Fluid and electrolyte emergencies in critically ill

patients

Fluid and electrolyte emergencies in critically ill

patients

Dr.V.P.CHANDRASEKARANHOD, Dept. of Emergency & Critical

Care Medicine, VMKVMC , Salem

IntroductionIntroduction

• Total body water (60%)

• Two third is intracellular fluid (40%)

• One third is extra cellular fluid (20%)

- Interstitial fluid (15%)

- Intravascular fluid (5%)

Fluid shifts

INTRACELLULAR 30 LIT

INTERSTITIAL 9 LIT IV 3 LIT

EXTRACELLULAR

mEq/L ICF ECFPlasma Interstitial

15 142 144150 4 42 5 2.527 3 1.5

1 103 11410 27 30100 2 220 1 1- 5 563 16 6

150

Na+

K+

Ca2+

Mg2+

Cl-

HCO3-

HPO42-

SO42-

Organic acid

Protein

142

OsmolarityOsmolarity

Measurement of the total solutes in a water

solution per liter.

Osmolarity = [sodiumx2

]+urea/2.8+glucose/18

Serum osmolarity is 280-300 mOsm/L

280-300 mOsmol/L- Isotonic

> 300 mOsmol/L – Hypertonic

< 280 mOsmol/L - Hypotonic

2 litres of

blood

3 litres9 litres30 litres

30 litres 9 litres 5 litres

2 litres of

colloid

30 litres 9 litres 3 litres

30 litres 9 litres 5 litres

29 litres 8 litres 7 litres

30 litres 9 litres 3 litres

2 litres of

0.9% saline

30 litres 9 litres 5 litres

29 litres 10.5 litres 4.5 litres

30 litres 9 litres 3 litres

2 litres of 5%dextrose

31 litres 9.7 litres

3.3 litres

Basic principles of fluid therapy

Basic principles of fluid therapy

Replace Replace

Maintain Maintain

Repair Repair

Abnormal loss: GIT, 3rd space,Ongoing loss, septic and Hypovolemic shock

Abnormal loss: GIT, 3rd space,Ongoing loss, septic and Hypovolemic shock

Insensible water loss + urine Insensible water loss + urine

Acid base, electrolyte imbalancesAcid base, electrolyte imbalances

The rules of fluid replacementThe rules of fluid replacement

• Replace blood with blood

• Replace plasma with colloid

• Resuscitate with colloid / crystalloid

• Replace ECF depletion with saline

• Rehydrate with dextrose

Case ScenarioCase Scenario

• 45 yr old was brought to ER with h/o loose stools & vomiting since 2 days

• Drowsy and lethargic with signs of severe dehydration, BP-80/50 , PR-120

What is initial fluid of choice?

• Isotonic saline / Ringer’s lactate

• No dextrose containing fluid initially

Case Study #1

• HPI:• A 55 year old man is in the Neuro ICU for acute

non hemorrhagic stroke.

• Hospital course: • Decreasing urine output (< 0.5 ml/kg/hr) over the

last 24 hours. What is your differential diagnosis?

What diagnostic studies would you order?

Case Study #1

Differential diagnosisCase Study #1

Differential diagnosis

Oliguria

1) Pre-Renal (decreased effective renal blood flow)

Diminished intravascular volume, cardiac dysfunction, vasodilatation

2) Post-Renal

Outlet obstruction (intrinsic vs. extrinsic), foley catheter occlusion

3) Renal

Acute tubular necrosis, acute renal failure, SIADH, ...

Case Study #1

Laboratory studiesSerum studiesSodium 120 mEq/L BUN 4 mg/dLChloride 98 mEq/L Creatinine 0.4 mg/dLPotassium 3.7 mEq/L Glucose 129 mg/dLBicarbonate 25 mEq/L Osmolality 260

mosmol/kgUrine studiesSpecific gravity 1.025 Sodium 58 mEq/LOsmolality 645 mosmol/kg

What are the primary abnormalities?

Case Study #1

Laboratory studiesMajor abnormalities

1) Hyponatremia2) Oliguria (inappropriately concentrated urine)

What is the most likely explanation for these findings?

Case Study #1 Syndrome of Inappropriate

Antidiuretic Hormone (SIADH)

• Variable etiology• Trauma• Infection• Psychosis• Malignancy• Medications• Diabetic ketoacidosis• CNS disorders• Positive pressure ventilation• “Stress”

Case Study #1 SIADH

Case Study #1 SIADH

• Manifestations• By definition, “inappropriate” implies having

excluded normal physiologic reasons for release of ADH:

• 1) In response to hypertonicity.• 2) In response to life threatening hypotension.

• Hyponatremia• Oliguria• Concentrated urine

• elevated urine specific gravity• “inappropriately” high urine osmolality in face

of hyponatremia• Normal to high urine sodium excretion

Case Study #1 SIADH

Case Study #1 SIADH

• Diagnosis• Critical level of suspicion.

• Demonstration of inappropriately concentrated urine in face of hyponatremia

urine osmolality, SG, urine sodium excretion

• Be certain to exclude normal physiologic release of ADH

• Rule out hypothyroidism, hypoaldosteronism, renal failure or diuretic therapy before diagnosing SIADH.

Case Study #1 SIADH

• Treatment• Fluid restriction

• Avoid hypotonic fluids

• Hypertonic saline / oral sodium chloride

• Frusemide.

Case Study #1

The saga continues….

Hospital course:

Four hours after beginning fluid restriction,

you are called because the patient is having a

generalized seizure. There is no response to

two doses of IV lorazepam and a loading dose

of fosphenytoin

What is the most likely explanation?

Case Study #1

The saga continues

Seizure

1) Worsening hyponatremia

2) Intracranial event

3) Meningitis

4) Other electrolyte disturbance

5) Medication

6) Hypertension

What diagnostic studies would you order?

Case Study #1

The saga continues

Stat labs:

Sodium 110 mEq/L

What would you do now?

Case Study #1 Hyponatremic seizure

• Treatment • Hypertonic saline (3% NaCl) infusion

• To correct sodium to 125 mEq/L, the deficit is equal to

0.6 X weight[kg] X (125 - measured sodium)

0.6 X 60 X (125-110) = 54O mEq

Newer methodNewer method• Calculation of expected change of Na with 1 litre of 3%

NaCl

• Change in S.Na+ concentration = infusate Na/L – S.Na

total body water + 1

• = 513 – 110 / 0.6 x 60 +1

• = 403 / 37 = 10.9 mEq/L

• To raise 4 mEq/L of Na, amount of 3% NaCl required is 366 ml ( 4/10.9 x 1000 = 366 ml )

• Required rate of infusion of 3% NaCl is 366/4 = 92 ml/hr

Case Study #2

HPI:

A 5 month-old girl presents with a one day history of irritability and fever. Mother reports three days of “bad” vomiting and diarrhea.

Home meds:

Paracetamol and ibuprofen for fever

PE:

BP 70/40, HR 200, R 60, T38.3 C. Irritable, sunken eyes and fontanelle.

Case Study #2Case Study #2

No one can obtain IV access after 15 minutes, what would you do now?

Case Study #2

Place intraosseous lineBolus 40 ml/kg of isotonic saline

Reassessment (HR 170, RR 40, BP 75/40)

Serum studiesSodium 164 mEq/L BUN 75 mg/dL

Chloride 139 mEq/L Creatinine 3.1 mg/dL

Potassium 5.5 mEq/L Glucose 101 mg/dL

Bicarbonate 12 mEq/L

pH 7.07 pCO2 11

pO2 121 HCO3 8

Case Study #2Case Study #2

What is the most likely explanation of

this patients acidosis?

Case Study #2

Metabolic acidosis and the anion gap

Case Study #2

Metabolic acidosis and the anion gap

Anion Gap

Sodium - (chloride + bicarbonate)

Normal 12 +/- 2 meq/L

Elevated anion gap consistent with excess acid

Normal anion gap consistent with excess loss of base

164 - (139 + 12) = 13

1. Normal gap 2. Increased gap

1. Renal “HCO3” losses

2. GI “HCO3” losses

Proximal RTA Distal RTA Diarrhea

1. Acid prod 2. Acid elimination

LactateDKAKetosisToxins Alcohols Salicylates Iron

Renal disease

Case Study #2

Metabolic acidosis and the anion gap

Case Study #2

Metabolic acidosis and the anion gap

Case Study #2

Treatment of HypernatremiaCase Study #2

Treatment of Hypernatremia

• To stop ongoing fluid loss

• To correct water deficit

= plasma Na – 140 x 0.6 x body wt. in kg

140

• Water deficit can be replaced with water by mouth or IV 5% dextrose or 0.45% NaCl

Case Study #3

• HPI:

• A 50 year old man was involved in a motor vehicle accident two days ago. He sustained an isolated head injury with intraventricular hemorrhage and multiple large cerebral contusions. Three hours ago, he had an episode of severe intracranial hypertension (ICP 90mm Hg, MAP 50mm Hg, requiring volume plus epinephrine infusion for hypotension. Over the last two hours, his urine output has increased to 150 - 200 ml/hour

What is your differential diagnosis?What test would you order?

Case Study #3

Differential diagnosisCase Study #3

Differential diagnosisPolyuria

1) Central diabetes insipidusDeficient ADH secretion (idiopathic, trauma, pituitary

surgery, hypoxic ischemic encephalopathy)

2) Nephrogenic diabetes insipidusRenal resistance to ADH (X-linked hereditary, chronic

lithium, hypercalcemia, ...)

3) Primary polydipsia (psychogenic)Primary increase in water intake (psychiatric),

occasionally hypothalamic lesion affecting thirst center

4) Solute diuresisDiuretics (lasix, mannitol,..), glucosuria, high protein

diets, post-obstructive uropathy, resolving ATN, ….

Case Study #3

Laboratory studiesSerum studiesSodium 155 mEq/L BUN 13 mg/dLChloride 114 mEq/L Creatinine 0.6 mg/dLPotassium 4.2 mEq/L Glucose 86 mg/dLBicarbonate 22 mEq/L Serum osmolality: 320 mosmol/kg

OtherUrine specific gravity 1.005, no glucose.Urine osmolality: 160 mosmol/kg

What are the main abnormalities?

Case Study #3

Laboratory studies

Major abnormalities

1) Hypernatremia2) Polyuria (inappropriately dilute urine)

What is the most likely explanation?

Case Study #3

Diabetes InsipidusDiagnosis

Central Diabetes insipidus

1) Polyuria2) Inappropriately dilute urine (urine osmolality < serum osmolality)

May be seen with midline defectsFrequently occurs in brain dead patients

What should you do to treat this patient?

Case Study #3

Diabetes Insipidus

• Treatment

• ADH preparations - dDAVP nasal spray

• Potentiate ADH effect – chlorpropamide, carbamazepine, NSAID’s.

• Increase ADH release – Clofibrate

Warning

• Closely monitor for development of hyponatremia

Case Study #4

• HPI:

• An 35 year old lady with Chronic kidney disease presents with irritability. She is on nightly peritoneal dialysis at home. The lab calls a panic potassium value of 7.1 meq/L. The tech says it is not hemolyzed.

What do you do now?

Case Study #4

Hyperkalemia• Treatment

• Immediately repeat serum potassium. Do not wait for confirmatory labs especially if

ECG changes present.

• Anticipatory Stop potassium administration including

feeds

ECGECG

• What is this rhythm?• What is your immediate treatment?

Case Study #5

Hyperkalemia• Treatment (cont)• Control effects

• Antagonism of membrane actions of potassium10% Calcium gluconate 10-20 ml over 5 - 10 minutes;

may repeat x2

• Shift potassium intracellularly Glucose 1 gm/kg plus 0.1 unit/kg regular insulin Alkali therapy - Sodium bicarbonate 1 mEq/kg IV Inhaled 2 adrenergic agonist

• Removal of potassium from the bodyLoop / thiazide diureticsCation exchange resin: sodium polstyrene sulfonate

(Kayexelate) 1 gm/kg PO or PR (or both)Dialysis

Case Study #5

• HPI:

• A three year old boy is recovering from septic shock. He received 150 ml/kg in fluid boluses in the first 24 hours and has anasarca. You begin him on a frusemide infusion for diuresis. He develops severe weakness and begins to hypoventilate. You notice unifocal premature ventricular beats on his cardiac monitor.

What is your differential diagnosis?

What tests would you order?

Case Study #6

Laboratory studiesSerum studiesSodium 134 mEq/L BUN 11 mg/dLChloride 98 mEq/L Creatinine 0.4 mg/dLPotassium 2.4 mEq/L Calcium 9.2 mg/dLBicarbonate 27 mEq/L Phosphorus 3.2 mg/dL

OtherECG: Unifocal PVC’s

What is the main abnormality?

Case Study #6

Laboratory studies

Major abnormality

1) Hypokalemia

What would you do now?

Case Study #6

Hypokalemia

• Treatment• Oral

• Safest, although solutions may cause diarrhea• IV

• do not exceed 40 mEq/L or 10 – 20 mEq/hr potassium.

- never give inj.Kcl directly intravenously.never give inj.Kcl directly intravenously.

• Replace magnesium also if low

• (25-50 mg/kg MgSO4)

Summary

• Disorders of sodium, water, and potassium regulation are common in critically ill children

• Diagnostic approach must be considered carefully for each patient

• Strict attention to detail is important in providing safe and effective therapy