Prophylactic Ondansetron in Post-op Cardiac Surgery Patients to Prevent Post-operative Nausea and Vomiting
Prophylactic Ondansetron in Post-op Cardiac Surgery Patients to Prevent Post-operative Nausea and Vomiting
To evaluate the effectiveness of a prophylactic dose of ondansetron in decreasing the
 incidence of post-operative nausea and vomiting in cardiac surgery patients after cessation
 of post-operative sedation. In patients who have undergone open heart surgery, a single
 prophylactic dose of ondansetron 4 mg IV given at the time of discontinuing propofol sedation
 will result in a 50% reduction of the rate of post-operative nausea and vomiting in the first
 24 post-operative hours compared to placebo.
Post-operative nausea and vomiting (PONV) is a significant source of morbidity for patients
 undergoing general anesthesia, and in particular, patients undergoing cardiac anesthesia.
 Despite its common occurrence, literature on PONV prophylaxis in the cardiac surgical
 population is limited relative to other surgical populations.

 A rational approach to preventing PONV would be to administer prophylaxis prior to extubation
 once post-operative sedation has ceased. This timing of administration would be more
 standardized across patients, as duration of surgery and time of extubation after surgery can
 vary considerably, rendering plasma levels of PONV prophylaxis agents highly variable across
 patients.

 At St. Paul's Hospital, PONV prophylaxis has not been a routine part of cardiac anesthesia
 care. Furthermore, there are no standardized guidelines, and practice varies between care
 providers. Following surgery, patients recover from anesthesia and are extubated in the
 cardiac surgery ICU (CSICU). They are usually sedated on a propofol infusion for one to four
 hours after surgery until they are ready for extubation. When PONV occurs, the first line
 drug for treatment is ondansetron 4 mg. The investigators therefore propose the use of a
 single, prophylactic dose of ondansetron (4 mg IV), given at the time of propofol cessation.
 A randomized, double blinded placebo controlled model will be utilized
Inclusion Criteria:

 -  Elective (outpatient) and urgent (inpatient) cardiac surgery procedures requiring
 cardiopulmonary bypass, including:

 -  Coronary artery bypass grafting (CABG)

 -  Valve surgery (ie. repair and/or replacement)

 -  CABG and valve surgery

 Exclusion Criteria:

 -  Undergoing 'off-pump' CABG (not involving the cardiopulmonary bypass machine)

 -  With a contraindication to the study drug - including but not limited to congenital
 Long QT Syndrome, allergy to ondansetron, or a history of migraines

 -  Unable to understand the consent process, either due to language limitations or
 cognitive limitations if a translator or substitute decision maker is not available

 -  Receiving heart transplants, ventricular assist devices or on extra-corporeal membrane
 oxygenation (ECMO)

 -  Intubated for more than 12 hours post-operatively

 -  With a known history of PONV

 -  Sedated with dexmedatomine instead of propofol