Randomized Trial of Ultralow vs Standard Pneumoperitoneum during Robotic Prostatectomy

Laparoscopic and robotic surgery have traditionally been performed with pneumoperitoneum of 12-15 mmHg. Based upon our previous retrospective study showing an advantage to using ultralow pneumoperitoneum during robotic prostatectomy (RP), we performed a randomized, double-blinded, controlled trial of RP at 6 mmHg vs 15 mmHg to assess postoperative pain and opioid use.

Patients undergoing RP with lymphadenectomy by a single surgeon were randomized to pneumoperitoneum pressures of 6 mmHg vs 15 mmHg. Pain scores and opioid use were recorded every 2 hours until discharge. Groups underwent intention-to-treat analysis on the primary outcome of pain scores up to 8 hours after post-anesthesia care unit.

A total of 138 patients were randomized to RP at 6 mmHg or 15 mmHg (67 and 71, respectively). Mean console time was 7 minutes longer at 6 mmHg (135 vs 128 minutes, p=0.02). Mean estimated blood loss was similar (p=0.4) with no transfusions in either group. Most patients were discharged on the same day as surgery (88% vs 84%, p=0.5). There was no statistically significant difference observed in morphine equivalents administered during surgery or used postoperatively, yet 6 mmHg patients had lower immediate (0-4 hours) mean pain scores (2.1 vs 3.5, p <0.01) and lower maximum pain scores (3.0 vs 5.2, p <0.01). Shoulder pain was lower in 6 mmHg patients (0.03 vs 0.15, p=0.01), as was groin pain (0.6 vs 1.2 p=0.01). Patients reported flatus earlier with 6 mmHg (mean 1.0 day vs 1.3 days, p <0.01).

Pneumoperitoneum pressure of 6 mmHg during RP has several advantages over the commonly used level of 15 mmHg without any identified disadvantages. Surgeons should consider using lower insufflation pressures.