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Propofol for sedation can shorten the duration of ED stay in joint reductions
American Journal of Emergency Medicine (2012) 30, 1352–1356
www.elsevier.com/locate/ajem
Original Contribution
Propofol for sedation can shorten the duration of ED stay in joint reductions Yi-Kung Lee MD, MPH a, b , Chien-Chih Chen MD, MS c , Hsin-Yi Lin MD a , Chen-Yang Hsu MD d , Yung-Cheng Su MD, MPH a, b,⁎ a
Emergency Department, Buddhist Tzu Chi Dalin General Hospital, Chiayi County 622, Taiwan (R.O.C.) School of Medicine, Tzu Zhi University, Hualien, Taiwan c Division of Emergency Medicine, Keelung Hospital, Department of Health, Executive Yuan, Keelung, Taiwan d Department of Public Heath, National Taiwan University b
Received 31 August 2011; accepted 20 September 2011
Abstract Background: For joint reductions, adequate sedation is often required. Propofol has increasingly been used for sedation in the emergency department (ED) in recent years. The benefits of propofol are the rapid onset of action and the short recovery time. However, whether these characteristics can shorten the duration of ED stay is not been proved. Objective: Our study retrospectively compared patients receiving propofol for sedation during joint reductions with those who received sedatives other than propofol. The primary objective was to compare the duration of ED stay between the 2 groups. The secondary outcomes were rate of adverse events and the success of the procedure. Methods: Patients were included if they had a dislocated joint requiring management in the ED. The following covariates were recorded on a standard form for each patient: age, sex, indication for procedural sedation, sedative used, pain medications used, physician levels, duration of ED stay, failed reduction, and adverse events. We further matched each patient in the propofol group to the patient in the nonpropofol group using a standard propensity score greedy-matching algorithm. The primary and secondary outcomes were compared accordingly. Results: A total of 241 patients met our inclusion criteria and were enrolled for further analysis. In the propensity score assignment, 56 patients (28 in each group) were further selected. The duration of ED stay in the propofol group is significantly shorter compared with the nonpropofol group (127 vs 192 minutes, P = .0019). The successful reduction rate is higher in the propofol group (96.4% vs 64.3%, P = .002). The complication rate is similar in both groups (3.6% vs 0%, P = .313). Conclusion: Propofol is a safe sedative with few complications and higher successful rates when applied in the joint reductions. It can also shorten the duration of ED stay. © 2012 Elsevier Inc. All rights reserved.
⁎ Corresponding author. Tel.: +886 5 2648000x5838; fax: +886 5 2648499. E-mail address: [email protected] (Y.-C. Su). 0735-6757/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.ajem.2011.09.024
Propofol can shorten ED stay in joint reductions
1. Introduction Joint dislocations is an urgent condition that emergency physicians should manage promptly to restore the function and relieve pain. During the joint reductions, adequate sedation is often required. The use of sedation not only can increase both patient and physician satisfaction [1] but also can improve the performance of this painful procedure [2]. Traditionally, sedation for joint reductions was provided by benzodiazepine with or without narcotics. Since the introduction in 1989, propofol (2,6-diisopropylphenol) has increasingly been used as an alternative choice for sedation in the emergency department (ED). The benefits of propofol are the rapid onset of action and the short recovery. The rate of adverse events, mainly hypoxia [3], is not significant higher compared with other sedatives [4-6]. One meta-analysis focused on the propofol for sedation during colonoscopy found that the discharge time would be shorter with use of propofol [7]. Because the ED overcrowding is a growing concern [8], propofol may have the potential to safely discharge patients receiving procedure sedation such as joint reductions in a shorter time. Several studies have been conducted regarding propofol in comparison with other medications for sedation in the ED, but the primary outcomes were mainly complication rates [4-6]. One study [9] failed to find the shorter ED stay on patients using propofol, but the result was limited to the small case numbers. Our study retrospectively compared patients receiving propofol for procedural sedation during joint dislocations with those who received sedatives other than propofol. The primary objective was to compare the duration of ED stay between the 2 groups. The secondary outcomes were rate of adverse events and the success of the procedure.
1353 excluded if the closed reduction was not performed in the ED because of concomitant life-threatening injuries (eg, intracranial hemorrhage or unstable hemodynamic status), a known allergy or hypersensitivity to any of the study drugs or other contraindication to sedation. Patients who did not receive any sedative for reduction and those who need to be hospitalized were also excluded. We searched our electronic medical records during the study period for patients who received close reductions of hips, shoulders, and elbows in our hospital to identify our study cohort. Medications, duration of ED stay, age, sex, and treating physicians were directly retrieved from computerized records. We further reviewed all the medical charts to gather the detailed information such as failed reduction and complications. For patients with unsuccessful reduction who required further intervention in the operating room, the ED stay was defined as the duration between the time of arrival and time when patients were sent to operating room. All patients received supplemental oxygen and were monitored with respiratory rate, pulse oximeter, electrocardiography, and blood pressure during procedure sedation in the ED. The emergency physicians performed all sedations. Propofol was administered intravenously as an initial bolus of 0.5 mg/kg up to a maximum total dose of 1 mg/kg if required. Other sedatives were also titrated based on the weight-based recommendation dose. The following covariates were recorded on a standard form for each patient: age, sex, indication for procedural sedation, sedative used, physician levels (residents or attending physicians), pain medications used, duration of ED stay, failed reduction, and adverse events (eg, hypotension, hypoxia, apnea, etc). Patients receiving propofol as the first sedative would be classed into the propofol group; patients receiving first medication other than propofol would be labeled as the control group.
2. Methods
2.3. Propensity score methods
2.1. Study setting The study was a retrospective observational study. Buddhist Tzu Chi Dalin General Hospital is a teaching hospital with 42 000 ED visits per year. On average, we received 2 to 3 episodes of joint dislocations every month. Medical records for patients with joint dislocations in the ED between July 2000 and July 2011 were reviewed, and data were extracted by 2 authors (SYC and LYK). The analysis was performed by another author (HCY) after the completion of the data collection. The study was approved by the institutional review boards of Buddhist Tzu Chi Dalin General Hospital.
In this study, the propensity score was the conditional probability for using propofol under possible confounders. Age, sex, indications for procedure sedation, pain medications use, accompanied fractures, associated trauma, prosthetic joints, and physician levels were added into a multivariable logistic regression model to predict the effect of propofol use [10]. The predicted probability from the model was used as the propensity score for each patient. We then matched each patient in the propofol group to the patient in the nonpropofol group with the closest propensity score using a standard greedy-matching algorithm [11]. After the 1:1 matched groups were assembled, the primary and secondary outcomes were compared accordingly.
2.2. Patients
2.4. Statistical analysis
Patients were considered for inclusion if they had a dislocated joint requiring management in the ED. They were
Continuous variables were compared with the t test, and categorical variables, with the χ 2 test. The duration of ED
1354
Y.-K. Lee et al.
stay was defined as the duration from ED arrival to discharge. Kaplan-Meier curves were plotted to show the trend. A patient with failed reduction in the ED was regarded as censored (nonevent) on the time when he or she left the ED. Log-rank test was used to compare the difference of ED stay between the propofol and nonpropofol groups. Ninety-five percent confidence interval (CI) and P value were reported. P b .05 was considered significant. All analyses were performed using Statistical Analysis Software for Windows, version V.9.2 (SAS Institute Inc, Cary, NC) and STATA version 11.2 (StataCorp, College Station, TX).
3. Results By reviewing of medical records, we identified 428 episodes of joint dislocations diagnosed in the ED during the 11-year study period. A total of 241 patients met our inclusion criteria and, therefore, were enrolled for further analysis. The selection process was summarized in Fig. 1. There were 170 patients in the propofol group and 71 in the nonpropofol group. In the nonpropofol group, 68 patients received midazolam as the initial sedative, 2 received lorazepam, and 1 received ketamine. The baseline characteristics of both groups are shown in Table 1. Before adjustment for possible confounding variables, the average duration of ED stay was 120 minutes (95% CI, 105-136 minutes) in the propofol group and 301 minutes (95% CI, 194-408 minutes) in the nonpropofol group, respectively. The differences of duration between the 2 groups were statistically significant, with 181 minutes shorter in the propofol group (P b .0001). The successful reduction rates in the ED were much higher in the propofol group (90% vs 70.4%, P b .0001), and the all causes of complications were similar (2.4% vs 4.2%, P = .43). All patients with complications managed a complete recovery after adequate treatment (Table 1).
Table 1 Baseline characteristics of the propofol and the nonpropofol groups Propofol group Nonpropofol P (n = 170) group (n = 71) Men, n (%) 75 (44.1) Age (y) Mean (SD) 58.1 (19.7) N70 y, n (%) 61 (35.9) Type of dislocations, n (%) Hip 68 (40) Shoulder 75 (44.1) Elbow 27 (15.9) Trauma-related 77 (45.3) dislocations, n (%) Physician levels, n (%) Residents 57 (33.5) Attending physician 113 (66.5) Fracture 8 (4.7) dislocations, n (%) Prosthetic joints, 60 (35.3) n (%) Pain medications use, 39 (22.9) n (%) Duration, mean (SE) 120 (7.9) Complications, n (%) 4 (2.4) Apnea 2 (1.2) Hypotension 2 (1.2) Death 0 (0) Success, n (%) 153 (90)
42 (59.2)
.0332
48.1 (21.6) 14 (19.7)
.0008 .0135
36 (50.7) 22 (31.0) 13 (18.3) 28 (39.4)
.161
.403 .001
9 (17.7) 62 (87.3) 9 (12.7)
.028
29 (40.8)
.416
59 (83.1)
b.0001
301 (53.5) 3 (4.2) 1 (1.4) 2 (2.8) 0 (0) 50 (70.4)
.0013 .43
b.0001
In the propensity score assignment, the possible confounding variables mentioned above were added into the multivariate logistic model to predict the effect of propofol use. The propensity score–matching process selected 28 patients from the propofol group and the other 28 from the nonpropofol group for further analysis (Fig. 1). Baseline characteristics were similar in the 2 groups (Table 2). In the propensity score–matched subcohort, the propofol group was again found to be associated with shorter ED stay compared with the nonpropofol group (192 vs 127 minutes, P = .0019). Kaplan-Meier curves (Fig. 2) showed a discharge benefit favoring the propofol group over the nonpropofol group.
4. Discussion
Fig. 1
Selection Process of Patients.
It is known that propofol has shorter duration compared with other sedatives [7,9]. Whether the pharmaceutical effect could alter the duration of ED stay had not been proved. Dunn et al [9] compared the duration of ED stay between the propofol group and midazolam group during the procedure sedation and did not find the benefit. However, small case numbers and various indications for procedure sedation may limit their study results. In our study, we found that the use of propofol for joint reductions could actually shorten the
Propofol can shorten ED stay in joint reductions
1355
Table 2 Baseline characteristics of the propofol and the nonpropofol groups Propofol Nonpropofol P group (n = 28) group (n = 28) Men, n (%) 15 (53.6) Age (y) Mean (SD) 50.7 (3.7) N70 y, n (%) 4 (14.3) Type of dislocations, n (%) Hip 8 (28.6) Shoulder 11 (39.3) Elbow 9 (32.1) Trauma-related 16 (57.1) dislocations, n (%) Physician levels, n (%) Residents 4 (14.3) Attending physician 24 (85.7) Fracture dislocations, 1 (3.6) n (%) Prosthetic joints, n 6 (21.4) (%) Pain medications use, 19 (67.9) n (%) Duration, mean (SE) 127 (20.2) Complications, n (%) 1 (3.6) Apnea 1 (3.6) Hypotension 0 (0) Death 0 (0) Success, n (%) 27 (96.4)
16 (57.1)
.788
44.6 (4.2) 3 (10.7)
.28 .686
8 (28.6) 12 (42.9) 8 (28.6) 15 (53.6)
.95
.788 1.000 Fig. 2
4 (14.3) 24 (85.7) 2 (7.1)
.553
6 (21.4)
1.000
18 (64.3)
.778
192 (25.3) 0 (0) 0 (0) 0 (0) 0 (0) 18 (64.3)
.0019 .313
.002
duration of ED stay compared with other sedatives. The effects not only can save the use of monitoring beds and decrease the costs of observation but also can lessen the burden of ED staffs. The adverse events in both groups are similarly rare, mainly apnea and hypotension. The results are compatible with previous studies [5,7,12]. Because we did not use objective measurement tools such as capnography [12], the events of respiratory depression might be underreported. Nevertheless, there is no serious adverse outcome in our study cohort, indicating that the use of propofol for joint reductions is relatively safe. The successful rates of reductions are significant higher in the propofol group. Because propofol has shorter onset and more predictable sedative effect, it is reasonable that when the reductions are initiated, the operators will encounter less resistance, and thus, the performance outcome will be better. The characteristics of propofol can also attribute to shorter ED stay by decreasing the manipulation time. However, because we did not record the sedation level using a standard form such as the observer's assessment of anaesthesia and sedation (OAAS) scale, we could not prove that the deeper sedation levels are the cause of higher successful rates. We had to acknowledge some study limitations. Our study was conducted in the retrospective fashion, and as a result, the unmeasured confounding and missing data would
Survival Curves of Propofol and Non-propofol Group.
be argued. Most of our core variables were retrieved from the computerized records, and missing data were not an important issue. The discharge benefit in the propofol group is significant enough that we did not think that there were other possible factors that could fully explain the effect. Furthermore, propofol is a unique sedative, and the emergency physicians will easily notice the rapid onset of the effect even if the study was conducted in the randomized design. In conclusion, our study has shown propofol to be effective for use in joint reduction in the ED. The low complication rates indicate that it could be safely administered in the ED under close monitoring. Its use not only can shorten the overall duration of ED stay, but also the probability of successful reductions will also be higher.
References [1] McQuaid KR, Laine L. A systematic review and meta-analysis of randomized, controlled trials of moderate sedation for routine endoscopic procedures. Gastrointest Endosc 2008;67(6):910-23. [2] Radaelli F, Meucci G, Sgroi G, et al. Technical performance of colonoscopy: the key role of sedation/analgesia and other quality indicators. Am J Gastroenterol 2008;103(5):1122-30. [3] Miner JR, Burton JH. Clinical practice advisory: Emergency department procedural sedation with propofol. Ann Emerg Med. 2007;50(2): 182-7, 7 e1. [4] McGrane O, Hopkins G, Nielson A, et al. Procedural sedation with propofol: a retrospective review of the experiences of an emergency medicine residency program 2005 to 2010. Am J Emerg Med 2011. [5] Mallory MD, Baxter AL, Yanosky DJ, et al. Emergency physicianadministered propofol sedation: a report on 25,433 sedations from the pediatric sedation research consortium. Ann Emerg Med 2011;57(5) 462-8.e1. [6] Rahman NH, Hashim A. Is it safe to use propofol in the emergency department? A randomized controlled trial to compare propofol and midazolam. Int J Emerg Med 2010;3(2):105-13. [7] Singh H, Poluha W, Cheung M, et al. Propofol for sedation during colonoscopy. Cochrane Database Syst Rev 2008(4):CD006268. [8] Hoot NR, Aronsky D. Systematic review of emergency department crowding: causes, effects, and solutions. Ann Emerg Med 2008;52(2): 126-36.
1356 [9] Dunn T, Mossop D, Newton A, et al. Propofol for procedural sedation in the emergency department. Emerg Med J 2007;24(7): 459-61. [10] Zhehui L, Gardiner JC, Bradley CJ. Applying propensity score methods in medical research: pitfalls and prospects. Med Care Res Rev 2010;67(5):528-54.
Y.-K. Lee et al. [11] Seeger JD, Williams PL, Walker AM. An application of propensity score matching using claims data. Pharmacoepidemiol Drug Saf 2005;14(7):465-76. [12] Miner JR, Gray RO, Bahr J, et al. Randomized clinical trial of propofol versus ketamine for procedural sedation in the emergency department. Acad Emerg Med 2010;17(6):604-11.
www.elsevier.com/locate/ajem
Original Contribution
Propofol for sedation can shorten the duration of ED stay in joint reductions Yi-Kung Lee MD, MPH a, b , Chien-Chih Chen MD, MS c , Hsin-Yi Lin MD a , Chen-Yang Hsu MD d , Yung-Cheng Su MD, MPH a, b,⁎ a
Emergency Department, Buddhist Tzu Chi Dalin General Hospital, Chiayi County 622, Taiwan (R.O.C.) School of Medicine, Tzu Zhi University, Hualien, Taiwan c Division of Emergency Medicine, Keelung Hospital, Department of Health, Executive Yuan, Keelung, Taiwan d Department of Public Heath, National Taiwan University b
Received 31 August 2011; accepted 20 September 2011
Abstract Background: For joint reductions, adequate sedation is often required. Propofol has increasingly been used for sedation in the emergency department (ED) in recent years. The benefits of propofol are the rapid onset of action and the short recovery time. However, whether these characteristics can shorten the duration of ED stay is not been proved. Objective: Our study retrospectively compared patients receiving propofol for sedation during joint reductions with those who received sedatives other than propofol. The primary objective was to compare the duration of ED stay between the 2 groups. The secondary outcomes were rate of adverse events and the success of the procedure. Methods: Patients were included if they had a dislocated joint requiring management in the ED. The following covariates were recorded on a standard form for each patient: age, sex, indication for procedural sedation, sedative used, pain medications used, physician levels, duration of ED stay, failed reduction, and adverse events. We further matched each patient in the propofol group to the patient in the nonpropofol group using a standard propensity score greedy-matching algorithm. The primary and secondary outcomes were compared accordingly. Results: A total of 241 patients met our inclusion criteria and were enrolled for further analysis. In the propensity score assignment, 56 patients (28 in each group) were further selected. The duration of ED stay in the propofol group is significantly shorter compared with the nonpropofol group (127 vs 192 minutes, P = .0019). The successful reduction rate is higher in the propofol group (96.4% vs 64.3%, P = .002). The complication rate is similar in both groups (3.6% vs 0%, P = .313). Conclusion: Propofol is a safe sedative with few complications and higher successful rates when applied in the joint reductions. It can also shorten the duration of ED stay. © 2012 Elsevier Inc. All rights reserved.
⁎ Corresponding author. Tel.: +886 5 2648000x5838; fax: +886 5 2648499. E-mail address: [email protected] (Y.-C. Su). 0735-6757/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.ajem.2011.09.024
Propofol can shorten ED stay in joint reductions
1. Introduction Joint dislocations is an urgent condition that emergency physicians should manage promptly to restore the function and relieve pain. During the joint reductions, adequate sedation is often required. The use of sedation not only can increase both patient and physician satisfaction [1] but also can improve the performance of this painful procedure [2]. Traditionally, sedation for joint reductions was provided by benzodiazepine with or without narcotics. Since the introduction in 1989, propofol (2,6-diisopropylphenol) has increasingly been used as an alternative choice for sedation in the emergency department (ED). The benefits of propofol are the rapid onset of action and the short recovery. The rate of adverse events, mainly hypoxia [3], is not significant higher compared with other sedatives [4-6]. One meta-analysis focused on the propofol for sedation during colonoscopy found that the discharge time would be shorter with use of propofol [7]. Because the ED overcrowding is a growing concern [8], propofol may have the potential to safely discharge patients receiving procedure sedation such as joint reductions in a shorter time. Several studies have been conducted regarding propofol in comparison with other medications for sedation in the ED, but the primary outcomes were mainly complication rates [4-6]. One study [9] failed to find the shorter ED stay on patients using propofol, but the result was limited to the small case numbers. Our study retrospectively compared patients receiving propofol for procedural sedation during joint dislocations with those who received sedatives other than propofol. The primary objective was to compare the duration of ED stay between the 2 groups. The secondary outcomes were rate of adverse events and the success of the procedure.
1353 excluded if the closed reduction was not performed in the ED because of concomitant life-threatening injuries (eg, intracranial hemorrhage or unstable hemodynamic status), a known allergy or hypersensitivity to any of the study drugs or other contraindication to sedation. Patients who did not receive any sedative for reduction and those who need to be hospitalized were also excluded. We searched our electronic medical records during the study period for patients who received close reductions of hips, shoulders, and elbows in our hospital to identify our study cohort. Medications, duration of ED stay, age, sex, and treating physicians were directly retrieved from computerized records. We further reviewed all the medical charts to gather the detailed information such as failed reduction and complications. For patients with unsuccessful reduction who required further intervention in the operating room, the ED stay was defined as the duration between the time of arrival and time when patients were sent to operating room. All patients received supplemental oxygen and were monitored with respiratory rate, pulse oximeter, electrocardiography, and blood pressure during procedure sedation in the ED. The emergency physicians performed all sedations. Propofol was administered intravenously as an initial bolus of 0.5 mg/kg up to a maximum total dose of 1 mg/kg if required. Other sedatives were also titrated based on the weight-based recommendation dose. The following covariates were recorded on a standard form for each patient: age, sex, indication for procedural sedation, sedative used, physician levels (residents or attending physicians), pain medications used, duration of ED stay, failed reduction, and adverse events (eg, hypotension, hypoxia, apnea, etc). Patients receiving propofol as the first sedative would be classed into the propofol group; patients receiving first medication other than propofol would be labeled as the control group.
2. Methods
2.3. Propensity score methods
2.1. Study setting The study was a retrospective observational study. Buddhist Tzu Chi Dalin General Hospital is a teaching hospital with 42 000 ED visits per year. On average, we received 2 to 3 episodes of joint dislocations every month. Medical records for patients with joint dislocations in the ED between July 2000 and July 2011 were reviewed, and data were extracted by 2 authors (SYC and LYK). The analysis was performed by another author (HCY) after the completion of the data collection. The study was approved by the institutional review boards of Buddhist Tzu Chi Dalin General Hospital.
In this study, the propensity score was the conditional probability for using propofol under possible confounders. Age, sex, indications for procedure sedation, pain medications use, accompanied fractures, associated trauma, prosthetic joints, and physician levels were added into a multivariable logistic regression model to predict the effect of propofol use [10]. The predicted probability from the model was used as the propensity score for each patient. We then matched each patient in the propofol group to the patient in the nonpropofol group with the closest propensity score using a standard greedy-matching algorithm [11]. After the 1:1 matched groups were assembled, the primary and secondary outcomes were compared accordingly.
2.2. Patients
2.4. Statistical analysis
Patients were considered for inclusion if they had a dislocated joint requiring management in the ED. They were
Continuous variables were compared with the t test, and categorical variables, with the χ 2 test. The duration of ED
1354
Y.-K. Lee et al.
stay was defined as the duration from ED arrival to discharge. Kaplan-Meier curves were plotted to show the trend. A patient with failed reduction in the ED was regarded as censored (nonevent) on the time when he or she left the ED. Log-rank test was used to compare the difference of ED stay between the propofol and nonpropofol groups. Ninety-five percent confidence interval (CI) and P value were reported. P b .05 was considered significant. All analyses were performed using Statistical Analysis Software for Windows, version V.9.2 (SAS Institute Inc, Cary, NC) and STATA version 11.2 (StataCorp, College Station, TX).
3. Results By reviewing of medical records, we identified 428 episodes of joint dislocations diagnosed in the ED during the 11-year study period. A total of 241 patients met our inclusion criteria and, therefore, were enrolled for further analysis. The selection process was summarized in Fig. 1. There were 170 patients in the propofol group and 71 in the nonpropofol group. In the nonpropofol group, 68 patients received midazolam as the initial sedative, 2 received lorazepam, and 1 received ketamine. The baseline characteristics of both groups are shown in Table 1. Before adjustment for possible confounding variables, the average duration of ED stay was 120 minutes (95% CI, 105-136 minutes) in the propofol group and 301 minutes (95% CI, 194-408 minutes) in the nonpropofol group, respectively. The differences of duration between the 2 groups were statistically significant, with 181 minutes shorter in the propofol group (P b .0001). The successful reduction rates in the ED were much higher in the propofol group (90% vs 70.4%, P b .0001), and the all causes of complications were similar (2.4% vs 4.2%, P = .43). All patients with complications managed a complete recovery after adequate treatment (Table 1).
Table 1 Baseline characteristics of the propofol and the nonpropofol groups Propofol group Nonpropofol P (n = 170) group (n = 71) Men, n (%) 75 (44.1) Age (y) Mean (SD) 58.1 (19.7) N70 y, n (%) 61 (35.9) Type of dislocations, n (%) Hip 68 (40) Shoulder 75 (44.1) Elbow 27 (15.9) Trauma-related 77 (45.3) dislocations, n (%) Physician levels, n (%) Residents 57 (33.5) Attending physician 113 (66.5) Fracture 8 (4.7) dislocations, n (%) Prosthetic joints, 60 (35.3) n (%) Pain medications use, 39 (22.9) n (%) Duration, mean (SE) 120 (7.9) Complications, n (%) 4 (2.4) Apnea 2 (1.2) Hypotension 2 (1.2) Death 0 (0) Success, n (%) 153 (90)
42 (59.2)
.0332
48.1 (21.6) 14 (19.7)
.0008 .0135
36 (50.7) 22 (31.0) 13 (18.3) 28 (39.4)
.161
.403 .001
9 (17.7) 62 (87.3) 9 (12.7)
.028
29 (40.8)
.416
59 (83.1)
b.0001
301 (53.5) 3 (4.2) 1 (1.4) 2 (2.8) 0 (0) 50 (70.4)
.0013 .43
b.0001
In the propensity score assignment, the possible confounding variables mentioned above were added into the multivariate logistic model to predict the effect of propofol use. The propensity score–matching process selected 28 patients from the propofol group and the other 28 from the nonpropofol group for further analysis (Fig. 1). Baseline characteristics were similar in the 2 groups (Table 2). In the propensity score–matched subcohort, the propofol group was again found to be associated with shorter ED stay compared with the nonpropofol group (192 vs 127 minutes, P = .0019). Kaplan-Meier curves (Fig. 2) showed a discharge benefit favoring the propofol group over the nonpropofol group.
4. Discussion
Fig. 1
Selection Process of Patients.
It is known that propofol has shorter duration compared with other sedatives [7,9]. Whether the pharmaceutical effect could alter the duration of ED stay had not been proved. Dunn et al [9] compared the duration of ED stay between the propofol group and midazolam group during the procedure sedation and did not find the benefit. However, small case numbers and various indications for procedure sedation may limit their study results. In our study, we found that the use of propofol for joint reductions could actually shorten the
Propofol can shorten ED stay in joint reductions
1355
Table 2 Baseline characteristics of the propofol and the nonpropofol groups Propofol Nonpropofol P group (n = 28) group (n = 28) Men, n (%) 15 (53.6) Age (y) Mean (SD) 50.7 (3.7) N70 y, n (%) 4 (14.3) Type of dislocations, n (%) Hip 8 (28.6) Shoulder 11 (39.3) Elbow 9 (32.1) Trauma-related 16 (57.1) dislocations, n (%) Physician levels, n (%) Residents 4 (14.3) Attending physician 24 (85.7) Fracture dislocations, 1 (3.6) n (%) Prosthetic joints, n 6 (21.4) (%) Pain medications use, 19 (67.9) n (%) Duration, mean (SE) 127 (20.2) Complications, n (%) 1 (3.6) Apnea 1 (3.6) Hypotension 0 (0) Death 0 (0) Success, n (%) 27 (96.4)
16 (57.1)
.788
44.6 (4.2) 3 (10.7)
.28 .686
8 (28.6) 12 (42.9) 8 (28.6) 15 (53.6)
.95
.788 1.000 Fig. 2
4 (14.3) 24 (85.7) 2 (7.1)
.553
6 (21.4)
1.000
18 (64.3)
.778
192 (25.3) 0 (0) 0 (0) 0 (0) 0 (0) 18 (64.3)
.0019 .313
.002
duration of ED stay compared with other sedatives. The effects not only can save the use of monitoring beds and decrease the costs of observation but also can lessen the burden of ED staffs. The adverse events in both groups are similarly rare, mainly apnea and hypotension. The results are compatible with previous studies [5,7,12]. Because we did not use objective measurement tools such as capnography [12], the events of respiratory depression might be underreported. Nevertheless, there is no serious adverse outcome in our study cohort, indicating that the use of propofol for joint reductions is relatively safe. The successful rates of reductions are significant higher in the propofol group. Because propofol has shorter onset and more predictable sedative effect, it is reasonable that when the reductions are initiated, the operators will encounter less resistance, and thus, the performance outcome will be better. The characteristics of propofol can also attribute to shorter ED stay by decreasing the manipulation time. However, because we did not record the sedation level using a standard form such as the observer's assessment of anaesthesia and sedation (OAAS) scale, we could not prove that the deeper sedation levels are the cause of higher successful rates. We had to acknowledge some study limitations. Our study was conducted in the retrospective fashion, and as a result, the unmeasured confounding and missing data would
Survival Curves of Propofol and Non-propofol Group.
be argued. Most of our core variables were retrieved from the computerized records, and missing data were not an important issue. The discharge benefit in the propofol group is significant enough that we did not think that there were other possible factors that could fully explain the effect. Furthermore, propofol is a unique sedative, and the emergency physicians will easily notice the rapid onset of the effect even if the study was conducted in the randomized design. In conclusion, our study has shown propofol to be effective for use in joint reduction in the ED. The low complication rates indicate that it could be safely administered in the ED under close monitoring. Its use not only can shorten the overall duration of ED stay, but also the probability of successful reductions will also be higher.
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