In-hospital resuscitation: association between ACLS training and survival to discharge

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1 Resuscitation 47 (2000) In-hospital resuscitation: association between ACLS training and survival to discharge Francis C. Dane a, *, Katherine S. Russell-Lindgren b, David C. Parish c, Marcus D. Durham d, Terry D. Brown Jr e a Departments of Psychology and Internal Medicine, Medical Center of Central Georgia, Mercer Uni ersity, 707 Pine Street, Macon, GA 31201, USA b Department of Healthcare Systems and Informatics, Georgia College & State Uni ersity, currently School of Nursing, Uni ersity of Tennessee at Chattanooga, Chattanooga, TN, USA c Department of Internal Medicine, Medical Center of Central Georgia, Mercer Uni ersity, Macon, GA, USA d Department of Internal Medicine, Mercer Uni ersity, Macon, GA, USA e Department of Internal Medicine, Medical Center of Central Georgia, currently Department of Psychology, Springfield College, Springfield, MA, USA Received 2 December 1999; received in revised form 21 February 2000; accepted 21 February 2000 Abstract Context: No data have been published on the relationship between advanced cardiac life support (ACLS) training of the individual who initiates resuscitation efforts and survival to discharge. Objecti e: To determine whether patients whose arrests were discovered by nurses trained in ACLS had survival rates different from those discovered by nurses not trained in ACLS. Design: Cohort case-comparison. Setting: A 550-bed, tertiary care center in central Georgia. Subjects: Patients whose cardiopulmonary arrest was discovered by a nurse who activated the in-hospital resuscitation mechanism. Main outcome measure: Patient survival to discharge. Results: Initial rhythm was strongly related to survival to discharge and individually associated with 57% of the variability in survival. Nurse s training in advanced cardiac life support was also strongly related to survival and individually associated with 29% of the variability. Combining both the variables determined 62% of the variability in survival to discharge. Patients discovered by an ACLS-trained nurse (n=88) were about four times more likely to survive (33 survivors, 38%) than were patients, discovered by a nurse without training in ACLS (n=29, three survivors, 10%). Conclusion: Arrest discovery by nurses trained in ACLS is significantly and dramatically associated with higher survival-to-discharge rates Elsevier Science Ireland Ltd. All rights reserved. Keywords: Advanced life support; Resuscitation; Outcome The modern era of cardiopulmonary resuscitation (CPR) began when Kouwenhoven et al. [1] reported successful resuscitation using a combination of closed-chest cardiac massage, closed-chest defibrillation, rescue breathing, and cardiotonic drugs. In the nearly 40 years gone by, more than 100 studies of in-hospital resuscitation have been published [2,3]. Success rates for resuscitation vary considerably [3 7]. Average survival to discharge * Corresponding author. Tel.: ; fax: address: dane fc@mercer.edu (F.C. Dane). has been about 15%, but more recent reports have yielded higher survival rates [2,8 11]. Cardiopulmonary resuscitation (CPR) has been described as a desperate intervention with limited success [12]. Despite this concern, about pre-hospital and about in-hospital resuscitation interventions are attempted each year [8]. While employed regularly, few intervention procedures have been scientifically validated and no evidence exists that CPR significantly reduces inhospital deaths [3]. Nevertheless, accreditation standards in the US include organized plans for CPR in every hospital and a policy requiring /00/$ - see front matter 2000 Elsevier Science Ireland Ltd. All rights reserved. PII: S (00)

2 84 F.C. Dane et al. / Resuscitation 47 (2000) written resuscitation orders (advance directives) for every patient. Clinical personnel are required to maintain proficiency in basic life support [13]. Physicians are often in a position, therefore, of explaining the need for resuscitation orders and providing advice concerning advance directives without sufficient scientific information upon which to base such explanations or advice. The advanced cardiac life support (ACLS) course was developed by the American Heart Association in the 1970s. Over the past 25 years, teaching programs have expanded and multiplied. In fiscal year 1995, over people trained in ACLS in the US alone [8]. The Utstein consensus conference estimated expenditures related to resuscitation training to be over one billion dollars yearly in the US [3]. Despite efforts of this magnitude, only a few researchers have demonstrated improved outcome related to offering ACLS training in an institution [8,14,15] and none have assessed the effect of training on the outcome of efforts initiated by the trainee. Pre-hospital researchers have consistently found level of the community training to be directly related to the rates of survival [16]. If ACLS training programs are worth the money, time and effort involved, there should be evidence that the training enhances survival. The purpose of the present study was to determine the effect of training nurses in the protocols of ACLS [17]. Among hospital staff, nurses are most likely to be in a position to discover and identify patients in unexpected cardiopulmonary distress [18]. Nurses trained in ACLS protocols may be more likely than untrained staff to distinguish urgent from emergent conditions. One would expect, then, the ACLS-trained nurses to activate in-hospital resuscitation mechanisms more promptly as well as begin to employ ACLS protocols more often than nurses without ACLS training. Prompt activation of resuscitation mechanisms and less delay in the initiation of resuscitation protocols may be associated with higher survival-to-discharge rates. 1. Methods Data for the present study were part of a larger project in which all resuscitation attempts (hereafter called codes ) at the Medical Center of Central Georgia (MCCG), a 550-bed, tertiary care hospital, have been examined since 1 January 1987 [2]. In this study, we linked data regarding nurses who initiated resuscitation efforts collected by an author (KSR-L) as part of a dissertation research with data from our ongoing registry study of in-hospital resuscitation. A cohort of 120 nurses, who initiated a resuscitation effort in an intensive care unit (ICU) or medical surgical floor area and agreed to the nurse researcher s interview, was developed by daily review of resuscitation attempts during the study period. At MCCG, ACLS-trained nurses are authorized to implement all interventions, except intubation, contained in the appropriate algorithm. Although ACLStrained nurses may defibrillate, administer ACLS drugs, etc., an ACLS-trained physician (and the rest of the resuscitation team) arrives within 60 s of the code initiation. Data from the registry related to the outcome of relevant patients was added to the nurse interview information. Data were collected from 1/1996 through 2/1997. Each nurse who was interviewed had initiated resuscitation efforts within the previous 24 h; only the first such event was recorded for each nurse. Relevant Institutional Review Boards approved the data collection procedures. Informed consent was obtained from the nurses, but informed consent from the patients was not required. For each of the 120 codes, information obtained from or about the initiating nurse relevant to the present study included gender, age, years of employment in patient care, basic nursing degree, highest earned degree, employment status (fullversus part-time), shift assignment, years employed at MCCG, present status of training in ACLS, year first trained in ACLS, number of times training in ACLS was renewed, present status of dysrhythmia recognition credentials, number of times the nurse participated earlier in resuscitations, and with whom the nurse discussed the patient s status prior to calling the code. Patient information relevant to the present study included location in hospital, age, gender, intubation, ventilation, and cardiac monitor status, and initial rhythm. Initial rhythm was defined as that which was displayed on an existing monitor when the code was called or the first rhythm to appear on a monitor established after the code was called. All

3 F.C. Dane et al. / Resuscitation 47 (2000) rhythms were identified consistent with the in-hospital Utstein style [3]. Prior to analysis, initial rhythm was coded numerically in ascending order of severity, which variable was labeled rhythm severity [2]. In the larger registry of resuscitation attempts (n 4000), survival is associated with rhythms such that survival decreases ordinally from supraventricular tachycardia (SVT), ventricular tachycardia (VT), perfusing, ventricular fibrillation (VF), pulseless electrical activity (PEA), and asystole. Survival to discharge (yes/no) was used as the outcome variable. 2. Results Nearly 32% (38/120) of the patients survived to discharge. In order to assess the association with survival, each of the variables listed above was individually entered into a logistic regression analysis as the sole predictor variable; survival to discharge was the response variable. Only ACLS training and rhythm severity were significant, single predictors of survival. Rhythm severity was inversely related to survival, X 2 (1)=8.0, P 0.005, OR=0.63 (Table 1) and individually associated with 57% of the variability in survival, as measured via concordance rate. Subsequent analyses of contrast codes among rhythms revealed that the difference in survival rates between VF and PEA was significant, X 2 (1)=6.70, P 0.01, OR=6.3, but no other adjacent rhythms evidenced significantly different survival rates. Nurse s training in ACLS was directly related to survival, X 2 (1)=6.47, P 0.02, OR=2.3 (Table 2) and individually accounted for about 29% of the variability in survival (via concordance rate). Survival was almost four times higher when the nurse who called the code was trained in ACLS. When initial rhythm, X 2 (1)=5.51, P 0.02, OR=0.67, and nurse s ACLS training, X 2 (1)= 4.16, P 0.05, OR=1.97, were simultaneously entered into the regression model, both remained significant predictors of survival. That the combination of both the variables accounted for only about 62% of the variability in survival is evidence of some overlap in their relationships with survival. When training X rhythm interaction terms were entered into the model, however, there was no evidence of a significant interaction effect; all interaction 2 values were less than one. Table 1 Survival rates for initial rhythms Rhythm Events Survivors Percent survived Supraventricular tachycardia (SVT) Ventricular tachycardia (VT) Perfusing Ventricular fibrillation (VF) Pulseless electrical activity (PEA) Asystole Total Table 2 Survival rates for nurse s certification in ACLS a Training status Events Survivors Percent survival Trained Floor Unit Not trained Floor Unit Total a Training history was unavailable for three nurses.

4 86 F.C. Dane et al. / Resuscitation 47 (2000) Comment We found ACLS training among nurses to be strongly and dramatically associated with a fourfold increase in survival to discharge. The association between ACLS training and survival that maintained after controlling for rhythm severity indicates that ACLS-trained nurses provide an independent contribution to the increased survival rate. The overlapping effect of rhythm and training reflects the degree to which the initial rhythm is a stage in the dying process. For example, asystole, the final common pathway, is the end stage rhythm. PEA represents a later stage in dying than rhythms in which a patient still has a pulse. VF and PEA both decay to asystole. However, each rhythm also clearly has a rapid decrease in survivability related to time from the onset of arrest. Early identification and activation of resuscitation protocols may improve survival even within rhythm. In-hospital resuscitation studies show substantial differences in rates of survival [3,4] with little evidence to explain the variance. This report is one facet of an ongoing study of in-hospital resuscitation that seeks to identify patient and institutional variables associated with improved survival. The presence of an established database allowed us to address the question of the effect of nurse ACLS training on survival. This study is a found experiment [19] or quasiexperimental design. Given the unproved but common belief that ACLS training is good for patient care, it would be unethical to assign ACLS trained nurses randomly to units. We have controlled for institutional and code team variables by comparing trained and untrained nurses at one institution; i.e. regardless of the training status of the nurse who called the code, the same code team responded to the call. Surprisingly, none of the other nurse (age, length of tenure, etc.) or patient variables (gender, monitor status, etc.) analyzed were found to be significantly associated with outcome. We focused on arrests initiated by nurses. Only high arrest volume areas of the hospital were included, and only the first event initiated by a nurse was considered. Codes called by physicians, respiratory therapists, patient care assistants or family members were not eligible. During the calendar year of 1996 there were 329 admissions to MCCG in which 401 codes were conducted and included in the longitudinal registry. This study population had a survival of 32%, the registry group for 1996 had a survival rate of 33.4%. While survival at the institution is uncommonly high, the cohort included in this study is not unusual with respect to the institution. Nevertheless, studies of the effect of training on other groups of responders will be needed. This is the first study to demonstrate higher rates of hospital survival among patients whose resuscitations are initiated by ACLS trained nurses. Prior studies have demonstrated higher rates of immediate code survival [14,15] and higher numbers of patients successfully resuscitated in a hospital in association with broad ACLS training programs, but no prior study has linked outcome to the person who recognized the dying process and initiated efforts at resuscitation. The ACLS training effects demonstrated here may be an inhospital marker similar to bystander CPR effect in pre-hospital studies. What we cannot identify from these data is the mechanism whereby the ACLS-trained nurses improve survival to discharge. As a first attempt, two of the authors (KSR-L & DCP) independently judged whether the code was initiated early (before required by AHA algorithm) or not. Both the judges were blind to the training status of the nurse who called the code. Although, we were able to establish that ACLS-trained nurses may be calling codes somewhat earlier than nurses not trained in ACLS, we were not able to establish a direct connection between survival and this variable in the current data. It is also logical to assume that ACLS-trained nurses are more likely to initiate ACLS protocols upon discovering or witnessing an arrest, but we cannot test that assumption with the present data. Whatever the causal mechanism may be, we believe it lies within the nurses or their activities. The same resuscitation team responded to codes called by ACLS-trained and untrained nurses, so the activities of the resuscitation team per se are probably not related to the training effect reported herein. While the current data represent evidence that ACLS training is associated with increased survival of patients, the present study requires replication. The data were obtained from a single institution, and this institution has been demonstrated to have a higher resuscitation survival rate

5 F.C. Dane et al. / Resuscitation 47 (2000) than that typically reported in the literature [2]. However, survival rates reported herein are consistent with overall survival rates at this institution during the years The institution has made considerable effort to increase the proportion of ACLS-trained nurses in all nursing areas, including non-intensive or cardiac care units. Special efforts have been made to enhance response time and team skills. The standard code team includes at least five ACLS-trained personnel. Whether increasing the proportion of ACLStrained nurses will affect survival rates at other institutions remains to be seen, but the present data clearly establish a benefit to be obtained from the bedside presence of ACLS-trained nursing staff when patients arrest. Acknowledgements Portions of this research were funded by a Teaching Methods Grant from the American Heart Association to the first author, and by grants from the Clinical Research Committee, MCCG/MUSM, and from the MedCen Foundation to the third author. Other portions of the data were submitted by the second author to the Medical College of Georgia in partial fulfillment of requirements for a doctoral degree. References [1] Kouwenhoven WB, Jude JR, Knickerbocker GG. Closed-chest cardiac massage. J Am Med Assoc 1960;173: [2] Parish DC, Dane FC, Montgomery M, Wynn LJ, Durham MD. Resuscitation in the hospital: differential relationships between age and survival across rhythms. Critical Care Med 1999;27: [3] Utstein Style Writing Group. Recommended guidelines for reviewing, reporting, and conducting research on in-hospital resuscitation: the in-hospital Utstein style. Ann Emerg Med 1997;29: [4] Schneider AP, Nelson DJ, Brown DD. In-hospital cardiopulmonary resuscitation: a 30-year review. J Am Board Family Phys 1993;6: [5] McGrath RB. In-house cardiopulmonary resuscitation after a quarter of a century. Ann Emerg Med 1987;16: [6] Cohn EB, Lefevre F, Yarnold PR, Arron MJ, Martin GJ. Predicting survival from in-hospital CPR: metaanalysis and validation of a prediction model. J Gen Intern Med 1993;8: [7] Jastremski MS. In-hospital cardiac arrest. Ann Emerg Med 1993;22: [8] Camp BN, Parish DC, Andrews RH. The impact of advanced cardiac life support training on resuscitation efforts and survival in a rural hospital. Ann Emerg Med 1997;29: [9] Fitzgerald JD, Wenger NS, Califf RM, Phillips RS, Desbiens NA, Liu H, Lynn J, Wu AW, Connors AF, Oye RK. Functional status among survivors of in-hospital cardiopulmonary resuscitation. Arch Intern Med 1997;157:72 6. [10] Miranda DR. Quality of life after cardiopulmonary resuscitation. Chest 1994;106: [11] Fifield DH. Outcomes of resuscitative efforts at Wild Rose Hospital. Wisconsin Med J 1994;93:55 7. [12] Schultz SC, Cullinane DC, Pasquale MD, Magnant C, Evans S. Predicting in-hospital mortality during cardiopulmonary resuscitation. Resuscitation 1996;33:13 7. [13] Terrace, IL. Comprehensive accreditation manual for hospitals. Joint Commission on Accreditation of Healthcare Organizations, [14] Lowenstein SR, Sabyan EM, Lassen CF, Kern DC. Benefits of training physicians in advanced cardiac life support. Chest 1986;89: [15] Sanders AB, Berg RA, Burress M, Genova RT, Kern KB, Ewy GA. The efficacy of an ACLS training program for resuscitation from cardiac arrest in a rural community. Ann Emerg Med 1994;23:56 9. [16] Pepe PE, Brown CG. ACLS does it really work? Ann Emerg Med 1994;23: [17] Nayak A. In: Cummins R, editor. Textbook of advanced cardiac life support. Dallas: American Heart Association, [18] Vrtis M. Cost/benefit analysis of cardiopulmonary resuscitation: a comprehensive study, Part II. Nursing Manage 1992;23: [19] Phillips DF, Halebsky SC. The epidemiology of found experiments. J Am Med Assoc 1995;273:1221..