase or decrease in HCO3HCO3-- of 10 mEq/Lof 10 mEq/L is associated with a is associated with a directly-related increase or decrease of directly-related increase or decrease of 0.15 pH0.15 pH
Severe AcidosisSevere Acidosis
pH < 7.2pH < 7.2 decreased responsiveness to decreased responsiveness to
catecholaminescatecholamines cardiac dysfunctioncardiac dysfunction arrhythmiasarrhythmias increased potassium serum levelsincreased potassium serum levels
NutritionNutrition
GoalsGoals
Why important?
What nutrients are needed?
How much nutrition is necessary?
How to administer nutrition to patient?
Why Nutrition?Why Nutrition?
• Growth
• Immunity
• Wound healing
What Nutrition?What Nutrition?• Water
• Carbohydrate (Glucose) – 60-70% of total kcal
• Protein – 1.0-2.0 gm/kg/day
• Fat/Lipids – 15-40% of total kcal
• Vitamins/Minerals/Elements
How Much How Much Nutrition?Nutrition?
• Water - You already know this part!
• Glucose @ 2-6 mg/kg/min
• Protein @ 1-2 g/kg/day
• Fat/Lipids @ 1-2 g/kg/day
• Vitamins/Minerals/Elements - A, D, E, K, B, C, Zinc, Chromium, Selenium, Phosphate, etc.
How Much How Much Nutrition?Nutrition?
• Harris-Benedict Equation for Basal Energy Expenditure (BEE) in kilocalories =
✓ Male: 66+(13.8xW)+(5xH)-(6.8xA)✓ Female: 655+(9.6xW)+(1.85xH)-(4.7xA)✓ Range: 20-40 kcal/kg/day
• Multiply by stress factor (1.2-2.0)i.e. burn, trauma, sepsis, increased activity
• Indirect Calorimetry – estimate RestingEnergy Expenditure and efficiency of fuel burning
How Much How Much Nutrition?Nutrition?Caloric Goal = 25-30 kcal/kg/day
Higher for burn patients (hypercatabolic)• Glucose (2-6 mg/kg/min) @ 4 kcal/gm• Protein (1-2 g/kg/day) @ 4 kcal/gm• Fat/Lipids (1-2 g/kg/day) @ 9 kcal/gm
Nutritional Status Parameters• N2 Balance = N2 in – N2 out• N2 in = Protein intake (gm/day) / 6.25• N2 out = UUN + 4• Albumin / Transferrin / PreAlbumin / RBP• Anthropometrics (TSF, MAC)
Metabolic StressMetabolic Stress
• Sepsis (infection)Sepsis (infection)
• Trauma (including burns)Trauma (including burns)
• SurgerySurgery
• Once the systemic response is Once the systemic response is activated, the physiologic and activated, the physiologic and metabolic changes that follow are metabolic changes that follow are similar and may lead to septic similar and may lead to septic shockshock
OverfeedingOverfeeding• Enough but not too muchEnough but not too much
• Excess calories:Excess calories:– HyperglycemiaHyperglycemia
• Diuresis – complicates Diuresis – complicates fluid/electrolyte balancefluid/electrolyte balance
– Hepatic steatosis (fatty liver)Hepatic steatosis (fatty liver)
– Excess COExcess CO22 production production
• Exacerbate respiratory insufficiencyExacerbate respiratory insufficiency• Prolong weaning from mechanical Prolong weaning from mechanical
ventilationventilation
How to Give How to Give Nutrition?Nutrition?• Enteral - via the gut
• Preferred method• Prevent intestinal atrophy• Protect from bacterial translocation
across basement membrane• Gastric stress ulcer prevention
• Parenteral - via the vein• Only for severely protein-malnourished
patients who cannot be fed enterally in the long-term
• Higher risk of complications and infections, related to catheters and lipids (?)
Tube Feeding
• Used when oral feeding cannot be tolerated (altered mental status, endotracheal intubation, facial trauma, dysphagia, etc)
• Nasogastric or orogastric tube is most common route
• Nasoduodenal or nasojejunal tube more appropriate for patients at risk for aspiration, reflux, or continuous vomiting
Enteral Tube Feeding
Alternate Routes for Enteral Tube Feeding
• Percutaneous Endoscopic Gastrostomy (PEG)
• Percutaneous Endoscopic Jejunostomy (PEJ)
• Open (surgical) Gastrostomy
• Feeding Jejunostomy
• Esophagostomy
Tube-Feeding Formula
• Generally prescribed by the physician
• Important to regulate amount and rate of administration
• Diarrhea is most common complication
• Wide variety of commercial formulas available
Parenteral Feeding Routes
• Peripheral Parenteral Nutrition (PPN) : uses less concentrated solutions through small peripheral veins when feeding is necessary for a brief period (<10 days)
• Total Parenteral Nutrition (TPN) : used when energy and nutrient requirement is large or to supply full nutritional support for long periods of time through large central vein
Questions?Questions?
Thank You!Thank You!