Baylor University Medical Center Proceedings January 2014, Volume 27, Number 1 | Page 7

Continuous electrocardiogram, pulse oximetry (SpO2), and
transcutaneous carbon dioxide (tcpCO2) monitoring (TOSCA®,
Radiometer, Copenhagen, Denmark) was in place while the
patients were on the study drug. Blood pressure, heart rate,
respiratory rate, SpO2, tcpCO2, pain score, and RSS were assessed and recorded every 2 hours and immediately preceding
and 30 minutes following study drug titration. If the study drug
remained off for >4 hours, the patient was withdrawn from the
study. Concomitant medications (including any concomitant
vasoactive medication required), total opioids administered,
and adverse events were recorded. The study drug was discontinued at hour 24 of infusion, which was approximately 42 to
48 hours postsurgery or when the prepared study drug expired,
whichever was sooner.
This was a double-blind, placebo-controlled randomized
superiority pilot study. The primary outcome of interest was
the amount of self-administered opioid medication during 24
hours after PACU or ICU discharge and 24 to 48 hours after
surgery. The active drug study group was treated with low-dose
dexmedetomidine and the placebo group with saline. Secondary outcomes were average pain scores, average sedation level
as measured by RSS, instances of respiratory depression and
hemodynamic instability, and the adverse effects of dexmedetomidine in this patient group.
To calculate an appropriate sample size and baseline opioid use, a preparatory chart review study was conducted. The
medical records of 10 patients who would be typical of those
presenting to this study were reviewed for their opioid use in
the first 24 hours after discharge from the ICU or PACU. Fentanyl, hydromorphone, and other opioids were converted to
intravenous morphine sulfate equivalents (mg) (Table 1). The
data suggested that in a group of 10 thoracotomy patients,
the amount of self-administered opioid in the first 24 hours
post-PACU or ICU would range from 68 to 122.5 mg with a
mean of 85 mg and a standard deviation of 20 mg. Of interest
was to reduce the opioid use by half, i.e., to a mean value of
42.5 mg. Assuming that low-dose dexmedetomidine causes the
average total opioid use during the first 24 h