The purposes of this study is to investigate the effects of moderate vs. deep neuromuscular block on respiratory mechanics and biotrauma in patients with intraoperative protective lung ventilation for laparoscopy.

Mechanical ventilation results in the disruption of the alveolar-capillary barrier and increased permeability, a hallmark of experimental ventilator-induced lung injury. These mechanical forces also induce an increase in the concentrations of inflammatory cytokines.

The benefits of deep neuromuscular blocks for laparoscopic procedures are controversial and most of the studies undertaken have only sought to improve surgical conditions. Theoretically, deep neuromuscular block permits a lower abdominal insufflation pressure, which leads to better respiratory mechanics and gas exchange. The investigators examined the effects of moderate vs. deep neuromuscular block on respiratory mechanics and biotrauma in patients with intraoperative protective lung ventilation for laparoscopy. The investigators hypothesized that deep neuromuscular block (PTC 1 or 2) and low pressure pneumoperitoneum (8 mmHg) would improve respiratory mechanics and reduce inflammatory processes associated with biotrama during mechanical ventilation compared with moderate neuromuscular block (TOF count 1 or 2 ) and standard pressure pneumoperitoneum (12-15 mmHg).

Inclusion Criteria:

• ASA physical status I or II, aged 25 to 80 years, scheduled for laparoscopic surgery with trendelenburg position

Exclusion Criteria:

• cerebrovascular disease
• uncontrolled hypertension, asthma, COPD
• neuromuscular disorder
• patients who have had abdominal surgery
• morbid obesity (body mass index > 35 kg/m2)

baseline, end of pneumoperitoneum, 24 hr after surgery