Lower intra-abdominal pressure has no cardiopulmonary benefits during laparoscopic colorectal surgery: a double-blind, randomized controlled trial.

BACKGROUND: Higher intra-abdominal pressure may impair cardiopulmonary functions during laparoscopic surgery. While 12-15 mmHg is generally recommended as a standard pressure, the benefits of lower intra-abdominal pressure are unclear. We thus studied whether the low intra-abdominal pressure compared with the standard pressure improves cardiopulmonary dynamics during laparoscopic surgery.

METHODS: Patients were randomized according to the intra-abdominal pressure and neuromuscular blocking levels during laparoscopic colorectal surgery: low pressure (8 mmHg) with deep-block (post-tetanic count 1-2), standard pressure (12 mmHg) with deep-block, and standard pressure with moderate-block (train-of-four count 1-2) groups. During the laparoscopic procedure, we recorded cardiopulmonary variables including cardiac index, pulmonary compliance, and surgical conditions. We also assessed postoperative pain intensity and recovery time of bowel movement. The primary outcome was the cardiac index 30 min after onset of laparoscopy.

RESULTS: Patients were included in the low pressure with deep-block (n = 44), standard pressure with deep-block (n = 44), and standard pressure with moderate-block (n = 43) groups. The mean (SD) of cardiac index 30 min after laparoscopy was 2.7 (0.7), 2.7 (0.9), and 2.6 (1.0) L min-1  m-2 in each group (P = 0.715). The pulmonary compliance was higher but the surgical condition was poorer in the low intra-abdominal pressure than the standard pressure (both P < 0.001). Other variables were comparable between groups.

CONCLUSION: We observed few cardiopulmonary benefits but poor surgical conditions in the low intra-abdominal pressure during laparoscopy. Considering cardiopulmonary dynamics and surgical conditions, the standard intra-abdominal pressure may be preferable to the low pressure for laparoscopic surgery.