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Fluid and electrolytes
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Fluid and electrolytes

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Fluid and electrolytes Fluid and electrolytes Presentation Transcript

  • Ranjit PandeyRanjit Pandey PharmacistPharmacist ranjitpandey17@gmail.comranjitpandey17@gmail.com Fluid and Electrolyte BalanceFluid and Electrolyte Balance in Surgeryin Surgery
  • Body Fluid CompartmentsBody Fluid Compartments ∀→→ accurate replacement of fluid requiresaccurate replacement of fluid requires knowledge of distribution of water,knowledge of distribution of water, electrolytes and colloids across variouselectrolytes and colloids across various body fluid compartments.body fluid compartments. • TBW of an adult healthy patient is 60% ofTBW of an adult healthy patient is 60% of body wt. (eg. 70 kgbody wt. (eg. 70 kg →→ 42 L)42 L)
  • TBWTBW Intracellular compartmentIntracellular compartment (2/3)(2/3) Extracellular compartment (1/3)Extracellular compartment (1/3) ICVICV 40 % of TBWt. (28 L)40 % of TBWt. (28 L) ECVECV 20 % of TBWt (14L)20 % of TBWt (14L) RBC volume 2-3 %RBC volume 2-3 % of TBWtof TBWt Intravascular fluidIntravascular fluid OR PlasmaOR Plasma volumevolume (1/4 of ECV = 5%(1/4 of ECV = 5% TBWt = 3.5 L)TBWt = 3.5 L) Interstitial fluidInterstitial fluid (3/4 of ECV =(3/4 of ECV = 15 % TBWt.15 % TBWt. = 10.5 L)= 10.5 L) Total Blood volume ~ 7-8 % of TBWtTotal Blood volume ~ 7-8 % of TBWt (4.9- 5.6 L)(4.9- 5.6 L)
  • The electrolytes and colloid composition markedlyThe electrolytes and colloid composition markedly different at intra and extra cellular fluiddifferent at intra and extra cellular fluid compartmentscompartments ElectrolytesElectrolytes Intracellular (mEq/L)Intracellular (mEq/L) ExtracellularExtracellular (mEq/L)(mEq/L) Intravascular (mEq/L)Intravascular (mEq/L) Interstitial (mEq/L)Interstitial (mEq/L) NaNa++ 1010 145145 142142 KK++ 140140 44 44 CaCa++++ <1<1 33 33 MgMg++++ 5050 22 22 ClCl-- 44 105105 110110 HCO3HCO3-- 1010 2424 2828 PO4PO4-- 7575 22 22 Protein (g/dl)Protein (g/dl) 1616 77 22
  • Volume of DistributionVolume of Distribution • It’s the volume in which the administered solution will equilibrateIt’s the volume in which the administered solution will equilibrate over the short term.over the short term. Examples:Examples: • Total body waterTotal body water →→ distribution vol for Nadistribution vol for Na++ free waterfree water • ECVECV →→ for crystalloid solfor crystalloid sol • PlasmaPlasma →→ for most of the colloidsfor most of the colloids Eg. in 70 Kg man, 1000 ml blood loss due to RTA ie. 20 % of totalEg. in 70 Kg man, 1000 ml blood loss due to RTA ie. 20 % of total blood vol lossblood vol loss • It can be replaced by D5W / RL / 5% albuminIt can be replaced by D5W / RL / 5% albumin • Volume needed to infuse =Volume needed to infuse = (Expected plasma vol increment X(Expected plasma vol increment X distribution vol) / plasma voldistribution vol) / plasma vol volume infused = (1000ml X ?) / 3.5 Lvolume infused = (1000ml X ?) / 3.5 L • for D5W, 1000 X D5W (42 L) / 3.5 = 12 Lfor D5W, 1000 X D5W (42 L) / 3.5 = 12 L • for NS,for NS, 1000 X NS (14 L) / 3.5 = 4 L1000 X NS (14 L) / 3.5 = 4 L • for Albumin,for Albumin, 1000 X Plasma vol (3.5 L) / 3.5 = 1 L1000 X Plasma vol (3.5 L) / 3.5 = 1 L
  • Maintenance body fluid and electrolytes requirementMaintenance body fluid and electrolytes requirement • Urinary loss = 1000 ml /dayUrinary loss = 1000 ml /day • GI loss = 100 – 200 ml /dayGI loss = 100 – 200 ml /day • Insensible water loss = 8 – 12 ml /kg/dayInsensible water loss = 8 – 12 ml /kg/day Over all fluid requirements depends on body wt and can be calculated by either of the formulae Wt.Wt. ml/kg/hml/kg/h ml/kg/dayml/kg/day 11stst 10 Kg10 Kg 44 100100 22ndnd 10 Kg10 Kg 22 5050 Each Kg above 20 kgEach Kg above 20 kg 11 2020 Eg. 31 KgEg. 31 Kg 40 + 20 + 11 = 7140 + 20 + 11 = 71 ml/hr (1704 ml)ml/hr (1704 ml) 1000 + 500 + 2201000 + 500 + 220 1720 ml1720 ml
  • Maintenance Electrolytes requirementsMaintenance Electrolytes requirements :: Na+ = 1.0 – 2.0 mEq/kg/dayNa+ = 1.0 – 2.0 mEq/kg/day K+ = 0.5 – 1.0 mEq/Kg/dayK+ = 0.5 – 1.0 mEq/Kg/day (Supplement of other electrolyte eg Ca, Mg PO4 not needed for patient with(Supplement of other electrolyte eg Ca, Mg PO4 not needed for patient with normal nutritional status.)normal nutritional status.) • Depending on the estimated Na+ and K+ requirement – variousDepending on the estimated Na+ and K+ requirement – various maintenance fluids can be use to achieve (for 60 kg BWt) 60 – 120maintenance fluids can be use to achieve (for 60 kg BWt) 60 – 120 mEq Na+/day and 30-60 mEq K+/daymEq Na+/day and 30-60 mEq K+/day FluidsFluids NaNa++ (mEq/l)(mEq/l) KK++ (mEq/l)(mEq/l) ClCl-- (mEq/l)(mEq/l) CaCa++++ (mEq/l)(mEq/l) LactateLactate glucoseglucose Normal (0.9%) salineNormal (0.9%) saline (NS)(NS) 154154 00 154154 00 00 00 Dextrose 5% in waterDextrose 5% in water (D5W)(D5W) 00 00 00 00 00 5050 D5W + ½ NSD5W + ½ NS 7777 00 7777 00 00 5050 2/3 D5W + 1/3 NS2/3 D5W + 1/3 NS 5050 00 5050 00 00 3333 Lactated Ringer’sLactated Ringer’s 130130 44 109109 33 2828 00 For maintenance, best fluid being the D5W ½ NS or 2/3 D5W, 1/3 NS with added K+ @ 20 mEq/L NS alone → not good, as may develop hyperchloremic metabolic acidosis.
  • Perioperative Fluid RequirementPerioperative Fluid Requirement • The mount of fluid administered in the immediate post op periodThe mount of fluid administered in the immediate post op period (12-24 hours) must take into account the(12-24 hours) must take into account the existing deficit +existing deficit + maintenance requirement + any ongoing lossesmaintenance requirement + any ongoing losses Existing deficitsExisting deficits →→ intra op blood loss, fluid loss by evaporationintra op blood loss, fluid loss by evaporation and 3rd space loss or extravascular fluid sequestrationand 3rd space loss or extravascular fluid sequestration • (* surgeons estimated blood loss is often 50% less than the actual loss)(* surgeons estimated blood loss is often 50% less than the actual loss) • Extra vascular fluid sequestrationExtra vascular fluid sequestration is another important factor inis another important factor in which – extensive dissection @ operative site cause capillary leakwhich – extensive dissection @ operative site cause capillary leak resulting to extravasations of intravascular fluid into the intestitiumresulting to extravasations of intravascular fluid into the intestitium with edema formation. Eg. in herniorrhapy its ~ 4ml/kg/hr and inwith edema formation. Eg. in herniorrhapy its ~ 4ml/kg/hr and in aneurysmectomy -~ 8 ml/kg/hr (it may continue till 24 hours post op)aneurysmectomy -~ 8 ml/kg/hr (it may continue till 24 hours post op) Ongoing fluid lossOngoing fluid loss – represents GI loss from stomas, tubes drains– represents GI loss from stomas, tubes drains and fistulas. The electrolytes composition of these losses dependsand fistulas. The electrolytes composition of these losses depends on their origin and need to select the best fluid for replacement.on their origin and need to select the best fluid for replacement.
  • SourceSource Volume (ml)Volume (ml) NaNa++ mEq/lmEq/l ClCl-- mEq/lmEq/l KK++ mEq/lmEq/l HCO3HCO3-- mEq/lmEq/l HH++ mEq/lmEq/l StomachStomach 1000 – 42001000 – 4200 20-12020-120 130130 10-1510-15 -- 30-10030-100 DuodenumDuodenum 100-2000100-2000 110110 115115 1515 1010 -- IleumIleum 1000-30001000-3000 80-15080-150 60-10060-100 1010 30-5030-50 -- Colon (diarrhea)Colon (diarrhea) 500-1700500-1700 120120 9090 2525 4545 -- BileBile 500-1000500-1000 140140 100100 55 2525 -- PancreasPancreas 500-1000500-1000 140140 3030 55 115115 --
  • Post Op fluid orderPost Op fluid order • should based on existing deficit / maintenanceshould based on existing deficit / maintenance requirement / ongoing lossrequirement / ongoing loss • need frequent assessment of intravenous vol statusneed frequent assessment of intravenous vol status →→ BP, PS hourly U/OBP, PS hourly U/O • preferred fluid for immediate post op period is NS or RLpreferred fluid for immediate post op period is NS or RL in compared to dextrose containing sol, due to theirin compared to dextrose containing sol, due to their small vol of distributionsmall vol of distribution • on first Post op morning, the fluid is switched to dextroseon first Post op morning, the fluid is switched to dextrose containing sol (2/3 D5W, 1/3 NS or D5W, ½ NS) withcontaining sol (2/3 D5W, 1/3 NS or D5W, ½ NS) with added KCl (provided adequate U/O)added KCl (provided adequate U/O)
  • Disorder of NaDisorder of Na++ HomeostasisHomeostasis • Normal Na+ conc = 135 – 145 mEq/lNormal Na+ conc = 135 – 145 mEq/l • Na is major determinant of plasma osmolarityNa is major determinant of plasma osmolarity • Normally, Posm is maintained by water excretion by kidney &Normally, Posm is maintained by water excretion by kidney & normal thirst mechanism to intake waternormal thirst mechanism to intake water • ADH – plays major role,ADH – plays major role, →→ in hypo-osomolar condition, ADHin hypo-osomolar condition, ADH maximally inhibited leading to excretion of diluted urinemaximally inhibited leading to excretion of diluted urine →→ in hyperin hyper osmolar condition – ADH is activatedosmolar condition – ADH is activated • In an especial condition where both plasma osmolarity and lowIn an especial condition where both plasma osmolarity and low blood volume (pressure) presentblood volume (pressure) present →→ later plays dominant rolelater plays dominant role
  • Hyponatremia (NaHyponatremia (Na++ < 120 mEq/l)< 120 mEq/l) • In hyponatermia, always assess the serum osmolarityIn hyponatermia, always assess the serum osmolarity • Depending on the ser. Osmol., hypernatremaia can be % into 3 groupDepending on the ser. Osmol., hypernatremaia can be % into 3 group (1) Hyperosmolar hyponatermia(1) Hyperosmolar hyponatermia • (dilutional hyponatremia)(dilutional hyponatremia) [ osmolarity[ osmolarity ↑↑, Na, Na↓↓]] • eg. hyperglycemia, mannitoleg. hyperglycemia, mannitol • Tx definitiveTx definitive (2) normo osmolar hyponatremia(2) normo osmolar hyponatremia • pseudo hypeonatremia [-,pseudo hypeonatremia [-, ↓↓]] • rare conditionrare condition • eg. hyperlipedemia, hyper proteinemiaeg. hyperlipedemia, hyper proteinemia • Tx not requiredTx not required (3) hypo osmolar hypohatremia(3) hypo osmolar hypohatremia • true hyponatremiatrue hyponatremia • frequent causefrequent cause • depending on the ECF vol. 3 typesdepending on the ECF vol. 3 types
  • (a) with reduction in extracellular vol (hypovolumic hyponatremia)(a) with reduction in extracellular vol (hypovolumic hyponatremia) ∀ ↑↑ ADH secretionADH secretion • kidney’s ability to excrete free water impairedkidney’s ability to excrete free water impaired • aggravated by Na+ sol administration or ingestion of free water due toaggravated by Na+ sol administration or ingestion of free water due to thirstthirst • MC cause due to Na+ loss eg perioperative isotonic losses (plasma,MC cause due to Na+ loss eg perioperative isotonic losses (plasma, gastric) which replace by Na+ free water (hypotonic sol)gastric) which replace by Na+ free water (hypotonic sol) • Tx replacement of extravascular fluid with isotonic fluidsTx replacement of extravascular fluid with isotonic fluids (b) with increaded extracelular vol(b) with increaded extracelular vol • 2nd most common condition2nd most common condition • usually seen with edema state eg due to low cardiac out put state orusually seen with edema state eg due to low cardiac out put state or cirrhosis and hypoalbuminemiacirrhosis and hypoalbuminemia • tx both Na+ and water restriction and use loop diuretics whichtx both Na+ and water restriction and use loop diuretics which ↑↑ Na andNa and water loss, where Water>Na loss and correct hypo natremiawater loss, where Water>Na loss and correct hypo natremia © with normal extracellular vol© with normal extracellular vol • SIADH secretionSIADH secretion • Resulted by nausea / pain / narcoticsResulted by nausea / pain / narcotics • Tx , Mx of underlying cause and water restrictionTx , Mx of underlying cause and water restriction
  • Symptoms of HyponatremiaSymptoms of Hyponatremia • depends on the rate ofdepends on the rate of ↓↓ NaNa • if the rate is slow, no symptoms even till as low as 110 mEq/lif the rate is slow, no symptoms even till as low as 110 mEq/l • if its rapid, symptoms ofif its rapid, symptoms of ↑↑ ICP due to cerebral edema (most prominentICP due to cerebral edema (most prominent feature) result @ 125 mEq/lfeature) result @ 125 mEq/l • don’t correct Na+ deficit too rapids, as it may cause irreversible bran stemdon’t correct Na+ deficit too rapids, as it may cause irreversible bran stem injury due to central pontine myelinosis due to cell shrinkageinjury due to central pontine myelinosis due to cell shrinkage • goal of correction is approx 0.5 mEq/hour ( can be correct more rapidly ifgoal of correction is approx 0.5 mEq/hour ( can be correct more rapidly if symptomatic)symptomatic) • use 3% NS till symptoms improve or plasma Na+ increased by 5 mEq/luse 3% NS till symptoms improve or plasma Na+ increased by 5 mEq/l whichever come firstwhichever come first • Na+ deficit = 0.6 x lean B Wt. (120 – measure plasmaNa+ deficit = 0.6 x lean B Wt. (120 – measure plasma Na+)Na+)
  • HypernatremiaHypernatremia • not as common asnot as common as ↓↓ Na+Na+ • due to excessive free water loss, most commonly extradue to excessive free water loss, most commonly extra renal losses eg. fever, hyperventilation or burns, severerenal losses eg. fever, hyperventilation or burns, severe diarrheadiarrhea • also may cause due to polyuria with renal free water lossalso may cause due to polyuria with renal free water loss eg in osmotic diuresis induced by hyperglycemiaeg in osmotic diuresis induced by hyperglycemia • if its sever, confusion, coma and intracranial Hge mayif its sever, confusion, coma and intracranial Hge may occur and tissue perfusion is compromisedoccur and tissue perfusion is compromised • initially 0.9 NS is the Tx of choice toinitially 0.9 NS is the Tx of choice to ↑↑ tissue perfusiontissue perfusion • after adequate tissue perfusion 0.5 NS or D5W can beafter adequate tissue perfusion 0.5 NS or D5W can be usedused • shouldn’t be corrected faster than 0.5 – 1.0 mEq/ hourshouldn’t be corrected faster than 0.5 – 1.0 mEq/ hour • water deficit = total body water x [ (plasma Nawater deficit = total body water x [ (plasma Na ++ % desired% desired plasma Naplasma Na++ ) – 1]) – 1]
  • Disorder of potassium homeostasisDisorder of potassium homeostasis HypokalemiaHypokalemia • extra renal lossesextra renal losses – GI (vomiting / nasogastric suctionGI (vomiting / nasogastric suction – DiarrheaDiarrhea – Massive burnMassive burn – Profuse sweatingProfuse sweating • renal lossesrenal losses – vomitingvomiting →→ extracellular vol contrationextracellular vol contration →→ ↑↑aldosteronaldosteron levellevel →→ Na+ and water retentionNa+ and water retention →→K+ excretionK+ excretion • transcellular flux of K+ into the celltranscellular flux of K+ into the cell
  • Major problems associated with HypokalemiaMajor problems associated with Hypokalemia • cardia arrhythmia, usually express when K+ level falls <3 mEq/lcardia arrhythmia, usually express when K+ level falls <3 mEq/l • muscular weakness (<2.5 mEq/l)muscular weakness (<2.5 mEq/l) • ECG changes T-wave flattening or inversion, depressed ST, develop uECG changes T-wave flattening or inversion, depressed ST, develop u wave, Q-T prolongationwave, Q-T prolongation Whenever possible, KWhenever possible, K++ supplementation should be done orallysupplementation should be done orally But if KBut if K++ is <3.0is <3.0 →→ parenteral route is preferredparenteral route is preferred Rate of administration KRate of administration K++ should be not greater than 20 – 40 mEq/hshould be not greater than 20 – 40 mEq/h
  • HyperkalemiaHyperkalemia • mostly caused my rapid administration or transcellular flux of K+mostly caused my rapid administration or transcellular flux of K+ • renal imparement of K+ excretion also causerenal imparement of K+ excretion also cause ↑↑K+ flux to extracellularK+ flux to extracellular space may occur in case of metabolic acidosis, DM or rhabdomyolysisspace may occur in case of metabolic acidosis, DM or rhabdomyolysis • succinyl choline may alsosuccinyl choline may also ↑↑ K+ (transient)K+ (transient) • in surgical Patient, most frequently it occurs as a result of impairedin surgical Patient, most frequently it occurs as a result of impaired renal excretion due to oliguric renal dysfunction. Therefore, K+ shouldrenal excretion due to oliguric renal dysfunction. Therefore, K+ should be avoided in IVF for 1st post op day.be avoided in IVF for 1st post op day. Major problems ofMajor problems of ↑↑K+K+ • like hypokalemia, it also cause cardiac abnormality with weakness andlike hypokalemia, it also cause cardiac abnormality with weakness and myocardiacl irritabilitymyocardiacl irritability • ECG changes -ECG changes - ↑↑ t wave, narrow peaked symmetrical t wave, followedt wave, narrow peaked symmetrical t wave, followed by reduced p wave and widening QRS complexby reduced p wave and widening QRS complex →→ ultimately goes toultimately goes to ventricular fibrillationventricular fibrillation • For mild hyperkalemia (<6 mEq/l) tx conservatively by reducing dailyFor mild hyperkalemia (<6 mEq/l) tx conservatively by reducing daily intakeintake • If K+ raise acutely above 6.0If K+ raise acutely above 6.0
  • TreatmentTreatment Mechanism of actionMechanism of action Time frameTime frame Intravenous calciumIntravenous calcium gluconategluconate Antagonize effects of hyperkalemiaAntagonize effects of hyperkalemia on the cell memberaneon the cell memberane Second to minSecond to min Glucose, insulin,Glucose, insulin, sodiumsodium bicarbonatebicarbonate Translocation of K into cellsTranslocation of K into cells 30-6- min30-6- min Rectally or orallyRectally or orally administered Kadministered K++ binding resinsbinding resins Binds and hastens excretion of KBinds and hastens excretion of K secreted into colonsecreted into colon 1-4 hr (rectal) >6 h (oral)1-4 hr (rectal) >6 h (oral) DialysisDialysis Movement across a concentrationMovement across a concentration gradient and excretedgradient and excreted immediateimmediate