DeXFLoW: Dead Space in Mechanical Ventilation With Constant Expiratory Flow

• Sponsor: University Hospital, Antwerp (Other)
• Overall Status: Not yet recruiting
• CT.gov ID: NCT06024993
• Collaborator: Universiteit Antwerpen (Other)
• Enrollment: 13
• Location: 1
• Arms: 2
• Anticipated Duration (Months): 12
• Patients Per Site Per Month: 1.1

Study Details

Study Description

Brief Summary

Conventional continuous mandatory mechanical ventilation relies on the passive recoil of the chest wall for expiration. This results in an exponentially decreasing expiratory flow.

Flow controlled ventilation (FCV), a new ventilation mode with constant, continuous, controlled expiratory flow, has recently become clinically available and is increasingly being adopted for complex mechanical ventilation during surgery.

In both clinical and pre-clinical settings, an improvement in ventilation (CO2 clearance) has been observed during FCV compared to conventional ventilation. Recently, Schranc et al. compared flow-controlled ventilation with pressure-regulated volume control in both double lung ventilation and one-lung ventilation in pigs. They report differences in dead space ventilation that may explain the improved CO2 clearance, although their study was not designed to compare dead space ventilation within the group of double lung ventilation.

Dead space ventilation, or "wasted ventilation", is the ventilation of hypoperfused lung zones, and is clinically relevant, as it is a strong predictor of mortality in patients with the acute respiratory distress syndrome (ARDS) and is correlated with higher airway driving pressures which are thought to be injurious to the lung (lung stress).

This trial aims to study the difference in dead space ventilation between conventional mechanical ventilation in volume-controlled mode and flow controlled-ventilation.

Condition or Disease	Intervention/Treatment	Phase
Mechanical Ventilation; Artificial Respiration	Device: Flow-controlled ventilation (FCV); Device: Conventional volume-controlled ventilation (VCV)	N/A

Study Design

• Study Type: Interventional
• Anticipated Enrollment: 13 participants
• Allocation: Randomized
• Intervention Model: Crossover Assignment
• Intervention Model Description: Crossover volume-controlled ventilation and flow-controlled ventilationCrossover volume-controlled ventilation and flow-controlled ventilation
• Masking: Double (Participant, Outcomes Assessor)
• Masking Description: During analysis the groups (flow-controlled ventilation and volume-controlled ventilation) will be blinded. Participants know that they will be exposed to both modes of ventilation, but are unaware of the randomized sequence (FCV-VCV or VCV-FCV). It is impossible to mask the investigators delivering the intervention.
• Primary Purpose: Basic Science
• Official Title: Dead Space in Mechanical Ventilation With Constant Expiratory Flow
• Anticipated Study Start Date: Dec 1, 2023
• Anticipated Primary Completion Date: Jul 1, 2024
• Anticipated Study Completion Date: Dec 1, 2024

Arms and Interventions

Arm	Intervention/Treatment
Experimental: FCV-VCV After titration of ventilation in baseline VCV (all arms), participants will first receive 30 min of baseline-matched FCV and subsequently 30 min of baseline-matched VCV.	Device: Flow-controlled ventilation (FCV); 30 minutes of FCV, delivered with the CE-marked Evone ventilator (Ventinova medical, the Netherlands); Device: Conventional volume-controlled ventilation (VCV); 30 minutes of conventional VCV, delivered with the CE-marked Aisys CS3 (GE Healthcare, USA) or Flow-i (Getinge, Sweden) ventilators.
Experimental: VCV-FCV After titration of ventilation in baseline VCV (all arms), participants will first receive 30 min of baseline-matched VCV and subsequently 30 min of baseline-matched FCV.	Device: Flow-controlled ventilation (FCV); 30 minutes of FCV, delivered with the CE-marked Evone ventilator (Ventinova medical, the Netherlands); Device: Conventional volume-controlled ventilation (VCV); 30 minutes of conventional VCV, delivered with the CE-marked Aisys CS3 (GE Healthcare, USA) or Flow-i (Getinge, Sweden) ventilators.

Outcome Measures

Primary Outcome Measures

1. Change in Bohr dead space ventilation (VDBr/VT) [During FCV and VCV measurements (30 minutes)]

   Quantified by the Bohr approach with volumetric capnography

Secondary Outcome Measures

1. Change in Enghoff dead space ventilation (VDEng/VT) [During FCV and VCV measurements (30 minutes)]

   Quantified by the Enghoff approach with volumetric capnography

2. Change in physiological dead space volume (Vdfys) [During FCV and VCV measurements (30 minutes)]

   Measured with volumetric capnography and Enghoff's approach

3. Change in airway dead space volume (Vdaw) [During FCV and VCV measurements (30 minutes)]

   Measured with volumetric capnography and Fletcher's approach

4. Change in alveolar dead space volume (Vdalv) [During FCV and VCV measurements (30 minutes)]

   As measured with volumetric capnography and Fletcher's approach

5. Ventilatory efficiency (VE/VCO2) [During FCV and VCV measurements (30 minutes)]

   Ratio of minute ventilation to carbon dioxide output

6. Change in airway driving pressure (∆Paw) [During FCV and VCV measurements (30 minutes)]

   Calculated as the difference between the plateau pressure (Pplat) during an inspiratory pause and the dynamic positive end-expiratory pressure (PEEP), as no expiratory hold is possible on the Evone.

7. Change in transpulmonary shunt fraction (Qs/Qt) [During FCV and VCV measurements (30 minutes)]

   calculated with the modified Berggren equation

8. Change in global lung hyperdistention (hyperdistentionEIT) [During FCV and VCV measurements (30 minutes)]

   Calculated from electric impedance tomography

9. Change in anterio-posterior distribution of ventilation on EIT (AP) [During FCV and VCV measurements (30 minutes)]

   % anterior / % posterior

10. Change in right-left distribution of ventilation on EIT (RL) [During FCV and VCV measurements (30 minutes)]

    % right / % left

11. Change in 4-layered distribution of ventilation on EIT [During FCV and VCV measurements (30 minutes)]

12. Change in centre of ventilation on EIT [During FCV and VCV measurements (30 minutes)]

13. Change in cardiac index (CI) [During FCV and VCV measurements (30 minutes)]

    Calculated from the arterial waveform (pulse contour analysis) by the HemoSphere monitor

14. Change in mean arterial pressure (MAP) [During FCV and VCV measurements (30 minutes)]

    Measured on a radial artery line

15. Change in partial pressure of arterial CO2 (PaCO2) [During FCV and VCV measurements (30 minutes)]

    Measured on an arterial blood gas

16. Change in peak expiratory flow (PEF) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

17. Change in peak inspiratory flow (PIF) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

18. Change in mean airway pressure (MPaw) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

19. Change in tidal volume (TV) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

20. Change in respiratory rate (RR) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

21. Change in minute ventilation (MV) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

22. Change in inspiratory time (Ti) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

23. Change in expiratory time (Te) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

24. Change in ratio of inspiratory time to total breath time (Ti / Tt) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

25. Change in positive end-expiratory pressure (PEEP) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

26. Change in peak inspiratory pressure (PIP) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

27. Change in plateau pressure (Pplat) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

28. Change in static airway compliance (Caw) [During FCV and VCV measurements (30 minutes)]

    Calculated as tidal volume / airway driving pressure

29. Change in end-tidal CO2 (ETCO2) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

30. Change in global airway resistance (Raw) [During FCV and VCV measurements (30 minutes)]

    As measured by the citrex respiratory monitor

31. Change in global airway time constant (TAUaw) [During FCV and VCV measurements (30 minutes)]

    Calculated as global airway resistance x global airway compliance

32. Change in total energy [During FCV and VCV measurements (30 minutes)]

    As calculated from monitoring data

33. Change in dissipated energy [During FCV and VCV measurements (30 minutes)]

    As calculated from monitoring data

34. Change in P/F ratio [During FCV and VCV measurements (30 minutes)]

    Calculated as partial pressure of arterial oxygen divided by inspiratory fraction of oxygen

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years to 70 Years
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Inclusion Criteria:

• Adults [18-70] yrs

• General anaesthesia for elective surgery

• Arterial line, central venous line and endotracheal tube as part of standard of care

• Expected duration of controlled mechanical ventilation ≥ 60 minutes

• Supine position (0±10°)

Exclusion Criteria:

• One lung ventilation

• Known pregnancy

• Increased abdominal pressure (laparoscopy or BMI > 30kg/m2)

• COPD GOLD IV or home oxygen dependence

• Clinical signs of raised intracranial pressure

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Antwerp University Hospital (UZA)	Edegem	Antwerp	Belgium	2650

Sponsors and Collaborators

• University Hospital, Antwerp
• Universiteit Antwerpen

Investigators

• Principal Investigator: Vera Saldien, M.D., Ph.D., Antwerp University Hospital / University of Antwerp

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: University Hospital, Antwerp
• ClinicalTrials.gov Identifier: NCT06024993
• Other Study ID Numbers: 003029
• First Posted: Sep 6, 2023
• Last Update Posted: Sep 6, 2023
• Last Verified: Mar 1, 2023

• Studies a U.S. FDA-regulated Drug Product: No
• Studies a U.S. FDA-regulated Device Product: No
• Product Manufactured in and Exported from the U.S.: No

Study Results

No Results Posted as of Sep 6, 2023