Airway opening pressure is a key parameter in assessing respiratory mechanics. Current practice primarily relies on indirect assessments of lung mechanics, but growing evidence suggests that direct airway opening pressure measurement could enhance individualized ventilatory strategies. Significant airway opening pressure suggests incomplete alveolar recruitment at end-expiration, which may contribute to ventilation-perfusion mismatch, increased respiratory effort, and postoperative pulmonary complications such as atelectasis and impaired gas exchange. Determining the prevalence and clinical relevance of significant airway opening pressure in post-cardiac surgery patients could contribute to more personalized respiratory strategies and improve postoperative care.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
196
Airway opening pressure will be measured within one hour of intensive care unit admission (using a standardized low-flow insufflation maneuver flow 5-6 LPM). The inflection point on the pressure-time or pressure-volume waveform- depending on ventilator model-will define the airway opening pressure.
Institut universitaire de cardiologie et de pneumologie de Québec - Université Laval
Québec, Quebec, Canada
Prevalence of significant airway opening pressure
airway opening pressure ≥ 5 cmH₂O
Time frame: up to 1 hour after intensive care admission
Airway opening pressure prevalence based on body mass index
Airway opening pressure prevalence base on Obesity status (body mass index ≥30 vs. \<30 kg/m²)
Time frame: up to 1 hour
Airway opening pressure prevalence based on cardiopulmonary bypass duration
Airway opening pressure prevalence based on cardiopulmonary bypass duration (minutes)
Time frame: up to 1 hour
Airway opening pressure prevalence based on left ventricular dysfunction
Airway opening pressure prevalence based on left ventricular dysfunction (Ieft ventricular ejection fraction \< 50 percent vs \> 50 percent)
Time frame: up to 1 hour
Airway opening pressure prevalence based on inotropic support
Airway opening pressure prevalence based on use of amines (\< 0.1 mcg/kg/min or norepinephrine equivalent vs \> 0.1 mcg/kg/min or norepinephrine equivalent)
Time frame: up to 1 hour
Airway opening pressure prevalence based on age
Airway opening pressure prevalence base on age
Time frame: up to 1 hour
Airway opening pressure prevalence based on intraoperative fluid balance
Airway opening pressure prevalence base on intraoperative fluid balance
Time frame: up to 1 hour
Feasibility of airway opening pressure measurement
proportion of patients in whom the maneuver is successfully completed
Time frame: up to 1 hour
Positive end expiratory pressure level
Number of times Positive end expiratory pressure is set greater than measured airway opening pressure
Time frame: up to 1 hour
Extubation
Correlation between airway opening pressure and time to extubation
Time frame: Day7
Patient position
Comparison of airway opening pressure values in flat versus semi-recumbent (30-degree) positions
Time frame: up to 1 hour
Hemodynamic tolerance base on blood pressure drop
Evaluation of hemodynamic tolerance based on arterial pressure during positive end-expiratory pressure adjustment (if inotropic agents are required, an increase of more than 0.05 mcg/kg/min in norepinephrine equivalent is considered significant)
Time frame: up to 15 minutes
Hemodynamic tolerance base on pulse oxygen saturation drop
Evaluation of hemodynamic tolerance based on pulse oxygen saturation. A decrease in pulse oxygen saturation of 5 percent from baseline or more is considered significant.
Time frame: up to 15 minutes
Non-interruptive airway opening pressure measurement method
The novel non-interruptive airway opening pressure measurement method will be validated
Time frame: up to 1 hour
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