RESPIRATORY MONITORING DURING POSTOPERATIVE ANALGESIA

Respiratory monitoring, using a novel flow sensor based on an acoustic principle, has been investigated in 30 patients during postoperative analgesia. Each patient was subjected to monitoring and human observat ion for 8 hr. The study was performed by independent observers at thre e clinics. Significant correlation was noted between respiratory rate (RR) determined by the sensor and the observers. Recordings of respira tory duration index (RDI), breathing time intervals (BTIs) indicated h igh sensitivity of the instrument to respiratory depression and pertur bations in the breathing rhythm. More than 800 apnea alarms were noted , using an alarm setting of 30 sec; 61% of the categorized alarms were noted by the observers as true apneas. From the recordings it was sho wn that the number of alarms can be reduced by a factor of four if the alarm setting is changed to 45 sec. We conclude that the suggested te chnique, with slight modifications, provides adequate respiratory moni toring of patients during postoperative analgesia.