Fluids and Electrolytes

JAMES ZENGFLUIDS AND ELECTROLYTES

COMPLICATED?

SIMPLE?

BODY COMPARTMENTSIntracellular 30LExtracellular 15LNaKInterstitial 12LPlasma 3L

REPLACEMENTLostOngoing lossesMaintenance

SOURCES OF LOSSRenalGISkinHaemorrhageThird Space

BASAL FLUIDS

1.6L

Urine 500 Stool 200Skin 500Lungs 400

BASAL ELECTROLYTES

Na2mmol/kg/d (140mmol)

K1mmol/kg/d (70mmol)

INPUT

PARENTERAL FLUIDSCrystalloidsAqueous solutionsSolutes in water

normal saline, 5% dextrose, 4% and 1/5, hartmanns (CSL)

ColloidsLarger insoluble moleculesHigh oncotic pressure

Albumin, Synthetics (gelofusine, pentastarch), blood

COMPOSITION OF FLUIDS

FluidOsmolpHNaClKCaOtherSerum2907.414010041.2CSL2786.51301094328 lacNS30851541545%277450g gluc4%+1/5284313140g glucGelo3087.4154125

25yo maleMBA. Weber C # (nothing else)Theatre some time tomorrow.

SIMPLE

REPLACEMENTLostOngoing lossesMaintenance

30yo female. Stabbed a few times. HR120. BP80/60. Conscious. For theatre.

A BIT HARDER

REPLACEMENTLostOngoing lossesMaintenance

ESTIMATING BLOOD LOSS

IIIIIIIV

BACK TO THE STABBINGReplace!

2x 16G1+1L StatConsider blood products

74yo ladyLBODifficult hartmannsx2 PRC intraopHb 90IHD, diabeticD2 post opUO 15mL

MORE COMPLICATEDLostLost

REPLACEMENTLostOngoing lossesMaintenance

WHOA!Is she dry?

If dry, how much?

How do I give it?

Monitoring?

HISTORYDry

ThirstWeaknessDizzinessWet

SOBSOADistension

EXAMLook at the chart, fasting status.

Arterial (dry)Hr, bp (postural), urine output trend, GCS

Venous (wet)JVP, Chest, ascites, oedema

TESTS?

Not really useful acutely

Worth doing for monitoring

SO WHAT DO I DO?Is she dry?

If dry, how much?

How do I give it?

Monitoring?

DRY?Maintenance1.5L/dLost~1L Blood, probably replacedCorrect any imbalances, estimate hydration statusOngoingProbably increased in third space

WET?

Poor renal perfusionPump failure, sepsis, drugsRenalDrugs, ATN, GNPost renal

HYPONATRAEMIADryExcessive loss of sodium containing fluidsRenal, GI, skinGive slow replacementWet (or normal)Inappropriate free water retentionSIADH (central, peripheral)CirrhosisCCFRestrict fluidTreat cause

HYPERNATRAEMIADry (or normal)Excess free water lossDiabetes insipidus (central or peripheral)Loss from GI and skinReplace free waterWetInappropriate sodium retentionHyperaldosteronism (adenoma, poor perfusion, low oncotic pressure)Renal failureTreat cause

HYPERKALAEMIAShift from cellsAcidosis, Rhabdo, tumour lysisInappropriate retentionHypoaldosterone, addisons, drugs

Fatal arrythmiasSmall P, tented Ts, sinusoidal rhythm

HYPERKALAEMIACa carbonate 10mL 10% centrallyInsulin 10U (50ml 50% dextrose)BicarbSalbutamolRisoniumDialysis

HYPOKALAEMIAUsually lost somewhere (GI, renal) or redistributed (alkalosis)

Replacement (oral or IV)Also replace Mg

*Some physiology, conceptsPractical things*1. NaKATPase2. capillary membrane3. permiability to electrolytes*Colloids should stay in the vesselsNo evidence *Ns has enough sodium and fluid in about 2 bags No potassiumCsl doesnt either!*Fit youngNot much lossMaybe some swelling for ongoing lossesFast for a day or twoCouple of bags of whatever, give some K

*Fit youngNot much lossMaybe some swelling for ongoing lossesFast for a day or twoCouple of bags of whatever, give some K

***Occult blood lossChestAbdomenPelvisOn the floor*Remember to do some testCoags and xmatch*****Something in the order of 250-500mLsGive slightly more than basal requirements over the next 24hrs, 2-2.5L (10hr bags)Monitor electrolytes**