[Severe hypotension during anesthesia in a patient on long-term antidepressant therapy]

A 71-year-old woman on chronic therapy with mianserine and amantadine was scheduled to undergo abdominal hysterectomy under spinal anesthesia. Following spinal anesthesia she developed hypotension refractory to continuous intravenous fluid infusion as well as multiple boluses of ephedrine. Because the maximum level of analgesia was T 8, general anesthesia was added using laryngeal mask airway. Immediately after anesthetic induction, a marked hypotension occurred. Blood pressure again did not respond to ephedrine but went up excessively to a small dose of epinephrine without any changes in heart rate. Epinephrine infusion at a low dose rate was needed to sustain the blood pressure during surgery. Both depletion of presynaptic norepinephrine store and down-regulation of postsynaptic beta-receptor may have led to abnormal response to catecholamines in this case.