COMPARISON OF LORAZEPAM ALONE VS LORAZEPAM, MORPHINE, AND PERPHENAZINE FOR CARDIAC PREMEDICATION

Purpose: To compare the effects of two premedication regimens on cardi orespiratory variables, sedation, and anxiety in patients scheduled fo r coronary artery bypass graft (CABG) surgery. Methods: This was a pro spective randomized, double-blind clinical trial. Sixty-eight patients were monitored for 1.5 hr before and 2.0 hr after premedication with lorazepam (0.03 mg . kg(-1) sl), morphine (0.15 mg . kg(-1) im), and p erphenazine (0.05 mg . kg(-1) im) [Group 1], or with lorazepam (0.03 m g . kg(-1) sl) and saline (1.5 ml im) [Group 2]. All were continuously monitored with a 12-lead ECGST monitors, respiratory inductive plethy smography RIP), digital pulse oximetry, intra-arterial blood pressure, and arterial blood gas analysis. Sedation and anxiety scores were als o recorded. Results: The incidence and duration of myocardial ischaemi a was low and similar in Groups 1 and 2. Patients in Group 1, but not in Group 2, had a greater number of events (P < 0.04) and duration (P < 0.02) of O-2 desaturation; higher PaCO2 (P < 0.001), and more haemod ynamic events (P < 0.006) after premedication when compared with basel ine. There was no difference in RIP or ECG variables between the two g roups. Following premedication, both groups reported reduced anxiety s cores and elevated sedation scores (P < 0.01), with sedation greater i n Group 1 than in Group 2 (P < 0.01). Conclusion: In CABG patients, pr emedication with lorazepam provides adequate anxiolysis and sedation, and the addition of morphine and perphenazine results in elevated PaCO 2, arterial haemoglobin desaturation and potentially adverse haemodyna mic changes.