Anesthesia practice in the 21st century is increasingly outcomes-oriented and evidence-based, but there remain significant gaps in our knowledge, even for commonly-encountered clinical situations. Currently, the two most commonly used drugs used for maintenance of anesthesia in cardiac surgical patients are isoflurane and sevoflurane. There is a belief among many cardiac anesthesiologists that sevoflurane is a better cardiac anesthetic than isoflurane, but there is very little data to support this notion. In fact, very little is known about their comparative effects on important patient outcomes because there has not been a large head-to-head prospective randomized clinical trial. This project will supply the data necessary to critically compare the two anesthetics.
Current evidence supports the superiority of sevoflurane for myocardial protection during cardiac surgery when compared to total intravenous anesthesia with propofol. However, there is no evidence to suggest that sevoflurane is superior to isoflurane for myocardial protection during cardiac surgery. Sevoflurane may potentially reduce the rate of post-cardiac surgery atrial fibrillation and the time to tracheal extubation compared to isoflurane, but the literature is equivocal on these two important outcomes. Anesthesiologists still frequently use isoflurane for maintenance of cardiac anesthesia, and this is likely because there is substantial uncertainty about whether or not sevoflurane is superior to isoflurane, given the lack of head-to-head RCTs. A large, prospective, pragmatic RCT can ultimately assist clinicians by providing evidence of the non-inferiority (or, possibly the superiority) of one anesthetic compared to the other on important patient outcomes such as ICU length of stay, mortality, renal dysfunction, time to tracheal extubation after cardiac surgery, rates of clinically-important atrial fibrillation, and myocardial damage.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
464
The intervention in this trial is randomization to either maintenance of anesthesia with sevoflurane or maintenance of anesthesia with isoflurane. The designated volatile anesthetic will be given at a strict minimal amount throughout the entire cardiac surgery (including cardiopulmonary bypass). This regimen (administration throughout the entire operation) has proved to have the greatest efficacy. Apart from this intervention, the anesthetic for patients participating in this trial will not be substantially different from normal practice, as the intention is to allow normal practice (with the exception of the choice of volatile anesthetic agent) to maximize the applicability and external validity of the trial. The management of anticoagulation, cardiac surgical techniques, and other aspects of the procedure will be managed in an unaltered fashion. No IV drug infusions will be permitted until after protamine administration.
University Hospital - London Health Sciences Centre
London, Ontario, Canada
Composite of: prolonged ICU stay (>= 48 hours) OR death within 30 days of operation
Time frame: 30 days of operation
Postoperative cardiac troponin T
Troponin T sampled at 6 hours after admission to the ICU. The time of sampling will be recorded. The sample will be taken from an indwelling venous or arterial cannula (if one exists) or by venipuncture.
Time frame: 6 hours after admission to ICU
Length of stay in the ICU (criteria)
The time from admission in ICU (time 0) until the patient's transfer orders to the floor are enacted.
Time frame: Participants will be followed for the duration of ICU stay, an expected average of 1 day
30-day all-cause mortality
A participant who has died for any reason before the end of 30th day after the operation. Day 1 is the first calendar day after first being admitted to the ICU.
Time frame: 30 days after operation
Duration of tracheal intubation
The time from being admitted to the ICU (time 0) until the patient's tracheal tube is removed for the first time.
Time frame: Participants will be followed for the duration of ICU stay, an expected average of 1 day
Inotrope or vasopressor usage in the ICU
A participant who is treated at any time after the first hour of their ICU stay with an inotropic or vasopressor by infusion.
Time frame: Participants will be followed for the duration of ICU stay, an expected average of 1 day
Prolonged inotrope or vasopressor usage in the ICU
Any patient requiring 12 or more continuous hours of any combination of inotropic or vasopressor agent (including the first hour) in the ICU.
Time frame: Participants will be followed for the duration of ICU stay, an expected average of 1 day
Peak postoperative serum creatinine
Peak postoperative creatinine as recorded in the hospital chart.
Time frame: Participants will be followed for the duration of hospital stay, an expected average of 1 week
New-onset dialysis
Any patient, not previously on dialysis, requiring postoperative dialysis (hemodialysis or peritoneal dialysis).
Time frame: Participants will be followed for the duration of hospital stay, an expected average of 1 week
Incidence of new-onset atrial fibrillation
We will capture the proportion of patients who have clinically significant new atrial fibrillation at any time from ICU admission until the end of POD 4. The adjudication of atrial fibrillation will be recorded by the blinded research nurse.
Time frame: Until end of post-operative day 4
Incidence of intra-aortic balloon pump usage
The proportion of patients having an intra-aortic balloon pump inserted (either in the operating room or in the ICU).
Time frame: Participants will be followed for the duration of ICU stay, an expected average of 1 day
Length of stay in the ICU (actual)
The time from admission in ICU (time 0) until the patient is discharged from the ICU.
Time frame: Participants will be followed for the duration of ICU stay, an expected average of 1 day
Length of stay in the hospital (actual)
The time from admission to the ICU until the patient is discharged home from the hospital.
Time frame: Participants will be followed for the duration of hospital stay, an expected average of 1 week
Readmission to ICU
Readmission to the ICU for any reason.
Time frame: Participants will be followed for the duration of hospital stay, an expected average of 1 week
Perioperative stroke
A new neurological abnormality persisting \> 24 hours with documentation by formal neurological examination and evidence of new brain lesions on a brain imaging study.
Time frame: Participants will be followed for the duration of hospital stay, an expected average of 1 week
1-year all-cause mortality
A participant who has died for any reason within the first year after the operation. For example, if the operation takes place on June 20 2011, then mortality up to and including June 19 2012 will be counted.
Time frame: One year after operation
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