Obesity, PEEP and Postoperative Oxygenation

Not Applicable

Completed

• Conditions: Oxygenation
• Interventions: Procedure: PEEP during awakening; Procedure: ZEEP during awakening

• Registration Number: NCT04150276
• Lead Sponsor: Region Västmanland

Brief Summary

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.

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 Timeline

• Study First Submitted: 2019-10-31
• Study First Submitted QC: 2019-10-31
• Study First Posted: 2019-11-04
• Study Start: 2019-12-03
• Status Verified: 2023-01
• Primary Completion: 2023-01-25
• Study Completion: 2023-01-25
• Last Update Submitted: 2023-01-25
• Last Update Posted: 2023-01-26

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 60

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 & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
PEEP during awakening	PEEP during awakening	PEEP is maintained throughout emergence preoxygenation and awakening.
ZEEP during awakening	ZEEP during awakening	ZEEP will be used during emergence preoxygenation and awakening.

Primary Outcome Measures

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

Secondary Outcome Measures

Name	Time	Method
Need for postoperative supplemental oxygen	First 3 hours postoperatively.	Number of patients and amount of oxygen needed in the respective group postoperatively.

Trial Locations

Locations (1)

Dep. of Anaesthesia and Intensive Care; 🇸🇪 Västerås, Region Västmanland, Sweden