Power Dissipation in Flow-controlled Ventilation (POWER-FLOW)

Power Dissipation in Low Tidal Volume Versus Individualized Flow-controlled Ventilation - a Randomized, Clinical Cross-over Trial

The goal of this randomized clinical cross-over trial is to compare power dissipation (Pd) during flow-controlled ventilation with either standard of low tidal volume ventilation or compliance guided individualization of ventilator settings. This study is performed in patients scheduled for open abdominal surgery and the primary and secondary outcome parameters are:

• power dissipation [J/min] during ventilation calculated by integrating the hysteresis of the tracheal pressure-volume loop
• applied mechanical power during ventilation calculated by published formulas [1]
• oxygenation of the blood assessed by PaO2/FiO2 ratio
• decarboxylation assessed by required respiratory minute volume to maintain normocapnia
• comparison of respiratory variables in low tidal volume versus individualized ventilation Participants will randomly receive either low tidal volume (LTV) or individualized flow-controlled ventilation [2]. In the LTV group, the positive end-expiratory pressure will be set to 5 cmH2O and the peak pressure set to achieve a tidal volume of 7 ml/kg predicted body weight. In the individualized group positive end-expiratory and peak pressure will be titrated to achieve the highest compliance [2]. In both groups the flow will be set to achieve normocapnia (PaCO2 35-45 mmHg). After obtaining three consecutive measurements the ventilation strategy will be switched to the alternative regime in a cross-over design and again, three measurements recorded.

The investigators hypothesize, that individualized ventilator settings are able to improve ventilation efficiency in terms of a lower required minute volume to maintain normocapnia and thus is able to reduce power dissipation during ventilation. Secondary endpoint will be a comparison of Pd to calculated mechanical power, as a currently accepted surrogate parameter for ventilation invasiveness [2] and also outcome predictor. Additionally, gas exchange parameters such as oxygenation and decarboxylation will be compared between low tidal volume and individualized ventilation.

Study Overview

• Status: Recruiting
• Conditions: Abdominal Surgery; Mechanical Ventilation
• Intervention / Treatment: Device: Evone

Detailed Description

After anesthesia induction and securing the airway with a tracheal tube, tha patients will be ventilated with flow-controlled ventilation (FCV) using standard of low tidal volume ventilation with a positive end-expiratory pressure (PEEP) of 5 cmH2O and the peak pressure set to achieve a tidal volume of 7 ml/kg predicted body weight. I:E ration will be set to 1:1, the gas flow adjusted to achieve normocapnia and the fraction of inspired oxygen adjusted to achieve normoxia. After opening the abdominal cavity baseline parameters will be recorded and subsequently the study participant randomized to one of the following treatment group:

• low tidal volume ventilation (LTV): PEEP will be set to 5 cmH2O, peak pressure adjusted to achieve a tidal volume of 7 ml/kg predicted body weight and the flow set to achieve normocapnia (PaCO2 of 35-45 mmHg)
• individualized FCV: PEEP and peak pressure will be titrated based on dynamic compliance. First PEEP well be increased or decreased until the highest tidal volume at the same driving pressure can be achieved. Then the driving pressure or peak pressure will be increased, until there is no further over-proportional increase in tidal volume (previous tidal volume + measured compliance). Finally the gas flow will be set to achieve normocapnia (PaCO2 of 35-45 mmHg) Three measurements will be obtained with 15 minutes in between and subsequently the ventilation setting switched to the alternative group, followed by additional three consecutive measurements. After obtaining all study related measurements the observation period ends and the patient will be further treated with the ventilation strategy that results in the lowest energy dissipation.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Patrick Spraider, PhD; Phone Number: +43 512 504 80329; Email: patrick.spraider@i-med.ac.at

Study Locations

• Austria
  • Tyrol
    • Innsbruck, Tyrol, Austria, 6020
      • Recruiting
      • Medical University of Innsbruck
      • Contact: Patrick Spraider, PhD; Phone Number: +43 512 504 80329; Email: patrick.spraider@i-med.ac.at

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Male and female subjects ≥ 18 years
• Body weight ≥ 40 kg
• Elective open abdominal surgery under general anaesthesia - American Society of Anesthesiologists Classification I-III
• Written informed consent

Exclusion Criteria:

• Emergency surgery
• American Society of Anesthesiologists Classification IV-V
• Female subjects known to be pregnant
• Known participation in another interventional clinical trial

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: low tidal volume ventilation; Flow-controlled ventilation will be established with a PEEP of 5 cmH2O, peak pressure set to achieve a tidal volume of 7 ml/kg predicted body weight and the flow set to achieve normocapnia at an I:E ration of 1:1. Three consecutive measurements of power dissipation with 15 minutes in between will be obtained. Additionally secondary outcome parameters such as respiratory parameters and results of arterial blood gas analysis will be recorded at each measurement timepoint.	Device: Evone; Evone (Ventinova Medical B.V., Eindhoven, The Netherlands) is a ventilator, which is able to perform flow-controlled ventilation (FCV). Moreover it provides direct tracheal pressure measurements and combined with the constant gas flow of FCV a precise determination of dynamic compliance is feasible. Thus not only PEEP but also peak pressure can be titrated based on dynamic compliance. Additionally intratracheal pressure-volume loops can be measured and thus power dissipation calculated, which represents the primary outcome parameter of this trial.
Experimental: individualized FCV; Flow-controlled ventilation will be individualized with compliance guided PEEP and peak pressure titration. The flow will be set to achieve normocapnia at an I:E ration of 1:1. Three consecutive measurements of power dissipation with 15 minutes in between will be obtained. Additionally secondary outcome parameters such as respiratory parameters and results of arterial blood gas analysis will be recorded at each measurement timepoint.	Device: Evone; Evone (Ventinova Medical B.V., Eindhoven, The Netherlands) is a ventilator, which is able to perform flow-controlled ventilation (FCV). Moreover it provides direct tracheal pressure measurements and combined with the constant gas flow of FCV a precise determination of dynamic compliance is feasible. Thus not only PEEP but also peak pressure can be titrated based on dynamic compliance. Additionally intratracheal pressure-volume loops can be measured and thus power dissipation calculated, which represents the primary outcome parameter of this trial.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Power dissipation (Pd)	The hysteresis of the tracheal pressure-volume relationship represents the power, that is dissipated during one ventilation cycle. Together with the respiratory rate, overall power dissipation can be calculated in J/min.	Pd will be calculated and recorded three times in each treatment arm with 15 minutes in between.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mechanical power (MP)	Applied mechanical power during inspiration will be calculated based on a published formula by Gattinoni et al.	MP will be calculated and recorded three times in each treatment arm with 15 minutes in between.
PaO2/FiO2 ratio	Oxygenation will be assessed with the help of an arterial blood gas analysis	PaO2/FiO2 ratio will be measured and recorded three times in each treatment arm with 15 minutes in between.
Minute volume (MV)	Required respiratory minute volume to maintain normocapnia will be recorded.	MV will be recorded three times in each treatment arm with 15 minutes in between

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Respiratory measurement variables	Ventilator settings and readings with positive end-expiratory pressure, peak pressure, respiratory rat, flow rate, compliance and resistance will be recorded.	Respiratory measurement variables will be recorded three times in each treatment arm with 15 minutes in between

Collaborators and Investigators

• Sponsor: Medical University Innsbruck
• Investigators: Principal Investigator: Patrick Spraider, PhD, Medical University of Innsbruck, Department of Anesthesia and Intensive Care Medicine

Publications and helpful links

General Publications

• Gattinoni L, Tonetti T, Cressoni M, Cadringher P, Herrmann P, Moerer O, Protti A, Gotti M, Chiurazzi C, Carlesso E, Chiumello D, Quintel M. Ventilator-related causes of lung injury: the mechanical power. Intensive Care Med. 2016 Oct;42(10):1567-1575. doi: 10.1007/s00134-016-4505-2. Epub 2016 Sep 12.
• Spraider P, Abram J, Martini J, Putzer G, Glodny B, Hell T, Barnes T, Enk D. Flow-controlled versus pressure-controlled ventilation in cardiac surgery with cardiopulmonary bypass - A single-center, prospective, randomized, controlled trial. J Clin Anesth. 2023 Dec;91:111279. doi: 10.1016/j.jclinane.2023.111279. Epub 2023 Oct 3.

Study record dates

Study Major Dates

• Study Start (Actual): January 31, 2024
• Primary Completion (Estimated): April 30, 2025
• Study Completion (Estimated): May 30, 2025

Study Registration Dates

• First Submitted: January 16, 2024
• First Submitted That Met QC Criteria: January 16, 2024
• First Posted (Actual): January 24, 2024

Study Record Updates

• Last Update Posted (Actual): March 12, 2024
• Last Update Submitted That Met QC Criteria: March 11, 2024
• Last Verified: January 1, 2024

More Information

Terms related to this study

• Keywords: Mechanical Power; Flow-controlled Ventilation; Power Dissipation
• Other Study ID Numbers: 1091/2023

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: The IPD can be requested from the principal investigator.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No