Article, Emergency Medicine

Procedural sedation with propofol: a retrospective review of the experiences of an emergency medicine residency program 2005 to 2010

Unlabelled imageAmerican Journal of Emergency Medicine (2012) 30, 706-711

Original Contribution

Procedural sedation with propofol: a retrospective review of the experiences of an emergency medicine residency program 2005 to 2010?

Owen McGrane MD?, Gerald Hopkins MD, Adam Nielson MD, Christopher Kang MD

Department of Emergency Medicine, Madigan Army Medical Center, Tacoma, WA, USA

Received 3 February 2011; revised 1 April 2011; accepted 1 April 2011

Abstract

Objectives: The objective of this study is to evaluate the types and rates of adverse events associated with the use of propofol for procedural sedation by physicians from our emergency medicine residency program and compare those Adverse event rates with those rates already published for all moderate and deep sedatives for procedural sedation, including propofol.

Methods: This study was a retrospective chart review of all 215 procedural sedations performed with propofol in our emergency department (ED) from June 2005 to December 2010. The mean patient age was 29 years (SD, 22.1 years; range, 1-91 years). Adverse events were compiled and examined from chart data and compared with similar published studies on adverse event rates using propofol.

Results: Of the 215 patients, 10 (4.65%) experienced adverse events related to procedural sedation with propofol. Our frequency of adverse events was not statistically different from the published rate for all moderate and deep sedatives (P = .407). Of all the adverse events, hypotension was the most common, occurring in 5 (2.33%) of the 215 patients. Of the 215 patients, 3 (1.40%) experienced brief hypoxia, with 2 (0.93%) of 3 patients requiring jaw thrust airway repositioning. Two (0.93%) of the 215 patients developed brief apnea that required brief bag valve mask-assisted ventilation. No patient required any advanced airway management. All 215 patients recovered completely from the procedural sedation and were discharged from the ED in stable and improved condition.

Conclusions: The adverse event rates from our study correlate with those of numerous earlier as well as recently published studies of moderate and deep sedatives, including propofol. The disciplined use of propofol by emergency physicians should continue to provide ED patients with the best available management options and care while additional focused and larger scale research is conducted to definitively confirm the premise that emergency physicians can continue to safely perform procedural sedation with propofol.

? The views expressed are those of the authors and do not reflect the official policy of the Department of the Army, the Department of Defense or the U.S. Government.

* Corresponding author.

E-mail address: [email protected] (O. McGrane).

Introduction

Background

Procedural sedation with propofol has been successfully performed by board-certified emergency physicians for more

0735-6757/$ – see front matter. doi:10.1016/j.ajem.2011.04.002

than a decade. Procedural sedation is frequently used in the emergency department (ED) to facilitate brief, potentially painful procedures, such as Orthopedic reductions, cardio- versions, and radiologic procedures. Propofol has many properties that make it ideal for use for ED procedural sedation, including rapid induction of sedation and a short half-life that allows patients to recover quickly without residual sedation. After an Intravenous bolus dose of propofol, there is rapid equilibration between the plasma and brain, accounting for its rapid onset of induction. Plasma levels are rapidly reduced because of tissue distribution and metabolism by the liver. Propofol is therefore often used in conjunction with other sedatives such as ketamine (ketofol) with success and safety [1]. Propofol has been well studied and known to produce both moderate and deep sedation. Several studies have outlined the dose-dependent adverse effects of propofol, including lack of adequate sedation, oversedation, nausea and vomiting, hypotension, and respiratory depression. These effects, however, are not unique to propofol and are associated with other agents used by emergency physicians for procedural sedation. Unlike procedures such as bronchoscopy, endoscopy, and colonoscopy, where propofol is frequently used, our use of propofol in the ED is not always afforded the ideal preparation (NPO status for several hours, generally more medically stable or medically cleared patients) and yet the use of propofol in EDs is well documented [1-20].

Importance

Procedural sedation with propofol in the ED was first described by Swanson et al [2] in 1996. Over the following decade, the use and popularity of propofol increased to such an extent that, in 2007, the American College of Emergency Physicians (ACEP) issued a clinical practice advisory (CPA) to provide evidence-based recommendations for the admin- istration of propofol for ED procedural sedation [3].

In February 2010, the Department of Health & Human Services’ Centers for Medicare & Medicaid Services (CMS) issued the memo, Revised Hospital Anesthesia Services Interpretive Guidelines, which advised that, “all services along the continuum of anesthesia services provided in a hospital must be organized under a single Anesthesia Service” [21]. The continuum of anesthesia includes minimal sedation, moderate sedation/analgesia (“conscious seda- tion”), deep sedation, and general anesthesia. The revised CMS guidelines also focused specifically on the propofol package insert, which specifies that propofol be used for deep and general anesthesia. Although some emergency physi- cians possess clinical privileges for moderate and deep sedation, many other emergency physicians possess privi- leges for only moderate sedation. The revised CMS guidelines therefore could effectively prohibit the use of propofol by many emergency physicians without the involvement of their anesthesia services, which according to the CMS rules may result in a CRNA or anesthesiologist

coming to help a board-certified emergency physician who is capable of identifying and managing emergent airway problems. This prohibition has the potential to immediately restrict individualized management options available to ED patients or require the involvement of anesthesia services, which could lengthen ED visits, require greater use of Hospital resources, and increase Associated costs.

The adverse events associated with the use of propofol are not unique to propofol but are also observed with other medications used by emergency physicians for moderate and deep sedation. These events include pain with injection, nausea and vomiting, lack of adequate sedation, over- sedation, hypotension, hypoxia, respiratory depression and apnea, and respiratory arrest. Numerous studies that have analyzed the adverse events associated with moderate and deep Sedative agents, including propofol, have identified an overall complication rate of less than 5% [1-20]. Many of these events can be easily managed with the transient use of airway repositioning such as the jaw thrust, supplemental oxygen, intravenous fluids, and, on occasion, noninvasive assisted ventilation.

Materials and methods

Study design

This institutional review board-approved retrospective analysis used data from our ED electronic medical record (EMR) system, Essentris, and ED Sedation quality assurance log from June 1, 2005, to December 31, 2010. Our ED EMR contains an ED evaluation record, physician sedation record, and nursing sedation record. The ED evaluation record contains the initial physician evaluation, ED course, diagnoses, a special notation if a procedural sedation was performed, and the final disposition for every ED patient. The physician sedation record contains the indication for the procedural sedation, patient weight, a presedation assess- ment, the dose(s) and route(s) of administration of all medication used, notation of any interventions and compli- cations, and a postsedation assessment. The nursing sedation record contains the indication for the procedural sedation; patient weight; a presedation nursing assessment; the dose(s), route(s), and time(s) of administration of all medication used; record of pulse rate, respiratory rate, blood pressure, and pulse oximetry readings throughout the entire duration of the procedural sedation; notation of any interventions and complications; and a postsedation nursing assessment. The ED sedation quality assurance log contains records for all ED procedural sedations. Each record contains the age, sex, and weight of the patient; indication for the procedural sedation; name(s), dose(s), and route(s) of all Medication administered; notation of the occurrence and nature of any interventions and complications; and the final disposition of the patient.

Setting

The study site, Madigan Army Medical Center (MAMC), is a 200-bed suburban government tertiary-care, level II trauma, and academic training health care facility with 70 000 annual ED visits located in Western Washington state. The MAMC serves a diverse patient population of 300 000 eligible active duty, dependent, and retired beneficiaries as well as regional civilian trauma patients. Pediatric patients comprise nearly 15% of the total ED population. The emergency medicine (EM) residency program is composed of 3 classes of 12 resident physicians. All staff emergency physicians possess clinical privileges for both moderate and deep sedation. Per MAMC ED policy, all procedural sedations must be performed by a minimum of an EM resident physician and an ED staff nurse certified to perform procedural sedation and be supervised by an EM-trained and board-certified emergency physician at the bedside. An ED sedation quality assurance log is maintained and updated monthly with all procedural sedations performed in the ED.

Data collection and outcome measures

All procedural sedations performed with propofol in the MAMC ED from June 1, 2005, to December 31, 2010, were identified by querying the ED EMR system, Essentris, for any ED evaluation record diagnosis associated with procedural sedation, special notation of a procedural sedation being performed, physician sedation record, and nursing sedation record. Each identified record and the total number of procedural sedations performed were then corroborated with the ED sedation quality assurance log.

The study investigators reviewed each of the identified procedural sedations performed with propofol for the following 10 data points: patient age, patient weight, indication for procedural sedation, total dose of propofol administered, use of any additional medication, multiple vital sign records throughout the procedural sedation, notation of the occurrence of an adverse event in any record, nature of the adverse event, intervention performed in response to an adverse event, and final patient disposition. An adverse event was defined as any occurrence of hypotension (defined as systolic blood pressure b90 mm Hg for patient ages 18-91 years, N20% decrease from presedation baseline systolic blood pressure for patient ages b18 years), aspiration, pulse oximetry less than 90%, unanticipated hospitalization related to the procedural sedation, apnea (defined as no respiratory effort combined with no end-tidal CO2 waveform or hypoxia without evidence of obvious airway obstruction), and death. After review, no procedural sedations were excluded from the study.

Table 1 Patient demographics

All of the data points from each of the identified records were then entered, compiled, and analyzed in a Microsoft Excel spreadsheet on a secure computer system in accor- dance with institutional research data and Protected Health Information policies.

Our overall frequency of adverse events was compared with the published 2007 ACEP CPA for emergency department procedural sedation with propofol adverse events rate of 5% for all moderate and deep sedatives for sedations [3], including propofol, using a 1-sample z test. To capture a 5% incidence rate of serious adverse effects with 3% margin of error and with 80% confidence at a risk ? rate of 5%, a power analysis indicated that a minimum sample size of 215 was required.

Results

Demographics

A total of 215 procedural sedations performed with propofol in the ED were identified and analyzed. The mean patient age was 29 years (SD, 22.1 years; range, 1-91 years). Patients underwent procedural sedation most often for joint reduction (37%), fracture reduction (36%), and abscess incision and drainage (12%). Propofol was the sole medication used in 80% of the cases and used in conjunction with ketamine in 18% of the cases. Propofol was used in conjunction with midazolam or methohexital in less than 1% of the cases. The average total dose was 2.1 mg/kg (SD, 1.6 mg/kg). Complete demographic data are presented in Table 1.

Adverse events

Of the 215 patients, 10 (4.65%) experienced adverse events related to procedural sedation with propofol. Using a 1-sample z test to compare our frequency of adverse events to the frequency published in the 2007 ACEP CPA for emergency department procedural sedation with propofol [3], we found that our rate of 4.65% is not statistically

All subjects, 95% CI N = 215

Age (y), mean (SD) 29 (22.1) Procedure, n (%)

Dislocation reduction

79 (37)

(30%-44%)

Fracture reduction

77 (36)

(29%-43%)

Abscess incision and drainage

24 (11)

(7%-16%)

Cardioversion

10 (5)

(2%-8%)

Radiology procedure

8 (4)

(2%-7%)

Laceration

7 (3)

(1%-7%)

Chest thoracostomy

4 (2)

(1%-5%)

Endoscopy

3 (1)

(0%-4%)

Lumbar puncture

1 (b1)

(0%-3%)

Foreign body removal

1 (b1)

(0%-3%)

Hemorrhoidectomy

1 (b1)

(0%-3%)

All subjects, 95% CI N = 215

Subjects with adverse 10 (4.65) (2%-8%) sedation event

Average total dose of propofol 2.1 (1.6) (mg/kg), mean (SD)

Sedation event

Hypotension 5 (2.33) (1%-5%)

Desaturation b90% 3 (1.40) (0%-4%)

Desaturation b90% 2 (0.93) (0%-3%) requiring intervention

Apnea event 2 (0.93) (0%-3%)

Values are presented as n (%), unless otherwise indicated.

different from the published rate of 5% (P = .407). Hypotension was the most common adverse event, occurring in 5 (2.33%) of the 215 patients. Three (1.40%) of the

Table 2 Adverse events

215 patients experienced brief hypoxia (lowest recorded level, 86%), with 2 (0.93%) of 3 patients requiring jaw thrust airway repositioning. Of the 206 patients, 2 (0.93%) developed apnea that required brief, bag valve mask- assisted ventilation (b59 seconds). No patient required any advanced airway management (Table 2). All 215 patients recovered completely from the procedural sedation and were discharged from the ED in stable and improved condition.

Limitations and additional considerations

To better appreciate our data and results and how they may contribute to the larger discussion of whether emergency physicians can safely use propofol, several limitations, strengths, and additional considerations specific to this study protocol should be recognized and acknowledged.

The principal limitation of this study protocol is that all

215 procedural sedations identified and analyzed were performed in an ED with an EM residency program. As noted earlier, per our ED policy, every procedural sedation must be performed by a minimum of an EM resident

Table 3 Adverse event comparison

physician and an ED staff nurse certified to perform procedural sedation and be supervised by an EM-trained and board-certified emergency physician. This staffing may represent more personnel for a procedural sedation than other EDs. In addition, our ED guidelines for the use of propofol for procedural sedation recommend an initial intravenous bolus dose of 0.75 mg/kg followed by 0.5 mg/kg as needed to achieve and maintain sedation until the completion of the indicated procedure. This protocol may use different dosing and be more regimented than those used by other emergency physicians. The studies by Taylor, Miner, and Burton et al used a dosing regimen with an initial bolus of 1.0 to

1.5 mg/kg. With the advent of technologies of capnography, the safety of propofol use can be further ensured; however, given the time frame of the study, only a portion of our sedations incorporated the use of this technology. Further- more, although one of the largest to date, our sample size of

215 cases may still not be sufficient to make definitive conclusions regarding adverse event rates and the overall safety of procedural sedations with propofol by emergency physicians. Thus, although some general comparisons with recently published studies can be made, a rigorous meta- analysis was not conducted and remains beyond the scope of this study (Table 3).

As compared with other previously published studies of the use of propofol by emergency physicians, our study protocol has several positive features that should be noted. First, our study protocol evaluated every case identified. No cases were excluded. In addition, our study protocol included a wide range of patient ages (b1-91 years) and indications for procedural sedation. Lastly, although previously noted as a potential limitation, the involvement of EM resident physicians may also be recognized as a strength because the procedural sedations were performed by physicians with varying Experience levels.

Several additional considerations should be acknowl- edged. All of our staff emergency physicians possess clinical privileges for moderate and deep sedation. Although all of the procedures were successfully completed, our study protocol did not evaluate the duration of the procedural sedation. Patient as well as Physician satisfaction with the

Study

Apnea

95% CI

Desaturation

95% CI

Hypotension

95% CI

McGrane et al

0.93% (2/215)

(0%-3%)

1.40%

(3/215)

(0%-4%)

2.33% (5/215)

(1%-5%)

Anderson et al a

4% (5/125)

(1%-9%)

4.8%

(6/125)

(2%-10%)

0% (0/125)

(0%-3%)

Miner et al, 2007 b

12% (13/109)

(7%-20%)

9.2%

(10/109)

(4%-16%)

3.7% (4/109)

(1%-9%)

Miner et al, 2010 b

26% (13/50)

(15%-40%)

14%

(7/50)

(6%-27%)

4% (2/50)

(0%-14%)

Sacchetti et al a

0% (0/47)

(0%-8%)

0%

(0/47)

(0%-88%)

0% (0/47)

(0%-8%)

Weaver et al b

2.4% (2/82)

(0%-9%)

11%

(9/82)

(5%-20%)

0% (0/82)

(0%-9%)

Burton et al

Unknown

(6%-10%)

7.7%

(61/792)

3.5% (28/792)

(2%-5%)

Burton et al was multicenter, pediatric/adult study.

a Pediatric patients only.

b Adult patients only.

procedural sedation, such as depth and quality of the sedation, was not assessed.

Discussion

With a diverse patient population who may require a variety of procedures, the ability to conduct individualized procedural sedation is a fundamental skill required of emergency physicians [22]. For the past 15 years, thousands of patients have had the discomfort and anxiety associated with potentially painful procedures mitigated by procedural sedation with propofol provided by emergency physicians [1-20]. However, revised administrative guidelines have called into question the ability of emergency physicians to safely use propofol for procedural sedation [21].

For the 215 procedural sedations performed with propofol by our emergency physicians, our overall complication rate was 4.65%. This rate closely correlates with the overall complication rate for adverse events related to all moderate and deep sedatives cited in the 2007 ACEP CPA for emergency department procedural sedation with propofol [3]. Furthermore, our identified rates of respiratory depres- sion (including the use of bag valve mask-assisted ventilation) and hypotension were also comparable or lower than the numerous studies. There was no trend of adverse events with age, but there appeared to be more significant events with higher ASA class in our study.

When compared with studies of procedural sedations with propofol by emergency physicians, our study results support the premise that emergency physicians can safely and independently perform procedural sedation with propofol. In addition, when complications arise, emergency physicians are uniquely trained to handle the emergent airway. In a 2010 study comparing the complication rates of 46 procedural sedations with ketamine with 50 procedural sedations with propofol, Miner et al reported 13% of cases that received stimulation to induce breathing and 9% of cases needed an airway adjunct. In a 2010 study of 386 propofol procedural sedations by Kuypers et al [20], their patients experienced hypoventilation (11%), desaturation (5%), hypotension (3%), and bradycardia (1%), all of which resolved with simple supportive interventions. In a 2007 study of

82 patients receiving procedural sedation with propofol, Weaver et al [17] reported that 11% of cases experienced pulse oximetry levels below 90%, 2% of cases became apneic, and 1% to 2% of cases required airway repositioning. These rates correlate with those cited in the 2007 ACEP CPA for emergency department procedural sedation with propofol and are higher than those identified in our study [3].

Translating data from various study protocols to clinical practice continues to present a challenge. Although recent study results, including our data, suggest that emergency physicians can appropriately perform procedural sedation with propofol, additional focused research is required. Prospective studies that identified factors that contributed

to hypoxic or hypotensive episodes, such as any weight- based bolus dosing ranges, and comparisons of the rates of adverse events between emergency physicians with moder- ate vs deep sedation clinical privileges would be valuable. Finally, larger prospective studies will be required to confirm and better delineate the incidence and etiologies of adverse events associated with ED propofol use.

Conclusion

As the number and complexity of ED patients continue to increase, procedural sedation will remain a fundamental skill required of emergency physicians. Propofol possesses several properties well suited for ED procedural sedation and has been widely used for more than 15 years. Because of reportedly patient safety-based administrative revisions, the availability and accepted use of propofol in the ED may continue to be threatened and curtailed despite adverse event rates comparable with other traditional sedatives. The adverse event rates from our study correlate with those of numerous earlier as well as recently published studies of moderate and deep sedatives, including propofol. In fact, the results of our study suggest a trend in improvement in adverse event rates since the 2007 studies. As one can see, the adverse event rates in the Weaver 2002 to 2003 study were much higher than our study done approximately 7 years later. Although additional focused and larger scale research is conducted to further validate that emergency physicians are safely performing procedural sedation with propofol, the disciplined use of propofol by emergency physicians should continue to provide ED patients with the best available management options and medical care.

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