Evaluation of the Risk of Hyperoxia-induced Hypercapnia in Obese Patients in a Cardiac Surgery Postoperative Setting
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Laval University
- Enrollment
- 30
- Locations
- 2
- Primary Endpoint
- Difference in PaCO2
Study Overview
Brief Summary
This study aims to evaluate the risk of hyperoxia-induced hypercapnia in post-op obese cardiac surgery patients. It will compare two oxygenation modes in terms of their effect on the arterial partial pressure of carbon dioxide (PaCO2) : manual titration of oxygen delivery for a peripheral oxygen saturation (SpO2) target of > or = 95 % versus automatic titration by a closed-loop system for a SpO2 target of 90%. 15 post-op obese cardiac surgery patients will be recruited and each will receive both interventions (cross-over design). The main outcome will be the PaCO2, which will be compared after each study period. The research hypothesis is that the usual SpO2 target of > or = 95 % is associated with a greater PaCO2 compared with a lesser SpO2 target of 90%.
Detailed Description
This study aims to evaluate the risk of hyperoxia-induced hypercapnia in post-op obese cardiac surgery patients.
The investigators will compare two oxygenation modes in terms of their effect on PaCO2 : a SpO2 target of > or = 95 % achieved with manual titration (usual practice) and a more conservative SpO2 target of 90 % achieved with automatic titration by a closed-loop system (FreeO2).
The choice of a SpO2 target of 90 % is consistent with recent guidelines issued by the British Thoracic Society and the Thoracic Society of Australia and New Zealand, which both recommend a SpO2 target of 88-92 % for morbidly obese patients (BMI > 40 kg/m2).
FreeO2 is a closed-loop oxygen delivery system which adjusts the oxygen flow according to the patient's real-time SpO2 and a target programed by the physician. The system also records data on heart rate, respiratory rate and SpO2. Its safety and efficacy have been tested in healthy subjects as well as in patients suffering from COPD or acute respiratory distress in the emergency room, with promising results.
The research hypothesis is that the usual SpO2 target of > or = 95 % is associated with a greater PaCO2 compared with a lesser SpO2 target of 90%.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Supportive Care
- Masking
- None
Eligibility Criteria
- Ages
- 18 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •BMI > 30 kg/m2
- •SpO2 > or = 95 % before extubation
- •Procedure : coronary artery bypass
Exclusion Criteria
- •Comorbidities : chronic obstructive pulmonary disease, cystic fibrosis, restrictive syndrome not associated with obesity (pulmonary fibrosis, neuromuscular junction disease, etc.)
- •Obstructive sleep apnea requiring a positive-pressure mask in the posteoperative period
- •FreeO2 device unavailable
- •Inclusion in another study that does not permit dual inclusion
Arms & Interventions
Group A
15 patients who will receive usual care for 30 minutes and then switch to FreeO2 for another 30 minutes
Intervention: FreeO2 (Other)
Group A
15 patients who will receive usual care for 30 minutes and then switch to FreeO2 for another 30 minutes
Intervention: Usual care (Other)
Group B
15 patients who will be oxygenated by FreeO2 for 30 minutes and then switch to usual care for another 30 minutes
Intervention: FreeO2 (Other)
Group B
15 patients who will be oxygenated by FreeO2 for 30 minutes and then switch to usual care for another 30 minutes
Intervention: Usual care (Other)
Outcomes
Primary Outcomes
Difference in PaCO2
Time Frame: At 30 minutes (first intervention) and at 1h (second intervention)
Difference in end-of-period PaCO2 on arterial blood gas
Secondary Outcomes
- Difference in respiratory rate (manual and monitor)(At 0, 10, 20, 30, 40, 50 and 60 minutes)
- Difference in arterial blood pressure(At 0, 10, 20, 30, 40, 50 and 60 minutes)
- Difference in vasopressor dosage(At 0, 10, 20, 30, 40, 50 and 60 minutes)
- Difference in PaO2(At 30 minutes (first intervention) and at 1h (second intervention))
- Difference in percentage of time spent in hyperoxemia (SpO2 > 96 %)(In the first 30 minutes (first intervention) and between 30 min and 1h (second intervention))
- Difference in mean heart rate(In the first 30 minutes and between 30 and 60 minutes)
- Difference in pulmonary artery pressure(At 0, 10, 20, 30, 40, 50 and 60 minutes)
- Difference in percentage of time spent in severe hypoxemia (SpO2 < 85 %)(In the first 30 minutes (first intervention) and between 30 min and 1h (second intervention))
- Difference in pH(At 30 minutes (first intervention) and at 1h (second intervention))
- Difference in percentage of time spent in hypoxemia (SpO2 < 88%)(In the first 30 minutes (first intervention) and between 30 min and 1h (second intervention))
- Difference in body temperature(At 0, 10, 20, 30, 40, 50 and 60 minutes)
Investigators
François Lellouche
MD, PhD
Laval University