Evaluation of Acid-base Disorders and Ventilation Settings in Cardiogenic Shock and Post-cardiac Arrest Patients: Comparison With VentilO Algorithm (VentilO CU)

This study aims to better understand how mechanical ventilation settings affect patients admitted to the coronary care unit after cardiac arrest or with cardiogenic shock. These patients often require mechanical ventilation, but current guidelines provide limited evidence on the best approach. Improper ventilation settings can lead to acid-base imbalances, such as respiratory acidosis or alkalosis, which may worsen patient outcomes.

The retrospective analysis will include 100 adult patients (50 post-cardiac arrest and 50 with cardiogenic shock) who were mechanically ventilated upon admission. The study has two main objectives:

Determine how often acid-base disorders occur in these patients and describe their characteristics.

Compare the initial ventilator settings chosen by clinicians with those suggested by VentilO, a decision-support algorithm.

The investigators will evaluate the potential effect of the VentilO recommendations on the first arterial (or capillary) blood gases compared to the real settings.

This information will help refine the algorithm and guide future research on improving ventilation strategies for critically ill cardiac patients.

Participation does not involve any intervention, as the study uses existing medical records.

Study Overview

• Status: Not yet recruiting
• Conditions: Cardiogenic Shock; Mechanical Ventilation; Cardiac Arrest (CA); Acid Base Disorder
• Intervention / Treatment: Other: Initiation of mechanical ventilation

• Study Type: Observational
• Enrollment (Estimated): 100

Contacts and Locations

• Study Contact: Name: Francois Lellouche; Phone Number: 3572 1-418-656-8711; Email: francois.lellouche@criucpq.ulaval.ca

Study Locations

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

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

post cardiac arrest or cardiogenic shock

Description

Inclusion Criteria:

• Adult (Age >=18 years old)
• Under mechanical ventilation with endotracheal tube for :

post cardiac arrest or cardiogenic shock

- Bood gases result availability up to 4 hours after coronary unit admission

Exclusion Criteria:

• Lack of patient anthropometric data (height and weight) available in the patient record
• No information in the record regarding the data on the humidification systems used at the time of the first blood gas test upon admission to the coronary care unit.
• Patient stabilzed in other hospital before coronary unit admission or adjustment of respiratory parameters after a blood gas test.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patient post cardiac arrest	Other: Initiation of mechanical ventilation; Blood gases evaluation after initiation of mechanical ventilation
Patient with cardiogenic shock	Other: Initiation of mechanical ventilation; Blood gases evaluation after initiation of mechanical ventilation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Acid-base disorder (respiratory acidosis)	Presence of respiratory acisosis define by pH< 7.35 and PaCO2 > 45 mmHg	Up to 4 hours after admission to the coronary care unit - First blood gas sample
Acid-base disorder (respiratory alcalosis)	Presence of respiratory alcalosis define by by pH>7.45 and PaCO2 < 35 mmHg	Up to 4 hours after admission to the coronary care unit - First blood gas sample

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ventilator setting (Respiratory rate)	Respiratory rate set by the doctor, these setting will be compared to the suggestion of the algorithm	Up to 4 hour after coronary unit admission - At the last ventilator setting before blood gas sample
Ventilator setting (Tidal volume)	Tidal volume set by the doctor, these setting will be compared to the suggestion of the algorithm	Up to 4 hour after coronary unit admission - At the last ventilator setting before blood gas sample
Acid-base disorder (metabolic acidosis)	Presence of metabolic acidosis define by HCO3 < 20 mmol/L	Up to 4 hours after admission to the coronary care unit - First blood gas sample
Acid-base disorder (metabolic alcalosis)	Presence of metabolic acidosis define by HCO3 > 28 mmol/L	Up to 4 hours after admission to the coronary care unit - First blood gas sample
Optimal acid-base result	Presence of optimal pH (7.35-7.45) with optimal PCO2 (35-45 mmHg)	Up to 4 hours after admission to the coronary care unit - First blood gas sample
Mechanical ventilation duration	Time spent with invasive mechanical ventilation aftercoronary unit admission and hospital discharge	Up to 90 days
Vasopressor duration	Duration of vasopressor or inotrop administration	Day 28
Hospital length of stay	Coronary unit admission through hospital discharge	Up to 90 days
Mortality	Mortality at coronary unit	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 mmol/L creatinine in 48 hours or 1.5x over the baseline	Up to 90 days. Coronary unit stay - admission through discharge or until death if occured

Collaborators and Investigators

• Sponsor: Laval University

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: March 5, 2026
• First Submitted That Met QC Criteria: March 18, 2026
• First Posted (Actual): March 20, 2026

Study Record Updates

• Last Update Posted (Actual): March 20, 2026
• Last Update Submitted That Met QC Criteria: March 18, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Infarction; Necrosis; Myocardial Ischemia; Myocardial Infarction; Ischemia; Shock; Pathological Conditions, Signs and Symptoms; Heart Arrest; Shock, Cardiogenic
• Other Study ID Numbers: 2026-4504

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