Article

Improving clinical outcomes in cardiac arrest cases through chest compression-only cardiopulmonary resuscitation

122 Correspondence

intubations. Although it may be true that different endotra- cheal tubes may be more suitable for use with the Pentax AWS, we did not evaluate this in our study. In answer to the correspondent’s question regarding the interincisor distances in the 3 difficult airway scenarios, the range was from 1.8 to

2.8 cm. We would agree that the limited mouth opening and the relatively bulky blade (1.6 cm) was one of the main causes for difficulty to pass the Pentax AWS into the mouth, particularly with the most difficult airway setting. As mentioned in the letter, manipulating the Pentax AWS may obtain a more favorable epiglottic position. Although we did not evaluate this specifically, some participants did withdraw and reinsert the Pentax AWS to achieve this.

The correspondent also raises a valid disadvantage of the Pentax AWS in that it has only one fixed-size blade that could cause failure to intubate some patients with large distances from the mouth to the larynx and also make it inappropriate currently for pediatric intubation. Given that the Pentax AWS blades are disposable, perhaps different size blades could be designed to overcome this problem in the future.

Being a manikin study, we did not assess the other potential problems of the AWS such as fogging, which is more likely in the anesthetic setting. Anecdotally, a major potential problem for emergency physicians is obscuration of the lens by blood or other airway debris. Further studies in real-life emergency intubations are required.

Sam S. Phillips

Emergency Department Sir Charles Gairdner Hospital

Nedlands Western Australia, Australia

Antonio Celenza

Emergency Department Sir Charles Gairdner Hospital

Nedlands Western Australia, Australia Discipline of Emergency Medicine University of Western Australia

Crawley Western Australia, Australia

E-mail address: [email protected] doi:10.1016/j.ajem.2010.09.008

Improving clinical outcomes in cardiac arrest cases through chest compression-only cardiopulmonary resuscitation

To the Editor,

This literature reveals the challenges of teaching mouth- to-mouth (MTM) ventilation, and the authors suggest that

MTM ventilation be omitted from cardiopulmonary resus- citation (CPR) courses [1]. From my experience as a CPR instructor and designer of resuscitation courses for layper- sons, I strongly agree with their recommendation and would like to augment their discussion with additional evidence and suggest what a good CPR course for laypersons should be. Compared with chest compressions, MTM ventilation is a complicated and cumbersome technique that comprised a sequence of different types of motions requiring that various actions be done simultaneously. Therefore, trainees often require more time to acquire this skill than chest compres- sions or fail to achieve a satisfactory level of MTM ventilation skills. This study also suggests that the more complex the skills and hand motions are, the more difficult it

is to retain without supplemental training.

Cardiopulmonary resuscitation courses can positively influence learners’ attitudes toward using the techniques. Even though most people know that it is important for a person in cardiac arrest to receive immediate CPR, the percentage of bystanders who actually administer CPR is still insufficient. What are the barriers preventing them from doing so? Several barriers were identified by the pre/post-CPR course surveys done by Hamasu et al [2] The two main barriers are one’s lack of confidence in their CPR skills and their anxiety over a potentially negative outcome. Based on postcourse surveys, CPR training classes alleviated these concerns dramatically. A prospective, observational study done in real-life settings revealed that having had CPR training is a positive predictor of CPR performance in all bystanders [3]. However, this study also reported that only 35% of CPR-trained bystanders provided CPR. The 2 main barriers that prevented the other group from administering the technique were panic (38.7%) and a lack of confidence (10.8%). On the other hand, recent CPR training (within 5 years) is a positive predictor of CPR-trained bystanders choosing to perform CPR. These 2 studies suggest that bystanders’ attitudes are closely connected to their confidence and comfort with their skill level. In other words, if they do not feel they have attained or maintained their skills, they will lack or lose confidence and be unlikely to offer resuscitation.

Ideally, we should provide comprehensive CPR courses more frequently to help people attain and retain CPR skills and boost their confidence. However, resources are not infinite. If it is difficult to attain and maintain skills for 2 Resuscitation techniques, we should consider focusing on the more important and simpler one, chest compressions. This would allow for a shorter and simpler course, and likely aid in attainment and retention of skills and confidence. Nishyama et al [4] reported that a group receiving only 7 minutes of self-learning video training for chest compres- sion-only CPR showed a significantly higher rate of chest compression attempts compared with the control group. Also, when both groups underwent a 1-hour hands-on training session for compression-only CPR, they both significantly increased their chest compression attempt rate and the quality of their chest compressions. This evidence

Correspondence 123

supports the efficacy of short compression-only CPR courses. This should become the standard.

Recently, 2 large prospective randomized trials were published to compare the Clinical effectiveness of chest compression-only CPR and conventional CPR in the context of dispatcher-assisted CPR [5,6]. Neither study showed a significant difference between the 2 methods. Therefore, the key point in improving survival rates and Favorable neurologic outcomes for victims of cardiac arrest is not the CPR method itself. The more important point is increasing the likelihood that bystanders will provide immediate CPR. I strongly believe that eliminating MTM ventilation from CPR courses for laypersons will make CPR methods more practical for them and help us provide more courses to more people with greater frequency using the same amount of resources. This, in turn, will lead to more positive clinical outcomes for cardiac arrest patients because more people will be likely to administer chest compression-only CPR.

Kohhei Nakagawa MD

Family Medicine Faculty Development Fellowship

UPMC St Margaret Hospital Lawrenceville Family Health Center Pittsburgh, PA 15213, USA

doi:10.1016/j.ajem.2010.09.004

References

  1. Choi HJ, Lee CC, Lim TH, et al. Effectiveness of mouth-to-mouth ventilation after video self-instruction training in lay persons. Am J Emerg Med 2010;28:654-7.
  2. Hamasu S, Morimoto T, Kuramoto N, et al. Effects of BLS training on factors associated with attitude toward CPR in college students. Resuscitation 2009;80:359-64.
  3. Swor R, Khan I, Domeier R, et al. CPR training and CPR performance: do CPR-trained bystanders perform CPR? Acad Emerg Med 2006;13: 596-601.
  4. Nishyama C, Iwami T, Kawamura T, et al. Effectiveness of simplified chest compression-only CPR training program with or without preparatory self-learning video: a randomized controlled trial. Resus- citation 2009;80:1164-8.
  5. Rea TD, Fahrenbruch C, Culley L, et al. CPR with chest compression alone or with rescue breathing. N Engl J Med 2010;363:423-33.
  6. Svensson L, Bohm K, Castren M, et al. Compression-only CPR or standard CPR in out-of-hospital cardiac arrest. N Engl J Med 2010;363:434-42.

    Difficulties and possible solutions for tracheal intubation with the airway scopeB

    To the Editor,

    The recent article of Cho et al [1] comparing the tracheal intubation using Airway Scope (AWS) and Macintosh

    ? All authors have no financial support and potential conflicts of interest for this work.

    laryngoscope during chest compressions on a fresh cadaver model was of great interest to us. In this study, participants replied that tracheal intubation was more difficult with the AWS than with the Macintosh laryngoscope. Also, most participants felt that they could visualize the glottis easily and rapidly but had difficulty with advancing the endotra- cheal tube (ETT). However, the authors did not report the detailed reasons of difficulties for tracheal intubation with the AWS and solutions to resolve these problems.

    According to our experience and available literatures, difficulty may indeed be encountered with the tracheal intubation with the AWS, and there are some notes helpful in enhancing the practical utility of the AWS.

    First, the curvature of PBlade and the whole length (32.5 cm) of the AWS may make its insertion into the mouth difficult in patients with fixed neck flexion or barrel chests because of the AWS handle hitting the chest [2]. A lateral insertion technique or a stepwise insertion technique (ie, insertion of the PBlade followed by its attachment to the handle) can be used for successful insertion [3].

    Second, according to the manufacturer’s manual, the PBlade tip of the AWS should be inserted posterior to the epiglottis, directly elevating it out of the way (Miller-type approach). However, a common problem with the AWS is the difficulty in inserting the PBlade tip into the posterior surface of the epiglottis, with the PBlade tip repeatedly entering the vallecula. In this case, indirectly elevating epiglottis can affect Laryngeal view and obstruct the insertion of the ETT. A manikin study showed that when the PBlade tip was deliberately inserted into the vallecula (Macintosh- type approach), tracheal intubation failed in 12 of 15 attempts due to ETT impingement onto the epiglottis [4]. In the patients with simulated restricted neck mobility, this issue had resulted in multiple intubation attempts in 42% of patients [5]. It is easily corrected by partially withdrawing the device, and with a subsequent scooping movement of the PBlade, lifting the epiglottis, and advancing the ETT into the trachea. A second solution is to insert a Gum elastic bougie through the ETT and into the trachea and then railroad the ETT over the bougie via the vocal cords [6].

    Third, one of the most important features of the AWS that facilitates intubation is a target mark on the monitor, which indicates the direction of travel of the ETT as it advances from the guiding channel. Before advancing the ETT, the glottis must be positioned at the center of the target mark [7]. In some cases, however, when the PBlade tip is correctly placed behind the epiglottis, it may be impossible to align the target mark with the glottis. Therefore, difficulty in advancing the ETT may be faced, as the ETT tip may swerve from the target mark and collide with the arytenoids. In this situation, the External laryngeal manipulation should be applied to displace the larynx and direct the ETT tip into the glottis.

    Fourth, selection of the ETT types is important for successful intubation with the AWS, because the direction of ETT advancement from the guiding channel is defined by the

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