- Email: [email protected]
Public-access automated external defibrillators and defibrillation for out-of-hospital cardiac arrest
Correspondence / American Journal of Emergency Medicine 34 (2016) 2029–2049
Sebastian Aleksandrowicz, MSc, EMT-P Polish Society of Disaster Medicine, Poland
A comparison of GlideScope and Macintosh laryngoscopes for endotracheal intubation performed by nurses☆ To the Editor, Emergency physicians, paramedics and nurses working in Emergency Medical Services in Poland are primarily responsible for rapid advanced airway management in many emergency situations, such as trauma or cardiopulmonary resuscitation [1,2]. Because endotracheal intubation is still considered the optimal method for airway management, medical staff should be able to intubate emergency patients. It is worth noting that in pre-hospital situations the patient should be treated as if they have a potentially full stomach and therefore an increased risk of aspiration of gastric contents into the respiratory tract [3]. Therefore, endotracheal intubation is the optimal method of securing airways. The aim of the study was to evaluate GlideScope (GLS; Verathon Medical BV, Boerhaaveweg, Ijsselstein, The Netherlands) and Macinosh laryngoscopes (MAC; HEINE Optotechnik, Munich, Germany) for intubation on normal airways performed by nurses. This study was approved by the institutional review board of the International Institute of Rescue Research and Education (Approval no. 22.06.2016.07), and written informed consent was obtained from each participant. After obtaining voluntary written informed consent, 35 nurses, aged 23 to 38 years with a minimum 1-year experience in the field of anesthesiology and critical care or emergency medicine participated. The study was conducted in June 2016. Before the study, all participants received 30-minute training which included a demonstration of a proper endotracheal intubation procedure using GLS and MAC laryngoscopes. After the demonstration, participants had a 20-minute training session to ensure they were familiar with proper use of the laryngoscopes. Participants were split into two groups using ResearchRandomizer software (www. randomizer.org). The first group started intubation with GLS while the second used MAC. Participants had a maximum of three intubation attempts for each device. A semi rigid stylet was inserted in the tracheal tube. After completing the procedure, participants had a 20-minute rest and then performed intubation using the other device. The primary endpoint was the time to tracheal intubation. Secondary endpoints were the success of the first intubation attempt and overall intubation success rate. Moreover, we measured dental trauma, which was assessed using a previously described grading scale of pressure on the teeth (0 = none, 1 = mild, 2 = moderate and 3 = severe) [4]. Participants also rated the view of the larynx on the Cormack and Lehane classification system on a scale of I to IV [5]. At the end of the trial, participants rated the difficulty of using each device on a Visual Analogue Scale from ‘0’ (extremely easy) to ‘10’ (extremely difficult). Statistical analysis was performed with the Statistica statistical package version 12.0 for Windows (StatSoft, Tulsa, OK). P b .05 was considered statistically significant. The median time for endotracheal intubation was significantly longer when GLS was used compared to MAC (45.8 [interquartile range 41.555.5] vs 37.5 [interquartile range 30-42.5], respectively; P = .009). Comparing GLS and MAC, there was no significant difference in success of the first intubation attempt (68.5% vs 74.3%, respectively; P = .054), or overall intubation success rate (94.3% vs 100%; P = .87). The dental trauma index was significantly less when GLS was used compared to the MAC (P = .032). The Cormack-Lehane classification was lower in the MAC group than the GLS group, but not statistically significant (P = .063). The Visual Analogue Scale score for the GLS group was significantly lower than the MAC group (3.2 vs 4.4 points, respectively; P = .012). In conclusion, our findings demonstrate that although intubation takes longer with the GLS, its reduced intubation difficulty and improved glottic view make it more suitable than the MAC when intubation is performed by nurses. Moreover, lower forces are applied when the GLS is used to achieve tracheal intubation, which may reduce the dental injuries. ☆ Source of support: No sources of financial and material support to be declared.
2041
Lukasz Szarpak, PhD, DPH, EMT-P Department of Emergency Medicine Medical University of Warsaw, Warsaw, Poland Corresponding author. Department of Emergency Medicine Medical University of Warsaw, Lindleya 4 Str., 02-005 Warsaw, Poland Tel.: +48 500186225 E-mail address: [email protected] http://dx.doi.org/10.1016/j.ajem.2016.07.047 References [1] Akın Paker S, Dagar S, Gunay E, Temizyurek Cebeci Z, Aksay E. Assessment of prehospital medical care for the patients transported to emergency department by ambulance. Turk J Emerg Med 2015;15(3):122–5. http://dx.doi.org/10.1016/j.tjem.2015.11.005. [2] Szarpak L, Karczewska K, Evrin T, Kurowski A, Czyzewski L. Comparison of intubation through the McGrath MAC, GlideScope, AirTraq, and miller laryngoscope by paramedics during child CPR: a randomized crossover manikin trial. Am J Emerg Med 2015;33(7):946–50. http://dx.doi.org/10.1016/j.ajem.2015.04.017. [3] Truszewski Z, Szarpak Ł, Smereka J, Kurowski A, Evrin T, Czyzewski Ł. Comparison of the VivaSight single lumen endotracheal tube and the Macintosh laryngoscope for emergency intubation by experienced paramedics in a standardized airway manikin with restricted access: a randomized, crossover trial. Am J Emerg Med 2016;34(5): 929–30. http://dx.doi.org/10.1016/j.ajem.2016.02.054. [4] Rodriguez-Nunez A, Oulego-Erroz I, Perez-Gay L, Cortinas-Diaz J. Comparison of the GlideScope Videolaryngoscope to the standard Macintosh for intubation by pediatric residents in simulated child airway scenarios. Pediatr Emerg Care 2010;26(10): 726–9. http://dx.doi.org/10.1097/PEC.0b013e3181f39b87. [5] Kurowski A, Szarpak L, Truszewski Z, Czyzewski L. Can the ETView VivaSight SL rival conventional intubation using the Macintosh laryngoscope during adult resuscitation by novice physicians?: a randomized crossover manikin study. Medicine (Baltimore) 2015;94(21), e850. http://dx.doi.org/10.1097/MD.0000000000000850.
Public-access automated external defibrillators and defibrillation for out-of-hospital cardiac arrest☆,☆☆,★,★★,☆☆☆,★★★ To the Editor, Out-of-hospital cardiac arrest (OHCA) is a public health concern particularly in aging societies [1]. Despite its poor prognosis at large, early interventions, including chest compression and defibrillation using an automated external defibrillator (AED) by bystanders, increase patient survival probabilities. Defibrillation is an effective intervention for those with shockable arrhythmias [2]. In Japan, defibrillation by laypersons using public-access AEDs has been permitted since 2004. Reportedly, increasing the number of public-access AEDs has contributed to improving the prognosis of the patients [3]. For efficient use, public-access AEDs should be deployed in densely crowded places, such as public transport nodes. We examined the association between the deployment of AEDs in public transport nodes and the use of public-access defibrillators for OHCA patients.
☆ Contribution: SN and TS conceived the study design and obtained the data. SN analyzed the data with the support of AT. All authors equally contributed to the interpretation of the results. SN drafted the manuscript and all authors equally contributed to revising and finalizing the manuscript. ☆☆ Presentation: This study was presented at the 2nd International Conference on Transport and Health held in San Jose, California, USA, 13–15 June 2016. ★ Funding support: this study was supported by JSPS KAKENHI (Grant No. 26249073). The funding body did not play any roles in the study. ★★ Data access: the first author (SN) had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. The first author (SN) conducted the data analyses and is responsible for the analyses. ☆☆☆ Conflict of interest: none declared. ★★★ Ethical consideration: this study was approved by the ethics committee of Teikyo University School of Medicine.
Correspondence / American Journal of Emergency Medicine 34 (2016) 2029–2049
Proportion of public-access AED use among patients who received defibrillation
2042
deployed in places with low probability of OHCA occurrence and were never used [6]. Public-access AED deployment should be guided by information on the frequency of OHCA occurrence.
0.4 0.35 0.3 0.25
Shinji Nakahara, MD, PhD Department of Emergency Medicine Teikyo University School of Medicine, Tokyo, Japan Corresponding author at: Teikyo University School of Medicine Department of Emergency Medicine, 2-11-1 Kaga Itababshi, 173-8606, Japan Tel.: +81 3 3964 1211; fax: +81 3 5375 0854 E-mail address: [email protected]
0.2 0.15 0.1 0.05 0 0.10
1.00
10.00
100.00
1000.00
No. of AEDs in transport nodes / 1000km2 inhabitable area (log-scale)
Ayako Taniguchi, PhD Department of Risk Engineering, University of Tsukuba Tsukuba, Ibaraki, Japan E-mail address: [email protected]
Figure. Public-access AEDs deployment in transport nodes and AED use among OHCA patients who received defibrillation.
This ecological study used prefectures (local administrative units) as the analyzing units; there are 47 prefectures in Japan. Data on the number and site of public-access AEDs deployed in transport nodes (railway stations and bus terminals) in each prefecture as of 25 July 2014 were obtained from the nationwide registry of public-access AEDs maintained by the Japan Foundation of Emergency Medicine. The registry is accessible on the foundation's website (https://www.qqzaidanmap.jp/ aeds/list). The first author reviewed the obtained list of 2951 publicaccess AEDs and excluded those deployed outside the transport facilities (e.g., AEDs in stores near a train station); stations of ropeways and trams were included. Finally, we obtained a list of 2913 public-access AEDs. Data on defibrillation by a bystander using public-access AEDs or an ambulance crew between 2010 and 2012 for OHCA patients aged between 15 and 74 years were derived from the national registry of OHCA patients. Data of inhabitable areas were derived from the Ministry of Land, Infrastructure, Transport and Tourism. The density of defibrillator in each prefecture was calculated by dividing the number of defibrillators in transport nodes by inhabitable area. Six out of 47 prefectures were excluded because no defibrillator deployment was recorded in the corresponding transport nodes of those prefectures. We calculated the correlation with its 95% confidence interval between the proportion of public-access AED use among OHCA patients receiving defibrillation and the density of defibrillators. The densities were logtransformed because of the extremely skewed distribution. A total of 378 070 OHCA patients were registered during the study period. Of these, 6096 patients aged between 15 and 74 years with events of presumed cardiac origin were witnessed by non-family bystanders and underwent defibrillation either by the bystander or ambulance crews. Among the 41 analyzed prefectures, the proportions of public-access AED use by bystanders among those who received defibrillation ranged from 4.3% to 37.1%, and the median was 19.4%; the densities ranged from 0.4 to 683.8 (per 1000 km2) and the median was 7.7. The correlation coefficient (95% confidence interval) between the proportions and the log-transformed densities was 0.58 (0.33–0.75) (Figure). Our finding implies that with increased deployment of public-access AEDs in transport nodes, the probabilities of defibrillation by bystanders for OHCA patients also increase. This is probably because in Japan the occurrence of cardiac arrest is high in public transport nodes, particularly in railway stations [4,5]. Public transport nodes are extremely crowded in Japan, where public transportation is the main mode of commuting. Without considering the site of AED deployment, clear associations between the deployed number of AEDs and the frequency of AED use for OHCA patients could not be detected because many of the AEDs were
Tetsuya Sakamoto, MD, PhD Department of Emergency Medicine Teikyo University School of Medicine, Tokyo, Japan E-mail address: [email protected]
http://dx.doi.org/10.1016/j.ajem.2016.07.044
References [1] Kyukyukyujo-no genkyo 2015. Current situations in emergency medical services and rescue services 2015. Tokyo: Fire and Disaster Management Agency; 2015. [2] Hazinski MF, Nolan JP, Aickin R, Bhanji F, Billi JE, Callaway CW, et al. Part 1: executive summary: 2015 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations. Circulation 2015;132(16 Suppl. 1):S2–39. [3] Nakahara S, Tomio J, Ichikawa M, Nakamura F, Nishida M, Takahashi H, et al. Association of bystander interventions with neurologically intact survival among patients with bystander-witnessed out-of-hospital cardiac arrest in Japan. JAMA 2015; 314(3):247–54. [4] Murakami Y, Iwami T, Kitamura T, Nishiyama C, Nishiuchi T, Hayashi Y, et al. Outcomes of out-of-hospital cardiac arrest by public location in the public-access defibrillation era. J Am Heart Assoc 2014;3(2):e000533. [5] Muraoka H, Ohishi Y, Hazui H, Negoro N, Murai M, Kawakami M, et al. Location of outof-hospital cardiac arrests in Takatsuki City: where should automated external defibrillator be placed. Circ J 2006;70(7):827–31. [6] Folke F, Lippert FK, Nielsen SL, Gislason GH, Hansen ML, Schramm TK, et al. Location of cardiac arrest in a city center: strategic placement of automated external defibrillators in public locations. Circulation 2009;120(6):510–7.
Contrast-induced nephropathy related to adverse events in pulmonary embolism patients: causation or conflation? To the Editor, I read with great interest the article by Yazici et al [1] entitled, “Relation of contrast nephropathy to adverse events in pulmonary emboli patients diagnosed with contrast CT” in this month's American Journal of Emergency Medicine. In this retrospective study of 189 patients with acute pulmonary embolism (APE), the authors found a 13% incidence of contrast-induced nephropathy (CIN) and reported a significantly
Sebastian Aleksandrowicz, MSc, EMT-P Polish Society of Disaster Medicine, Poland
A comparison of GlideScope and Macintosh laryngoscopes for endotracheal intubation performed by nurses☆ To the Editor, Emergency physicians, paramedics and nurses working in Emergency Medical Services in Poland are primarily responsible for rapid advanced airway management in many emergency situations, such as trauma or cardiopulmonary resuscitation [1,2]. Because endotracheal intubation is still considered the optimal method for airway management, medical staff should be able to intubate emergency patients. It is worth noting that in pre-hospital situations the patient should be treated as if they have a potentially full stomach and therefore an increased risk of aspiration of gastric contents into the respiratory tract [3]. Therefore, endotracheal intubation is the optimal method of securing airways. The aim of the study was to evaluate GlideScope (GLS; Verathon Medical BV, Boerhaaveweg, Ijsselstein, The Netherlands) and Macinosh laryngoscopes (MAC; HEINE Optotechnik, Munich, Germany) for intubation on normal airways performed by nurses. This study was approved by the institutional review board of the International Institute of Rescue Research and Education (Approval no. 22.06.2016.07), and written informed consent was obtained from each participant. After obtaining voluntary written informed consent, 35 nurses, aged 23 to 38 years with a minimum 1-year experience in the field of anesthesiology and critical care or emergency medicine participated. The study was conducted in June 2016. Before the study, all participants received 30-minute training which included a demonstration of a proper endotracheal intubation procedure using GLS and MAC laryngoscopes. After the demonstration, participants had a 20-minute training session to ensure they were familiar with proper use of the laryngoscopes. Participants were split into two groups using ResearchRandomizer software (www. randomizer.org). The first group started intubation with GLS while the second used MAC. Participants had a maximum of three intubation attempts for each device. A semi rigid stylet was inserted in the tracheal tube. After completing the procedure, participants had a 20-minute rest and then performed intubation using the other device. The primary endpoint was the time to tracheal intubation. Secondary endpoints were the success of the first intubation attempt and overall intubation success rate. Moreover, we measured dental trauma, which was assessed using a previously described grading scale of pressure on the teeth (0 = none, 1 = mild, 2 = moderate and 3 = severe) [4]. Participants also rated the view of the larynx on the Cormack and Lehane classification system on a scale of I to IV [5]. At the end of the trial, participants rated the difficulty of using each device on a Visual Analogue Scale from ‘0’ (extremely easy) to ‘10’ (extremely difficult). Statistical analysis was performed with the Statistica statistical package version 12.0 for Windows (StatSoft, Tulsa, OK). P b .05 was considered statistically significant. The median time for endotracheal intubation was significantly longer when GLS was used compared to MAC (45.8 [interquartile range 41.555.5] vs 37.5 [interquartile range 30-42.5], respectively; P = .009). Comparing GLS and MAC, there was no significant difference in success of the first intubation attempt (68.5% vs 74.3%, respectively; P = .054), or overall intubation success rate (94.3% vs 100%; P = .87). The dental trauma index was significantly less when GLS was used compared to the MAC (P = .032). The Cormack-Lehane classification was lower in the MAC group than the GLS group, but not statistically significant (P = .063). The Visual Analogue Scale score for the GLS group was significantly lower than the MAC group (3.2 vs 4.4 points, respectively; P = .012). In conclusion, our findings demonstrate that although intubation takes longer with the GLS, its reduced intubation difficulty and improved glottic view make it more suitable than the MAC when intubation is performed by nurses. Moreover, lower forces are applied when the GLS is used to achieve tracheal intubation, which may reduce the dental injuries. ☆ Source of support: No sources of financial and material support to be declared.
2041
Lukasz Szarpak, PhD, DPH, EMT-P Department of Emergency Medicine Medical University of Warsaw, Warsaw, Poland Corresponding author. Department of Emergency Medicine Medical University of Warsaw, Lindleya 4 Str., 02-005 Warsaw, Poland Tel.: +48 500186225 E-mail address: [email protected] http://dx.doi.org/10.1016/j.ajem.2016.07.047 References [1] Akın Paker S, Dagar S, Gunay E, Temizyurek Cebeci Z, Aksay E. Assessment of prehospital medical care for the patients transported to emergency department by ambulance. Turk J Emerg Med 2015;15(3):122–5. http://dx.doi.org/10.1016/j.tjem.2015.11.005. [2] Szarpak L, Karczewska K, Evrin T, Kurowski A, Czyzewski L. Comparison of intubation through the McGrath MAC, GlideScope, AirTraq, and miller laryngoscope by paramedics during child CPR: a randomized crossover manikin trial. Am J Emerg Med 2015;33(7):946–50. http://dx.doi.org/10.1016/j.ajem.2015.04.017. [3] Truszewski Z, Szarpak Ł, Smereka J, Kurowski A, Evrin T, Czyzewski Ł. Comparison of the VivaSight single lumen endotracheal tube and the Macintosh laryngoscope for emergency intubation by experienced paramedics in a standardized airway manikin with restricted access: a randomized, crossover trial. Am J Emerg Med 2016;34(5): 929–30. http://dx.doi.org/10.1016/j.ajem.2016.02.054. [4] Rodriguez-Nunez A, Oulego-Erroz I, Perez-Gay L, Cortinas-Diaz J. Comparison of the GlideScope Videolaryngoscope to the standard Macintosh for intubation by pediatric residents in simulated child airway scenarios. Pediatr Emerg Care 2010;26(10): 726–9. http://dx.doi.org/10.1097/PEC.0b013e3181f39b87. [5] Kurowski A, Szarpak L, Truszewski Z, Czyzewski L. Can the ETView VivaSight SL rival conventional intubation using the Macintosh laryngoscope during adult resuscitation by novice physicians?: a randomized crossover manikin study. Medicine (Baltimore) 2015;94(21), e850. http://dx.doi.org/10.1097/MD.0000000000000850.
Public-access automated external defibrillators and defibrillation for out-of-hospital cardiac arrest☆,☆☆,★,★★,☆☆☆,★★★ To the Editor, Out-of-hospital cardiac arrest (OHCA) is a public health concern particularly in aging societies [1]. Despite its poor prognosis at large, early interventions, including chest compression and defibrillation using an automated external defibrillator (AED) by bystanders, increase patient survival probabilities. Defibrillation is an effective intervention for those with shockable arrhythmias [2]. In Japan, defibrillation by laypersons using public-access AEDs has been permitted since 2004. Reportedly, increasing the number of public-access AEDs has contributed to improving the prognosis of the patients [3]. For efficient use, public-access AEDs should be deployed in densely crowded places, such as public transport nodes. We examined the association between the deployment of AEDs in public transport nodes and the use of public-access defibrillators for OHCA patients.
☆ Contribution: SN and TS conceived the study design and obtained the data. SN analyzed the data with the support of AT. All authors equally contributed to the interpretation of the results. SN drafted the manuscript and all authors equally contributed to revising and finalizing the manuscript. ☆☆ Presentation: This study was presented at the 2nd International Conference on Transport and Health held in San Jose, California, USA, 13–15 June 2016. ★ Funding support: this study was supported by JSPS KAKENHI (Grant No. 26249073). The funding body did not play any roles in the study. ★★ Data access: the first author (SN) had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. The first author (SN) conducted the data analyses and is responsible for the analyses. ☆☆☆ Conflict of interest: none declared. ★★★ Ethical consideration: this study was approved by the ethics committee of Teikyo University School of Medicine.
Correspondence / American Journal of Emergency Medicine 34 (2016) 2029–2049
Proportion of public-access AED use among patients who received defibrillation
2042
deployed in places with low probability of OHCA occurrence and were never used [6]. Public-access AED deployment should be guided by information on the frequency of OHCA occurrence.
0.4 0.35 0.3 0.25
Shinji Nakahara, MD, PhD Department of Emergency Medicine Teikyo University School of Medicine, Tokyo, Japan Corresponding author at: Teikyo University School of Medicine Department of Emergency Medicine, 2-11-1 Kaga Itababshi, 173-8606, Japan Tel.: +81 3 3964 1211; fax: +81 3 5375 0854 E-mail address: [email protected]
0.2 0.15 0.1 0.05 0 0.10
1.00
10.00
100.00
1000.00
No. of AEDs in transport nodes / 1000km2 inhabitable area (log-scale)
Ayako Taniguchi, PhD Department of Risk Engineering, University of Tsukuba Tsukuba, Ibaraki, Japan E-mail address: [email protected]
Figure. Public-access AEDs deployment in transport nodes and AED use among OHCA patients who received defibrillation.
This ecological study used prefectures (local administrative units) as the analyzing units; there are 47 prefectures in Japan. Data on the number and site of public-access AEDs deployed in transport nodes (railway stations and bus terminals) in each prefecture as of 25 July 2014 were obtained from the nationwide registry of public-access AEDs maintained by the Japan Foundation of Emergency Medicine. The registry is accessible on the foundation's website (https://www.qqzaidanmap.jp/ aeds/list). The first author reviewed the obtained list of 2951 publicaccess AEDs and excluded those deployed outside the transport facilities (e.g., AEDs in stores near a train station); stations of ropeways and trams were included. Finally, we obtained a list of 2913 public-access AEDs. Data on defibrillation by a bystander using public-access AEDs or an ambulance crew between 2010 and 2012 for OHCA patients aged between 15 and 74 years were derived from the national registry of OHCA patients. Data of inhabitable areas were derived from the Ministry of Land, Infrastructure, Transport and Tourism. The density of defibrillator in each prefecture was calculated by dividing the number of defibrillators in transport nodes by inhabitable area. Six out of 47 prefectures were excluded because no defibrillator deployment was recorded in the corresponding transport nodes of those prefectures. We calculated the correlation with its 95% confidence interval between the proportion of public-access AED use among OHCA patients receiving defibrillation and the density of defibrillators. The densities were logtransformed because of the extremely skewed distribution. A total of 378 070 OHCA patients were registered during the study period. Of these, 6096 patients aged between 15 and 74 years with events of presumed cardiac origin were witnessed by non-family bystanders and underwent defibrillation either by the bystander or ambulance crews. Among the 41 analyzed prefectures, the proportions of public-access AED use by bystanders among those who received defibrillation ranged from 4.3% to 37.1%, and the median was 19.4%; the densities ranged from 0.4 to 683.8 (per 1000 km2) and the median was 7.7. The correlation coefficient (95% confidence interval) between the proportions and the log-transformed densities was 0.58 (0.33–0.75) (Figure). Our finding implies that with increased deployment of public-access AEDs in transport nodes, the probabilities of defibrillation by bystanders for OHCA patients also increase. This is probably because in Japan the occurrence of cardiac arrest is high in public transport nodes, particularly in railway stations [4,5]. Public transport nodes are extremely crowded in Japan, where public transportation is the main mode of commuting. Without considering the site of AED deployment, clear associations between the deployed number of AEDs and the frequency of AED use for OHCA patients could not be detected because many of the AEDs were
Tetsuya Sakamoto, MD, PhD Department of Emergency Medicine Teikyo University School of Medicine, Tokyo, Japan E-mail address: [email protected]
http://dx.doi.org/10.1016/j.ajem.2016.07.044
References [1] Kyukyukyujo-no genkyo 2015. Current situations in emergency medical services and rescue services 2015. Tokyo: Fire and Disaster Management Agency; 2015. [2] Hazinski MF, Nolan JP, Aickin R, Bhanji F, Billi JE, Callaway CW, et al. Part 1: executive summary: 2015 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations. Circulation 2015;132(16 Suppl. 1):S2–39. [3] Nakahara S, Tomio J, Ichikawa M, Nakamura F, Nishida M, Takahashi H, et al. Association of bystander interventions with neurologically intact survival among patients with bystander-witnessed out-of-hospital cardiac arrest in Japan. JAMA 2015; 314(3):247–54. [4] Murakami Y, Iwami T, Kitamura T, Nishiyama C, Nishiuchi T, Hayashi Y, et al. Outcomes of out-of-hospital cardiac arrest by public location in the public-access defibrillation era. J Am Heart Assoc 2014;3(2):e000533. [5] Muraoka H, Ohishi Y, Hazui H, Negoro N, Murai M, Kawakami M, et al. Location of outof-hospital cardiac arrests in Takatsuki City: where should automated external defibrillator be placed. Circ J 2006;70(7):827–31. [6] Folke F, Lippert FK, Nielsen SL, Gislason GH, Hansen ML, Schramm TK, et al. Location of cardiac arrest in a city center: strategic placement of automated external defibrillators in public locations. Circulation 2009;120(6):510–7.
Contrast-induced nephropathy related to adverse events in pulmonary embolism patients: causation or conflation? To the Editor, I read with great interest the article by Yazici et al [1] entitled, “Relation of contrast nephropathy to adverse events in pulmonary emboli patients diagnosed with contrast CT” in this month's American Journal of Emergency Medicine. In this retrospective study of 189 patients with acute pulmonary embolism (APE), the authors found a 13% incidence of contrast-induced nephropathy (CIN) and reported a significantly