Anesthesia
Conditions
Keywords
Bariatric, Obese, Laparoscopic, Electrical impedance tomography
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.
Interventions
OTHERElectrical impedance tomography during anesthesia
Thoracic electrical impedance tomography measurements ( min each) 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 EIT-measurement will be performed before discharge at home. For this, resulting potential differences are measured, and impedance distribution sampled at 30 Hz will be calculated. Relative change in poorly ventilated lung regions (silent spaces) and end-expiratory lung impedance (EELI) and measures of ventilation inhomogeneity will be calculated using customised code (Matlab R2021a, The MathWorks, Nattick, Massachusetts, USA).
Sponsors
Insel Gruppe AG, University Hospital Bern
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| 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 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 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) |
| 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) |
| Duration of anaesthesia | Up to 90 to 180 minutes | Duration of anaesthesia |
| 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. |
| Duration of surgical procedure. | Up to 90 to 150 minutes | Duration of surgical procedure. |
Countries
Switzerland
Outcome results
None listed