Discharge Readiness After Propofol With or Without Dexmedetomidine for Colonoscopy

A Randomized Controlled Trial

Leonard U. Edokpolo, M.D.; Daniel J. Mastriano, M.D.; Joanna Serafin, Ph.D.; Jeremy C. Weedon, Ph.D.; Maryam T. Siddiqui, M.D.; Dennis P. Dimaculangan, M.D.

Disclosures

Anesthesiology. 2019;131(2):279-286. 

In This Article

Results

One hundred and twenty-two adults, scheduled for colonoscopy, consented to study participation between May 2017 and March 2018; 114 patients were randomized to either propofol–dexmedetomidine (n = 58) or propofol only (n = 56; Figure 1). Thirteen subjects were excluded from the analysis after randomization, as described in figure 1, such that only 51 subjects receiving propofol-dexmedetomidine and 50 subjects receiving only propofol were included in the final per-protocol analysis for noninferiority trials. There were no clinically important differences between groups in age, sex, race/ethnicity, body mass index, baseline mean arterial pressure, baseline heart rate, duration of procedure, and time of arrival in the PACU (Table 1).

Figure 1.

Consolidated Standards of Reporting Trials flow diagram. IV, intravenous line.

Results for the primary outcome are shown in figure 2. Significantly fewer subjects receiving propofol–dexmedetomidine met validated discharge criteria within 30 min from procedure end time: 26 of 51 (51%) subjects receiving propofol-dexmedetomidine, compared with 44 of 50 (88%) subjects receiving propofol, scored greater than or equal to 9 on the Modified Post Anesthetic Discharge Scoring System scale within 30 min from the procedure end time (P < 0.001).

Figure 2.

Cumulative distribution comparing the proportion of subjects in each group who were ready for discharge at various time points from procedure end. Readiness for discharge was assessed every 10 min from procedure end time using the Modified Post Anesthetic Discharge Scoring System (MPADSS). Readiness for discharge is defined as a score of 9 or 10 on the MPADSS scale. P < 0.001 for generalized log-rank test for difference between the two groups. The method of Turnbull was used to estimate cumulative distribution of time to MPADSS greater than 8 in the presence of both interval- and right-censoring.

For the 30-min discharge outcome, a 90% Farrington–Manning CI was constructed for risk difference between study arms. Given that the margin of inferiority was prespecified as 20 percentage points, this CI is (0.204 to 0.501). P < 0.001 for generalized log-rank test for difference between the two groups.

Delay in discharge readiness was primarily due to inability to ambulate. Of the subjects receiving propofol-dexmedetomidine, 22 of 25 (88%) who failed to meet discharge criteria within 30 min scored a 0 out of 2 on the ambulation portion of the Modified Post Anesthetic Discharge Scoring System scale. Similarly, all six (100%) subjects receiving only propofol who failed to meet discharge criteria within 30 min also received a score of 0 out of 2 on the ambulation portion of the Modified Post Anesthetic Discharge Scoring System scale. Nursing staff reported that those patients who received a 0 on the ambulation portion of the Modified Post Anesthetic Discharge Scoring System scale were too drowsy to safely ambulate at that time point. These residual anesthetic effects had diminished significantly in both groups by 40 min from procedure end time such that an aggregate of 82% of subjects receiving propofol–dexmedetomidine (and 96% of subjects receiving propofol) had met Modified Post Anesthetic Discharge Scoring System criteria for discharge to home (Figure 2). In other words, the difference in discharge-readiness was less clinically important after 40 min, since the difference between both groups fell below our predetermined threshold of a 20% differential margin of clinical importance.

Intraprocedure findings and recovery outcomes are shown in Table 2. Propofol consumption was lower in subjects receiving propofol-dexmedetomidine, with a median (quartiles) value of 140 μg · kg−1 · min−1(120 to 200 μg · kg−1 · min−1) compared with 180 μg · kg−1 · min−1 (130 to 240 μg · kg−1 · min−1) in subjects receiving propofol (P = 0.011). The median (quartiles) percentage decrease in MAP, from baseline to lowest value during the procedure was −30% (−25% to −38%) in subjects receiving propofol-dexmedetomidine, and −21% (−14% to −29%) in subjects receiving propofol (P = 0.003). Sustained bradycardia occurred in 3 of 51(6%) subjects receiving propofol-dexmedetomidine and in 1 of 50 (2%) subjects receiving propofol (P = 0.617). Of the three patients in the propofol–dexmedetomidine group with sustained bradycardia, one patient had a preoperative baseline heart rate of 46 bpm. The other two patients had baseline heart rates in the mid-70s bpm. The only patient with sustained bradycardia in propofol group had a preoperative baseline heart rate of 70 bpm. No episodes of apnea requiring intervention with positive pressure ventilation occurred in either group.

There was no significant difference between groups in the median Aldrete scores assessed immediately following the procedure: The median (quartiles) Aldrete score was 5 (4 to 6) in subjects receiving propofol–dexmedetomidine and 5 (4 to 6) in subjects receiving propofol (P = 0.112). However, two (4%) subjects receiving propofol–dexmedetomidine and four (8%) subjects receiving propofol scored greater than or equal to 9 on the Aldrete scale at this stage (not shown). At the time of PACU arrival, fewer subjects receiving propofol–dexmedetomidine scored greater than or equal to 9 on the Aldrete scale: the median (quartiles) Aldrete score was 8 (7 to 9) in subjects receiving propofol–dexmedetomidine and 10 (9 to 10) in subjects receiving propofol (P < 0.001).

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