When to Stop CPR and When to Perform Rhythm Analysis: Potential Confusion Among ACLS Providers
Journal of Intensive Care Medicine 1-7 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0885066614561589 jic.sagepub.com
Brandon Giberson, BS1, Amy Uber, BS1, David F. Gaieski, MD2, Joseph B. Miller, MD3, Charles Wira, MD4, Katherine Berg, MD5, Tyler Giberson, BS1, Michael N. Cocchi, MD1,6, Benjamin S. Abella, MD, MPhil2, and Michael W. Donnino, MD1,5
Abstract Background: Health care providers nationwide are routinely trained in Advanced Cardiac Life Support (ACLS), an American Heart Association program that teaches cardiac arrest management. Recent changes in the ACLS approach have de-emphasized routine pulse checks in an effort to promote uninterrupted chest compressions. We hypothesized that this new ACLS algorithm may lead to uncertainty regarding the appropriate action following detection of a pulse during a cardiac arrest. Methods: We conducted an observational study in which a Web-based survey was sent to ACLS-trained medical providers at 4 major urban tertiary care centers in the United States. The survey consisted of 5 multiple-choice, scenario-based ACLS questions, including our question of interest. Adult staff members with a valid ACLS certification were included. Results: A total of 347 surveys were analyzed. The response rate was 28.1%. The majority (53.6%) of responders were between 18 and 32 years old, and 59.9% were female. The majority (54.2%) of responders incorrectly stated that they would continue CPR and possibly administer additional therapies when a team member detects a pulse immediately following defibrillation. Secondarily, only 51.9% of respondents correctly chose to perform a rhythm check following 2 minutes of CPR. The other 3 survey questions were correctly answered an average of 89.1% of the time. Conclusion: Confusion exists regarding whether or not CPR and cardiac medications should be continued in the presence of a pulse. Education may be warranted to emphasize avoiding compressions and medications when a palpable pulse is detected. Keywords cardiopulmonary arrest, CPR, cardiac arrest, guidelines
Introduction Sudden cardiac arrest is a leading cause of death, resulting in over 300 000 deaths in the United States each year.1 Advances in cardiopulmonary resuscitation (CPR), widespread availability of automatic external defibrillators (AED), and the establishment of the ‘‘Chain of Survival’’ have helped to improve outcomes for patients with cardiac arrest. The American Heart Association (AHA) offers training in Basic Life Support (BLS) and Advanced Cardiac Life Support (ACLS) to teach bystanders and health care providers the proper management of cardiac arrest. Every 5 years, the AHA reevaluates and revises the guidelines based on expert consensus and advancements in the science of resuscitation. Recent literature on cardiac arrest has demonstrated the life-saving importance of beginning CPR early, minimizing interruptions in chest compressions, and performing highquality CPR.2,3 In light of these findings, there has been a paradigm shift in cardiac arrest management; the focus has
1
Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA 2 Department of Emergency Medicine, Hospital of University of Pennsylvania, Philadelphia, PA, USA 3 Henry Ford Hospital, Detroit, MI, USA 4 Yale School of Medicine, Department of Emergency Medicine, New Haven, CT, USA 5 Department of Medicine, Division of Pulmonary, Critical Care, Beth Israel Deaconess Medical Center, Boston, MA, USA 6 Department of Anesthesia Critical Care, Beth Israel Deaconess Medical Center, Boston, MA, USA
Received February 4, 2014, and in revised form August 22, 2014. Accepted for publication September 26, 2014. Corresponding Author: Michael W. Donnino, Beth Israel Deaconess Medical Center, One Deaconess Road, W/CC 2, Boston, MA 02215, USA. Email: [email protected]
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moved away from lengthy interruptions in CPR (eg, prolonged rhythm checks, pulse checks, ventilation procedures, placing central venous access lines, etc), toward the promotion of virtually uninterrupted chest compressions. In the most recent guideline change, the AHA has adopted a new algorithm to simplify the ACLS approach and reflect this paradigm shift. The new cardiac arrest guideline is illustrated with a circular algorithm that begins with a rhythm check, followed by defibrillation (if indicated), and then immediately followed by chest compressions. The image does not indicate a specific pause to check for a pulse.4 In an effort to emphasize the importance of CPR and to simplify the algorithm, the AHA has de-emphasized routine pulse checks. This de-emphasis of pulse checks likely improves the chances of continuous CPR but could theoretically lead to situations where pulse checks are not performed and CPR continues on patients in whom return of spontaneous circulation has been achieved. In clinical practice, multiple authors of this article have observed instances of ACLS providers continuing chest compressions in the presence of a palpable pulse. We hypothesize that the lack of emphasis on pulse checks in the current guidelines may lead to confusion such that providers may sometimes believe CPR should be performed in patients with a palpable pulse. To investigate this potential confusion, we created an online survey to assess ACLS providers’ knowledge and interpretation of the guidelines. We created multiple questions, one of which presented a scenario in which the ACLS algorithm was not strictly followed in that a pulse check was performed and a pulse was detected immediately after defibrillation. Respondents were then tested to see whether they would recognize ROSC and cease CPR or whether they would continue chest compressions in a patient with a detectable pulse. Four additional questions served as controls for general knowledge of ACLS management including questions regarding medications, differential diagnosis, and when to perform a rhythm check.
Methods Survey Design We conducted an observational Web-based survey, which allowed for easy distribution across several sites. Surveys were sent electronically to ACLS providers (physicians and nurses) at 4 academic tertiary care centers in the United States. The lead study site was Beth Israel Deaconess Medical Center in Boston, Massachusetts. Other participating sites included Yale New Haven Hospital in New Haven, Connecticut, Henry Ford Hospital in Detroit, Michigan, and Hospital of the University of Pennsylvania in Philadelphia, Pennsylvania. The survey consisted of 5 scenario-based, multiple-choice questions— including the question of interest—regarding ACLS care (see Figure 1 for complete survey).
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A post arrest patient is found to have peaked T waves in all leads upon examination of a 12-lead ECG. Which of the following 5-H’s and 5-T’s should be seriously considered? a) Hypovolemia b) Hyperkalemia c) Tamponade d) Hydrogen Ion (acidosis) A patient is unresponsive and found to be in ventricular fibrillation. A shock is delivered. The team leader orders the continuation of 2 minutes of compressions but before the "compressor" commences his 2 minutes of compressions, another member of the team detects a carotid pulse. In this case, you should: a) Cease CPR b) Provide an additional 2 minutes of chest compressions but do not deliver any medications during this period c) Provide an additional 2 minutes of chest compressions and consider providing 1 mg or epinephrine or 40 Units of vasopressin d) Provide an additional 2 minutes of chest compressions and consider providing 300 mg of amiodarone e) Both c and d A patient is found to be in an asystolic arrest and 5 cycles of CPR and one round of Epinephrine has just been administered. What is the next step in managing the resuscitation of this patient? a) Resume CPR for 5 cycles b) Administer Vasopressin 40 U c) Check the rhythm and defibrillate if indicated d) Administer amiodarone 300 mg For a patient in PEA, which of the following should be given first? a) Amiodarone b) Lidocaine c) Norepinephrine d) Epinephrine A patient is found by the monitor to be in a sinus bradycardia with a rate in the 30’s, and is found to have associated altered mental status, shortness of breath, and hypotension. Which of the following drugs should be considered? a) Atropine b) Lidocaine c) Amiodarone d) Magnesium
Figure 1. Full survey as given to participants with correct answers italicized.
Participant Selection The survey was completed by several departments at the 4 centers listed previously, all of which require ACLS certification for clinical staff. Investigators at each site distributed the survey via e-mail to ACLS-trained nurses and residents in the emergency department, internal medicine residents, and nurses and attending physicians in the intensive care units. Inclusion
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Table 1. Participant Baseline Characteristics. Characteristic
n (%)
Female 208 (59.9) Age 18-32 186 (53.6) Age 33-39 71 (20.5) Age 40þ 90 (25.9) Emergency dept nurse 124 (35.7) Intensive care nurse 39 (11.2) Emergency dept attending physician 15 (4.3) Emergency dept resident physician 63 (18.2) Critical care attending physician 8 (2.3) Internal medicine resident physician 85 (24.5) Other (eg, critical care fellow, ED/ICU nurse practitioner, 13 (3.7) emergency medical technician) Abbreviations: dept, department; ED, emergency department; ICU, intensive care unit.
Figure 3. A. Results of pulse detection question of interest. B, Results of pulse detection question by answer choice.
Figure 2. Full survey results.
criteria consisted of adult (18 years of age) staff members of participating institutions with valid ACLS certification. Exclusion criteria consisted of expired or lack of ACLS certification and failure to complete all portions of the survey.
Data Collection and Analysis Demographic information was collected from each participant as part of the survey including sex, age range, job title, and institution of employment. Survey answers were collected at each center and compiled together at the lead center for analysis. We used simple descriptive statistics to report our findings. Data involving employment location were deidentified during analysis in order to report findings anonymously. Due to the observational design of this investigation, a waiver of informed consent was granted from each center’s institutional review board.
Results Between the 4 centers, of the 1272 participants surveyed, 358 participants responded, giving us a response rate of 28.1%. In all, 11 participants were excluded due to lack of ACLS certification
or failure to complete the entire survey, leaving 347 completed surveys for analysis. Table 1 describes the baseline characteristics of the survey participants. In all, 53.6% of responders were between the ages of 18 to 32 and 59.9% were female. The full survey is presented in Figure 1, and the percentage of correct answers for each question is displayed in Figure 2. Only 159 (45.8%) responders correctly stated they would cease CPR when a team member detected a palpable pulse following defibrillation, with 188 (54.2%) responding that they would continue compressions and possibly administer medications in this scenario (Figure 3A). In all, 78 (22.5%) stated that they would provide an additional 2 minutes of chest compressions but would not deliver any medications during this period; 18 (5.2%) would provide an additional 2 minutes of chest compressions and consider providing 1 mg of epinephrine or 40 units of vasopressin, and 37 (10.7%) answered they would provide an additional 2 minutes of chest compressions and consider providing 300 mg of amiodarone. Finally, 55 (15.9%) chose the option of 2 minutes of chest compressions, 1 mg of epinephrine (or 40 units of vasopressin) and 300 mg of amiodarone (Figure 3B). Similar to our central study question, only 180 (51.9%) correctly answered question 3, a question assessing the proper steps following 5 cycles of CPR in an asystolic arrest. The correct answer is to perform a rhythm check and defibrillate if indicated, but only approximately half of the respondents chose this option (Figure 4). Of the remainder, 136 (39.2%) chose to resume CPR, 27 (7.8%) chose to administer vasopressin, and 3 (0.9%) chose to administer amiodarone.
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Figure 4. Results of rhythm check question by answer choice.
In contrast to these 2 questions, 345 (99.4%) respondents correctly answered a question assessing which medication to administer first during a PEA arrest, 337 (97.7%) respondents correctly identified the likelihood of hyperkalemia based on a 12-lead electrocardiogram, and 306 (89.0%) correctly chose to administer atropine in sinus bradycardia (Figure 2). Among the respondents who incorrectly answered the question of interest, 82 (44.3%) also incorrectly answered the rhythm check question. Of the 82 participants who incorrectly answered the rhythm and pulse check questions, 72 (87.8%) correctly answered the remaining 3 questions. No significant differences were found between ages, level of training, or hospital of employment.
Discussion In a survey of ACLS-trained health care providers, we found that more than half of those providers would continue chest compressions in the presence of a palpable pulse. In addition, over 30% of responders also indicated they would provide a pharmacologic intervention such as epinephrine, amiodarone, or both. We also found that approximately half of the surveyed providers erroneously chose not to do a rhythm check after epinephrine and 5 cycles of CPR in an asystolic arrest. The question on timing of chest compressions (question 2) could be construed as slightly ‘‘deceptive,’’ since a pulse was stated to be checked when compressions should have been delivered per the guidelines; however, our rationale for this approach was to test the root question of whether CPR should be performed in an adult patient with a pulse. This also reflects a potential real-world scenario. Our question about rhythm check was straightforward (question 3), and the percentage of incorrect answers were similar to question 2. In contrast, respondents performed very well on the 3 questions that did not involve timing of a pulse or rhythm check, registering correct answers over 89% of the time. These results reveal the existence of potential confusion regarding both timing of pulse and rhythm checks and the application of CPR to a patient with a palpable pulse. A plausible explanation may be that the emphasis on continuous
chest compressions has caused the pendulum to swing too far such that patients with return of spontaneous circulation may inadvertently be exposed to ongoing chest compressions and/ or ACLS medications at cardiac arrest doses. In addition, because pulse and rhythm checks were generally done simultaneously in the old algorithm, the de-emphasis of pulse checks may have inadvertently led to a decreased awareness of when to do rhythm checks as well. In the last decade, the American Heart Association has made several key changes to the ACLS guidelines based upon research demonstrating the benefits of continuous chest compressions. In 2005, the ACLS algorithm recommending defibrillation followed by a pulse check was changed to defibrillation followed by 2 minutes of uninterrupted compressions without pausing for a pulse check or rhythm analysis. In 2010, the circular algorithm described previously was adopted in an effort to simplify the ACLS approach and to remind providers of the importance of high-quality CPR. This circular diagram does not include a reminder for a pulse check or indicate when one should occur. The timing and duration of a pulse check is given only vague and brief coverage in the 2010 Circulation guidelines publication and in the ACLS course manual, which states that ‘‘periodic pauses in CPR should be as brief as possible and only as necessary to assess rhythm, shock VF/VT, perform a pulse check when an organized rhythm is detected, or place an advanced airway.’’4 These changes have been largely driven by literature supporting the importance of chest compressions. Early CPR has been shown to be predictive of survival to hospital discharge,5-7 and minimizing time between compressions and defibrillation was shown to increase the likelihood of shock success for VF/VT arrests.8,9 Studies such as these demonstrate the importance of early, high-quality, uninterrupted chest compressions, whereas other cardiac arrest therapies such as advanced airways and certain medications have not been proven to increase survival rates.10-16 Further research has demonstrated that providers often take too long to check for a pulse17,18 and that pausing for a pulse check after a defibrillation may decrease myocardial perfusion during the critical postdefibrillation period.4 In place of manual pulse checks, the ACLS guidelines propose using physiologic measurements to identify ROSC, such as central venous oxygen saturation (SCVO2) or end-tidal CO2 (PETCO2). An abrupt increase in either of these parameters has been shown to be a reliable indicator of ROSC.19-35 Alternatively, a continuous arterial pressure measurement during cardiac arrest may serve as a gold standard to determine ROSC. These physiologic parameters may be reliable measurements of ROSC and perhaps the ideal monitoring devices during cardiac arrest; however, this monitoring capability may not be available for all patients with cardiac arrest. Each of the physiologic parameters described requires the patient to have either an arterial catheter, central venous catheter, or be intubated. These require the availability of equipment/expertise and take some time to establish and thus are not always available during the resuscitation.
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Few would argue that administering 1 mg of epinephrine to a patient with a pulse is not harmful. What is less clear is whether or not continuing compressions on a patient for 2 minutes after they have restoration of an organized perfusing rhythm could cause harm or worsen outcomes. In rare cases, a blunt strike to the area of the chest directly over the heart can induce ventricular fibrillation. This phenomenon known as commotio cordis is thought to occur when significant blunt force is applied during the ascending phase of the t-wave when the ventricular myocardium is repolarizing.36 This short window of vulnerability (10-30 ms) along with the amount of force necessary to induce VF by this mechanism (estimated energy of at least 50 J) makes this event extremely rare in everyday life. However, it has been reported that in a heart under ischemic conditions (specifically coronary artery insufficiency), the energy threshold required to induce VF is considerably lowered.37 In cardiac arrest, a state of extreme coronary ischemia, it is recommended that chest compressions be delivered in the center of the chest at a rate of at least 100 times per minute possibly increasing the risk of inducing VF by this mechanism if the patient has a perfusing rhythm. Capucci et al found that performing chest compressions after successful defibrillation into a normal electric rhythm might have been a trigger for recurrent ventricular fibrillation and they hypothesized this was due to this proposed mechanism.38 Given this potential complication, performing ongoing chest compressions in a patient with a perfusing rhythm may be cause for concern. The impetus for this study came from multiple authors witnessing events where a team member detected a pulse, yet compressions were continued for some period of time or for ‘‘another 2 minutes.’’ Although correct in the intention to promote continuous chest compressions, this paradigm shift toward high-quality CPR and de-emphasis of pulse checks may have inadvertently led to confusion about what to do when a pulse is actually (even if unintentionally) detected. As suggested by our survey results, this confusion may be leading some to incorrectly believe that detection of a palpable pulse is not a reason to cease chest compressions. To avoid this potential confusion without losing the benefit of continuous CPR, the current AHA guidelines provide guidance on how best to approach. For example, one recommendation is the use of continuous end-tidal CO2 monitoring that will allow for continuous chest compressions while monitoring for ROSC. If the end-tidal CO2 markedly increases, this is an indication that ROSC has been achieved. If end-tidal CO2 is not available and also consistent with AHA guidelines, pulse checks can be incorporated during rhythm analysis, advanced airway placement, or any other natural pause in CPR. This study has some limitations. First, this was an individually taken online survey, in which respondents had unlimited time to consider their answers—a situation unlike a true cardiac arrest setting where decisions are often made quickly and by teams of providers. Although a collaborative decision may reduce the likelihood of a knowledge gap affecting patient care, the aim of this investigation was to expose a potential knowledge gap. Additionally, the percentage of those surveyed is
small compared to the number of ACLS providers nationwide, and the response rate was relatively low. Although our survey mimics ACLS testing scenarios, we have not established the reliability and validity of the survey used in this study. More than half of the respondents of the survey were between the ages of 18 and 32, indicating that the majority of the health care professionals completing this survey likely had not been ACLS certified for an extended period of time. Although our survey found no statistical significance of the age of the responders on their answer choices, the authors acknowledge that practical experience is likely important in enhancing the ability to successfully manage a cardiac arrest. To that end, we used age as a surrogate for experience but did not have a direct measurement for experience such as years of ACLS certification. Finally, one might consider our question about the pulse check ‘‘deceptive’’ in that the checking of a pulse was performed outside the standard ACLS recommendations (ie, recommendation to go directly from defibrillation to compressions and not a pulse check). This was done intentionally to mimic real-world scenarios that sometimes occur and to examine respondents’ root understanding of whether or not CPR should ever be performed when a pulse is detected. One could, however, consider this to be confusing to the respondent. Despite these limitations, the sample size was large and multidisciplinary in composition, and other questions in the survey showed consistency among the responders, with the large majority correctly answering the 3 questions unrelated to rhythm and pulse checks. This suggests that the sample of respondents was knowledgeable of the ACLS guidelines and that confusion on this issue was not due to chance.
Conclusion This investigation revealed that confusion exists among ACLS-trained health care providers regarding whether or not CPR should be continued in the presence of a palpable pulse. We also found that confusion exists in the recommended timing of a rhythm check. Acknowledgment The authors would like to acknowledge the assistance of Francesca Montillo in preparing the article.
Declaration of Conflicting Interests The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: At the time of conception and writing of the manuscript Dr. Donnino was not a paid consultant to the American Heart Association but he did become a paid consultant when the manuscript was in the page proof stage.
Funding The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Dr. Donnino is supported by NIH grant number 1K02HL107447-01-A1.
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33. Bhende MS, Karasic DG, Karasic RB. End-tidal carbon dioxide changes during cardiopulmonary resuscitation after experimental asphyxial cardiac arrest. Am J Emerg Med. 1996;14(4):349-350. 34. Falk JL, Rackow EC, Weil MH. End-tidal carbon dioxide concentration during cardiopulmonary resuscitation. N Engl J Med. 1988;318(10):607-611. 35. Ornato JP, Shipley JB, Racht EM, et al. Multicenter study of a portable, hand-size, colorimetric end-tidal carbon dioxide detection device. Ann Emerg Med. 1992;21(5):518-523.
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Journal of Intensive Care Medicine 1-7 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0885066614561589 jic.sagepub.com
Brandon Giberson, BS1, Amy Uber, BS1, David F. Gaieski, MD2, Joseph B. Miller, MD3, Charles Wira, MD4, Katherine Berg, MD5, Tyler Giberson, BS1, Michael N. Cocchi, MD1,6, Benjamin S. Abella, MD, MPhil2, and Michael W. Donnino, MD1,5
Abstract Background: Health care providers nationwide are routinely trained in Advanced Cardiac Life Support (ACLS), an American Heart Association program that teaches cardiac arrest management. Recent changes in the ACLS approach have de-emphasized routine pulse checks in an effort to promote uninterrupted chest compressions. We hypothesized that this new ACLS algorithm may lead to uncertainty regarding the appropriate action following detection of a pulse during a cardiac arrest. Methods: We conducted an observational study in which a Web-based survey was sent to ACLS-trained medical providers at 4 major urban tertiary care centers in the United States. The survey consisted of 5 multiple-choice, scenario-based ACLS questions, including our question of interest. Adult staff members with a valid ACLS certification were included. Results: A total of 347 surveys were analyzed. The response rate was 28.1%. The majority (53.6%) of responders were between 18 and 32 years old, and 59.9% were female. The majority (54.2%) of responders incorrectly stated that they would continue CPR and possibly administer additional therapies when a team member detects a pulse immediately following defibrillation. Secondarily, only 51.9% of respondents correctly chose to perform a rhythm check following 2 minutes of CPR. The other 3 survey questions were correctly answered an average of 89.1% of the time. Conclusion: Confusion exists regarding whether or not CPR and cardiac medications should be continued in the presence of a pulse. Education may be warranted to emphasize avoiding compressions and medications when a palpable pulse is detected. Keywords cardiopulmonary arrest, CPR, cardiac arrest, guidelines
Introduction Sudden cardiac arrest is a leading cause of death, resulting in over 300 000 deaths in the United States each year.1 Advances in cardiopulmonary resuscitation (CPR), widespread availability of automatic external defibrillators (AED), and the establishment of the ‘‘Chain of Survival’’ have helped to improve outcomes for patients with cardiac arrest. The American Heart Association (AHA) offers training in Basic Life Support (BLS) and Advanced Cardiac Life Support (ACLS) to teach bystanders and health care providers the proper management of cardiac arrest. Every 5 years, the AHA reevaluates and revises the guidelines based on expert consensus and advancements in the science of resuscitation. Recent literature on cardiac arrest has demonstrated the life-saving importance of beginning CPR early, minimizing interruptions in chest compressions, and performing highquality CPR.2,3 In light of these findings, there has been a paradigm shift in cardiac arrest management; the focus has
1
Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA 2 Department of Emergency Medicine, Hospital of University of Pennsylvania, Philadelphia, PA, USA 3 Henry Ford Hospital, Detroit, MI, USA 4 Yale School of Medicine, Department of Emergency Medicine, New Haven, CT, USA 5 Department of Medicine, Division of Pulmonary, Critical Care, Beth Israel Deaconess Medical Center, Boston, MA, USA 6 Department of Anesthesia Critical Care, Beth Israel Deaconess Medical Center, Boston, MA, USA
Received February 4, 2014, and in revised form August 22, 2014. Accepted for publication September 26, 2014. Corresponding Author: Michael W. Donnino, Beth Israel Deaconess Medical Center, One Deaconess Road, W/CC 2, Boston, MA 02215, USA. Email: [email protected]
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moved away from lengthy interruptions in CPR (eg, prolonged rhythm checks, pulse checks, ventilation procedures, placing central venous access lines, etc), toward the promotion of virtually uninterrupted chest compressions. In the most recent guideline change, the AHA has adopted a new algorithm to simplify the ACLS approach and reflect this paradigm shift. The new cardiac arrest guideline is illustrated with a circular algorithm that begins with a rhythm check, followed by defibrillation (if indicated), and then immediately followed by chest compressions. The image does not indicate a specific pause to check for a pulse.4 In an effort to emphasize the importance of CPR and to simplify the algorithm, the AHA has de-emphasized routine pulse checks. This de-emphasis of pulse checks likely improves the chances of continuous CPR but could theoretically lead to situations where pulse checks are not performed and CPR continues on patients in whom return of spontaneous circulation has been achieved. In clinical practice, multiple authors of this article have observed instances of ACLS providers continuing chest compressions in the presence of a palpable pulse. We hypothesize that the lack of emphasis on pulse checks in the current guidelines may lead to confusion such that providers may sometimes believe CPR should be performed in patients with a palpable pulse. To investigate this potential confusion, we created an online survey to assess ACLS providers’ knowledge and interpretation of the guidelines. We created multiple questions, one of which presented a scenario in which the ACLS algorithm was not strictly followed in that a pulse check was performed and a pulse was detected immediately after defibrillation. Respondents were then tested to see whether they would recognize ROSC and cease CPR or whether they would continue chest compressions in a patient with a detectable pulse. Four additional questions served as controls for general knowledge of ACLS management including questions regarding medications, differential diagnosis, and when to perform a rhythm check.
Methods Survey Design We conducted an observational Web-based survey, which allowed for easy distribution across several sites. Surveys were sent electronically to ACLS providers (physicians and nurses) at 4 academic tertiary care centers in the United States. The lead study site was Beth Israel Deaconess Medical Center in Boston, Massachusetts. Other participating sites included Yale New Haven Hospital in New Haven, Connecticut, Henry Ford Hospital in Detroit, Michigan, and Hospital of the University of Pennsylvania in Philadelphia, Pennsylvania. The survey consisted of 5 scenario-based, multiple-choice questions— including the question of interest—regarding ACLS care (see Figure 1 for complete survey).
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A post arrest patient is found to have peaked T waves in all leads upon examination of a 12-lead ECG. Which of the following 5-H’s and 5-T’s should be seriously considered? a) Hypovolemia b) Hyperkalemia c) Tamponade d) Hydrogen Ion (acidosis) A patient is unresponsive and found to be in ventricular fibrillation. A shock is delivered. The team leader orders the continuation of 2 minutes of compressions but before the "compressor" commences his 2 minutes of compressions, another member of the team detects a carotid pulse. In this case, you should: a) Cease CPR b) Provide an additional 2 minutes of chest compressions but do not deliver any medications during this period c) Provide an additional 2 minutes of chest compressions and consider providing 1 mg or epinephrine or 40 Units of vasopressin d) Provide an additional 2 minutes of chest compressions and consider providing 300 mg of amiodarone e) Both c and d A patient is found to be in an asystolic arrest and 5 cycles of CPR and one round of Epinephrine has just been administered. What is the next step in managing the resuscitation of this patient? a) Resume CPR for 5 cycles b) Administer Vasopressin 40 U c) Check the rhythm and defibrillate if indicated d) Administer amiodarone 300 mg For a patient in PEA, which of the following should be given first? a) Amiodarone b) Lidocaine c) Norepinephrine d) Epinephrine A patient is found by the monitor to be in a sinus bradycardia with a rate in the 30’s, and is found to have associated altered mental status, shortness of breath, and hypotension. Which of the following drugs should be considered? a) Atropine b) Lidocaine c) Amiodarone d) Magnesium
Figure 1. Full survey as given to participants with correct answers italicized.
Participant Selection The survey was completed by several departments at the 4 centers listed previously, all of which require ACLS certification for clinical staff. Investigators at each site distributed the survey via e-mail to ACLS-trained nurses and residents in the emergency department, internal medicine residents, and nurses and attending physicians in the intensive care units. Inclusion
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Table 1. Participant Baseline Characteristics. Characteristic
n (%)
Female 208 (59.9) Age 18-32 186 (53.6) Age 33-39 71 (20.5) Age 40þ 90 (25.9) Emergency dept nurse 124 (35.7) Intensive care nurse 39 (11.2) Emergency dept attending physician 15 (4.3) Emergency dept resident physician 63 (18.2) Critical care attending physician 8 (2.3) Internal medicine resident physician 85 (24.5) Other (eg, critical care fellow, ED/ICU nurse practitioner, 13 (3.7) emergency medical technician) Abbreviations: dept, department; ED, emergency department; ICU, intensive care unit.
Figure 3. A. Results of pulse detection question of interest. B, Results of pulse detection question by answer choice.
Figure 2. Full survey results.
criteria consisted of adult (18 years of age) staff members of participating institutions with valid ACLS certification. Exclusion criteria consisted of expired or lack of ACLS certification and failure to complete all portions of the survey.
Data Collection and Analysis Demographic information was collected from each participant as part of the survey including sex, age range, job title, and institution of employment. Survey answers were collected at each center and compiled together at the lead center for analysis. We used simple descriptive statistics to report our findings. Data involving employment location were deidentified during analysis in order to report findings anonymously. Due to the observational design of this investigation, a waiver of informed consent was granted from each center’s institutional review board.
Results Between the 4 centers, of the 1272 participants surveyed, 358 participants responded, giving us a response rate of 28.1%. In all, 11 participants were excluded due to lack of ACLS certification
or failure to complete the entire survey, leaving 347 completed surveys for analysis. Table 1 describes the baseline characteristics of the survey participants. In all, 53.6% of responders were between the ages of 18 to 32 and 59.9% were female. The full survey is presented in Figure 1, and the percentage of correct answers for each question is displayed in Figure 2. Only 159 (45.8%) responders correctly stated they would cease CPR when a team member detected a palpable pulse following defibrillation, with 188 (54.2%) responding that they would continue compressions and possibly administer medications in this scenario (Figure 3A). In all, 78 (22.5%) stated that they would provide an additional 2 minutes of chest compressions but would not deliver any medications during this period; 18 (5.2%) would provide an additional 2 minutes of chest compressions and consider providing 1 mg of epinephrine or 40 units of vasopressin, and 37 (10.7%) answered they would provide an additional 2 minutes of chest compressions and consider providing 300 mg of amiodarone. Finally, 55 (15.9%) chose the option of 2 minutes of chest compressions, 1 mg of epinephrine (or 40 units of vasopressin) and 300 mg of amiodarone (Figure 3B). Similar to our central study question, only 180 (51.9%) correctly answered question 3, a question assessing the proper steps following 5 cycles of CPR in an asystolic arrest. The correct answer is to perform a rhythm check and defibrillate if indicated, but only approximately half of the respondents chose this option (Figure 4). Of the remainder, 136 (39.2%) chose to resume CPR, 27 (7.8%) chose to administer vasopressin, and 3 (0.9%) chose to administer amiodarone.
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Figure 4. Results of rhythm check question by answer choice.
In contrast to these 2 questions, 345 (99.4%) respondents correctly answered a question assessing which medication to administer first during a PEA arrest, 337 (97.7%) respondents correctly identified the likelihood of hyperkalemia based on a 12-lead electrocardiogram, and 306 (89.0%) correctly chose to administer atropine in sinus bradycardia (Figure 2). Among the respondents who incorrectly answered the question of interest, 82 (44.3%) also incorrectly answered the rhythm check question. Of the 82 participants who incorrectly answered the rhythm and pulse check questions, 72 (87.8%) correctly answered the remaining 3 questions. No significant differences were found between ages, level of training, or hospital of employment.
Discussion In a survey of ACLS-trained health care providers, we found that more than half of those providers would continue chest compressions in the presence of a palpable pulse. In addition, over 30% of responders also indicated they would provide a pharmacologic intervention such as epinephrine, amiodarone, or both. We also found that approximately half of the surveyed providers erroneously chose not to do a rhythm check after epinephrine and 5 cycles of CPR in an asystolic arrest. The question on timing of chest compressions (question 2) could be construed as slightly ‘‘deceptive,’’ since a pulse was stated to be checked when compressions should have been delivered per the guidelines; however, our rationale for this approach was to test the root question of whether CPR should be performed in an adult patient with a pulse. This also reflects a potential real-world scenario. Our question about rhythm check was straightforward (question 3), and the percentage of incorrect answers were similar to question 2. In contrast, respondents performed very well on the 3 questions that did not involve timing of a pulse or rhythm check, registering correct answers over 89% of the time. These results reveal the existence of potential confusion regarding both timing of pulse and rhythm checks and the application of CPR to a patient with a palpable pulse. A plausible explanation may be that the emphasis on continuous
chest compressions has caused the pendulum to swing too far such that patients with return of spontaneous circulation may inadvertently be exposed to ongoing chest compressions and/ or ACLS medications at cardiac arrest doses. In addition, because pulse and rhythm checks were generally done simultaneously in the old algorithm, the de-emphasis of pulse checks may have inadvertently led to a decreased awareness of when to do rhythm checks as well. In the last decade, the American Heart Association has made several key changes to the ACLS guidelines based upon research demonstrating the benefits of continuous chest compressions. In 2005, the ACLS algorithm recommending defibrillation followed by a pulse check was changed to defibrillation followed by 2 minutes of uninterrupted compressions without pausing for a pulse check or rhythm analysis. In 2010, the circular algorithm described previously was adopted in an effort to simplify the ACLS approach and to remind providers of the importance of high-quality CPR. This circular diagram does not include a reminder for a pulse check or indicate when one should occur. The timing and duration of a pulse check is given only vague and brief coverage in the 2010 Circulation guidelines publication and in the ACLS course manual, which states that ‘‘periodic pauses in CPR should be as brief as possible and only as necessary to assess rhythm, shock VF/VT, perform a pulse check when an organized rhythm is detected, or place an advanced airway.’’4 These changes have been largely driven by literature supporting the importance of chest compressions. Early CPR has been shown to be predictive of survival to hospital discharge,5-7 and minimizing time between compressions and defibrillation was shown to increase the likelihood of shock success for VF/VT arrests.8,9 Studies such as these demonstrate the importance of early, high-quality, uninterrupted chest compressions, whereas other cardiac arrest therapies such as advanced airways and certain medications have not been proven to increase survival rates.10-16 Further research has demonstrated that providers often take too long to check for a pulse17,18 and that pausing for a pulse check after a defibrillation may decrease myocardial perfusion during the critical postdefibrillation period.4 In place of manual pulse checks, the ACLS guidelines propose using physiologic measurements to identify ROSC, such as central venous oxygen saturation (SCVO2) or end-tidal CO2 (PETCO2). An abrupt increase in either of these parameters has been shown to be a reliable indicator of ROSC.19-35 Alternatively, a continuous arterial pressure measurement during cardiac arrest may serve as a gold standard to determine ROSC. These physiologic parameters may be reliable measurements of ROSC and perhaps the ideal monitoring devices during cardiac arrest; however, this monitoring capability may not be available for all patients with cardiac arrest. Each of the physiologic parameters described requires the patient to have either an arterial catheter, central venous catheter, or be intubated. These require the availability of equipment/expertise and take some time to establish and thus are not always available during the resuscitation.
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Few would argue that administering 1 mg of epinephrine to a patient with a pulse is not harmful. What is less clear is whether or not continuing compressions on a patient for 2 minutes after they have restoration of an organized perfusing rhythm could cause harm or worsen outcomes. In rare cases, a blunt strike to the area of the chest directly over the heart can induce ventricular fibrillation. This phenomenon known as commotio cordis is thought to occur when significant blunt force is applied during the ascending phase of the t-wave when the ventricular myocardium is repolarizing.36 This short window of vulnerability (10-30 ms) along with the amount of force necessary to induce VF by this mechanism (estimated energy of at least 50 J) makes this event extremely rare in everyday life. However, it has been reported that in a heart under ischemic conditions (specifically coronary artery insufficiency), the energy threshold required to induce VF is considerably lowered.37 In cardiac arrest, a state of extreme coronary ischemia, it is recommended that chest compressions be delivered in the center of the chest at a rate of at least 100 times per minute possibly increasing the risk of inducing VF by this mechanism if the patient has a perfusing rhythm. Capucci et al found that performing chest compressions after successful defibrillation into a normal electric rhythm might have been a trigger for recurrent ventricular fibrillation and they hypothesized this was due to this proposed mechanism.38 Given this potential complication, performing ongoing chest compressions in a patient with a perfusing rhythm may be cause for concern. The impetus for this study came from multiple authors witnessing events where a team member detected a pulse, yet compressions were continued for some period of time or for ‘‘another 2 minutes.’’ Although correct in the intention to promote continuous chest compressions, this paradigm shift toward high-quality CPR and de-emphasis of pulse checks may have inadvertently led to confusion about what to do when a pulse is actually (even if unintentionally) detected. As suggested by our survey results, this confusion may be leading some to incorrectly believe that detection of a palpable pulse is not a reason to cease chest compressions. To avoid this potential confusion without losing the benefit of continuous CPR, the current AHA guidelines provide guidance on how best to approach. For example, one recommendation is the use of continuous end-tidal CO2 monitoring that will allow for continuous chest compressions while monitoring for ROSC. If the end-tidal CO2 markedly increases, this is an indication that ROSC has been achieved. If end-tidal CO2 is not available and also consistent with AHA guidelines, pulse checks can be incorporated during rhythm analysis, advanced airway placement, or any other natural pause in CPR. This study has some limitations. First, this was an individually taken online survey, in which respondents had unlimited time to consider their answers—a situation unlike a true cardiac arrest setting where decisions are often made quickly and by teams of providers. Although a collaborative decision may reduce the likelihood of a knowledge gap affecting patient care, the aim of this investigation was to expose a potential knowledge gap. Additionally, the percentage of those surveyed is
small compared to the number of ACLS providers nationwide, and the response rate was relatively low. Although our survey mimics ACLS testing scenarios, we have not established the reliability and validity of the survey used in this study. More than half of the respondents of the survey were between the ages of 18 and 32, indicating that the majority of the health care professionals completing this survey likely had not been ACLS certified for an extended period of time. Although our survey found no statistical significance of the age of the responders on their answer choices, the authors acknowledge that practical experience is likely important in enhancing the ability to successfully manage a cardiac arrest. To that end, we used age as a surrogate for experience but did not have a direct measurement for experience such as years of ACLS certification. Finally, one might consider our question about the pulse check ‘‘deceptive’’ in that the checking of a pulse was performed outside the standard ACLS recommendations (ie, recommendation to go directly from defibrillation to compressions and not a pulse check). This was done intentionally to mimic real-world scenarios that sometimes occur and to examine respondents’ root understanding of whether or not CPR should ever be performed when a pulse is detected. One could, however, consider this to be confusing to the respondent. Despite these limitations, the sample size was large and multidisciplinary in composition, and other questions in the survey showed consistency among the responders, with the large majority correctly answering the 3 questions unrelated to rhythm and pulse checks. This suggests that the sample of respondents was knowledgeable of the ACLS guidelines and that confusion on this issue was not due to chance.
Conclusion This investigation revealed that confusion exists among ACLS-trained health care providers regarding whether or not CPR should be continued in the presence of a palpable pulse. We also found that confusion exists in the recommended timing of a rhythm check. Acknowledgment The authors would like to acknowledge the assistance of Francesca Montillo in preparing the article.
Declaration of Conflicting Interests The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: At the time of conception and writing of the manuscript Dr. Donnino was not a paid consultant to the American Heart Association but he did become a paid consultant when the manuscript was in the page proof stage.
Funding The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Dr. Donnino is supported by NIH grant number 1K02HL107447-01-A1.
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