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 isstill considered the optimal method for airway management, medicalstaff should be able to intubate emergency patients. It is worth notingthat 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 Macinoshlaryngoscopes (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 eachparticipant. 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. Afterthe demonstration, participants had a 20-minute training session to ensure
they were familiar with proper use of the laryngoscopes. Participants weresplit 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. Aftercompleting the procedure, participants had a 20-minute rest and then performed intubation using the other device. The primary endpoint was thetime to tracheal intubation. Secondary endpoints were the success of theﬁrst intubation attempt and overall intubation success rate. Moreover, wemeasured dental trauma, which was assessed using a previously describedgrading 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 theCormack and Lehane classiﬁcation system on a scale of I to IV [5]. At theend 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 theﬁrst 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 groupthan the GLS group, but not statistically signiﬁcant (P = .063). The Visual
Analogue Scale score for the GLS group was signiﬁcantly lower than theMAC 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 isused 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, PolandTel.: +48 500186225
E-mail address: lukasz.szarpak@gmail.com
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 JEmerg 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 ofthe VivaSight single lumen endotracheal tube and the Macintosh laryngoscope for
emergency intubation by experienced paramedics in a standardized airway manikinwith 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 theGlideScope Videolaryngoscope to the standard Macintosh for intubation by pediatricresidents 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 deﬁbrillatorsand 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 anautomated external deﬁbrillator (AED) by bystanders, increase patient survival probabilities. Deﬁbrillation is an effective intervention for those withshockable 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 interpretationof the results. SN drafted the manuscript and all authors equally contributed to revisingand 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 ﬁrstauthor (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

2042deployed in places with low probability of OHCA occurrence and werenever used [6]. Public-access AED deployment should be guided by information on the frequency of OHCA occurrence.

0.4
0.35
0.30.25

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: snakahara-tky@umin.net

0.2
0.15
0.1
0.05
00.101.00

10.00

100.001000.00

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: taniguchi@risk.tsukuba.ac.jp

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 (railwaystations and bus terminals) in each prefecture as of 25 July 2014 wereobtained from the nationwide registry of public-access AEDs maintained by the Japan Foundation of Emergency Medicine. The registry isaccessible 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 anambulance crew between 2010 and 2012 for OHCA patients aged between 15 and 74 years were derived from the national registry ofOHCA 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 ofdeﬁbrillators 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. Wecalculated the correlation with its 95% conﬁdence interval between
the proportion of public-access AED use among OHCA patients receivingdeﬁbrillation 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 ofpresumed cardiac origin were witnessed by non-family bystanders andunderwent 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 thelog-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 inrailway stations [4,5]. Public transport nodes are extremely crowded inJapan, 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: sakat@med.teikyo-u.ac.jp

http://dx.doi.org/10.1016/j.ajem.2016.07.044

References[1] Kyukyukyujo-no genkyo 2015. Current situations in emergency medical services andrescue 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 patientswith 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 ofcardiac 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: causationor 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 ofEmergency Medicine. In this retrospective study of 189 patients withacute pulmonary embolism (APE), the authors found a 13% incidenceof contrast-induced nephropathy (CIN) and reported a signiﬁcantly