Evaluation of Low Pressure Pneumoperitoneum in Bariatric Surgery (ELOPES Study)

Study Overview
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Brief Summary
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This is a prospective study whereby it involves patients who are planned for bariatric surgery. In the bariatric surgery procedure, pneumoperitoneum pressure will be the experimental aspect in this study. The pneumoperitoneum pressure will be adjusted to either 8-10 mmHg of low pressure or to 12-15mmHg of standard pressure.

Detailed Description
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This will be a prospective study in patients aged between 18 and 70 years old who have already been screened and planned for elective bariatric surgery. In bariatric surgery, a large portion of the stomach will be removed. Pneumoperitoneum is also known as the abdominal pressure which will be the experimental aspect in this study. Laparoscopy surgery will be performed by introducing the camera (optical trocar) after making an incision at the belly button (umbilicus), and carbon dioxide which will be given at a rate of 5 L/min until the intra-abdominal pressure of either 8-10 mmHg (low-pressure group) or 12-15 mmHg (standard pressure group) is achieved. The remaining three standard ports will be placed and the laparoscopic sleeve gastrectomy will be performed at an insufflation rate of 15 L/min. The greater omentum will be divided at the greater curvature of the stomach using an ultrasonic dissector, beginning from the proximal antrum until the fundus. The omentum will be divided close to the stomach wall hence preserving the gastro-epiploic vessels. Short gastric vessels will be divided entirely from the stomach and this dissection will continue until the left crus of the diaphragm are exposed. Endoscopic staplers will then be used to staple and divide the stomach until the angle of His. A 39Fr gastric calibration tube will be placed along the lesser curvature of the stomach, acts as a guide during the division of the stomach. Finally, the divided stomach will be removed through a 12mm port site and the incision will be closed with sutures. Towards the end of the surgery, all residual pneumoperitoneum will be evacuated by keeping the trocar valves open under direct telescopic vision. The duration of surgery or any intraoperative complications will be recorded. The starting of surgery will be regarded after the induction of anaesthesia and the end of surgery is regarded when the end of skin closure. Operating field or also known as surgical view is defined as the view of the intra-abdomen. A clear operating field allows a good working space for the surgeon. Numeric rating score will be used to access the operating field during the surgery. Post-operative pain will be rated on a Visual Analog Scale at rest and with movement.

Official Title
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Evaluation of Low Pressure Pneumoperitoneum in Bariatric Surgery: A Prospective Randomized Study

Conditions
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Surgical View, Shoulder Tip Pain, Abdominal Pain

Intervention / Treatment
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* Procedure: Pneumoperitoneum Pressure


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-70 years Ability to give informed consent Patients who are approved by the anaesthetics to undergo bariatric surgery. Exclusion Criteria: Age below 18 and above 70 Inability to give informed consent Patient unfit for bariatric surgery including who has poor respiratory, cardiac, renal and liver function. Patient with Body Mass Index (BMI) >50 Patient with American Society of Anesthesiologists (ASA) >3

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: There will be two arms in this study. One arm will be the low pressure pneumoperitoneum group (8-10mmHg) where else the other arm will be the standard pressure pneumoperitoneum group (12-15mmHg).
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Low Pressure Group<br>Participants will undergo elective bariatric surgery. Participants under this group will be given intra-abdominal pressure of 8-10mmHg. The number of subjects anticipated for this arm will be 47. Participants in this low pressure group are expected to encounter lesser shoulder tip pain and abdominal pain. Operating field for surgeons also expected to be better. | Procedure: Pneumoperitoneum Pressure<br>* There will be two arms in this study. The participants recruited for this study are those who have been screened and planned for elective bariatric surgery.The pneumoperitoneum pressure will be adjusted to either 8-10mmHg or 12-15mmHg until a clear operating field is obtained by the surgeon. Low pneumoperitoneum pressure has been expected to give a clearer and better surgical view than standard pneumoperitoneum pressure. Participants under the low pressure group are expected to have lesser pain score on abdominal pain and shoulder tip pain as compared to participants in the standard pressure group.<br>|
| Experimental: Standard Pressure Group<br>Participants will undergo elective bariatric surgery. Participants under this group will be given intra-abdominal pressure of 12-15mmHg. The number of subjects anticipated for this arm will be 47. Participants in this group are expected to have an increased amount of shoulder tip pain and higher pain score postoperatively compared to low pressure group. Operating fields for surgeons are expected to be less clear. | Procedure: Pneumoperitoneum Pressure<br>* There will be two arms in this study. The participants recruited for this study are those who have been screened and planned for elective bariatric surgery.The pneumoperitoneum pressure will be adjusted to either 8-10mmHg or 12-15mmHg until a clear operating field is obtained by the surgeon. Low pneumoperitoneum pressure has been expected to give a clearer and better surgical view than standard pneumoperitoneum pressure. Participants under the low pressure group are expected to have lesser pain score on abdominal pain and shoulder tip pain as compared to participants in the standard pressure group.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Operating Field | Numeric rating score will be used to access the operating field during the surgery. The numeric rating score will be recorded after the surgery by the surgeon. The score ranges from 1 to 4 whereby 1 means poor space with excessive muscular contractions and unable to proceed with surgery safely. Numeric rating scale of 4 indicates good surgical space. If there was any compromise of the operating field (NOS score ≥ 3), the pneumoperitoneum pressure will be increased accordingly. | It will be assessed intraoperatively (during the surgery). | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain Score | The pain score will be assessed using visual analog scale (VAS) (0-10). A score of 0 means no pain, whereas a score of 10 equals the worst pain ever experienced. Post-operative pain will be rated on a visual analog score at rest. The time of arrival in the postoperative recovery room will be defined as zero hours postoperatively. The patients will be asked about the location of pain, whether at the shoulder, incision sites, and/or inside the abdomen by the medical doctors or nurses. | The abdomen and shoulder tip pain intensity will be rated up to 48 hours postoperatively. | 
| Duration of Surgery | The duration of surgery or any intraoperative complications will be recorded. | The starting of surgery will be regarded after the induction of anaesthesia and the end of surgery is regarded when the end of skin closure. |