Clinical trial NCT06024993: Dead Space in Mechanical Ventilation With Constant Expiratory Flow
Official title: Dead Space in Mechanical Ventilation With Constant Expiratory Flow
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Mechanical Ventilation
Artificial Respiration
Lead sponsor: University Hospital, Antwerp
Sponsor class: OTHER
Collaborators: name: Universiteit Antwerpen
First posted: 2023-09-06
Enrollment: 13
Sex: ALL
Minimum age (years): 18
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Crossover volume-controlled ventilation and flow-controlled ventilation
Primary purpose: BASIC_SCIENCE

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.


Eligibility criteria: 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 intra-abdominal pressure (pneumoperitoneum or obesity (BMI \> 30kg/m2))
* COPD GOLD IV or home oxygen dependence
* Cardiac pacemaker, implantable cardioverter-defibrillator (ICD) or thoracic neurostimulator
* Skin lesions (e.g. injury, inflammation) at the level where the Electrical Impedance Tomography (EIT) band is to be applied
* Clinical signs of raised intracranial pressure
* Potential interference with the surgery due to the setup of the study instruments.
* Patient refusal to participate

Primary outcomes:
measure: Change in Bohr dead space ventilation (VDBr/VT)
timeFrame: During FCV and VCV measurements (20 minutes)
Secondary outcomes:
measure: Change in Enghoff dead space ventilation (VDEng/VT)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in physiological dead space volume (Vdfys)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in airway dead space volume (Vdaw)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in alveolar dead space volume (Vdalv)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Ventilatory efficiency (VE/VCO2)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in airway driving pressure (∆Paw)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in transpulmonary shunt fraction (Qs/Qt)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in global lung hyperdistention (hyperdistentionEIT)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in anterio-posterior distribution of ventilation on EIT (AP)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in right-left distribution of ventilation on EIT (RL)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in 4-layered distribution of ventilation on EIT
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in centre of ventilation on EIT
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in cardiac index (CI)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in mean arterial pressure (MAP)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in partial pressure of arterial CO2 (PaCO2)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in peak expiratory flow (PEF)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in peak inspiratory flow (PIF)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in mean airway pressure (MPaw)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in tidal volume (TV)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in respiratory rate (RR)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in minute ventilation (MV)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in inspiratory time (Ti)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in expiratory time (Te)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in ratio of inspiratory time to total breath time (Ti / Tt)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in positive end-expiratory pressure (PEEP)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in peak inspiratory pressure (PIP)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in plateau pressure (Pplat)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in static airway compliance (Caw)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in end-tidal CO2 (ETCO2)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in global airway resistance (Raw)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in global airway time constant (TAUaw)
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in total energy
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in dissipated energy
timeFrame: During FCV and VCV measurements (20 minutes)
measure: Change in P/F ratio
timeFrame: During FCV and VCV measurements (20 minutes)
Other outcomes:
Locations:
city: Edegem
country: Belgium
facility: Antwerp University Hospital (UZA)
state: Antwerp
Study officials:
affiliation: Antwerp University Hospital / University of Antwerp
name: Vera Saldien, M.D., Ph.D.
role: PRINCIPAL_INVESTIGATOR
References: