Ketamine infusions

Over 200 patients undergoing major surgical procedures (body surface operations not requiring tracheal intubation or abdominal surgery requiring muscle relaxants and controlled ventilation). Detailed analysis limited to 70 patients with minimum operating time of 30 minutes. Excluded: hypertension, history of cerebrovascular accident, or known psychiatric upset.

Lorazepam 4 mg premedication (IV or oral), followed by ketamine induction (1 mg/kg) and maintenance infusion (1 mg/ml in 5% dextrose or balanced salt solution), with supplementary ketamine 0.25 mg/kg as needed.

Dosage requirements and cardiovascular effects