James R. Miner

To assess patients' ability to repeat and recall words presented to them while undergoing procedural sedation with propofol, and correlate their recall with their level of awareness as measured by bispectral index (BIS) monitoring. This was a prospective, single-intervention study of consenting adult patients undergoing procedural sedation with propofol between December 28, 2002, and October 31, 2003. BIS monitoring was initiated starting 3 minutes before the procedure and continuing until the patient had regained baseline mental status. At 1-minute intervals during the procedural sedation, until the patient regained baseline mental status at the end of the procedure, a word from a standardized list was read aloud, and the patient was asked to immediately repeat the word to the investigator. The BIS score at the time the word was read and the patient's ability to repeat the word were recorded. After the procedure, the patient was asked to state all of the words from the list that he or she could recall, and to identify the last word recalled from prior to the start of the procedure and the first word recalled from after the procedure was completed. Seventy-five consenting patients were enrolled; one patient was excluded from data analysis for a protocol violation. No serious adverse events were noted during the procedural sedations. The mean (+/-standard deviation) time of data collection was 16.4 minutes (+/-7.1; range 5 to 34 minutes). The mean initial (preprocedure) BIS score was 97.1 (+/-2.3; range 92 to 99). The mean lowest BIS score occurring during these procedural sedations was 66.9 (+/-14.4; range 33 to 91). The mean lowest BIS score corresponding to the ability of the patient to immediately repeat words read from the list was 77.1 (95% CI = 74.3 to 80.0). The mean highest BIS score corresponding to the inability to repeat words was 81.5 (95% CI = 78.1 to 84.8). The mean BIS score corresponding to the last word recalled from prior to the initiation of the sedation was 96.7 (+/-2.4; range 84 to 98). The mean BIS score corresponding to the first word recalled after the procedure was completed was 91.2 (95% CI = 88.1 to 94.3). All patients recalled at least one word that had been read to them during the protocol. The mean lowest BIS score for any recalled word was 91.5 (+/-11.1; range 79 to 98), and no words were recalled when the corresponding BIS score was less than 90. There is a range of BIS scores during which sedated patients are able to repeat words read to them but are not able to subsequently recall these words. Furthermore, patients had no recall of words repeated prior to procedural sedation in BIS ranges associated with recall after procedural sedation, suggestive of retrograde amnesia.

Although methohexital has been well studied for use in emergency department (ED) procedural sedation (PS), propofol has been evaluated less extensively for ED use. The authors hypothesized that there is no difference in the depth of sedation and the rate of respiratory depression (RD) between propofol and methohexital in PS during the reduction of fractures and dislocations in the ED. This was a randomized prospective study of nonintoxicated adult patients undergoing PS for fracture or dislocation reduction in the ED between July 2001 and March 2002. Patients were randomized to receive either propofol or methohexital, 1 mg/kg intravenously, followed by repeat boluses of 0.5 mg/kg every 2 minutes until adequate sedation was achieved. Doses, vital signs, end-tidal CO(2) (ETCO(2)) by nasal cannulae, pulse oximetry, and bispectral electroencephalogram analysis (BIS) scores were recorded. RD was defined as an ETCO(2) greater than 50 torr, an oxygen saturation less than 90% at any time, or an absent ETCO(2) waveform. After returning to baseline mental status, patients completed three 100-mm visual analog scales (VASs) regarding pain associated with the procedure, recall of the procedure, and satisfaction. RD rates and VAS outcomes were compared with chi-square tests. There were 109 patients enrolled; six were excluded for study protocol violations. Of the remaining 103 patients, 52 received methohexital (reduction successful in 94%) and 51 received propofol (98% successful). No cardiac rhythm abnormalities or significant decline in systolic blood pressure (>20%) was detected. Six patients required bag-valve-mask-assisted ventilations during the procedure, all for less than 1 minute; four of these patients received methohexital, and two received propofol. By the authors' definition, RD was seen in 25 of 52 (48%) patients receiving methohexital and 25 of 51 (49%) patients receiving propofol (p = 0.88). The mean minimum recorded BIS score was 66.2 (95% confidence interval [CI] = 62 to 70) for methohexital and 66 (95% CI = 60 to 71) for propofol. VAS results showed similar rates of reported pain, recall, and satisfaction for the two agents. The authors were unable to detect a significant difference in the level of subclinical RD or the level of sedation by BIS between the two agents. The use of either agent seems to be safe in the ED.

Objective: To determine whether there is a correlation between the level of sedation achieved during procedural sedation (PS) in the emergency department as determined by bispectral electroencephalographic (EEG) analysis (BIS) and the rate of respiratory depression (RD), the patient's perception of pain, recall of the procedure, and satisfaction. Methods: This was a prospective observational study conducted in an urban county hospital of adult patients undergoing PS using propofol, methohexital, etomidate, and the combination of fentanyl and midazolam. Consenting patients were monitored by vital signs, pulse oximetry, nasal‐sample end‐tidal carbon dioxide (ETCO₂), and BIS monitors during PS. Respiratory depression (RD) was defined as an oxygen saturation 10 mm Hg, or an absent ETCO₂ waveform at any time during the procedure. After the procedure, patients were asked to complete three 100‐mm visual analog scales (VASs) concerning their perception of pain, recall of the procedure, and satisfaction with the procedure. Patients were divided into four groups based on the lowest BIS score recorded during the procedure, group 1, >85; group 2, 70–85; group 3, 60–69; group 4, Results: One hundred eight patients were enrolled in the study. No serious adverse events were noted. RD was seen in three of 14 (21.4%) of the patients in group 1, seven of 34 (20.6%) in group 2, 16 of 26 (61.5%) in group 3, and 18 of 34 (52.9%) in group 4. The rate of RD in patients in group 2 was not significantly different from that in group 1 (p = 0.46). The rate of RD in group 2 was significantly lower than that in groups 3 (p = 0.0003) and 4 (p = 0.006). For the VAS data, when group 1 was compared with the combined groups 2, 3, and 4, it had significantly higher rates of pain (p = 0.003) and recall (p = 0.001), and a dissatisfaction rate (p = 0.085) that approached significance. When groups 2, 3, and 4 were compared with chi‐square test, there was not a significant difference in pain (p = 0.151), recall (p = 0.27), or satisfaction (p = 0.25). Conclusions: Patients with a lowest recorded BIS score between 70 and 85 had the same VAS outcomes as more deeply sedated patients and the same rate of RD as less deeply sedated patients. This range of scores represented the optimally sedated patients in this study.