Single intraoperative IV dose of methadone safe and may not prolong QTc significantly in cardiac surgical patients: Study

A total of 1,040 adult patients who underwent elective cardiac surgery between July 2020 and July 2023 at a tertiary academic medical institution were studied. Among those, 423 received intraoperative methadone 0.1 mg/kg and 617 other types of analgesics, as part of the enhanced recovery after cardiac surgery (ERACS) pathway. This retrospective cohort study used validated institutional electronic medical record data to study the perioperative effects of intravenous methadone. All adult patients undergoing elective cardiac surgery were included in this study and divided into two groups: those who received methadone and those who did not.

Main outcomes measu

• Primary Outcomes: Change in QTc and percentage QTc change between preoperative and postoperative measurements during intensive care unit admission.

• Secondary Outcomes: Intraoperative ventricular and atrial arrhythmias, length of stay in the ICU, 30-day mortality, 1-year mortality, and days to death.

• QTc intervals were measured before surgery, and immediately and at 24 hours postoperatively to determine the presence of significant differences and trends between the groups.

Key Findings

QTc Interval Changes

• QTc was prolonged at postoperative day one but resolved at 24 hours postoperative in the methadone and the nonmethadone cohorts.

• No significant differences in baseline QTc, immediate postoperative QTc, changes in QTc, or percent QTc changes were observed between groups.

Incidence of Arrhythmias

• No significant differences were noted postoperatively between the groups on ventricular arrhythmias and atrial fibrillation

Mortality Rates

• The groups were not significantly different when comparing 30-day mortality, 1-year mortality, days to death

• Days to death were comparable between the two groups.

Safety Profile

• The results verified that a single dose of methadone given in the operating room at a dose of 0.1 mg/kg does not significantly contribute to QTc prolongation and is not associated with an increased risk of arrhythmias.

A single dose of intraoperative intravenous methadone (0.1 mg/kg) was safe for adult cardiac surgical patients, with no significant prolongation or increased risk of arrhythmias on QTc intervals. These results bring out the potential of methadone as a safe analgesic in enhanced recovery pathways for cardiac surgery, addressing concerns regarding its impact on cardiac electrophysiology.

Reference:

McClain, M. R., Subramaniam, K., Cheema, R., Lavage, D. R., Lin, H.-H. S., Sultan, I., Sadhasivam, S., & Howard-Quijano, K. (2024). Intraoperative methadone in adult cardiac surgical patients and risks for postoperative QTc prolongation. Journal of Cardiothoracic and Vascular Anesthesia. https://doi.org/10.1053/j.jvca.2024.11.012