Optimal positive end-expiratory pressure during robot-assisted laparoscopic radical prostatectomy

BACKGROUND: Increased intra-abdominal pressure during laparoscopic surgery causes cephalad displacement of the diaphragm, resulting in the formation of atelectasis, which can be overcome by positive end-expiratory pressure (PEEP). The aim of this prospective study was to investigate the level of optimal PEEP to maintain adequate arterial oxygenation and hemodynamics during robot-assisted laparoscopic radical prostatectomy (RLRP). METHODS: One hundred patients undergoing RLRP were randomly allocated to one of five groups (n = 20) (0, 3, 5, 7 and 10 cmH(2)O of PEEP). Hemodynamic variables and respiratory parameters were measured at baseline with the patient in the supine position; at 30 min, 1, 2, 3 and 4 h during CO(2) insufflation with the patient in the post-Trendelenburg position; and after deflation in the supine position with increasing PEEP. RESULTS: The PaO(2) levels and alveolar-arterial difference in oxygen tension (AaDO(2)) were improved in patients with PEEPs compared with patients in whom PEEP was not used. The application of PEEP (10 cmH(2)O) resulted in higher PaO(2) levels compared to those with lower PEEP levels, but excessive peak airway pressure (PAP) was sometimes observed. The application of a PEEP of 7 cmH(2)O resulted in similar PaO(2) levels without causing excessive PAP. There was a significant difference in central venous pressure between the groups, but there were no significant differences in heart rate, mean arterial pressure or minute ventilation between the groups. CONCLUSIONS: A PEEP of 7 cmH(2)O is associated with the greater improvement of PaO(2) and AaDO(2) without causing excessive PAP during RLRP.