Influence of Oxygen on Perioperative Outcome in Patients Undergoing General Anaesthesia for Elective Non-cardiac Surgery

Not Applicable

Recruiting

• Conditions: Coronary Artery Disease; Anesthesia
• Interventions: Drug: Oxygen

• Registration Number: NCT04808401
• Lead Sponsor: Insel Gruppe AG, University Hospital Bern

Brief Summary

The purpose of this study is to investigate the impact of supraphysiologic oxygen (hyperoxia) on myocardial function in anaesthetized patients undergoing non-cardiac vascular surgery.

Detailed Description

Up to 110 patients with either proven coronary artery disease (CAD) or two or more risk factors for CAD undergoing elective or non-emergent non-cardiac vascular surgery will be recruited. Three blood samples for levels of myocardial biomarkers will be obtained at different perioperative time points (before anaesthesia induction, 2 hours after skin closure and 24 hours after the end of the surgery). The three myocardial biomarkers investigated are high-sensitive Troponin T (hsTnT), N-terminal (NT)-pro hormone BNP (NT-proBNP) and heart-type fatty acid binding protein (H-FABP). In the timeframe shortly after the induction of anaesthesia and prior to the start of surgery, myocardial strain as a marker of cardiac function will be measured by transesophageal echocardiography (TEE). Echocardiography measurements will be acquired at two different oxygen states for each patient.The fraction of inspired oxygen (FiO2) will be adjusted to reach a normoxaemic state (FiO2=0.3) and a hyperoxic state (FiO2=0.8). Patients will be randomized to which oxygen level is investigated first. Thereafter, the patients are again randomly assigned to either the normoxaemic or the hyperoxic state for the remainder of the perioperative treatment until 2 hours after skin closure. Surgery will be performed as planned by the treating team. Differences in the perioperative levels of myocardial biomarkers at the different time points and their dynamics will be assessed. Echocardiography images will be analyzed in a blinded manner for cardiac function and systolic and diastolic strain parameters. The results will help anaesthesiologists to better weigh risks and benefits when selecting an inspired oxygen fraction in such patients, and will help to evaluate hyperoxia as a risk factor for myocardial injury.

Study Timeline

• Study First Submitted: 2021-03-15
• Study First Submitted QC: 2021-03-18
• Study First Posted: 2021-03-22
• Study Start: 2021-05-07
• Status Verified: 2024-12
• Last Update Submitted: 2024-12-09
• Last Update Posted: 2024-12-13
• Primary Completion: 2027-12
• Study Completion: 2028-12

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 110

Inclusion Criteria

• Written informed consent
• Patients eligible for the study should be scheduled for elective or non-emergent non-cardiac vascular surgery under general anaesthesia with endotracheal intubation, and have either
• proven CAD and will undergo high- or intermediate surgical risk procedure according to European (European Society of Cardiology, ESC / European Society of Anaesthesiology and Intensive Care, ESAIC) guidelines on non-cardiac surgery.

or

• two or more risk factors for CAD and will undergo high- or intermediate surgical risk procedures according to European ESC/ESAIC guidelines on non-cardiac surgery.

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Exclusion Criteria

• Acute coronary event 30 days before surgery
• Acute congestive heart failure
• Hemodynamic instability before induction of aneasthesia (vasopressor or inotrope infusion since hospitalization for index surgery)
• Atrial fibrillation or other severe arrhythmia
• Severe pulmonary disease (dependent on oxygen therapy or the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 4 or severe carbon monoxide diffusion impairment or severe pulmonary hypertension)
• Preoperative oxygen saturation (SpO2) below 90% on room air
• Increased risk of oxygen toxicity (e.g., chemotherapy for malignancy within 3 months, bleomycin treatment, airway laser surgery)
• Scheduled surgery in the thoracic cavity
• ICU admission for respirator weaning and delayed extubation
• Pre-existing surgical site infection (SSI)
• Current active signs of systemic inflammatory response syndrome (SIRS) or sepsis according The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3)
• Pregnancy
• Emergency surgery (to be performed within less than 12 hours of scheduling)
• Ambulatory surgery
• Baseline hs-TnT level elevated above 65ng/L

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Normoxaemia First + Hyperoxia Procedure	Oxygen	Patients will undergo TEE imaging at normoxaemia (FiO2=0.3) first, and hyperoxia (FiO2=0.8) will be targeted second. After the image acquisition patients receive hyperoxic concentrations.
Hyperoxia First + Normoxaemia Procedure	Oxygen	Patients will undergo TEE imaging at hyperoxia (FiO2=0.8) first, and normoxaemia (FiO2=0.3) will be targeted second. After the image acquisition patients receive normoxic concentrations.
Normoxaemia First + Normoxia Procedure	Oxygen	Patients will undergo TEE imaging at normoxaemia (FiO2=0.3) first, and hyperoxia (FiO2=0.8) will be targeted second. After the image acquisition patients receive normoxic concentrations.
Hyperoxia First + Hyperoxia Procedure	Oxygen	Patients will undergo TEE imaging at hyperoxia (FiO2=0.8) first, and normoxaemia (FiO2=0.3) will be targeted second. After the image acquisition patients receive hyperoxic concentrations.

Primary Outcome Measures

Name	Time	Method
Difference in hsTnT from preoperative baseline	at 24 hours after surgery	ng/L

Secondary Outcome Measures

Name	Time	Method
Difference in high sensitive TnT from preoperative baseline	at 2 hours after surgery	ng/L
Incidence of myocardial injury in non-cardiac surgery (MINS)	at 24 hours after surgery	MINS is defined as an absolute change of hsTnT levels of at least 5ng/L from preoperative baseline or an hs-TnT level of at least 65ng/L
Difference in myocardial strain rate ratio between oxygen levels	Through study completion, within 1hour post-induction	Change in E/A ratio
Difference in myocardial velocities between oxygen levels	Through study completion, within 1hour post-induction	Change in displacement over time (millimeters/second)
Difference in ejection fraction (EF)	Through study completion, within 1hour post-induction	Percent (%)
Differences in heart type fatty acid binding protein (H-FABP) from preoperative baseline	at 2 hours and 24 hours after surgery	pg/ml
Difference in chamber volumes	Through study completion, within 1hour post-induction	Millilitres (ml)
Differences in N-terminal pro B-type natriuretic peptide (NT-proBNP) from preoperative baseline	at 2 hours and 24 hours after surgery	pg/ml
Difference in peak torsion	Through study completion, within 1hour post-induction	Degrees/centimeter (°/cm)
Difference in myocardial time to peak strain between oxygen levels	Through study completion, within 1hour post-induction	Milliseconds (ms)
Difference in myocardial strain rate between oxygen levels	Through study completion, within 1hour post-induction	Change in strain over time (/second)
Difference in myocardial displacement between oxygen levels	Through study completion, within 1hour post-induction	Millimeters (mm)
Difference in myocardial time to peak displacement between oxygen levels	Through study completion, within 1hour post-induction	Milliseconds (ms)
Difference in peak twist	Through study completion, within 1hour post-induction	Degrees (°)
Difference in myocardial velocity ratio between oxygen levels	Through study completion, within 1hour post-induction	Change in E/A ratio

Trial Locations

Locations (1)

Bern University Hospital, Inselspital; 🇨🇭 Bern, Switzerland