Effects of Individualized PEEP Guided by Driving Pressure on Postoperative Atelectasis in Patients With Morbid Obesity

Effects of Individualized Positive End-expiratory Pressure Guided by Driving Pressure on Postoperative Atelectasis After Bariatric Surgery in Patients With Morbid Obesity: A Single-center, Prospective, Randomized Controlled Study

Atelectasis is a common complication in patients undergoing surgery under general anesthesia, particularly in obese patients. Postoperative atelectasis could last for more than 24h and contribute to a variety of other complications, including hypoxemia and pneumonia. We plan to conduct a single-center, randomized controlled trial in patients undergoing bariatric surgery to test the hypothesis that driving pressure guided PEEP could reduce the postoperative atelectasis.

Study Overview

• Status: Recruiting
• Conditions: Pulmonary Atelectasis; Obesity, Morbid
• Intervention / Treatment: Procedure: Individualized PEEP group; Procedure: Fixed PEEP group

Detailed Description

Positive end-expiratory pressure (PEEP) is a strategy that helps to keep alveoli open during surgery and to prevent postoperative atelectasis. A fixed PEEP without considering the respiratory mechanics in individual patients, however, is not optimal. Individualized PEEP therefore has been increasingly studied, and has been shown to improve oxygenation in both nonobese and obese patients. Studies have shown that the occurrence and prognosis of PPCs are significantly associated with high driving pressure (DP), but not with VT and PEEP. Driving pressure-guided individualized PEEP is expected to be a novel perioperative lung protection strategy. Consequently, the main aim of this study is to investigate the effect of a driving pressure-guided individualized PEEP ventilation strategy on postoperative pulmonary atelectasis in morbidly obese patients undergoing bariatric surgery.

• Study Type: Interventional
• Enrollment (Estimated): 52
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: yong T Sun, PH.D; Phone Number: 18660795201; Email: sunyongtao1979@163.com

Study Locations

• China
  • Shandong
    • Jinan, Shandong, China, 250014
      • Recruiting
      • Qianfoshan Hospital, The First Hospital affiliated of Shandong First Medical University
      • Contact: yong T Sun, PH.D; Phone Number: 18660795201; Email: sunyongtao1979@163.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18 to 60 years old;
• Body mass index (BMI) ≥ 40 kg/m2;
• ASA classification I to III;
• Signing the informed consent form for this clinical study;

Exclusion Criteria:

• Respiratory infection within 4 weeks; severe respiratory system diseases; history of pulmonary and/or thoracic surgery; neuromuscular dysfunction;
• Serious cardiac, renal or haematopoietic diseases;
• Contraindications to PEEP；

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Individualized PEEP group; After recruitment maneuver, PEEP is titrated decreasingly using driving pressure guided individualised PEEP ventilation strategy, and the PEEP corresponding to the lowest driving pressure is the individualised PEEP.	Procedure: Individualized PEEP group; Individualized PEEP group: Recruitment Maneuver (RM) is performed first. In pressure control mode, PEEP and airway plateau pressure are increased to 20 cmH2O and 35 cmH2O at a rate of 5 cmH2O every 30s, and driving pressure is maintained at 15 cmH2O throughout. Subsequently, in volume-controlled ventilation mode, PEEP decreases from 20 cmH2O to 4 cmH2O at gradient of 2 cmH2O, and each PEEP level is maintained for 30s. The PEEP corresponding to the lowest driving pressure is the individualized PEEP we need. If multiple PEEP levels showed the same lowest driving pressure, the lowest PEEP value as the individualized PEEP. The above procedures are performed three times during the surgery (5 minutes after intubation,5 minutes after the beginning of pneumoperitoneum, and 5 minutes after the end of pneumoperitoneum).
Other: Fixed PEEP group; After recruitment maneuver, PEEP is fixed at 8cmH2O.	Procedure: Fixed PEEP group; After the same RM, PEEP is fixed at 8 cmH2O.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of postoperative pulmonary atelectasis	The primary outcome of this study is postoperative atelectasis measured by lung ultrasound. Each hemithorax is divided into 6 regions using 3 longitudinal lines (parasternal, anterior and posterior axillary)and 2 axial lines (one above the diaphragm and the other 1 cm above the nipples). The 12 lung regions were scanned sequentially from right to left, cranial to caudal and anterior to posterior. Each region is assessed using a 2-dimen-sional view with the probe placed parallel to the ribs. It distinguishes four progressive steps of loss of aeration according to the artifacts visualized in a scan: score 0, normal aeration (A-lines or no more than two B-lines); score 1, moderate loss of aeration (three or more well-spaced B-lines); score 2, severe loss of aeration(coalescent B-lines); and score 3, complete loss of aeration(tissue-like pattern). We define atelectasis to be significant if any region had a lung consolidation score of ≥2.	After 30 minutes of extubation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative pulmonary ultrasound score	Each hemithorax is divided into 6 regions using 3 longitudinal lines (parasternal, anterior and posterior axillary)and 2 axial lines (one above the diaphragm and the other 1 cm above the nipples). The 12 lung regions were scanned sequentially from right to left, cranial to caudal and anterior to posterior. Each region is assessed using a 2-dimen-sional view with the probe placed parallel to the ribs. It distinguishes four progressive steps of loss of aeration according to the artifacts visualized in a scan: score 0, normal aeration (A-lines or no more than two B-lines); score 1, moderate loss of aeration (three or more well-spaced B-lines); score 2, severe loss of aeration(coalescent B-lines); and score 3, complete loss of aeration(tissue-like pattern). We define atelectasis to be significant if any region had a lung consolidation score of ≥2. Based upon the LUS scoring system, each area is scored from 0-3, so a minimum zero or maximum 36 score is possible.	After 30 minutes of extubation

Collaborators and Investigators

• Sponsor: Yongtao Sun
• Investigators: Study Chair: yong t Sun, Ph.D, The First Affiliated Hospital of Shandong First Medical University

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2024
• Primary Completion (Estimated): December 31, 2024
• Study Completion (Estimated): December 31, 2024

Study Registration Dates

• First Submitted: December 12, 2023
• First Submitted That Met QC Criteria: December 12, 2023
• First Posted (Actual): December 26, 2023

Study Record Updates

• Last Update Posted (Estimated): June 4, 2024
• Last Update Submitted That Met QC Criteria: June 1, 2024
• Last Verified: June 1, 2024

More Information

Terms related to this study

• Keywords: Driving Pressure; Ventilator-induced Lung Injury; Individual Positive End-expiratory Pressure
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Overnutrition; Nutrition Disorders; Overweight; Body Weight; Obesity; Pulmonary Atelectasis; Obesity, Morbid
• Other Study ID Numbers: DP guided PEEP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No