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!