Electrolytes DisturbancesJamal A. Alhashemi, MBBS, MSc, FRPC, FCCP, FCCM

Professor of Anesthesiology & Critical Care MedicineFaculty of Medicine, King Abdulaziz University

Principles of Electrolyte Disturbances

Implies an underlying disease process Treat the electrolyte change, but seek the underlying causeClinical manifestations usually not specific to a particular electrolyte change, e.g., seizures, arrhythmias

Principles of Electrolyte Disturbances

Clinical manifestations determine urgency of treatment, not laboratory values

Speed and magnitude of correction dependent on clinical circumstances

Frequent reassessment of electrolytes required

Hypokalemia

Etiology – renal loss, extrarenal loss, transcellular shift, decreased intakeManifestations – cardiac, neuromuscular, gastrointestinalDeficit poorly estimated by serum levels

Hypokalemia

Titrate administration of K+ against serum level and manifestations

Correct hypomagnesemia

ECG monitoring with emergent administration

Allowable maximum iv dose per hour controversial

Treat hypokalemia urgently in acidosis

Hypokalemia

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Hyperkalemia

Etiology – renal failure, transcellular shifts, cell death, drugsManifestations – cardiac, neuromuscular

Hyperkalemia – Treatment

Stop intakeGive calcium for cardiac toxicityShift K+ into cell – glucose + insulin, NaHCO3, inhaled -agonist

Remove from body – diuretics, sodium polystyrene sulfonate, dialysis

Hyperkalemia

Hyponatremia

Hypo-osmolar hyponatremia Euvolemic Hypovolemic Hypervolemic

Normo- or hyperosmolar hyponatremia Pseudohyponatremia

Manifestations – neurologic, muscular, gastrointestinal

Hyponatremia – TreatmentHypovolemic Na – give normal saline, rule out adrenal insufficiencyHypervolemic Na – increase free water lossEuvolemic hyponatremia Restrict free water intake Increase free water loss Normal or hypertonic saline

Correct slowly due to possibility of demyelinating syndromes

Hyponatremia

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Hypernatremia

Etiology – H2O loss, H2O intake, Na intake

Manifestations – neurologic, muscular

H2O deficit (L) =

[ 0.6 wt (kg) ] [ obs Na - 1 ] 140

Hypernatremia – Treatment

Provide intravascular volume replacement

Consider giving one-half of free H2O deficit initially

Reduce Na cautiously: 0.5-1.0 mmol/L/hr

Secondary neurologic syndromes with rapid correction

Hypernatremia

Other Electrolyte DeficitsCa, PO4, Mg

May produce serious but nonspecific cardiac, neuromuscular, respiratory, and other effectsAll are primarily intracellular ions, so deficits difficult to estimateTitrate replacement against clinical findings

Other Electrolyte Disorders

Hypocalcemia Calcium chloride or gluconate Bolus + continuous infusion

Hypercalcemia Rehydration with normal saline Loop diuretics

Other Electrolyte Disorders

Hypophosphatemia IV replacement for level < 1 mg/dL (0.32

mmol/l)Hypomagnesemia Emergent administration over 5–10 mins Less urgent administration over

10–60 mins