Bariatric Electrical Impedance Tomography

Completed

• Conditions: Anesthesia

• Registration Number: NCT05187039
• Lead Sponsor: Insel Gruppe AG, University Hospital Bern

Brief Summary

This study investigates under controlled conditions the variation of poorly ventilated lung units (silent spaces) in obese patients scheduled for laparoscopic bariatric surgery in the perioperative phase.

Detailed Description

Eligible patients with written informed consent, scheduled for laparoscopic bariatric surgery. As for standard of care no premedication will be given for bariatric patients. Patients will be monitored according the local standard.

Thoracic electrical impedance tomography measurements (each measurement will last 1 min) will be performed at the following time points: before induction of the anaesthesia; before the surgical procedure when the induction is terminated and recruitment manoeuvers have been performed; after the termination of the surgical procedure; before transport to the Post anaesthesia Care Unit (PACU); before the discharge from the PACU after 2 hours of monitoring. An additional thoracic electrical impedance tomography measurement (duration 1 min) will be performed before discharge at home. For this, resulting potential differences are measured, and impedance distribution sampled at 30 Hz will be calculated by an automated linearized Newton-Raphson reconstruction algorithm. Relative change in poorly ventilated lung regions (silent spaces) and end-expiratory lung impedance (EELI) and measures of ventilation inhomogeneity such as the global inhomogeneity index will be calculated.

Study Timeline

• Study Start: 2021-10-19
• Study First Submitted: 2021-12-21
• Study First Submitted QC: 2021-12-21
• Study First Posted: 2022-01-11
• Primary Completion: 2022-11-01
• Status Verified: 2023-03
• Study Completion: 2023-03-08
• Last Update Submitted: 2023-03-08
• Last Update Posted: 2023-03-09

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

• BMI >40
• ASA physical status 1 to 4
• Over 18 years of age providing written informed consent

Exclusion Criteria

• BMI <40
• Known severe pulmonary hypertension,
• Need of home oxygen therapy
• Known heart failure
• Suspected, or known recent pulmonal infections

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Proportion of poorly ventilated lung areas (silent spaces)	2 hours	Proportion of poorly ventilated lung areas (silent spaces) by using electrical impedance tomography (EIT) before the discharge from PACU (two hours after admission to PACU).

Secondary Outcome Measures

Name	Time	Method
Duration of anaesthesia	Up to 90 to 180 minutes	Duration of anaesthesia
EIT-Measurement after the end of induction before the surgical procedure	2 minutes after the end of anesthesia induction	Detection of changes in silent spaces, ventilation inhomogeneity and end-expiratory lung impedance (EELI) by using electrical impedance tomography (EIT)
EIT-Measurement 2 minutes after the end of anaesthesia, before the transport in PACU	2 minutes after the end of anaesthesia, before the transport to PACU.	Detection of changes in silent spaces, ventilation inhomogeneity and end-expiratory lung impedance (EELI) by using electrical impedance tomography (EIT)
EIT-Measurement at the end of the surgical procedure	5 minutes after Capnoperitoneum	Detection of changes in silent spaces, ventilation inhomogeneity and end-expiratory lung impedance (EELI) by using electrical impedance tomography (EIT)
EIT-Measurement before discharge from the PACU	Two hours after admission of the patient at PACU, before first mobilisation and before discharge from PACU	Detection of changes in silent spaces, ventilation inhomogeneity and end-expiratory lung impedance (EELI) by using electrical impedance tomography (EIT)
EIT-Measurement before discharging the patient at home	At hospital discharge, up to 3 days	Detection of changes in silent spaces, ventilation inhomogeneity and end-expiratory lung impedance (EELI) by using electrical impedance tomography (EIT)
Duration of surgical procedure.	Up to 90 to 150 minutes	Duration of surgical procedure.
Desaturation below 90%.	During anaesthesia monitoring, from 1 to 10 minutes	Difference of formation and course of silent lung areas in patients with and without pre-existing CPAP-therapy
Follow up at 14 days	14 days	Follow-up by phone, regarding respiratory complications or need for rehospitalization.

Trial Locations

Locations (1)

University Hospital Bern; 🇨🇭 Bern, Switzerland