Effect of Lower Pneumoperitoneum Pressure During Laparoscopic and Robotic Hysterectomy

Minimally invasive hysterectomy, including conventional laparoscopic and robotic-assisted hysterectomy, is a commonly performed gynecologic surgery that universally results in postoperative pain for patients. Opioid medications are helpful to control postoperative pain and are routinely given to women who undergo minimally invasive hysterectomy. However, opioid abuse is on the rise in the United States, and there is increased awareness of misuse leading to abuse, overdose, and chronic opioid use. In addition to narcotic usage, postoperative pain also has negative effects on patient satisfaction and length of stay in the post-anesthesia care unit (PACU) leading to potential hospital admission. There is existing evidence that reducing the pressure used to create the pneumoperitoneum during laparoscopic surgery may affect pain scores that patients endorse in the PACU. Due to improved postoperative pain, patients may have decreased opioid use in the PACU and at home, shorter hospital stay, and improved overall patient satisfaction. If lower pneumoperitoneum pressures during laparoscopic surgery can be shown to reduce postoperative pain, then the ultimate question becomes whether there is ability to adapt this practice of using lower pressures to maintain pneumoperitoneum. It is unclear whether physician satisfaction will be affected.

There are several publications investigating the effect of lower pneumoperitoneum pressures on postoperative pain. A systematic review in 2016 included 238 patients (three RCTs), showed pneumoperitoneum pressures of 8mmHg had a statistically significant although minimal decrease in postoperative pain compared to 12mmHg, although lower pressures were associated with worse visualization. The authors concluded that the systematic review was inconclusive and further studies were necessary. A randomized pilot study with 60 patients comparing low pressure (7mmHg) using the AirSeal System versus standard insufflation (15mmHg), showed lower postoperative shoulder pain in the group with lower pressure using the AirSeal system. Two abstracts in the Journal of Minimally Invasive Gynecology present retrospective studies showing decreased postoperative pain with lower pneumoperitoneum pressure. The first abstract is from 2015, included a sample size of 170 patients who underwent benign robotic gynecologic surgery, 85 patients in each arm (12mmHg and 15mmHg). They showed no difference in median recovery time in the PACU and significantly lower median first pain score (5 vs 6, p=.04). The second abstract is from 2018 and included a sample size of 598 patients who underwent benign robotic gynecologic surgery, 99 patients in 15mmHg arm, 100 patients in 12mmHg arm, 99 patients in 10mmHg arm, and 300 patients in 8mmHg arm. They showed lower initial pain scores with each degree of lower pressure (5.9 vs 5.4 vs 4.4 vs 3.8, p=<.0001) and shorter hospital stays with lower pressures. They showed no difference in operative times or blood loss in the four arms. Similar studies have been done with cholecystectomy patients that have shown improved postoperative shoulder pain with lower pneumoperitoneum pressures. There is also an ongoing clinical trial that is still recruiting patients that is studying this similar comparison using 9mmHg vs 15mmHg with and without the AirSeal system.

However, the literature summarized here has never included blinding the intervention of lower pneumoperitoneum pressure to the surgeon to determine awareness of pressure and its effect on visualization and physician satisfaction.

Inclusion criteria

• female patients
• greater than or equal to 18 years old
• English-speaking
• undergoing laparoscopic or robotic total hysterectomy for benign indications by one of the two minimally invasive gynecologic surgeons at Banner University Medical Center - Phoenix

Exclusion criteria

• patients with body max index >35
• American Society of Anesthesiologists (ASA) score III or IV
• preoperative uterine weight estimated to be greater than 500gm (measured by sonography and using the following formula: length x width x anteroposterior diameter x 0.52)
• patients on chronic opioids for chronic pain (defined as > 3 months regular opioid use)
• patients who refuse participation in the study
• patients who do not provide informed consent