Prevalence and Clinical Impact of Airway Opening Pressure in Post-Cardiac Surgery Patients

Prevalence and Clinical Impact of Airway Opening Pressure in Post-Cardiac Surgery Patients: A Prospective Observational Study

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 Overview

• Status: Active, not recruiting
• Conditions: Cardiac Surgery; Mechanical Ventilation After Surgery
• Intervention / Treatment: Diagnostic test: Airway opening pressure

• Study Type: Interventional
• Enrollment (Estimated): 196
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Quebec
    • Québec, Quebec, Canada
      • Institut universitaire de cardiologie et de pneumologie de Québec - Université Laval

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Adult (≥18 years)
• Undergoing elective coronary artery bypass grafting (CABG) or valve surgery, or combined procedures with expected postoperative mechanical ventilation

Exclusion Criteria:

- Patient receiving invasive mechanical ventilation prior to surgery

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Post operative cardiac surgery	Diagnostic test: Airway opening pressure; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prevalence of significant airway opening pressure	airway opening pressure ≥ 5 cmH₂O	up to 1 hour after intensive care admission

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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)	up to 1 hour
Airway opening pressure prevalence based on cardiopulmonary bypass duration	Airway opening pressure prevalence based on cardiopulmonary bypass duration (minutes)	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)	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)	up to 1 hour
Airway opening pressure prevalence based on age	Airway opening pressure prevalence base on age	up to 1 hour
Airway opening pressure prevalence based on intraoperative fluid balance	Airway opening pressure prevalence base on intraoperative fluid balance	up to 1 hour
Feasibility of airway opening pressure measurement	proportion of patients in whom the maneuver is successfully completed	up to 1 hour
Positive end expiratory pressure level	Number of times Positive end expiratory pressure is set greater than measured airway opening pressure	up to 1 hour
Extubation	Correlation between airway opening pressure and time to extubation	Day7
Patient position	Comparison of airway opening pressure values in flat versus semi-recumbent (30-degree) positions	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)	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.	up to 15 minutes
Non-interruptive airway opening pressure measurement method	The novel non-interruptive airway opening pressure measurement method will be validated	up to 1 hour

Collaborators and Investigators

• Sponsor: Laval University

Study record dates

Study Major Dates

• Study Start (Actual): June 27, 2025
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): June 1, 2027

Study Registration Dates

• First Submitted: August 27, 2025
• First Submitted That Met QC Criteria: September 16, 2025
• First Posted (Estimated): September 23, 2025

Study Record Updates

• Last Update Posted (Estimated): September 23, 2025
• Last Update Submitted That Met QC Criteria: September 16, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: 2026-4399

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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