Right Ventricular Function and Respiratory Acidosis After Cardiac Surgery

Right heart dysfunction remains a frequent cause of morbidity and mortality after cardiac surgery. Respiratory acidosis, particularly when accompanied by hypoxemia, plays a significant role in right heart failure, primarily by increasing right ventricular afterload through pulmonary vasoconstriction and elevated pulmonary arterial pressures. This phenomenon leads to increased right ventricular workload, causing dilation, decreased contractility, and ultimately right heart failure. The study aims to evaluate the effect of respiratory acidosis on right ventricular function after cardiac surgery.

Study Overview

• Status: Not yet recruiting
• Conditions: Mechanical Ventilation; Hemodynamic Changes; Respiratory Acidosis in ICU Patients; Right Ventricular (RV) Dysfunction
• Intervention / Treatment: Other: Not applicable- observational study

Detailed Description

Post hoc analysis of data from two separate studies previously approved by the Research Ethics Board NCT05886413 and NCT06826794. A stratification according to respiratory acidosis defined by a pH <7.35 with PaCO₂ >45mmHg on the first arterial blood gas analysis at the intensive care unit arrival will be done.

• Study Type: Observational
• Enrollment (Estimated): 220

Contacts and Locations

• Study Contact: Name: Etienne Couture; Phone Number: 1-418-656-8711; Email: etienne.couture.3@ulaval.ca

Study Locations

• Canada
  • Quebec
    • Québec, Quebec, Canada, G1V4G5
      • Institut universitaire de cardiologie et de pneumologie de Quebec - Universite Laval

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Adult patients who underwent cardiac surgery mechanically ventilated in controlled mode, and had an arterial blood gas within the first hour following admission.

Description

Inclusion Criteria:

• Previously included and complete study NCT05886413 or NCT06826794

Exclusion Criteria:

• Absence of one or more of the following hemodynamic measurements: systolic or diastolic pulmonary artery pressure, central venous pressure, cardiac output
• Absence of arterial blood gas on arrival to the intensive care unit

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Retrospective cohort; Completed study. Adult patients who underwent cardiac surgery were included if they were admitted to the intensive care unit immediately after surgery, mechanically ventilated in controlled mode, and had an arterial blood gas within the first hour following admission.	Other: Not applicable- observational study; No intervention
Prospective cohort; Completed study. Adult patient included on open-label randomized study, comparing clinician-chosen initial mechanical ventilation parameters to those recommended by an algorithm immediately after ICU admission.	Other: Not applicable- observational study; No intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Right ventricular function per central hemodynamic assessment	Calculation of different predictor: Cardiac index, PAPi (pulmonary artery pulse pressure over central venous pressure) , RVSWI ((mean pulmonary artery pressure- central venous pressure) X stroke volume index X 0.0136) and RV-CPO	At intensive care unit admission - within the first 4 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intensive care unit length of stay	Intensive care unit admission through Intensive care unit discharge	Up to 28 days
Mechanical ventilation duration	Time spent with invasive mechanical ventilation between intensive care unit admission and hospital discharge	Day 28
Vasopressor duration	Duration of vasopressor or inotrope administration	Day 28
Acute renal failure	Rate of acute renal failure during coronary unit length of stay. Renal failure will be defined according to the usual criteria, i.e., an increase of >27 umol/L creatinine in 48 hours or 1.5x over the baseline	Day 28
Mortality	Mortality in intensive care unit	Day 28

Collaborators and Investigators

• Sponsor: Laval University

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): October 1, 2026

Study Registration Dates

• First Submitted: May 8, 2026
• First Submitted That Met QC Criteria: May 28, 2026
• First Posted (Actual): June 1, 2026

Study Record Updates

• Last Update Posted (Actual): June 1, 2026
• Last Update Submitted That Met QC Criteria: May 28, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 2027-4604

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