Isoflurane is noninferior to sevoflurane as an anaesthetic in cases of cardiac surgery, according to study results presented at the 2015 Annual Meeting of the Canadian Anesthesiologists’ Society (CAS).
“There was no evidence that there was a difference in effect between the 2 treatments,” said lead investigator Philip M. Jones MD, The University of Western Ontario, London, Ontario, Canada, speaking here on June 21.
The frequent application of sevoflurane, however, is costly, added Dr. Jones. He and his colleagues performed an economic analysis and calculated that in the United States, for example, if half of all cardiac surgeries used isoflurane instead of sevoflurane as the surgical anaesthetic, there would be an estimated $10 million in savings annually.
Both drugs are considered volatile anaesthetics.
During coronary-artery bypass graft (CABG) or CABG with single-valve repair or replacement or single-valve repair/replacement surgery, Dr. Jones and colleagues randomised 464 adult patients to anaesthesia with either sevoflurane (n = 231) or isoflurane (n = 233) at a dose of 0.5 to 2.0 minimum alveolar concentration.
The team used a composite primary outcome that included length of stay of 48 hours or longer in the intensive care unit (ICU) or all-cause mortality at 30 days after surgery.
The primary outcome occurred in 25% of patients receiving sevoflurane and 30% of patients receiving isoflurane, leading the investigators to conclude that sevoflurane was not superior to isoflurane. Isoflurane was not less effective than sevoflurane, however, in terms of secondary outcomes like new-onset haemodialysis, atrial fibrillation, stroke, all-cause mortality at 1 year, and readmission to ICU, added Dr. Jones.
Patients in both arms of this study were similar in terms of age, weight, gender, and presence of comorbidities.