Anesthesia Considerations 

SIADH

 

 

 

Considerations

 

• Hyponatremia:

  • ​Cerebral edema

  • ​Seizures

  • Coma

  • Respiratory arrest

• Associated conditions:

  • Tumours (lung, pancreas, prostate, lymphoma)

  • CNS insult (trauma, subarachnoid hemorrhage, tumour, infection)

  • Pulmonary (infection, cystic fibrosis, positive pressure ventilation)

  • Medications (opiates, oxytocin, chlorpropamide, vincristine)

  • Postoperative ADH secretion 

  • Idiopathic

  • Iatrogenic (hypotonic IV solutions)

 

 

Treatment

 

• Free water restriction

• Eliminate underlying cause

• Caution with rapid correction of serum sodium (central pontine myelinolysis)

 

 

Goals

 

• Preoperative correction of serum electrolytes when possible to target sodium >125

• Avoid overcorrection or overly rapid correction resulting in central pontine myelinolysis

• Correct underlying reversible etiologies (infection, tumour, medications, iatrogenic)

 

Management

 

• Restore sodium concentration

• Generally restrict free water (500mL-1L/day) 

• +/- loop diuretic 

• Acute:

  • Severe hyponatremia (<120mEq/L or neuro symptoms)

    • Hypertonic saline 3% 1-2 ml/kg/hr until sodium >125

    • Furosemide

    • Sodium bicarbonate (1 mEq/ml) to terminate seizures: 0.5-1mL/kg boluses prn

• Chronic:

  • Avoid rapid overcorrection (0.5-1 mEq/hr, <8 in mEq in 24hrs)

  • Demeclocycline 300-600 mg PO bid (antagonizes ADH at collecting duct)

  • Conivaptan = vasopressin receptor antagonist