Clinical trial NCT06236685: Optimizing the Assessment of Mechanical Ventilation by Integrating Advanced Monitoring Techniques [AVIM]
Official title: Optimizing the Assessment of Mechanical Ventilation by Integrating Advanced Monitoring Techniques
Study type: INTERVENTIONAL
Overall status: ENROLLING_BY_INVITATION
Phase: NA
Conditions: Mechanical Ventilation Complication
Ventilator-Induced Lung Injury
Keywords: electrical impedance tomography
expiratory time constant
mechanical energy
lung protective ventilation
ventilator-induced lung injury
expiratory flow
inspiratory hold maneuver
Lead sponsor: Czech Technical University in Prague
Sponsor class: OTHER
Collaborators: name: Military University Hospital, Prague
First posted: 2024-02-01
Enrollment: 100
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Intervention model description: The study will be conducted on patients provided with mechanical ventilation either on intensive care units or during anesthesia. Extended monitoring of ventilation, including electric impedance tomography and esophageal pressure readings will be applied.
Primary purpose: DIAGNOSTIC

Brief summary: The aim of this study is to collect synchronized data from multiple monitoring techniques of mechanical ventilation (pressure/flow waves from the ventilator, electrical impedance tomography - EIT, esophageal pressure, capnography) in patients ventilated either on intensive care units or during anesthesia and evaluate the data by detailed mathematical analysis, to test three hypotheses:

1. Various published methods of calculation of the expiratory time constant provide different results in most cases.
2. Inhomogeneous ventilation (as described by EIT) affects the form of the expiratory flow curve and thus the calculated expiratory time constants.
3. The calculation of mechanical energy transferred to the lungs is affected by the chosen technique and length of the inspiratory pause maneuver.

This study does not test any new or non-standard methods and does not in any way interfere with the course of treatment indicated by the clinician, apart from extending the monitoring techniques.

Detailed description: Mechanical ventilation is known to cause various complications, generally known as ventilator induced lung injury. Thus, detailed monitoring is essential. However, data interpretation is complicated in clinical practice. The investigators aim to collect synchronized data from multiple monitoring techniques of mechanical ventilation (pressure/flow waves from the ventilator, electrical impedance tomography - EIT, esophageal pressure, capnography) in patients ventilated either on intensive care units or during anesthesia and evaluate the data by detailed mathematical analysis. The results will be used to explore the complexity of seemingly simple and often used calculations describing the course of mechanical ventilation - mostly the expiratory time constant and amount of mechanical energy transferred to the lungs. The investigators primarily aim to test three hypotheses:

1. Various published methods of calculation of the expiratory time constant provide different results in most cases.
2. Inhomogeneous ventilation (as described by EIT) affects the form of the expiratory flow curve and thus the calculated expiratory time constants.
3. The calculation of mechanical energy transferred to the lungs is affected by the chosen technique and length of the inspiratory pause maneuver.

For this, the investigators plan to recruit 50 patients undergoing general anesthesia with controlled mechanical ventilation and 50 patients hospitalized on intensive care units. Monitoring of those patients will be protocolized and will in all cases include pressure/flow monitoring of the mechanical ventilator, capnography, and electrical impedance tomography. Esophageal pressure monitoring will be introduced where indicated by the clinician or where nasogastric tube insertion will be indicated (as the pressure can be measured by a combined catheter).

This study thus does not test any new or non-standard methods and does not in any way interfere with the course of treatment indicated by the clinician, apart from extending the monitoring techniques. Patient data will be anonymized and all the enrolled patients or their families will sign an informed consent as agreed by the ethical committee of our hospital.

Eligibility criteria: Inclusion Criteria:

* mechanical ventilation for anesthesia or in intensive care unit

Exclusion Criteria:

* disagreement with enrollment or incapacity to understand the patient information leaflet
* contraindications to electric impedance tomography (skin lesions in the place of electrode placement etc.)
* necessity to use a defined ventilator setting outside the study protocol

Primary outcomes:
measure: Expiratory time constant
timeFrame: 2 minutes after an intervention or a change in the ventilator settings
measure: Mechanical energy transferred to the lungs
timeFrame: 2 minutes after an intervention or a change in the ventilator settings
Secondary outcomes:
Other outcomes:
measure: Regional signals of electrical impedance tomography
timeFrame: 2 minutes after an intervention or a change in the ventilator settings
Locations:
city: Praha
country: Czechia
facility: Military University Hospital
Study officials:
affiliation: Czech Technical University
name: Karel Roubík, prof.
role: STUDY_DIRECTOR
References:
citation: Karagiannidis C, Waldmann AD, Roka PL, Schreiber T, Strassmann S, Windisch W, Bohm SH. Regional expiratory time constants in severe respiratory failure estimated by electrical impedance tomography: a feasibility study. Crit Care. 2018 Sep 21;22(1):221. doi: 10.1186/s13054-018-2137-3.
citation: Brunner JX, Laubscher TP, Banner MJ, Iotti G, Braschi A. Simple method to measure total expiratory time constant based on the passive expiratory flow-volume curve. Crit Care Med. 1995 Jun;23(6):1117-22. doi: 10.1097/00003246-199506000-00019.
citation: Candik P, Rybar D, Depta F, Sabol F, Kolesar A, Galkova K, Torok P, Donicova V, Imrecze S, Nosal M, Donic V. Relationship between dynamic expiratory time constant tau(edyn) and parameters of breathing cycle in pressure support ventilation mode. Physiol Res. 2018 Dec 18;67(6):875-879. doi: 10.33549/physiolres.933750. Epub 2018 Sep 11.
citation: Henderson WR, Molgat-Seon Y, Vos W, Lipson R, Ferreira F, Kirby M, Holsbeke CV, Dominelli PB, Griesdale DE, Sekhon M, Coxson HO, Mayo J, Sheel AW. Functional respiratory imaging, regional strain, and expiratory time constants at three levels of positive end expiratory pressure in an ex vivo pig model. Physiol Rep. 2016 Dec;4(23):e13059. doi: 10.14814/phy2.13059.
citation: Vogt B, Pulletz S, Elke G, Zhao Z, Zabel P, Weiler N, Frerichs I. Spatial and temporal heterogeneity of regional lung ventilation determined by electrical impedance tomography during pulmonary function testing. J Appl Physiol (1985). 2012 Oct;113(7):1154-61. doi: 10.1152/japplphysiol.01630.2011. Epub 2012 Aug 16.