Assessment of changes of regional ventilation distribution in the lung tissue depending on the driving pressure applied during high frequency jet ventilation

Szymon Bialka,Ewa Jedrusik,Damian Czyzewski,Maja Copik,Marek Filipowski,Kurt Ruetzler,Hanna Misiolek,Katarzyna Rybczyk,Eva Rivas,Aleksander Owczarek,Lukasz Szarpak

doi:10.1186/s12871-018-0552-2

Abstract

BackgroundElectrical impedance tomography (EIT) is a tool to monitor regional ventilation distribution in patient’s lungs under general anesthesia. The objective of this study was to assess the regional ventilation distribution using different driving pressures (DP) during high frequency jet ventilation (HFJV).MethodsProspective, observational, cross-over study. Patients undergoing rigid bronchoscopy were ventilated HFJV with DP 1.5 and 2.5 atm. Hemodynamic and ventilation parameters, as well as ventilation in different regions of the lungs in percentage of total ventilation, assessed by EIT, were recorded.ResultsThirty-six patients scheduled for elective rigid bronchoscopy. The final analysis included thirty patients. There was no significant difference in systolic, diastolic and mean arterial blood pressure, heart rate, and peripheral saturation between the two groups. Peak inspiratory pressure, mean inspiratory pressure, tidal volume, and minute volume significantly increased in the second, compared to the first intervention group. Furthermore, there were no statistically significant differences between each time profiles in all ROI regions in EIT.ConclusionsIn our study intraoperative EIT was an effective method of functional monitoring of the lungs during HFJV for rigid bronchoscopy procedure. Lower driving pressure was as effective in providing sufficient ventilation distribution through the lungs as the higher driving pressure but characterized by lower airway pressure.Trial registrationThe study was registered on ClinicalTrials.gov under no. NCT02997072.

Highlights

Electrical impedance tomography (EIT) is a tool to monitor regional ventilation distribution in patient’s lungs under general anesthesia
High frequency jet ventilation (HFJV) is a time cycled, pressure limited mode of ventilation that facilitate gas exchange by utilizing smaller tidal volumes from a high pressure at supraphysiologic frequencies between 120 and 400 min− 1 followed by a passive expiration [1]
high frequency jet ventilation (HFJV) is commonly used in Ear-Nose-Throat surgery, thoracic surgery and for rigid bronchoscopy [2, 3]

Summary

Introduction

Electrical impedance tomography (EIT) is a tool to monitor regional ventilation distribution in patient’s lungs under general anesthesia. The objective of this study was to assess the regional ventilation distribution using different driving pressures (DP) during high frequency jet ventilation (HFJV). High frequency jet ventilation (HFJV) is a time cycled, pressure limited mode of ventilation that facilitate gas exchange by utilizing smaller tidal volumes from a high pressure at supraphysiologic frequencies between 120 and 400 min− 1 followed by a passive expiration [1]. Mechanical ventilation with high tidal volume and low levels of positive end-expiratory pressure can promote ventilator induced lung injury (VILI), and increase morbidity and mortality [4]. Standardized measurements of ventilation parameters like tidal volume, peak volume or lung compliance, do not reliably translate the regional distribution of tidal volumes [5, 6]

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