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Chest injury following cardiopulmonary resuscitation: A prospective computed tomography evaluation
Resuscitation 84 (2013) 361–364
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Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Chest injury following cardiopulmonary resuscitation: A prospective computed tomography evaluation夽 Min Joung Kim a , Yoo Seok Park a , Seung Whan Kim b , Yoo Sang Yoon c , Kyeong Ryong Lee d , Tae Ho Lim e , Hoon Lim f , Ha Young Park g , Joon Min Park h , Sung Phil Chung a,∗ a
Department of Emergency Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea Department of Emergency Medicine, College of Medicine, Chungnam National University, Daejeon, Republic of Korea c Department of Emergency Medicine, Inje University Busan Paik Hospital, Busan, Republic of Korea d Department of Emergency Medicine, Konkuk University School of Medicine, Seoul, Republic of Korea e Department of Emergency Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea f Department of Emergency Medicine, Bucheon Hospital of Soonchuhyang University, Bucheon, Republic of Korea g Department of Emergency Medicine, Inje University Haeundae Paik Hospital, Busan, Republic of Korea h Inje University Ilsan Paik Hospital, Goyang, Republic of Korea b
a r t i c l e
i n f o
Article history: Received 23 February 2012 Received in revised form 22 June 2012 Accepted 2 July 2012 Keywords: Cardiopulmonary resuscitation Computed tomography Fracture
a b s t r a c t Introduction: Traumatic chest injuries may occur following cardiopulmonary resuscitation (CPR). The aim of this study was to address the frequency of injuries, especially rib and sternal fractures, and also to identify factors that contribute to post-CPR trauma. Methods: This study was a prospective cross-sectional study conducted in the emergency departments (ED) of eight academic tertiary care centers. To evaluate injuries secondary to CPR, we performed chest computed tomography (CT) in patients who were successfully resuscitated from cardiac arrest. Contributing factors that might be related to injuries were also investigated. Results: We enrolled 71 patients between 1 January 2011 and 30 June 2011. Rib and sternal fractures were diagnosed in 22 and 3 patients, respectively. Females were more susceptible to rib fracture (p = 0.036). When non-physicians participated as chest compressors in the ED, more ribs were fractured (p = 0.048). The duration of CPR and number of compressors were not contributing factors to trauma secondary to CPR. There was a wide variation in the frequency of rib fractures from hospital to hospital (0–83.3%). In high-risk hospitals (in which more than 50% of patients had rib fractures), the average age of the patients was higher, and non-physicians took part in ED CPR more often than they did at low-risk hospitals. Conclusion: The incidence of rib fracture following CPR was different in various hospitals. The presence of non-physician chest compressors in the ED was one of the contributing factors to rib fracture. Further studies on the influence of resuscitators and relation between quality of chest compression and CPRinduced injuries are warranted to reduce complications following CPR. © 2012 Elsevier Ireland Ltd. All rights reserved.
1. Introduction Chest compression is a vital component of cardiopulmonary resuscitation (CPR). According to the European Resuscitation Council (ERC) Guidelines and American Heart Association (AHA) guidelines, a rate of 100–120 compressions per minute and a depth of 5–6 cm is recommended for high-quality CPR.1,2 Moreover, as agonal gasping delays the start of CPR, the guidelines emphasize that the lay rescuer immediately begin CPR on victims who are
夽 A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2012.07.011. ∗ Corresponding author. Address: Department of Emergency Medicine, Gangnam Severance Hospital, 712 Eonju-ro, Gangnam-gu, Seoul 135-720, Republic of Korea. Tel.: +82 2 2019 3030; fax: +82 2 2019 4820. E-mail address: [email protected] (S.P. Chung). 0300-9572/$ – see front matter © 2012 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.resuscitation.2012.07.011
breathing abnormally. This policy could increase bystander CPR prevalence, while the possibility of administering CPR to unresponsive patients not in cardiac arrest would also be increased. Before the 2010 guidelines were implemented, White et al.3 reported that 18% of patients to whom dispatchers offered CPR instructions were not in arrest, but still received bystander chest compression. Traditionally, high quality chest compressions have been emphasized to improve the survivability of patients in cardiac arrest; therefore, we investigated exactly how many involuntary injuries resulted from CPR. Previous studies have shown varied incidences of rib and sternum fractures related to CPR.3–6 We performed chest computed tomography (CT) in patients who were successfully resuscitated from cardiac arrest to investigate chest injuries secondary to CPR. The aim of this study was to address the frequency of injuries (especially rib and sternal fractures) and to identify contributing factors.
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2. Methods This study was a prospective cross-sectional, multicenter study involving patients who survived cardiac arrest after CPR in the emergency departments (ED) of eight academic tertiary care centers. Research staff at participating hospitals endeavored to provide high-quality CPR and post-resuscitation care according to the 2010 ERC and AHA guidelines.7,8 Each hospital’s institutional review board approved the study protocol. Eligible patients were enrolled between January 1, 2011 and June 30, 2011. Both out-of-hospital and in-hospital cardiac arrest patients were included if spontaneous circulation was restored and the patient was sufficiently stabilized enough to be transferred to the CT room. Either the patients themselves or their legal representatives were informed about the trial, and their consent was documented. We excluded patients under the age of 18, those with traumatic cardiac arrest, and those who did not receive chest compressions. Chest CT (multidetector CT; 16 or 64 channel scanner) including axial, coronal, and sagittal images was performed within 48 h from the restoration of spontaneous circulation. Chest injuries related to cardiac compression were determined based upon the CT interpretation of each hospital’s radiologist. They all were subspecialty-trained chest radiologists with more than 5 years’ of experience. The research staff collected information on potential contributing factors such as age, gender, CPR duration (including pre-hospital CPR), type and number of compressors, total amount of epinephrine injected, total amount of shock energy delivered, and the use of an automatic mechanical compressor device. Data are presented as a number with percentage or median (IQR). Comparisons were performed using the Chi-square test, Fisher’s exact test or Mann–Whitney U test. We used the Statistical Package for the Social Sciences (SPSS) version 12.0 for Windows (SPSS Inc., Chicago, IL, USA). A p-value of <0.05 was considered statistically significant. 3. Results During the study period, 608 patients received cardiopulmonary resuscitation: 455 (75%) out-of-hospital cardiac arrests and 153 (25%) in-hospital cardiac arrests. Spontaneous circulation was restored in 285 (47%) patients. Among them, we excluded 15 patients under the age of 18, 31 patients with traumatic cardiac arrest and 12 patients who did not receive chest compressions. And we could not performed CT in 156 patients for various reasons such as unstable medical condition preventing transport to the CT room and refusal of CT evaluation because of lack of symptoms, economic reasons or hopeless cases. As a result, 71 patients were enrolled in this study (Fig. 1). Table 1 summarizes the chest injuries associated with CPR. Rib fracture, the most common injury, was diagnosed in 22 of 71 patients. Among 14 of 22 patients, multiple rib fractures (ranging from two to nine fractures) were observed. Sternal fracture was observed in three patients. Non-skeletal injuries, such as pneumothorax, hemothorax and lung contusions, were also observed. The median (IQR) age of the patients was 65 (55, 74) years and 45 patients were male. The initial cardiac rhythms were asystole in 42, pulseless electrical activity in 17 and ventricular fibrillation in 12 patients. Forty-five cardiac arrests were witnessed. In total, 57 cardiac arrests occurred outside the hospital, and CPR was performed by a layperson in 14 patients prior to the arrival of emergency medical services (EMS). The median (IQR) total CPR time was 15.0 (8.0, 26.0) minutes. There was a median of four compressors per patient, ranging from one to ten. We compared cardiac arrest-specific data between the rib fracture group and the non-rib fracture group (Table 2). The median
Fig. 1. Flow diagram of patient eligibility.
age (IQR) was 69.5 (56.0, 74.0) in the rib fracture group and 63.0 (49.5, 69.5) in the non-rib fracture group, but the difference was not statistically significant (p = 0.053). Females had a higher rate of rib fracture than males (12/26 vs. 10/45, p = 0.036). When nonphysicians participated as chest compressors in the ED, more ribs were fractured (p = 0.048). There was no significant difference in age, arrest location, duration of CPR, or number of compressors between these two groups. The frequency of rib fractures varied from hospital to hospital, ranging from 0 to 83.3% (Fig. 2). We used a 50% rib fracture rate to divide hospitals into two groups: high-risk hospitals and low-risk hospitals. Table 3 shows a comparison of potential risk factors for rib fracture between high-risk hospitals and low-risk hospitals. At high-risk hospitals, patients were significantly older than patients at low-risk hospitals (p = 0.002). Non-physicians took part in chest compression in 21 of 26 CPR situations at high-risk hospitals and in only 15 of 45 CPR situations at low-risk hospitals, which was a significant difference (p < 0.001). 4. Discussion Various rates of skeletal injury were reported in previous studies that investigated complications after CPR; 13–97% for rib fracture and 1–43% for sternal fracture.4,9,10 The incidence of fractures could vary depending on the diagnostic tool used. Lederer et al. reported that postmortem autopsy was more accurate for detecting rib and Table 1 Chest injuries associated with cardiopulmonary resuscitation. Complication Skeletal Rib fracture Number of fracture Single Multiple Side of fracture Rt Lt Both Sternal fracture Thoracic vertebral fracture Pulmonary Hemothorax Pneumothorax Lung contusion Pneumomediastinum
No. of patients (total = 71) 22 8 14 8 7 7 3 1 8 6 3 1
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363
Table 2 Comparison of cardiac arrest specific data between rib fracture group and non-rib fracture group. Variables
Total (n = 71)
Rib fracture (n = 22)
Non-rib fracture (n = 49)
p-value
Age, median (IQR) Sex, n Male Female Witness, n Witnessed Un-witnessed Arrest location, n In hospital Out of hospital Duration of CPR, median (IQR) Epinephrine, median (IQR) Defibrillation, median (IQR) Type of compressor, n Prehospital CPR Layperson EMS ED CPR Physician Non-physician Number of compressor, median (IQR)
65.0 (55.0, 74.0)
69.5 (56.0, 75.8)
63.0 (49.5, 69.5)
0.053 0.036
45 26
10 12
35 14
45 26
14 8
31 18
14 57 15.0 (8.0, 26.0) 2.0 (2.0, 4.0) 0 (0, 150.0)
4 18 13.5 (8.0, 25.5) 2.5 (2.0, 4.0) 0 (0, 180.0)
10 39 16.0 (7.5, 26.0) 2.0 (1.5, 4.0) 0 (0, 150.0)
0.799 0.433 0.867
14 40
5 10
9 30
0.669 0.215
64 36 4.0 (3.0, 5.0)
21 15 40 (3.0, 6.3)
43 21 3.0 (3.0, 5.0)
0.314 0.048 0.386
0.976
0.827
Fig. 2. Rib fractured patient of eight hospitals. *The number in bracket is enrolled patients of each hospital.
sternum fractures than X-ray.5 As this study investigated the rate of skeletal chest injury in successfully resuscitated patients, we adopted multidetector CT rather than autopsy to identify injuries in our participants. There was one previous study that used chest CT to identify complications secondary to chest compression.4 That study retrospectively interpreted CT findings of successfully resuscitated patients and reported a 65% and 30% incidence of rib fracture and sternal fracture, respectively, much higher than our results of 22/71 (31.0%) and 3/71 (4.2%), respectively. These might be caused by methodological differences in patient inclusion; prospective vs. retrospective. Table 3 Comparison of potential risk factors between high risk and low risk hospitals. Variables
Low risk hospital (n = 45)
High risk hospital (n = 26)
p-Value
Age, median (IQR) Sex, n Male Female CPR time, median (IQR) Compressor, n Prehospital CPR Layperson EMS ED CPR Physician Non-physician Number of compressor, median (IQR)
60.0 (48.0, 68.0)
71.0 (61.3, 80.3)
31 14 16.0 (7.5, 26.0)
14 12 14.5 (8.0, 25.5)
0.637
11 29
3 11
0.188 0.070
39 15 3.0 (2.5, 5.0)
25 21 4.0 (3.0, 6.0)
0.002 0.205
0.196 <0.001 0.455
We found that females were more susceptible to rib fracture. Black et al. also reported that more females than males sustained rib fractures, while no significant gender difference for sternal fractures was noted.6 Females are known to involve a higher frequency of osteoporosis and are generally older than males at the time of resuscitation.11 These are expected to account for the higher risk of rib fractures in females. We did not find a significant difference (p = 0.053) in age, but a positive correlation between age and rib fracture incidence was reported in other studies.6,12–15 Interestingly, we found that the incidence of rib fracture caused by chest compression varied from hospital to hospital (0–83.3%). This finding suggests that different methods of basic life support (BLS) training and different advanced cardiovascular life support team members at each hospital, as well as the characteristics of patients who visit these hospitals, greatly influenced complications related to CPR. Hospitals with a high incidence of rib fracture had more elderly patients and also more frequently included nonphysicians such as nurses, paramedics and medical students as chest compressors in ED CPR. Not much is known in regards to the influence of the resuscitator on post-CPR trauma. Assuming some traits of resuscitators affected the extent of injury from CPR, we suggest that there could be reversible causes of injuries and hope for improvement. Investigation into these reversible causes, which properties of chest compression induce chest injuries (too deep of compression, too fast of an acceleration in compression or wrong hand position etc.), and furthermore, what influences the compression quality of resuscitators should be continued. Unfortunately, we were unable to discover the reason why participation of non-physicians as compressors in ED CPR increased the frequency of rib fractures. Perhaps highly motivated providers push harder and faster, thereby causing more injuries during CPR. These could comprise less experienced providers or physicians who attempt to stand out in front of non-physicians. On the other hand, BLS training and occupational affiliation could also influence the quality of chest compression as reported in previous studies.16–19 New guidelines that emphasize the harder and faster compression than 2005 guidelines might induce different reactions in resuscitators according to basic knowledge, previous experience and mode of education. We are afraid that unconditional emphasis of deep and rapid compression would incite more CPR-related injuries. In addition to the training of high quality CPR, we should ruminate about the strategy of BLS education to reduce the rate of CPR-related injury.
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Few studies have established the relationship between the length of CPR and CPR-related injuries. Krischer et al. reported that 32% of the patients had rib fractures and a longer duration of CPR is associated with a higher frequency of rib fractures based upon an autopsy study.12 However, in our study there was no difference in the duration of CPR between the rib fracture group and the non-rib fracture group. One fact that could have affected this conflicting result is that the CPR duration of our study was relatively short to Krischer et al.’s study because we included patients who were successfully resuscitated from cardiac arrest, whereas Krischer et al. investigated non-survived and autopsied patients.12 It has been reported that the median duration of CPR was 17 min in survived patients and 43 min in non-survived patients.20,21 The result of Sladjana et al.’s study reporting that abandonment of further CPR occurred after 29 min from cardiac arrest would help understand difference of CPR duration between survived and nonsurvived patients.22 In theory, as the stiffness of ischemic tissue deteriorates, the incidence of rib fracture could increase with prolonged CPR. If so, our study on patients with a relatively short CPR duration could underestimate the actual complication rates. However, Baubin et al. empirically suggested that most damage might occur during the early stages of CPR.15 In prolonged CPR, increased fatigue in the compressor would weaken compression power and fewer complications wound occur.23 To explain the effect of CPR duration on injuries secondary to CPR, detailed investigations in regards to timing and the mechanism of rib fracture are warranted. Another reason for the conflicting results could be that all patients received only manual compressions in our study, whereas a mechanical chest compressor was applied in 63.5% of patients in Krischer et al.’s study.12 The mechanism and timing of rib fracture may differ depending on the mode of compression. For the same reason, Smekal et al. also could not determine the association between the duration of CPR and the incidence of rib fracture.24 5. Limitations This study has several limitations. First, we could not clarify the occupations and characteristics of non-physicians in the ED that influenced the risk of rib fracture. These non-physicians could have been nurses and paramedics who were affiliated with the ED or medical students training in emergency medicine. Those involved in resuscitations also could have varied depending on the situation at each hospital. Further research into human factors, such as BLS education level and CPR experience, will be required. Especially, it is necessary to investigate the relationship between the compression depth of individual providers and chest injuries secondary to CPR. Second, a large number of patients did not undergo CT evaluation and were excluded from the study. Their characteristics, such as gender and age, known as potential factors, were similar to the included patients; however, some unpredictable factors could have skewed our results. Third, although age has been overtly recognized as an influential factor on the potential for rib fracture caused by CPR, we were unable to show the statistical significance of this factor due to the small sample size. Lastly, fracture was diagnosed on the basis of CT findings without an autopsy correlation (because our participants were still alive). We might have overlooked a few patients whose fractures were too subtle to diagnose with CT alone. 6. Conclusion The number of rib fractures arising from chest compression was relatively high. However, the incidence of rib fracture varied greatly from hospital to hospital. Female patients and participation of non-physician chest compressors in ED CPR were associated with a higher incidence of rib fractures. Further studies to investigate
the cause of variability in complications by hospital after CPR and the influence of chest compression properties on CPR complication should be conducted. Conflict of interest None of the authors have any conflict of interest, financial or otherwise, relevant to the conduct or reporting of this study. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.resuscitation. 2012.07.011. References 1. Koster RW, Baubin MA, Bossaert LL, et al. European Resuscitation Council Guidelines for Resuscitation 2010 Section 2. Adult basic life support and use of automated external defibrillators. Resuscitation 2010;81:1277–92. 2. Berg RA, Hemphill R, Abella BS, et al. Part 5: adult basic life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010;122:685–705. 3. White L, Rogers J, Bloomingdale M, et al. Dispatcher-assisted cardiopulmonary resuscitation: risks for patients not in cardiac arrest. Circulation 2010;121:91–7. 4. Kim EY, Yang HJ, Sung YM, et al. Multidetector CT findings of skeletal chest injuries secondary to cardiopulmonary resuscitation. Resuscitation 2011;82:1285–8. 5. Lederer W, Mair D, Rabl W, Baubin M. Frequency of rib and sternum fractures associated with out-of-hospital cardiopulmonary resuscitation is underestimated by conventional chest X-ray. Resuscitation 2004;60:157–62. 6. Black CJ, Busuttil A, Robertson C. Chest wall injuries following cardiopulmonary resuscitation. Resuscitation 2004;63:339–43. 7. Deakin CD, Nolan JP, Soar J, et al. European Resuscitation Council Guidelines for Resuscitation 2010 Section 4. Adult advanced life support. Resuscitation 2010;81:1305–52. 8. Peberdy MA, Callaway CW, Neumar RW, et al. Part 9: post-cardiac arrest care: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010;122:768–86. 9. Hoke RS, Chamberlain D. Skeletal chest injuries secondary to cardiopulmonary resuscitation. Resuscitation 2004;63:327–38. 10. Boz B, Erdur B, Acar K, Ergin A, Turkcuer I, Ergin N. Frequency of skeletal chest injuries associated with cardiopulmonary resuscitation: forensic autopsy. Ulus Travma Acil Cerrahi Derg 2008;14:216–20. 11. Perers E, Abrahamsson P, Bång A, et al. There is a difference in characteristics and outcome between women and men who suffer out of hospital cardiac arrest. Resuscitation 1999;40:133–40. 12. Krischer JP, Fine EG, Davis JH, Nagel EL. Complications of cardiac resuscitation. Chest 1987;92:287–91. 13. Paaske F, Hansen JP, Koudahl G, Olsen J. Complications of closed-chest cardiac massage in a forensic autopsy material. Dan Med Bull 1968;15:225–30. 14. Kloss T, Puschel K, Wischhusen F, Welk I, Roewer N, Jungck E. Resuscitation injuries. Anasth Intensivther Notfallmed 1983;18:199–203. 15. Baubin M, Sumann G, Rabl W, Eibl G, Wenzel V, Mair P. Increased frequency of thorax injuries with ACD-CPR. Resuscitation 1999;41:33–8. 16. Sarac¸ L, Ok A. The effects of different instructional methods on students’ acquisition and retention of cardiopulmonary resuscitation skills. Resuscitation 2010;81:555–61. 17. Einspruch EL, Lynch B, Aufderheide TP, Nichol G, Becker L. Retention of CPR skills learned in a traditional AHA Heartsaver course versus 30-min video selftraining: a controlled randomized study. Resuscitation 2007;74:476–86. 18. Hamilton R. Nurses’ knowledge and skill retention following cardiopulmonary resuscitation training: a review of the literature. J Adv Nurs 2005;51:288–97. 19. Källestedt ML, Berglund A, Thoren AB, Herlitz J, Enlund M. Occupational affiliation does not influence practical skills in cardiopulmonary resuscitation for in-hospital healthcare professionals. Scand J Trauma Resusc Emerg Med 2011;19:3. 20. Amnuaypattanapon K, Udomsubpayakul U. Evaluation of related factors and the outcome in cardiac arrest resuscitation at Thammasat Emergency Department. J Med Assoc Thailand 2010;93:S26–34. 21. Kutsogiannis DJ, Bagshaw SM, Laing B, Brindley PG. Predictors of survival after cardiac or respiratory arrest in critical care units. CMAJ 2011;183:1589–95. 22. Sladjana A, Gordana P, Ana S. Emergency response time after out-of-hospital cardiac arrest. Eur J Intern Med 2011;22:386–93. 23. Foo NP, Chang JH, Lin HJ, Guo HR. Rescuer fatigue and cardiopulmonary resuscitation positions: a randomized controlled crossover trial. Resuscitation 2010;81:579–84. 24. Smekal D, Johansson J, Huzevka T, Rubertsson S. No difference in autopsy detected injuries in cardiac arrest patients treated with manual chest compressions compared with mechanical compressions with the LUCAS device—a pilot study. Resuscitation 2009;80:1104–7.
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Chest injury following cardiopulmonary resuscitation: A prospective computed tomography evaluation夽 Min Joung Kim a , Yoo Seok Park a , Seung Whan Kim b , Yoo Sang Yoon c , Kyeong Ryong Lee d , Tae Ho Lim e , Hoon Lim f , Ha Young Park g , Joon Min Park h , Sung Phil Chung a,∗ a
Department of Emergency Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea Department of Emergency Medicine, College of Medicine, Chungnam National University, Daejeon, Republic of Korea c Department of Emergency Medicine, Inje University Busan Paik Hospital, Busan, Republic of Korea d Department of Emergency Medicine, Konkuk University School of Medicine, Seoul, Republic of Korea e Department of Emergency Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea f Department of Emergency Medicine, Bucheon Hospital of Soonchuhyang University, Bucheon, Republic of Korea g Department of Emergency Medicine, Inje University Haeundae Paik Hospital, Busan, Republic of Korea h Inje University Ilsan Paik Hospital, Goyang, Republic of Korea b
a r t i c l e
i n f o
Article history: Received 23 February 2012 Received in revised form 22 June 2012 Accepted 2 July 2012 Keywords: Cardiopulmonary resuscitation Computed tomography Fracture
a b s t r a c t Introduction: Traumatic chest injuries may occur following cardiopulmonary resuscitation (CPR). The aim of this study was to address the frequency of injuries, especially rib and sternal fractures, and also to identify factors that contribute to post-CPR trauma. Methods: This study was a prospective cross-sectional study conducted in the emergency departments (ED) of eight academic tertiary care centers. To evaluate injuries secondary to CPR, we performed chest computed tomography (CT) in patients who were successfully resuscitated from cardiac arrest. Contributing factors that might be related to injuries were also investigated. Results: We enrolled 71 patients between 1 January 2011 and 30 June 2011. Rib and sternal fractures were diagnosed in 22 and 3 patients, respectively. Females were more susceptible to rib fracture (p = 0.036). When non-physicians participated as chest compressors in the ED, more ribs were fractured (p = 0.048). The duration of CPR and number of compressors were not contributing factors to trauma secondary to CPR. There was a wide variation in the frequency of rib fractures from hospital to hospital (0–83.3%). In high-risk hospitals (in which more than 50% of patients had rib fractures), the average age of the patients was higher, and non-physicians took part in ED CPR more often than they did at low-risk hospitals. Conclusion: The incidence of rib fracture following CPR was different in various hospitals. The presence of non-physician chest compressors in the ED was one of the contributing factors to rib fracture. Further studies on the influence of resuscitators and relation between quality of chest compression and CPRinduced injuries are warranted to reduce complications following CPR. © 2012 Elsevier Ireland Ltd. All rights reserved.
1. Introduction Chest compression is a vital component of cardiopulmonary resuscitation (CPR). According to the European Resuscitation Council (ERC) Guidelines and American Heart Association (AHA) guidelines, a rate of 100–120 compressions per minute and a depth of 5–6 cm is recommended for high-quality CPR.1,2 Moreover, as agonal gasping delays the start of CPR, the guidelines emphasize that the lay rescuer immediately begin CPR on victims who are
夽 A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2012.07.011. ∗ Corresponding author. Address: Department of Emergency Medicine, Gangnam Severance Hospital, 712 Eonju-ro, Gangnam-gu, Seoul 135-720, Republic of Korea. Tel.: +82 2 2019 3030; fax: +82 2 2019 4820. E-mail address: [email protected] (S.P. Chung). 0300-9572/$ – see front matter © 2012 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.resuscitation.2012.07.011
breathing abnormally. This policy could increase bystander CPR prevalence, while the possibility of administering CPR to unresponsive patients not in cardiac arrest would also be increased. Before the 2010 guidelines were implemented, White et al.3 reported that 18% of patients to whom dispatchers offered CPR instructions were not in arrest, but still received bystander chest compression. Traditionally, high quality chest compressions have been emphasized to improve the survivability of patients in cardiac arrest; therefore, we investigated exactly how many involuntary injuries resulted from CPR. Previous studies have shown varied incidences of rib and sternum fractures related to CPR.3–6 We performed chest computed tomography (CT) in patients who were successfully resuscitated from cardiac arrest to investigate chest injuries secondary to CPR. The aim of this study was to address the frequency of injuries (especially rib and sternal fractures) and to identify contributing factors.
362
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2. Methods This study was a prospective cross-sectional, multicenter study involving patients who survived cardiac arrest after CPR in the emergency departments (ED) of eight academic tertiary care centers. Research staff at participating hospitals endeavored to provide high-quality CPR and post-resuscitation care according to the 2010 ERC and AHA guidelines.7,8 Each hospital’s institutional review board approved the study protocol. Eligible patients were enrolled between January 1, 2011 and June 30, 2011. Both out-of-hospital and in-hospital cardiac arrest patients were included if spontaneous circulation was restored and the patient was sufficiently stabilized enough to be transferred to the CT room. Either the patients themselves or their legal representatives were informed about the trial, and their consent was documented. We excluded patients under the age of 18, those with traumatic cardiac arrest, and those who did not receive chest compressions. Chest CT (multidetector CT; 16 or 64 channel scanner) including axial, coronal, and sagittal images was performed within 48 h from the restoration of spontaneous circulation. Chest injuries related to cardiac compression were determined based upon the CT interpretation of each hospital’s radiologist. They all were subspecialty-trained chest radiologists with more than 5 years’ of experience. The research staff collected information on potential contributing factors such as age, gender, CPR duration (including pre-hospital CPR), type and number of compressors, total amount of epinephrine injected, total amount of shock energy delivered, and the use of an automatic mechanical compressor device. Data are presented as a number with percentage or median (IQR). Comparisons were performed using the Chi-square test, Fisher’s exact test or Mann–Whitney U test. We used the Statistical Package for the Social Sciences (SPSS) version 12.0 for Windows (SPSS Inc., Chicago, IL, USA). A p-value of <0.05 was considered statistically significant. 3. Results During the study period, 608 patients received cardiopulmonary resuscitation: 455 (75%) out-of-hospital cardiac arrests and 153 (25%) in-hospital cardiac arrests. Spontaneous circulation was restored in 285 (47%) patients. Among them, we excluded 15 patients under the age of 18, 31 patients with traumatic cardiac arrest and 12 patients who did not receive chest compressions. And we could not performed CT in 156 patients for various reasons such as unstable medical condition preventing transport to the CT room and refusal of CT evaluation because of lack of symptoms, economic reasons or hopeless cases. As a result, 71 patients were enrolled in this study (Fig. 1). Table 1 summarizes the chest injuries associated with CPR. Rib fracture, the most common injury, was diagnosed in 22 of 71 patients. Among 14 of 22 patients, multiple rib fractures (ranging from two to nine fractures) were observed. Sternal fracture was observed in three patients. Non-skeletal injuries, such as pneumothorax, hemothorax and lung contusions, were also observed. The median (IQR) age of the patients was 65 (55, 74) years and 45 patients were male. The initial cardiac rhythms were asystole in 42, pulseless electrical activity in 17 and ventricular fibrillation in 12 patients. Forty-five cardiac arrests were witnessed. In total, 57 cardiac arrests occurred outside the hospital, and CPR was performed by a layperson in 14 patients prior to the arrival of emergency medical services (EMS). The median (IQR) total CPR time was 15.0 (8.0, 26.0) minutes. There was a median of four compressors per patient, ranging from one to ten. We compared cardiac arrest-specific data between the rib fracture group and the non-rib fracture group (Table 2). The median
Fig. 1. Flow diagram of patient eligibility.
age (IQR) was 69.5 (56.0, 74.0) in the rib fracture group and 63.0 (49.5, 69.5) in the non-rib fracture group, but the difference was not statistically significant (p = 0.053). Females had a higher rate of rib fracture than males (12/26 vs. 10/45, p = 0.036). When nonphysicians participated as chest compressors in the ED, more ribs were fractured (p = 0.048). There was no significant difference in age, arrest location, duration of CPR, or number of compressors between these two groups. The frequency of rib fractures varied from hospital to hospital, ranging from 0 to 83.3% (Fig. 2). We used a 50% rib fracture rate to divide hospitals into two groups: high-risk hospitals and low-risk hospitals. Table 3 shows a comparison of potential risk factors for rib fracture between high-risk hospitals and low-risk hospitals. At high-risk hospitals, patients were significantly older than patients at low-risk hospitals (p = 0.002). Non-physicians took part in chest compression in 21 of 26 CPR situations at high-risk hospitals and in only 15 of 45 CPR situations at low-risk hospitals, which was a significant difference (p < 0.001). 4. Discussion Various rates of skeletal injury were reported in previous studies that investigated complications after CPR; 13–97% for rib fracture and 1–43% for sternal fracture.4,9,10 The incidence of fractures could vary depending on the diagnostic tool used. Lederer et al. reported that postmortem autopsy was more accurate for detecting rib and Table 1 Chest injuries associated with cardiopulmonary resuscitation. Complication Skeletal Rib fracture Number of fracture Single Multiple Side of fracture Rt Lt Both Sternal fracture Thoracic vertebral fracture Pulmonary Hemothorax Pneumothorax Lung contusion Pneumomediastinum
No. of patients (total = 71) 22 8 14 8 7 7 3 1 8 6 3 1
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Table 2 Comparison of cardiac arrest specific data between rib fracture group and non-rib fracture group. Variables
Total (n = 71)
Rib fracture (n = 22)
Non-rib fracture (n = 49)
p-value
Age, median (IQR) Sex, n Male Female Witness, n Witnessed Un-witnessed Arrest location, n In hospital Out of hospital Duration of CPR, median (IQR) Epinephrine, median (IQR) Defibrillation, median (IQR) Type of compressor, n Prehospital CPR Layperson EMS ED CPR Physician Non-physician Number of compressor, median (IQR)
65.0 (55.0, 74.0)
69.5 (56.0, 75.8)
63.0 (49.5, 69.5)
0.053 0.036
45 26
10 12
35 14
45 26
14 8
31 18
14 57 15.0 (8.0, 26.0) 2.0 (2.0, 4.0) 0 (0, 150.0)
4 18 13.5 (8.0, 25.5) 2.5 (2.0, 4.0) 0 (0, 180.0)
10 39 16.0 (7.5, 26.0) 2.0 (1.5, 4.0) 0 (0, 150.0)
0.799 0.433 0.867
14 40
5 10
9 30
0.669 0.215
64 36 4.0 (3.0, 5.0)
21 15 40 (3.0, 6.3)
43 21 3.0 (3.0, 5.0)
0.314 0.048 0.386
0.976
0.827
Fig. 2. Rib fractured patient of eight hospitals. *The number in bracket is enrolled patients of each hospital.
sternum fractures than X-ray.5 As this study investigated the rate of skeletal chest injury in successfully resuscitated patients, we adopted multidetector CT rather than autopsy to identify injuries in our participants. There was one previous study that used chest CT to identify complications secondary to chest compression.4 That study retrospectively interpreted CT findings of successfully resuscitated patients and reported a 65% and 30% incidence of rib fracture and sternal fracture, respectively, much higher than our results of 22/71 (31.0%) and 3/71 (4.2%), respectively. These might be caused by methodological differences in patient inclusion; prospective vs. retrospective. Table 3 Comparison of potential risk factors between high risk and low risk hospitals. Variables
Low risk hospital (n = 45)
High risk hospital (n = 26)
p-Value
Age, median (IQR) Sex, n Male Female CPR time, median (IQR) Compressor, n Prehospital CPR Layperson EMS ED CPR Physician Non-physician Number of compressor, median (IQR)
60.0 (48.0, 68.0)
71.0 (61.3, 80.3)
31 14 16.0 (7.5, 26.0)
14 12 14.5 (8.0, 25.5)
0.637
11 29
3 11
0.188 0.070
39 15 3.0 (2.5, 5.0)
25 21 4.0 (3.0, 6.0)
0.002 0.205
0.196 <0.001 0.455
We found that females were more susceptible to rib fracture. Black et al. also reported that more females than males sustained rib fractures, while no significant gender difference for sternal fractures was noted.6 Females are known to involve a higher frequency of osteoporosis and are generally older than males at the time of resuscitation.11 These are expected to account for the higher risk of rib fractures in females. We did not find a significant difference (p = 0.053) in age, but a positive correlation between age and rib fracture incidence was reported in other studies.6,12–15 Interestingly, we found that the incidence of rib fracture caused by chest compression varied from hospital to hospital (0–83.3%). This finding suggests that different methods of basic life support (BLS) training and different advanced cardiovascular life support team members at each hospital, as well as the characteristics of patients who visit these hospitals, greatly influenced complications related to CPR. Hospitals with a high incidence of rib fracture had more elderly patients and also more frequently included nonphysicians such as nurses, paramedics and medical students as chest compressors in ED CPR. Not much is known in regards to the influence of the resuscitator on post-CPR trauma. Assuming some traits of resuscitators affected the extent of injury from CPR, we suggest that there could be reversible causes of injuries and hope for improvement. Investigation into these reversible causes, which properties of chest compression induce chest injuries (too deep of compression, too fast of an acceleration in compression or wrong hand position etc.), and furthermore, what influences the compression quality of resuscitators should be continued. Unfortunately, we were unable to discover the reason why participation of non-physicians as compressors in ED CPR increased the frequency of rib fractures. Perhaps highly motivated providers push harder and faster, thereby causing more injuries during CPR. These could comprise less experienced providers or physicians who attempt to stand out in front of non-physicians. On the other hand, BLS training and occupational affiliation could also influence the quality of chest compression as reported in previous studies.16–19 New guidelines that emphasize the harder and faster compression than 2005 guidelines might induce different reactions in resuscitators according to basic knowledge, previous experience and mode of education. We are afraid that unconditional emphasis of deep and rapid compression would incite more CPR-related injuries. In addition to the training of high quality CPR, we should ruminate about the strategy of BLS education to reduce the rate of CPR-related injury.
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Few studies have established the relationship between the length of CPR and CPR-related injuries. Krischer et al. reported that 32% of the patients had rib fractures and a longer duration of CPR is associated with a higher frequency of rib fractures based upon an autopsy study.12 However, in our study there was no difference in the duration of CPR between the rib fracture group and the non-rib fracture group. One fact that could have affected this conflicting result is that the CPR duration of our study was relatively short to Krischer et al.’s study because we included patients who were successfully resuscitated from cardiac arrest, whereas Krischer et al. investigated non-survived and autopsied patients.12 It has been reported that the median duration of CPR was 17 min in survived patients and 43 min in non-survived patients.20,21 The result of Sladjana et al.’s study reporting that abandonment of further CPR occurred after 29 min from cardiac arrest would help understand difference of CPR duration between survived and nonsurvived patients.22 In theory, as the stiffness of ischemic tissue deteriorates, the incidence of rib fracture could increase with prolonged CPR. If so, our study on patients with a relatively short CPR duration could underestimate the actual complication rates. However, Baubin et al. empirically suggested that most damage might occur during the early stages of CPR.15 In prolonged CPR, increased fatigue in the compressor would weaken compression power and fewer complications wound occur.23 To explain the effect of CPR duration on injuries secondary to CPR, detailed investigations in regards to timing and the mechanism of rib fracture are warranted. Another reason for the conflicting results could be that all patients received only manual compressions in our study, whereas a mechanical chest compressor was applied in 63.5% of patients in Krischer et al.’s study.12 The mechanism and timing of rib fracture may differ depending on the mode of compression. For the same reason, Smekal et al. also could not determine the association between the duration of CPR and the incidence of rib fracture.24 5. Limitations This study has several limitations. First, we could not clarify the occupations and characteristics of non-physicians in the ED that influenced the risk of rib fracture. These non-physicians could have been nurses and paramedics who were affiliated with the ED or medical students training in emergency medicine. Those involved in resuscitations also could have varied depending on the situation at each hospital. Further research into human factors, such as BLS education level and CPR experience, will be required. Especially, it is necessary to investigate the relationship between the compression depth of individual providers and chest injuries secondary to CPR. Second, a large number of patients did not undergo CT evaluation and were excluded from the study. Their characteristics, such as gender and age, known as potential factors, were similar to the included patients; however, some unpredictable factors could have skewed our results. Third, although age has been overtly recognized as an influential factor on the potential for rib fracture caused by CPR, we were unable to show the statistical significance of this factor due to the small sample size. Lastly, fracture was diagnosed on the basis of CT findings without an autopsy correlation (because our participants were still alive). We might have overlooked a few patients whose fractures were too subtle to diagnose with CT alone. 6. Conclusion The number of rib fractures arising from chest compression was relatively high. However, the incidence of rib fracture varied greatly from hospital to hospital. Female patients and participation of non-physician chest compressors in ED CPR were associated with a higher incidence of rib fractures. Further studies to investigate
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