THE INFLUENCE OF CONTROLLED MANDATORY VENTILATION (CMV), INTERMITTENTMANDATORY VENTILATION (IMV) AND BIPHASIC INTERMITTENT POSITIVE AIRWAYPRESSURE (BIPAP) ON DURATION OF INTUBATION AND CONSUMPTION OF ANALGESICS AND SEDATIVES - A PROSPECTIVE ANALYSIS IN 596 PATIENTS FOLLOWING ADULT CARDIAC-SURGERY

The aim of the study was the determination of the influence of ventila tion modes on the consumption of analgesics and sedatives, duration of intubation and pulmonary gas exchange. Assist/controlled mandatory ve ntilation (S-CMV, 123 patients), synchronized intermittent mandatory v entilation (S-IMV, 431 patients) and biphasic positive airway pressure ventilation (BIPAP, 42 patients) were compared in a prospective, cont rolled, open clinical trial over an 18-month period. Five hundred and ninety-six adult patients with normal pulmonary function before surger y and uneventful course following coronary artery bypass graft surgery were studied. Patients ventilated with BIPAP had a significantly shor ter mean duration of intubation (10.1h, P<0.05) than patients treated with S-IMV (14.7 h) and S-CMV (13.2 h). In the S-CMV group, 39.9% of t he patients required single or multiple doses of midazolam, but only 1 3.5% in the S-IMV group and 9.5% in the BIPAP group. The mean total am ount of midazolam administered to these patients was significantly hig her in the S-CMV group (8.8 mg) than in the S-IMV group (6.6mg, P<0.05 ) and in the BIPAP group (4.3 mg, P<0.05). The consumption of pethidin e and piritramide did not differ between S-CMV and S-IMV, but was sign ificantly lower during BIPAP (P<0.05). After extubation the patients' PaCO2 was highest in the S-CMV group. We conclude that ventilatory sup port with BIPAP reduces the consumption of analgesics and sedatives, a nd the duration of intubation. The possibilty of unrestricted spontane ous breathing in all phases of the respiratory cycle is considered to be the reason. BIPAP seems to be an alternative to S-CMV and S-IMV in short-term ventilated patients.