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
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
Ondansetron/Zofran is an antiemetic drug used to prevent and treat nausea and vomiting.
Normal saline is salt water and is acting as a placebo in this study. A placebo is an inactive substance that looks identical to the test drug, but it contains no therapeutic ingredient.
St. Paul's Hospital
Vancouver, British Columbia, Canada
Occurrence of Post-operative Nausea and Vomiting (PONV)
Measured by asking the patient hourly to assess their post operative nausea and vomiting using a 10-point verbal Likert rating scale.
Time frame: First 24 hours post-extubation
Incidence of Rescue PONV medication administration
How many participants received rescue post-operative nausea and vomiting medication post-extubation after surgery.
Time frame: First 24 hours post-extubation
Time to first dose of rescue PONV medication
Time of administration of first dose of rescue post-operative nausea and vomiting medication
Time frame: First 24 hours post-extubation
Dose of any Rescue PONV medication
Dose of administered rescue post-operative nausea and vomiting medication after extubation.
Time frame: First 24 hours post-extubation
Time to first report of nausea or first vomit post-operatively
Time to first report of any nausea or vomiting after extubation post-operatively.
Time frame: First 24 hours post-extubation
Incidence of Post-operative nausea without vomiting
Nurses both asked patients' for a nausea severity rating and recorded any vomiting hourly.
Time frame: First 24 hours post-extubation
Severity Post-operative nausea without vomiting
Severity of post-operative nausea without vomiting based on a 10-point likert scale, recorded hourly.
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Time frame: First 24 hours post-extubation
Incidence of ventricular arrhythmias
Any sustained Ventricular Arrhythmias (i.e. lasting greater than 30 seconds)
Time frame: first 24 hours post-extubation