Comparison of Pneumoinsufflation Modes and Pressure Settings in Gynecology

This is a randomized-controlled double-blinded trial examining outcomes from total laparoscopic hysterectomies performed under low and high pressure pneumoperitoneum with either a novel pressure-barrier insufflator (AirSeal®) or conventional insufflator. All patients scheduled for total laparoscopic hysterectomy (without robotic-assistance) will be screened for eligibility in the study. If eligible, a standard informed consent process will ensue.

All research activities will commence on the day of surgery, in the pre-operative preparation area. Enrolled subjects will undergo standard registration and pre-operative preparation by the staff preoperative nurse, including placement of intravenous access line and administration of standard pre-operative intravenous medications (typically ondansetron, dexamethasone, and ketorolac). While in the pre-operative area, and prior to any sedative drug administration by anesthesia, the patient will complete an 11-point Numeric Rating Scale (NRS) for baseline pain, as well as a baseline 18-question quality of life survey with the Abdominal Surgery Impact Scale (ASIS). Both study instruments will be self-administered by the patients and collected by the research team. A baseline blood collection will be performed in the pre-operative area by the research team assistant and sent for inflammatory markers.

The subject will be moved to the operating room and the anesthesia team will apply the pads for use with the Cheetah Non-Invasive Cardiac Output Monitoring (NICOM) system, in addition to other standard anesthesia monitoring equipment. The Cheetah NICOM will be activated for baseline measurements prior to anesthesia induction. Induction, intubation, and anesthesia administration will be performed according to standard practice by a dedicated group of anesthesia providers. A second set of hemodynamic measurements from the Cheetah NICOM will be measured after intubation, prior to pneumoperitoneum. A select group of anesthesia providers familiar with the protocol will administer anesthesia using non-depolarizing muscle relaxants continuously adjusted to be no less than one twitch during pneumoperitoneum.

Prior to any incision, preoperative prophylactic antibiotics and surgical sterile preparation will be performed per usual technique. Bilateral upper extremities will be placed in a tucked position, and no shoulder pads will be used in any case. An 18g peripheral IV (ideally antecubital) will be placed to allow intra-operative blood draws. This may be placed before or after anesthesia induction, but prior to arm tucking.

Randomization will occur after the patient is anesthetized, but prior to surgical start time to allow proper equipment to be opened on the surgical field without waste. Randomization will be into one of four groups with equal allocation to each (1:1:1:1 ratio):

1. Conventional insufflation at 15mmHg intra-abdominal pressure. (Group 1)
2. Conventional insufflation at 9mmHg intra-abdominal pressure (Group 2)
3. AirSeal® insufflation at 15mmHg intra-abdominal pressure (Group 3)
4. AirSeal® insufflation at 9mmHg intra-abdominal pressure (Group 4) If randomized to an AirSeal® group, the tri-lumen filtered tube set and dedicated access trocar will be opened and placed on the surgical field. If randomized to the conventional insufflation group, conventional insufflation tubing with an additional conventional trocar will be opened and placed on the surgical field. The patient will remain blinded to randomization throughout the study, as will the research team assistant responsible for blood draws and administration of NRS and ASIS questionnaires.

Laparoscopic entry will typically be obtained by optical trocar in the periumbilical region, but placement may be modified at the surgeon's discretion. Initial pneumoperitoneum will be established through this trocar to a pressure of 15mmHg for all groups. Pressure will remain at this setting during Trendelenburg positioning and placement of other necessary laparoscopic trocars. Data will be recorded for the third time from the Cheetah NICOM at this point. Once all trocars are inserted, the AirSeal® system will be activated if necessary based on group randomization, and pressure will be decreased to 9mmHg if indicated based on randomization. Additional recordings of data from the Cheetah NICOM will occur 10 minutes and 30 minutes after pressure decrease, and the surgery will proceed according to the surgeon's preferred technique. Any surgeon-directed modifications of intra-abdominal pressure at any time for surgery completion and/or patient safety will be recorded.

Thirty minutes after pneumoperitoneum is established, the research team assistant will perform the second blood draw for inflammatory markers. The surgery will be completed per typical fashion, and total operative time and estimated blood loss will be recorded. A final Cheetah NICOM recording will be made 5 minutes after deflation of pneumoperitoneum.

The patient will emerge from anesthesia under their usual monitoring and be transferred to the post-anesthesia care unit (PACU) when meeting appropriate routine criteria. A staff PACU nurse will care for the subject in the PACU and administer pain medications as necessary and/or per patient request. All pain medication administration in the hospital will be recorded in the Epic electronic health record (EHR). The amount of each patient's narcotic administration will be recorded from the EHR and documented in study files. The staff PACU nurse will be blinded to subject group allocation.

The research team assistant will administer a NRS pain survey to the patient two hours post-operatively and inquire regarding presence of shoulder pain. The third blood draw will also occur at this timepoint by the research team assistant. All patients will undergo planned same-day discharge to home. If unable to be discharged, they will stay overnight in the hospital with documented rationale.

On the day after surgery, the subject will be contacted by the research team assistant who will administer a NRS pain survey by telephone (or in person if still in hospital) and ask patient to report number of narcotic pain pills used since discharge and dosage of each. Presence of shoulder pain will again be asked. If patient is still in the hospital, narcotic usage will be collected from the EHR.

Per standard routine, the patients will be asked to return to clinic two weeks post-operatively for evaluation and examination. The 18-question ASIS will be administered at this visit by the blinded research team assistant. If the patient cannot complete the "two-week visit" within 1-3 weeks after surgery, the research team assistant will administer the ASIS by telephone. The patient will exit the study after this visit. Blinding of the patient will be broken after administration of the ASIS, as it is standard practice to provide the patient with a copy of the operative report during this visit, which will describe the pneumoperitoneum settings used during their case.