Ketamine infusion for postoperative analgesia in asthmatics: a comparison with intermittent meperidine.

Narcotics commonly used for postoperative analgesia may release histamine and cause bronchospasm in asthmatics. Ketamine, on the other hand, provides analgesia and has the additional advantage of preventing and relieving bronchospasm. We therefore delivered subanesthetic doses of ketamine in combination with midazolam (5.88-6.42 micrograms.kg-1.min-1 and 1.17-1.28 micrograms.kg-1.min-1, respectively), via an infusion for postoperative analgesia after elective abdominal hysterectomy in patients with asthma. Data were compared with those from a similar group of patients receiving conventional intramuscular meperidine. A significant degree and earlier onset of analgesia (P < 0.05) was achieved in the ketamine group. For other variables no significant difference was observed between the groups (P > 0.05). Ketamine-midazolam infusion can thus provide a safe alternative to the usual parenteral narcotic therapy in asthmatics, in terms of analgesia and patient acceptability.