Early detection of opiate-induced respiratory depression in the postoperative phase]

We examined in 30 patients the efficacy of regular assessments of respiratory rate (every 15 minutes) and blood gas analysis (at 30, 60, 120, 180 minutes) and continuous monitoring via pulsoximeter and capnometer in recognizing early ventilatory problems. For postoperative analgesia the patients received randomly and double-blind patient-controlled intravenous or epidural analgesia with sufentanil. Within 15 minutes after the initial intravenous bolus injection of 15 micrograms sufentanil respiratory depression occurred in 4 patients. This was alerted by the Oscar-CO2-Monitor and -Pulsoximeter. Oxygen saturation time patterns of pulsoximetry and blood gas analysis correlated significantly (p < 0.001), although the mean values of the methods differed (NS). In contrast, carbon-dioxide pressure time patterns of capnometry and blood gas analysis correlated less significantly (p < 0.01) although the mean values of the methods correlated significantly (p < 0.01). Concomittant monitoring via pulsoximeter and capnometer is therefore superior to regulary assessments of respiratory rate and blood gas analysis and potentially useful for the clinical routine.