DOI: 10.1097/00000539-199902001-00024
,
Issn Print: 0003-2999
Publication Date: 1999/02/01
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Excerpt
INTRODUCTION: Previous reports have demonstrated synergism of midazolam and propofol for sedation in humans. The ED50 for the combination was approximately 45% less than expected from the ED50 values of the individual agents. Flumazenil, a benzodiazepine antagonist can shorten the recovery period following sedation with midazolam, and its use is not associated with major side effects. We hypothesized that midazolam and propofol with flumazenil reversal would not impair patient's cognitive and psychomotor function post procedure in outpatient sedation for gastrointestinal endoscopy.
METHODS: The study was approved by the Ethics Committee. After obtaining informed consent, 18 (10 female/8 male), healthy unpremedicated patients undergoing gastrointestinal endoscopy procedures were studied.
ANESTHETIC METHOD: Patients received midazolam 0.06 mgr K-1 and two minutes later, propofol 1.3 mg K-1. When procedure was ended they received flumazenil 0.5 mg. Total duration of procedure study was 14 +/- 3.5 minutes. Patients were presented with a series of tests previous to the anesthetic procedure (M1), 30 (M2) and 60 (M3) minutes after anesthetics discontinuation, cognitive function measurement of reaction time and amount of correct answers. Using the test evaluation of attention (TEA), standardized computerized assessment procedure for cognitive function each patients was presented with a block of 40 trials using a PC computer. Each trial consisted of a signal presented for 500 ms, a target stimulus letter X or sign + distributed randomly, separated by intervals of 3 seconds. Patients used the dominant hand to press on the keyboard as soon as the X or + appeared. Reaction time was recorded to the nearest millisecond.
Psychomotor functions were measured using Bender test. Each subject was presented with a block of 4 pictures out of 8 distributed randomly during 30 seconds in computer monitors; then the patients had to draw the pictures on paper in 60 seconds. The analysis of performance in Bender Test considered the amount of errors as an indicator of affections of psychomotor function.
RESULTS: Reaction time of test evaluation of attention (TEA) no change along the study was seem M1-M2 d=29.35 +/- 77.7 p=ns and M1-M3 d=14.34 +/- 60, p=ns. Amount of correct answers of TEA did not show a difference between M1 18.70 +/- 2.29 vs. M2 19.47 +/- 0.75 p=ns and M1 18.70 +/- 2.29 vs. M3 19.39 +/- 0.85 p=ns. The amount of errors in Bender test probed to be higher in M2 8.39 +/- 1.81 vs. M1 6.16 +/- 2.03 p = 0.002 and M3 6.83 +/- 1.46 vs. M1 6.16 +/- 2.03 p=ns.
DISCUSSION: We tested the hypothesis that the synergistic interaction which occurs when midazolam and propofol are combined for i.v. sedation with reversal by flumazenil did not impair patient's cognitive and psychomotor function. But we found that while 30 minutes after anesthetic discontinuation (M2), the cognitive function was recovered, the psychomotor functions were still impaired, and only recovered 30 minutes later (M3). This dissociation between cognitive and psychomotor function would be caused by an impairment in the intentional execution of the motive activity (he is unable to achieve his goal); while the patients' execution mechanisms would remain unaffected.
