electrolyte disorders in critically ill

7/30/2019 electrolyte disorders in critically ill

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Electrolytedisordersin

Criticallyillpatients

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6*3*,06/XFNQRZ,QGLD


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It is the internal environment (not the external world) that

provides the physical need for life

Ubaidur Rahaman, Senior Resident, CCM, SGPGIMS, Lucknow, India


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BODY FLUID COMPARTMENTSArrow represents fluid movement

Review ofMedical Physiology, William F. Ganong



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ElectrolyteCompositionofBodyFluidCompartments



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Compositionofbodyfluidslosingcontinuously

Source Daily Loss Na+ K+ Cl- HCO3-

Saliva 1000 30-80 20 70 30

Gastric 1000-2000 60-80 15 100 0Pancreas 1000 140 5-10 60-90 40-100

Bile 1000 140 5-10 100 40

Small Bowel 2000-5000 140 20 100 25-50

Large Bowel 200-1500 75 30 30 0

Sweat 200-1000 20-70 5-10 40-60 0

urine 1500-2000


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CompositionofIVfluidsincomparisontoPlasma

Fluid Na K Ca Mg Cl Buffers Glucose pH Osm

Plasma141 4.5 5 2 103

HCO3-26

Prot-160.7-1.1 7.4 290

NS 154 154 6.0 308

1/2NS 77 77 5.0 154

130 4 3 109 Lac-28 6.5 274

5%D 50 4.5 252

Plasmalyte140 5 3 98

Acet-27

Gluc-237.4 294

Gel

3%Saline 513 513 4.5 1026

5%Alb

20%Alb



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Sodium Water

disturbances



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Na is the most abundant molecule in ECFNa is the most osmotically active molecule in ECF

S. Osm ( mOsm/kg of water)

(2*[Na] + [Glucose/18] + [BUN/2.8]

Contribution of Gluc and BUN is

5 mOsm/L

Na in meq/L, Glucose in mg/dL, BUN in mg/dL)

Osmotic pressure and osmolality determinesdistribution of fluid in body compartments



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OSMOLALITY

280-295 mOsm/kg

Serum

Urine

24 hour urine sample-500-800 mOsm/kgExtreme range-50-1400mOsm/kg

Random urine sample- 300-900mOsm/kg

After overnight fluid restriction

Urine omolality > 3 times serum osmolality (>800)



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Real story in critically ill patients

S. Osm = 2* (140) + 90/18 + 5/2.8

= 280 + 5 + 1.7

= 286.7

S. Osm = 2* (145) + 180/18 + 60/2.8= 290 + 10 + 21

= 321



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Na WATER



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Na / water regulation

Thirst ADH RAA Kidney



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E idemiolo of electrol te disorder in ICU



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Intensive Care Medicine 2010, 36(2):304-11

Incidence and prognosis of dysnatremias present on ICU admission

Funk GC, Lindner G, Druml W, Metnitz B, Schwarz C, Bauer P, Metnitz PG

retrospective study in 77 medical, surgical, and mixed ICUs in Austria,

151,486 adults patients admitted over a period of 10 years (1998-2007).

75% patients had normal sodium levels (Na:135-145) on ICU admission

Incidence

hyponatremia-17.7%, Hypernatremia-6.9%

All types and grades of dysnatremia were associated with increased hospital mortality

independent mortality risk rising with increasing severity of both

hyponatremia and hypernatremia



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Critical Care 2008, 12:R162

The epidemiology of intensive care unit-acquired hyponatraemia

and hypernatraemia in medical-surgical intensive care unitsHenry Thomas Stelfox, Sofia B Ahmed, Farah Khandwala, David Zygun, Reza Shahpori, Kevin Laupland

8142 adults admitted in 3 medical-surgical ICUs Over 6 years

documented to have normal S. sodium levels (133 to 145 mmol/L) on

the first day of ICU admission

Incidence Hyponatremia- 11%, hypernatremia-26%

Median time to develop dysnatremia- 2 days

Median duration of dysnatremia-2 days

More than 1 distinct epi of dysnatremia- 25%

(Hyponatremia-16%, hypernatremia-19%)

hospital mortality increased significantly

Independent of SOI

( hypoNa-28%, hyperNa-34%, normoNa-16%)

Continued..Ubaidur Rahaman, Senior Resident, CCM, SGPGIMS, Lucknow, India


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and hypernatraemia in medical-surgical intensive care unitsHenry Thomas Stelfox, Sofia B Ahmed, Farah Khandwala, David Zygun, Reza Shahpori, Kevin Laupland

Continued..Ubaidur Rahaman, Senior Resident, CCM, SGPGIMS, Lucknow, India


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Increased risk of hypernatremia

Raised S.creatinine

Mechanical ventilation

Increased risk of both hyper and hyponatremia



and hypernatraemia in medical-surgical intensive care units

Henry Thomas Stelfox, Sofia B Ahmed, Farah Khandwala, David Zygun, Reza Shahpori, Kevin Laupland

Length of stay in ICU

Increased APACHE II score

Dysnatremias develop insidiously over 2 days

Difficult to identify as clinicians preoccupied with

more acute medical issues and other lab investigations



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Critically ill patients

prone toelectrolyte disturbances



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Disturbance in fluid and electrolyte homeostasissepsis, shock, cardiac failure, acute kidney injury, burn, surgery, C.N.S. disorders

Activation of neuro hormonal system- SNS, RAAS, Vasopressin

Non osmotic release of Vasopressin

pain, nausea, medication, hypovolemia Diuresisiotrogenic- renal and osmotic diuretics

Vasopressin deficiency in sepsis

Insensitivity to insensible losses

Impaired thirst mechanism

Inappropriate administration of fluid and electrolytes

Urea, glucose inducedHypokalemia, hypercalcemia

Drug induced- aminoglycoside, ampho B



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AmJKidneyDis2009Oct,54:674-679

tonicity balance in patients with Hypernatremia Acquired in the

Intensive Care UnitGregorL,NikolausK,UlrikeHolzinger,WilfredDruml,christiphschwartz

Solute balance= [Na+K]input [Na+K]outputContinued



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c

Urea/ glucose




Causes of ICU acquired hypernatremia

osmoti

DI

Nonoliguri

Addition of KCl to 0.9%saline led to positive solute balance in 27% patients

Hypertonic

Osm>150

Continued


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Positive solute balance contributed 56% cases

Primary reason was inadequate substitution of hypotonic losses

with isotonic or hypertonic fluids




m n um n n y x ng

inadequate intake of free water

Community acquired hypernatremia- hypovolemic hypernatria

ICU- euvolemic or hypervolemic hypernatremia

ContinuedUbaidur Rahaman, Senior Resident, CCM, SGPGIMS, Lucknow, India


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Characteristics of patientsContinued



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Characteristics of patients



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Patients admitted over 1 year

medical, surgical or neurological ICU

Renal dysfunction, Hypokalaemia, hypercalcemia, mannitol, sodium bicarbonate

hypernatremia 150 mmol/l in the ICU

Nephrol Dial Transplant 2008,23:1562-1568

Hypernatremia in critically ill patients: too little water and too much saltEwout J. Hoorn, Mecheil G.H.Betjes, Joachim Weigel, Robert Zietse

more common in cases

independently associated with hypernatraemia.

mortality was higher in case

Hypernatremia was independent predictor

Continued



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Approximately half of cases were polyuric, even when fluid balance was negative

+

Impaired thirst mechanism

Inappropriate iv fluid administration with isotonic fluids



Aim of treatment- negative solute balance

Hypotonic fluid may aggravate fluid overload

Diuretic may be considered:combination of loop diuretic and water or thiazide diuretic alone

Continued



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Potential factors contributing to hypernatremia

Page 1566





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Use of hypotonic fluid is avoided in ICU

Ca illar leakiness in se sis atients

Fear of hyponatremia as many patient show non osmotic release of

Vasopressin



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JUST ANANALYSIS



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NephrolDialTransplant2008,23:1562-1568

Hypernatremiaincriticallyillpatients:toolittlewaterandtoomuchsaltEwoutJ.Hoorn,MecheilG.H.Betjes,JoachimWeigel,RobertZietse

47-year-old male

(body weight 95 kg)

cystectomy complicated by

faecal peritonitis.

Tonicity balance illustrating mechanism of hypernatremia

large isotonic volume resuscitation,

+ hypertonic fluids (NaHCO3)

Water loss

Renal: renal insufficiency and

hyperglycaemianon-renal: wound drains and

colostomy



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IntensiveCareMed2001;27:921-924

Tonicitybalance,andnotelectrolytefreewatercalculations,moreaccuratelyguidetherapyforacutechangeinnatremia

A.P.C.P.Carlotti,D.Bohn,J.P.Mallie,M.L.Halperin

14 year old male

( weight 40 kg, total body water 24 L)

Operated for craniopharyngioma

During surgery

TBW* ( [S.Na] /140 ) - 1

excreted 4L in 9 hours

Over this period

P.[Na] rose from 140 to 157 meq/L

received 3 L of isotonic saline

His urine [Na+K] was 50 meq/L.

Free Water deficit: 24* [ (157/140) 1 ] = 2.9 L

2.9L

2.9L



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Intensive Care Med 2001;27:921-924

Tonicity balance, and not electrolyte free water calculations, more accurately

guide therapy for acute change in natremia

A.P.C.P. Carlotti, D. Bohn, J.P. Mallie, M.L. Halperin

4 L urine with 200meq Na= 1.3 L isotonic saline + 2.7 L of EFW



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Na

200 mmol

Tonicity balance



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1

3 situations with hypernatremia and negative balance of 2.7 L of EFW

2

3



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HYPERNATREMIA

True/ Relative water deficit

S. Na > 145 meq/L

Clinical manifestation

Lethargy, irritability, restlessness

Spasticity, hyperreflexia, seizure, coma

Death

Cerebral Hemorrhage/ ischemia

Insulin resistance, impaired gluconeogenesisCardiac dysfunction

Severity of symptoms correlate with rate and magnitude of change in [Na]



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Hypernatremia

Hypertonic saline load

NaHCO3, 3% saline

Hyperaldosteronism

Cushings syndrome

Primary

Na gain

HYPERVOLEMIA

Hypotonic

fluid loss

HYPOVOLEMIA

ISOVOLEMIA

Extra renal lossRenal loss

Diuresis

Osmotic

glucose, urea, mannitol, high osmolar feeds

Diuretics- frusemide, thiazide

Insensible loss

Fever, burn

Diabetes insipidusCDI

NDI

renal disease

Drugs- amphoterecin, aminoglycosides, lithium

Electrolyte disorders- hypokalemia, hypercalcemia

Azotemia out of proportion

to decrease in GFR

Catabolic patients with

Moderate renal

insuficiency on high

protein diet and stress

dose steroid



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Excretion ofsmall volume 800 mOsm/L)



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Hypernatremia

Urine volume

Hypotonic

fluid loss

>1000 ml


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HYPERNATREMIA

Correction

Risk : development of brain odema

Chronic hypernatramia- brain cells fully adapted

Risk is more

Acute hypernatremia: 1-2 meq/L/h ( 10-12 meq/L/day)

Chronic hypernatremia: 0.5 meq/L/h ( 8-10 meq/L/day)

GOAL

Na


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HYPERNATREMIA

Correction

TBW* ( [S.Na] /140 ) - 1

EFW deficit calculation (L)

Madias and Adrogue equation

Scan Page 74 JW LEE



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Mind it

Ongoing lossMust be considered

along with calculated water deficit

Formulas assume a closed system

Require separate account of ongoing losses

as



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70 kg women

Diarrhoea of volume 2 L/ day

S.[Na]= 160meq/L , S.[K]= 3.0meq/L

75 160 / (70*50) + 1 = - 2.3 meq/ L

Estimated change in S.[Na] with 1 L of N/2 saline

change of 10 meq/L = 4.3L of N/2 saline has to be given in 24 hours

But ongoing loss = 0.7 L + 2.0 L = 2.7 L / 24 hours

Total volume to be given

4.3 L + 2.7 L = 7.0 L / 24 hours



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Hypernatremia

Hypotonic fluid diuretic

Urine output < water replacement

HYPERVOLEMIAHypotonic

fluid loss

HYPOVOLEMIA

ISOVOLEMIA

Osmotic diuresis

Diabetes insipidus

Hemodynamically unstable

Correct volume with isotonic saline

Switch over to hypotonic fluid to

to correct Na

Remove / treat cause of DI

Replace losses with hypotonic fluid

CDI

Ddavp

NDI

low Na diet + thiazide low protein diet NSAID



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HYPERNATREMIA

summary of management

Hemodynamic unstable: resuscitate with isotonic fluid (0.9% saline or RL)

Switch over to hypotonic fluid once resuscitated

Hypovolemic hypernatremia:AIM- positive EFW and solute balance

isovolemic hypernatremia:AIM- positive EFW balance

Replace losses with Hypotonic fluid

Treatment of cause: DI

Hypervolemic hypernatremia:AIM- negative EFW and solute balance

Na restriction + Hypotonic fluid + frusemide

CDI: ADH analogue

dDAVP: 10-20 ug intranasal bd

or 1-2ug sc bd

NDI

remove/ correct causative agent

Thiazide/ indomethacin



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hypernatremia

Duration of h ernatremia

Absent/ mild neurologic signs

Na 155 me /L

Severe neurologic compromise

Initial acute management of

Na 2 days

Change in [Na] should not exceed

10 meq/L in first 24 hours



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DIABETES INSIPIDUS

Hypotonic urine in face of hyperosmolar plasma

CDI- Osm U


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HYP0NATREMIA

True/ Relative water excess

S. Na < 135 meq/L

Clinical manifestation

headache, nausea

lethargy, disorientation, restlessness

Muscle cramp, weakness, depressed reflexes, seizures, coma

Death

Chronic hyponatremia: developing over >48 hours

Adaptative mechanism minimize symptoms

Severity of symptoms correlate with rate and magnitude of fall in [Na]



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APP A H



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hyponatremia

Hypertonic HypoNaHyperglycemia

Hypertonic sodium free sol

(mannitol)

Hypotonic HypoNa

Isotonic HypoNaPseudohyponatremia

Hyperlipidemia

hyperproteinemia

Normal serum osmolality

low serum osmolality

high serum osmolality

Assess serum osmolality

hypotonic Hypovolemic

hyponatremia

Assess volume status

isovolemichypovolemic hypervolemic

hypotonic isovolemichyponatremia

hypotonic Hypervolemic

HyponatremiaCirrhosis

Congestive heart failure

Nephrotic syndrome

Renal falire

Discussed in next pages


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DiuresisOsmotic- glucose, urea, mannitol

Diuretics- thiazide, frusemide

Electrolytes-Hypokalemia, hypercalcemia

Drugs- aminoglycoside, ampho B

hypotonic Hypovolemic Hyponatremia

Adrenal deficiency

Mineralocorticoid deficiency

Renal

loss

LOSS

(both water and Na) = Negative water and Na balance

Salt wasting nephropathy

Cerebral salt wasting

GI lossnaso gastric aspirate,

abdominal Drains/ fistula

third space loss

(pancreatitis, ileus, obstruction)

Vomiting, diarrhea

Non renal

loss

Skin lossfever

open wounds,

burns

hemorrhage


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Acute psychosis

CNS disorders

Hypotonic Isovolemic Hyponatremia

Drug inducedOpiods

NSAIDS

Antipsychotics- haloperidolSSRI- fluoxetine, sertraline

Pain, nausea, stress

SIADH

Impaired free water loss in urine

Normal Na loss in urine

hypothyroidism

TCA

Carbamezapine

antineoplasticsPulmonary disease

Infections

malignancy

Cortisol deficiency


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CORRECTION


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PRECAUTION IN CORRECTION

Absolute magnitude of correction in 24 hoursmore important than rate

central pontine myelinosis

Initial rapid rate of correction tapering off after several hours

incurs less risk

than

slow steady correction that exceeds 12 meq/L in 24 hours

Increased risk

Hypoxemia, hypokalemia, malnutrition, alcoholism



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HYPONATREMIA

1-2 meq/L/h ( 10-12 meq/L/day)

Rate of correction

Symptomatic

or

Acute hyponatremia(change >0.5 meq/L/h or onset in < 48 hours)

0.5 meq/L/h ( 8-10 meq/L/day)Chronic hyponatremia

(Change over > 48 hours or unknown duration)

Increased risk of CPM

as adaptive mechanism has occured

120-130 meq/L

Lower iin patients with s.Na


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Any saline solution that is hyperosmolar to urine can increase [Na]

when

oral water intake is restricted

Mind it

RULE FOR CORRECTION

A crystalloid with an osmolarity less than urine osmolarity

may actually worsen hyponatremia,

even if the fluid [Na] is greater than serum [Na]

CONTINUED.



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Gain of 154 mOsm will be lost in 300 ml urine

Gain of 700 ml of EFW

(154* 1000/500= 300 ml, OsmU > 500)

60 years male, febrile encephalopathyBody weight: 60 kg, TBW: 36 L

Develops SIADH

S.[Na]= 118, urine Osm > 500 mOsm/L

Given 1 L of 0.9% saline

ONE RULE FOR CORRECTION

Na=154

Water=1000

Na=0

water= 700 Water= 300

Na=154

Na=115

Na=118

Simultaneous IV loop diuretic can counteract this phenomenonBy promoting free water excretion



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HYPONATREMIACALCULATION OF [Na] deficit

TBW* ( 140 s.Na)

Na deficit (meq)

Anticipated change in s.Na with 1L of fluid(Madias and Adrogue equation)

Scan Page 74 JW LEE



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HYPONATREMIA

Remove or treat cause

of hypertonicity

Hypertonic HypoNaHyperglycemia

Hypertonic sodium free sol

(mannitol)

Repeat lab

Use newer method of lab

Isotonic HypoNaPseudohyponatremia

Hyperlipidemia

hyperproteinemia

Fluid shift to ICF compartment does not take placeNeuronal cell swelling does not occur



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hypotonic hyponatremia

Primary polydypsia

Beer potomania

Post TURP

urine osmolality 100 mOsm/L

Urine [Na]

20meq/L

Renal loss Non renal loss

TreatmentcIsotonic saline to correct hypovolemia

Correct hypokalemia if present

hypervolemic

IsovolemicContinued

on next page

Continued.



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hypotonic hyponatremia

Assess volume status

Urine [Na]Urine [Na]

hypervolemic

urine osmolality > 100 mOsm/L

Urine [Na]

Isovolemic

20meq/L

Renal failure

Cirrhosis

Congestive heart failure

Nephrotic syndrome

EFW restriction

(restriction less than urine output)

>20meq/L

SIADH

Hypothyroidism

Cortisol deficiency,

Administer

saline with osmolality more than urine osmolality

Loop diuretic

ADH antagonist

Treat underlying disease

Stop drug causing increased ADHsecretionCorrect hypokalemia if present

TREATMENT



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HYPONATREMIA

summary of management

Replace calculated Na deficit with isotonic saline or RL

hypotonic Hypovolemic hyponatremiaAIM- positive water and Na balance

hypotonic isovolemic hyponatremia

AIM- negative EFW and positive Na balance

Symptomatic

frusemide ivi + 3% saline

Asymptomatic

Water restriction Intermittent frusemide enteral salt

hypotonic Hypervolemic hyponatremia

AIM- negative EFW and Na balance

Na and EFW restriction + frusemide

ADH antagonist( for chronic SIADH as delayed onset of action)

demeclocycline HCL: 600-1200mg PO daily

Phenytoin sod: 200-300mg PO daily

Lithium: 600-1200mg PO daily



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hyponatremia

Duration of h onatremia

Absent/ mild neurologic signs

Na < 125 me /L

Severe neurologic compromise

Initial acute management of

Na >125 me /L

Search for alternative cause

of neurologic compromize

3% saline ivi

Initial goalincrease [Na] by 1.5-2.0 meq/L/h

for 3-4 hours or until symptoms resolve Change in [Na] can occur rapildlyImmediate attainment to normalIs not goal

< 2 days

> 2 days

Change in [Na] should not exceed

10 meq/L in first 24 hours and

18 meq/L in first 48 hours



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SOLUTION=SOLUTE+SOLVENT

Molality: number of moles of a solute perkilogram of solvent

Molarity: number of moles of solute per litre of solution

Osmolality: number of osmoles of solute per kilogram of solvent

Tonicity = effective osmolality

sum of the concentrations of the solutes which have the capacity to exert anosmotic force across the membrane.



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Free water (FW)Calculated base on osmolality

(Na, Glucose, BUN)

As urea is freely permeable across all cell membraneDoes not contribute to effective osmolality ie tonicity

Electrolyte free water (EFW)Calculation based on S.[Na}

Modified Electrolyte free water (MEFW)Calculation takes into consideration Glucose along with s.[Na]



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hank You

electrolyte disorders in critically ill

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