Emergency medicine residents effectively direct Inhospital CArdiac arrest teams^B

Bruce D. Adams MD^a,c,*, Kathy Zeiler RN, MSN^b,

Walter O. Jackson MD^c, Brian Hughes MD^c

^aDepartment of Emergency Medicine, Brooke Army Medical Center, San Antonio, TX 78234-6200, USA

^bDepartment of Emergency Medicine, University Hospital, Augusta, GA 30901, USA

^cDepartment of Emergency Medicine, Medical College of Georgia, Augusta, GA 30912, USA

Abstract

Study Objective: We compared 2 models of physician leadership for inhospital cardiac arrest teams (CATs): emergency medicine (EM) residents and staff hospitalist physicians.

Methods: A before-after study was conducted on all adult inhospital CAT activations over a 2-year period. The primary outcome was return of spontaneous circulation (ROSC).

Results: There were 749 total code blues during the 2-year study period. Ninety-one were excluded by protocol. EM residents directed 288 codes, hospitalists directed 248 codes, and other specialties directed the remaining 62. There was no statistically significant difference in percent ROSC or survival to hospital discharge. EM residents responded first for 59.2% of the codes compared with a first response rate of 28% for hospitalists ( P b .05). Time to achieve ROSC was quicker in the EM resident cohort. Conclusion: Our findings validate the use of a 24-hour EM resident staffing model for CAT response to inhospital cardiac arrests.

Introduction

bCode blueQ or inhospital cardiopulmonary resuscitation (CPR) occurs frequently and unexpectedly [1,2]. Unfortu- nately, outcomes continue to be poor with sustained return of spontaneous circulation of about 40% to 60%

[3] and survival to hospital discharge of 15% or less

^B There were no external sources of financial support or grants for this study. This study was presented as a poster at the Council of Emergency Medicine Residency Directors Best Practices Conference (Washington, DC, February 2003) and at the American College of Emergency Physicians Scientific Assembly Research Forum (Boston, Mass, October 2003).

T Corresponding author. Department of Emergency Medicine, Brooke Army Medical Center, San Antonio, TX 78234-6200, USA.

E-mail address: [email protected] (B.D. Adams).

[1,3,4]. Multiple inhospital CPR studies previously have looked at variables that are difficult to modify such as presenting rhythm [1,5], sex [6], comorbidity, [7] hospital type [2,8], ward location [1,2], bdo-not-resuscitateQ (DNR) status [2], and Circadian variation (day shift vs night shift) [2]. Rapidly responding with a Multidisciplinary team is one of the few controllable elements that leads to improved outcomes [4,9,10].

Attending physicians often are not immediately available to supervise advanced cardiac life support (ACLS) measures on their patients. Accordingly, many hospitals maintain a cardiac arrest team (CAT), the composition of which varies considerably (Table 1) [2,9,11-15]. Whereas well-trained team leaders in ACLS improve patient survival [16], ACLS knowledge and protocol compliance can be surprisingly low

0735-6757/$ - see front matter. doi:10.1016/j.ajem.2005.02.013

Many factors are involved in designing staff coverage including salary

of the physicians, staff experience, acuity of the inpatients, staffing of the ED, familiarity with nursing staff and equipment, and feasibility of bany doctorQ being able to abandon clinical responsibilities to respond to a code. IM indicates internal medicine.

May not

be on 24-h coverage

Experienced,

often subspecialists

Hospitalists

24-h coverage Variable

supervision

Resident

coverage

Disadvantages

Medicolegal issues, less expertise Not all physicians at ease

with ACLS Not always physically present Abandonment of ER patients

Experienced

responder

EM attending

responds to ward

until relieved IM, EM,

anesthesiology, and cardiology fellows, etc New model, focus of current study

EM staff

Familiar with

family, staff

Attending May direct

physician by phone

bAny doctorQ First available Possibly

physician rapid

leads code response

Smaller hospitals Less

expensive

paramedic

Advantages

Comments

Select models for CPR code team leadership

Table 1

Model Nurse or

among nurses [17], house staff [18], and attending physi- cians [19,20]. If experienced leadership of a CAT is vital, which type of physician (or perhaps even nonphysician) should run the team? Some hospitals use emergency medicine (EM) resident physicians to direct their CAT. However, this practice has not been previously evaluated, and it is unknown whether EM resident leadership and staff physician leadership of the CAT are equally effective.

survival outcome differences recently have surfaced between different specialists and their respective manage- ment of several clinical conditions [21-24]. Whether this Medical specialty effect extends to inhospital CPR is currently unknown. Particularly relevant to this issue is the newly emerging specialty of the hospitalist. Hospitalists have been shown to improve admission rates, length of stay, hospital costs, bedside teaching, and even some clinical outcomes [15,25], but the particular role of hospitalists in code blue is also not well described. The purpose of our study was to determine which physician-staffing model is best for the CAT: EM residents or staff hospitalists?

Materials and methods

This was a before-after study design in a 550-bed community teaching hospital in the southeastern United States. The hospital annually admits 21,000 patients and performs 5,000 interventional cardiac procedures. The

institutional review board reviewed and approved the protocol. Participant physicians were blinded to the pres- ence of the study to avoid the Hawthorne effect (except for 1 author who directed 15 code blues as an EM resident and 4 code blues as an EM staff). A code blue was defined as respiratory distress requiring emergent airway management or a cardiorespiratory arrest requiring CPR or defibrillation. The subjects were all adult inhospital code blue activations between June 1999 and July 2001 excluding those that occurred in the ED, operating room, or cardiac catheteriza- tion suite. Also excluded were visitors to the hospital, pediatric arrests, patients with a preexisting DNR status (only if no resuscitation efforts were made), and False alarms where there was neither cardiac nor respiratory arrest.

A CAT composed of a pharmacist, chaplain, respiratory therapist, nurses and physician team leader responded to all code blue activations (Table 1). The specialty of the physician responder was the independent variable for our study. During the first year of the study, the physician designated for responding to the code was an EM resident who carried a dedicated pager during ED duties. On June 20, 2000, the local EM residency withdrew, and the community hospital replaced the residents with 24-hour in-house staff hospitalists. On November 1, 2001, EM residents were rehired to cover code blue response between 11:00 pm and 7:00 am, with the hospitalists now covering the balance. Hospitalists were defined for this study as staff internal medicine specialists or subspecialists with the assigned responsibility to supervise the CAT. The EM residents were all currently trained in ACLS. The hospitalists were not required by the hospital to have either ACLS or basic life support certification. Notification of the CAT was by pager and overhead public address system. Multiple physicians not on the CAT often initially responded to the arrest.

Data were collected for all patients on 2 supplemental forms designed along the Utstein style [26]. The CAT nurse recorded clinical information contemporaneously, and the physician directing the code then reviewed and signed the forms at the code’s conclusion. The data were entered into a spreadsheet for analysis [27]. We pulled and reviewed 229 of the full inpatient charts because of missing data (208 records) or because of concerns regarding physician leadership or ACLS compliance (21 records). We evaluated statistical significance with the t test and by Mann-Whitney rank sum test for continuous parameters. We used the Fisher’s exact test for categorical data and calculated the 95% confidence intervals (CIs) for Survival outcomes. Because many factors can influence CPR survival, we also performed a multivariate logistic regression analysis.

The primary outcome was immediate survival (defined as sustained ROSC at termination of code or at transfer). Secondary outcomes included survival to hospital dis- charge, code duration, and the time intervals from arrest (t₀) to first defibrillatory shock, endotracheal intubation, first epinephrine dose, ROSC, CAT physician arrival, and patient’s primary attending physician arrival (not necessar-

VF/VT	27	12.0	30	16.1	15	16.5	72 14.3
Asystole	59	26.2	50	26.9	22	24.2	131 26.1
Bradycardia	40	17.8	37	19.9	19	20.9	96 19.1
Sinus	54	24.0	24	12.9	9	9.9	87 17.3
PEA	35	15.6	30	16.1	21	23.1	86 17.1
Other	10	4.4	15	8.1	5	5.5	30 6.0
Not recorded	63		62		31		156

clearly in charge,Q as determined contemporaneously by the CAT supervising nurse and retrospectively by the hospital quality assurance director. Finally, we recorded whether the physicians performed their own intubation and use of DNR orders.

Table 2 Specialty composition of each major group of

physicians

Specialty No. of No. of codes physicians directed

ED residents (total = 288)

PGY

4 (EM-1)

3 (EM-2)

2 (EM-3)

Hospitalists (total = 248)

9

12

14

99

109

80

PGY indicates postgraduate year; EM, level of EM residency training;

CRNA, certified registered nurse anesthetist.

Table 4 Initial rhythm of code blue

Initial rhythm EM residents Hospitalist Other HCP All

n % n % n % n %

There was no significant difference between VF/VT and non-VF/VT

rhythms between groups ( P = .401, by Fisher’s exact test). PEA indicates pulseless electrical activity.

Cardiology	22	46
Family Medicine	2	2
Gastroenterology	2	2
General internal medicine	31	124
Hematology-oncology	4	5
Infectious disease	1	1
Nephrology	9	31
Endocrinology	1	3
Pulmonary/critical care	9	34
Other HCPs (total = 122)
Nurse only	-	5
Anesthesiologist/CRNA	-	4
Cardiothoracic surgery	6	26
General surgery	11	16
Emergency medicine staff	9	20
Urgent care physician	4	42
Other physician	4	4
Unknown	-	5

ily the hospitalist). We also determined which physician arrived first. We implicitly evaluated physician compliance with ACLS guidelines and whether bthe physician was

Table 3 Baseline clinical characteristics

T P b .05 by Fisher’s exact test.

Results

There were 749 code blues over the 24-month study period. Ninety-one code blues were excluded by protocol (catheterization laboratory = 6, EMS or ED = 71, hospital visitors = 3, operating room = 8, and pediatric = 3). This left 658 adult inhospital cardiac arrests among 582 unique patients (there were 64 patients with multiple codes). The distribution of CAT leader by specialty was EM residents (n = 288), hospitalists (n = 248), and all other health care providers (HCP) (n = 122). The EM residents directed

Parameter EM residents		Hospitalists	Other HCP	All
Age Average 69.0		66.8	66.3	67.3
Range 16-102		19-102	29-90	16-102
Gender
Male 109 (47.2%)		103 (48.1%)	54 (52.9%)	266 (48.6%)
Female 122 (52.8%)		111 (51.9%)	48 (47.1%)	281 (51.4%)
Not recorded 57		34	2	111
Race
Black	121 (54.8%)	94 (44.9%)	45 (45%)	260 (49.1%)
White	99 (44.8%)	114 (54.5%)	55 (55%)	268 (50.6%)
Other	1 (0.5%)	1 (0.5%)	0	2 (0.4%)
Not recorded	67	39	22	128
Time of day of code Day shift (7:00 am-7:00 pm)	89 (30.9%)T	161 (64.9%)T	66 (54.1%)	316 (48.0%)
Night shift (7:00 pm-7:00 am)	199 (69.1%)T	87 (35.1%)T	56 (45.9%)	342 (52.0%)
Type of arrest
Respiratory only	57 (19.8%)	37 (14.9%)	21 (17.2%)	115 (17.5%)
Cardiorespiratory	231 (80.2%)	211 (85.1%)	101 (82.8%)	543 (82.5%)

236 codes in their capacity as ED residents and led 52 more codes in their capacity as bmoonlightingQ overnight CAT physicians. Altogether, 150 individual physicians from 16 different specialties directed the 658 code blues (Table 2). The baseline characteristics between the different physi- cian groups were similar except that residents more likely directed codes during the night shift and hospitalists directed significantly more day shift codes (Table 3). The distribution of presenting dysrhythmia was similar between physician groups (Table 4). Codes located on monitored units occurred more often for the hospitalists (75.4% monitored, 24.6% unmonitored setting) than the residents (65.3% monitored, 34.7% unmonitored) ( P = .024). There was considerable year-to-year spillover in this before-after study, but most resident codes (78.5%) occurred in the first year of the study, and most hospitalist codes (57.5%)

occurred in the second year, P b .0001.

For the primary outcome of ROSC, there was no significant difference between the groups: EM residents = 61.1% (95% CI, 55.5%-66.7%), hospitalists = 58.5%

(95% CI, 52.3%-64.6%), all other HCP 65.6% (95% CI,

57.1%-74.0%), and all patients combined = 61.3% (95% CI, 57.8-64.8%). For the outcome of survival to hospital discharge, there was also no significant difference between the groups: EM residents = 24.3 % (95% CI, 19.7%-29.6%),

hospitalists = 22.6% (95% CI, 17.8%-28.2%), all other

HCP 33.6% (95% CI, 25.8%-42.4%), and all patients

combined = 25.4% (95% CI, 22.2%-28.8%). No survival difference was observed between all EM physicians (EM residents + EM staff) versus non-EM physicians, nor between the various medicine subspecialties. Analysis excluding the 19 unblinded code blues directed by a coauthor did not change the statistical findings.

Multivariate logistic regression reconfirmed that physi- cian specialty was not associated with immediate survival. Codes occurring in monitored intensive care unit settings (vs unmonitored ward settings) and respiratory arrests (vs cardiorespiratory arrest) were associated with better

T P b .001 by Mann-Whitney rank sum test.

3:24

2:37

4:15

9:00

5:45

9:52

23:35

2:12

1:55

4:04

11:26

8:32

12:35T

20:14T

2:09

3:22

4:17

8:54

4:12

11:25T

17:34T

2:34

3:23

4:18

7:53

5:13

4:51T

29:50T

25:05

25:29

25:53

Hospitalists All others All

EM

residents

23:43

Parameter

Duration of code

t₀

Compressions First shock First drug Achieve airway

First doctor arrival ROSC

Primary attending physician arrival

Table 5 Average duration and time intervals (minutes:

seconds) for each group of physicians

	n	%		n	%		n	%		n
Directing physician	26	5.6	29		6.9	16		7.9	71
Respiratory therapist	109	37.8	74		29.8	42		34.4	225
CRNA or	0	0.0	3		0.8	2		1.1	5
anesthesiologist
Already intubated	54	12.2	65		16.7	31		16.8	150
Never intubated	26	6.7	26		8.0	10		6.5	62
DNI/DNR status	13	3.6	13		4.3	3		2.1	29
Not recorded	60	17.2	38		13.3	18		12.9	116

survival. Age, sex, duration of code, and time of day (shift) were not associated with survival.

Table 6 Airway management of code blue

Intubated by:

EM

residents

Hospitalist Other HCP All

The secondary outcome Utstein style-defined time intervals are posted in Table 5. Time to achieve ROSC was significantly quicker in the resident cohort. In the 430 index cases where the nurse supervisor identified the sequence of arriving physicians, EM residents were the first to arrive 255 times (59.3%) compared with hospitalists arriving first to 120 code blues (27.9%) ( P b .05). The time until first physician arrival was contemporaneously recorded for only 49 codes. The average Response times were not statistically different between the physician groups, with both the residents and hospitalists arriving within 4 minutes in 67% of code blues. The attending physician’s arrival was recorded for 564 code blues. The attending of record was bedside at the start of the code in 41 (7.3%) instances, eventually responded in 446 (79.1%) instances, and did not respond at all in 77 (13.6%) instances. The attending physician took significantly longer than the other groups ( P b .0002) with an average of 30 minutes to respond (range, 0-54 minutes). Adequate team leadership and an appropriate ACLS protocol were implicitly considered by the CAT nurse and the hospital quality assurance director to have been followed in all cases. They did identify 6 instances (all with ROSC) when neither the hospitalist nor the EM resident responded.

Residents performed only 19.3% (vs hospitalists = 27.4% and all other HCP = 26.7%) ( P = .16) of all potential endotracheal intubations, delegating the remainder to Respiratory therapists (Table 6). There were 2 difficult intubations, both requiring the EM resident to take over from a respiratory therapist and perform rapid sequence intubation. The hospitalists ordered 2 patients to be made DNR during the code (at t = 4 and 15 minutes). An additional 4 hospitalist patients were of bdo-not-intubateQ (DNI) status and subsequently expired after only a bchemical code.Q The EM residents ordered 3 patients to be made DNR during the code (at t = 3, 14, and 18 minutes). An additional 2 DNR patients were inadvertently resus- citated until the nursing staff discovered the preexisting order. Three other EM resident patients had DNI orders and died after only a limited resuscitation.

Limitations

There were several limitations to our study. Because we were principally interested in the CAT process, we included isolated respiratory failure which skewed our overall survival rates higher than expected [28]. However, we also included the 14 DNR/DNI patients that received resuscita- tive efforts which would tend to balance out survival rates. Many code sheets lacked complete information, and as in most similar CPR studies, data were recorded after the event and not contemporaneously. Whereas physician arrival sequence was usually documented, arrival times were often not recorded properly in the bheat of battle.Q In retrospect, an Utstein-based point-of-care CPR data entry program may have produced more precise data than did our handwritten forms (which were often completed after a hectic code). With a single keystroke, a nurse recorder could accurately input important code events in real time into a Tablet PC or personal digital assistant [27].

Other recognized limitations include a considerable year- to-year spillover in this before-after design. However, the bias was likely negligible because we analyzed by the independent variable of physician specialty and not by year of code blue. We measured ROSC and survival to hospital discharge outcomes, but not the ideal 6- to 12-month survival. This common shortfall in community hospital- based CPR research [6,29] should not detract from our key focus on the timeliness of response, leadership, and immediate outcome of these codes. We performed implicit, not explicit, chart review when deciding on ACLS lead- ership and compliance, but because rigid ACLS compliance is not necessarily associated with improved outcome, this approach was a reasonable beginning [30,31]. Although previous investigators showed a worse survival for night shift cardiac arrests [2,32], our data did not. The prepon- derance of night shift code blues in the EM resident group might have obscured a true Survival benefit, but the sub- sequent multivariate logistic analysis did not confirm this.

Discussion

The residents reestablished ROSC significantly faster than the hospitalists did. However, we found no survival outcome difference between physician groups. We were 90% powered (2-tailed, a = .05) to detect a 15% difference in survival. Therefore, in this hospital setting, the EM resident model of CAT leadership was at least as successful as the staff hospitalist model.

We found that EM residents arrived first twice as often and achieved ROSC twice as fast as the staff hospitalists. This, despite being handicapped by both more unmoni- tored and more night-shift arrests, both factors that others have demonstrated to be independently associated with mortality [1,2,32]. This raises the interesting possibility that something intrinsic about the EM residents- training,

clinical style, or just better responsiveness- may actually be producing an outcome difference. EM residents are highly trained, motivated, and oriented toward a team resuscitation of the critically ill patient [33,34]. Therefore, it is not surprising that they performed at least as well as staff hospitalists. Although the residents, unlike the hos- pitalists, were required to have ACLS training, the clinical impact of this is not determinable by the current study [12,16,18,19,30].

On the other side, the hospitalists could boast equal survival outcomes despite longer ROSC intervals. Because their patients were more likely to be in an intensive care unit or on mechanical ventilation, presumably, these sicker patients would reasonably require a longer CPR interval before ROSC. Perhaps postresuscitative manage- ment such as ventilatory settings, transport, critical care medicine infusions, and subsequent procedures could have been superior in the hospitalist cohort, thereby offsetting their prolonged ROSC delay. Future studies comparing CAT physician leadership might focus more on post- resuscitation care.

We expected that EM residents would be more comfort- able with and therefore personally secure the airway, but they delegated to the respiratory therapist 4 of every 5 intubations. It is not clear why the EM residents passed on this valuable training opportunity, but technical difficulty did not seem to be a factor as previously reported [35]. We could not confirm that one specialty would be more likely than the other to pronounce patients to be on DNR status [36]. The duration of the code blue for both survivors and nonsurvivors was similar between physician groups. We also did not observe the interspecialty (specialist vs specialist) nor the intraspecialty (resident vs attending physician) that has been demonstrated for clinical settings other than CPR [21-24]. Finally, by our implicit nurse supervisor review, all physicians followed ACLS guidelines and effectively took charge of the CAT.

For this large community hospital setting, unless the primary attending physician was already at bedside at t₀, there was generally a significant time lapse until their arrival. In two thirds of our code blues, the residents and hospitalists both arrived within that recognized crucial 4-minute interval [37,38]. This emphasizes the importance of having in-house physicians when feasible.

Do we even need a physician on the CAT since Early defibrillation and basic life support by First responders (nurses in the hospital setting) account for so much of the survival benefit [14,39]? Our data (Table 5) indicate that for many codes, the CAT achieved ROSC even before physician arrival. Certainly, physician response time impacts survival if defibrillation is delayed (albeit inappropriately) until the actual arrival of the doctor [38]. But with our CAT model, skilled nurses and respiratory therapists often performed protocol-driven ACLS interventions such as defibrillation and endotracheal intubation before physician arrival. This reemphasizes that the bwhat Q and bwhenQ those interven-

tions are done (especially early defibrillation) are probably more important than bwho Q does them.

Beyond a need for speed, the qualified physician potentially brings much added value to the CAT. An experienced clinician best manages the complicated airway, decides DNR and medical futility [2] issues, and stabilizes complicated nonventricular fibrillation/ventricular tachy- cardia (VF/VT) patients [5,40]. Furthermore, physician interpretation of bedside tests such as capnometry and ultrasonography may improve the CPR decision-making process [41,42]. Finally, doctors can deviate from ACLS algorithms when the clinical situation warrants [30]. For example, if a patient with a suspected pulmonary embolism suddenly arrests, the physician might decide to administer life-saving thrombolytics [43]. The physician role on the CAT will continue to evolve.

The importance of early therapy, especially defibrillation, by nursing personnel for cardiac arrest cannot be over- emphasized. But physicians certainly serve a vital role during inhospital CPR. Whenever feasible, community hospitals should appoint physician leadership to the CAT. The EM resident model appears to be an acceptable alternative to the hospitalist model for a 24-hour physician staffing of the CAT for in-hospital cardiac arrest.

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