Obesity, PEEP and Postoperative Oxygenation (ZAPPAII)

Zero Positive End-expiratory Pressure Before Emergence Improves Postoperative Oxygenation in Obese Patients Undergoing Laparoscopic Surgery - a Randomized Clinical Trial

A study on overweight patients undergoing anesthesia for laparoscopic surgery.

- evaluation of positive end-expiratory pressure versus zero positive end-expiratory pressure during awakening on oxygenation in the early postoperative period.

Study Overview

• Status: Completed
• Conditions: Oxygenation
• Intervention / Treatment: Procedure: ZEEP during awakening; Procedure: PEEP during awakening

Detailed Description

Positive end-expiratory pressure (PEEP) is often used during mechanical ventilation to preserve end-expiratory lung volume. After emergence and extubation, this volume will diminish instantly. Some patients will have difficulties to restore functional residual capacity (FRC) during the early phase of recovery. If routine high FIO2 is being delivered together with maintained PEEP prior to extubation, several important prerequisites are established for the development of postoperative atelectasis. The investigators hypothesize that establishing zero positive end-expiratory pressure (ZEEP) immediately prior to emergence preoxygenation, will prevent gas with high oxygen concentration from entering dorso-basal areas of the lungs, and thereby diminishing postoperative atelectasis formation and improve oxygenation.

This randomized controlled study will study overweight patients undergoing general anesthesia for laparoscopic surgery. The patients in the two study groups will receive mechanical ventilation with identical settings, comprising low TV, PEEP, and no RM. Randomization will occur at the end of surgery, before awakening. The patients will be allocated to zero PEEP (ZEEP) or maintained PEEP during emergence preoxygenation and extubation. Importantly, the intervention group will have ZEEP established while still having low ETO2 levels, prior to any preoxygenation. Arterial blood gases will be collected before, during and after anaesthesia. Primary endpoint measure will be change in oxygenation from before awakening to after awakening.

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Region Västmanland
    • Västerås, Region Västmanland, Sweden
      • Dep. of Anaesthesia and Intensive Care

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Obese patients scheduled for elective laparocopic surgery.
• American Society of Anesthesiologists functional class I-III
• Body Mass Index 35-50 kg/m2

Exclusion Criteria:

• Body Mass Index ≥50 kg/m2
• Peripheral oxygen saturation (SpO2) breathing air <94 %
• Symtomatic asthma, COPD or heart failure
• Ischemic heart disease
• Hemoglobin < 100g/l
• Smokers and ex-smokers that stopped smoking < 9 months ago
• Need for peroperative RM and PEEP higher than in study protocol, as indicated by SpO2 <92% despite the stipulated FiO2 0.30-0.35.
• Obstructive sleep apnea syndrome on home-CPAP

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: ZEEP during awakening; ZEEP will be used during emergence preoxygenation and awakening.	Procedure: ZEEP during awakening; ZEEP will be established 2 min prior to the start of emergence preoxygenation and awakening.
Active Comparator: PEEP during awakening; PEEP is maintained throughout emergence preoxygenation and awakening.	Procedure: PEEP during awakening; PEEP will be maintained throughout emergence preoxygenation and awakening.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in oxygenation	Arterial blood samples will be collected for measurement of arterial oxygen partial pressure.	Bloodgases will be obtained 5 minutes before the start of the awakening procedure and 30 minutes after awakening and extubation.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Need for postoperative supplemental oxygen	Number of patients and amount of oxygen needed in the respective group postoperatively.	First 3 hours postoperatively.

Collaborators and Investigators

• Sponsor: Region Västmanland
• Investigators: Principal Investigator: Erland Östberg, MD, PhD, Region Västmanland

Study record dates

Study Major Dates

• Study Start (Actual): December 3, 2019
• Primary Completion (Actual): January 25, 2023
• Study Completion (Actual): January 25, 2023

Study Registration Dates

• First Submitted: October 31, 2019
• First Submitted That Met QC Criteria: October 31, 2019
• First Posted (Actual): November 4, 2019

Study Record Updates

• Last Update Posted (Estimate): January 26, 2023
• Last Update Submitted That Met QC Criteria: January 25, 2023
• Last Verified: January 1, 2023

More Information

Terms related to this study

• Keywords: Obesity; General anaesthesia; Mechanical ventilation; Atelectasis; Oxygenation; Positive end-expiratory pressure
• Other Study ID Numbers: Dnr 2019/04860

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: Please email request to the study principal investigator.
• IPD Sharing Time Frame: Data will be available after publication of study results, approximately 18 months after study completion.
• IPD Sharing Access Criteria: Data access requests will be reviewed by a review panel at the Center for Clinical Research, Västerås. Requestors will be required to sign a data acess agreement.
• IPD Sharing Supporting Information Type: Study Protocol; Statistical Analysis Plan (SAP)

Drug and device information, study documents

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