A randomized control trial using intraoperative dexmedetomidine during Roux-en-Y gastric bypass surgery to reduce...

Dexmedetomidine (DMET), a selective a2-adrenergic agonist, is an opioid-sparing adjuvant sedative that avoids respiratory depression and has been shown to be beneficial in bariatric surgery patients. Although benefit has been shown, prior studies have not evaluated the pain control effects of a single intraoperative bolus.

To evaluate the postoperative effects of a single intraoperative dose of DMET.

University Hospital, United States.

This is a prospective, randomized, double-blinded study registered with clinicaltrials.gov (#NCT02604940). Patients undergoing laparoscopic Roux-en-Y gastric bypass surgery were randomized and given either a placebo or an intraoperative DMET bolus, where 1 mg/kg was delivered over 10 minutes at the time of surgical closure. Measured outcomes included the following: postoperative pain scores, patient-controlled analgesia (PCA) opioid consumption, PCA demand bolus attempts, duration of postanesthesia care unit (PACU) stay, and vital signs. Descriptive statistics were recorded as frequencies and compared using Χ² analysis, and a Welch's 2-sample t test was used to compare continuous variables.

Forty-six participants undergoing laparoscopic Roux-en-Y gastric bypass surgery were randomized into placebo (n = 20) or DMET (n = 26) groups. There were no statistical differences in age (45.1 versus 43.2 yr, P = .522), sex (80% versus 81% female, P = .948), and body mass index (46.1 versus 45.6 kg/m², P = .818) between the 2 groups. There were no statistically significant differences in vital signs (heart rate, blood pressure, oxygen saturation, and respiration rate) between DMET and placebo groups in the preoperative and intraoperative period. During the initial 4 hours in the PACU postoperatively, mean heart rate (70 ± 12 versus 86 ± 14, P < .001), systolic blood pressure (107 ± 17 versus 148 ± 16, P < .001), and diastolic blood pressure (56 ± 15 versus 79 ± 13, P < .001) were significantly lower in the DMET-treated group compared with placebo. During the initial 4 hours in the PACU, mean self-reported pain scores were significantly lower in the DMET-treated group (3.6 ± 2.8) compared with the placebo group (6.7 ± 3; P = .005). The lower pain scores occurred with no significant difference in the mean opioid dosage received in the PACU between DMET-treated (2.66 ± 2.02 mg) and placebo (3.7 ± 2.3 mg; P = .09) groups. Also, there was no statistically significant difference in the total number of PCA attempts for opioids between the DMET-treated and placebo groups (P = .49).

A single bolus of DMET (1 mg/kg delivered over 10 min) administered at the time of surgical closure did not reduce immediate PACU usage of opioids but significantly reduced reported pain scores and caused a significant decrease in the number of attempts made by patients; this is a trend of decreased attempts over time (P = .04) in the DMET group. The trend of the mean total medication used over time indicates that there is neither an increasing nor decreasing trend for the DMET group, but there is an increasing trend in the total used over time for the placebo group. There was no statistically or clinically significant bradycardia, hypotension, hypoxia, respiratory depression intraoperative duration, or PACU stay. Reduced single bolus dosing of DMET required for analgesia in bariatric surgery patients is optimal from physiologic, level of care, and cost perspectives.