Article, Intubation

Is digital intubation an option for emergency physicians in definitive airway management?

Brief Report

Is digital intubation an option for emergency physicians in definitive airway management?

Scott E. Young DOa,*, Michael A. Miller MDa, Chad S. Crystal MDa,

Carl Skinner MDb, Troy P. Coon MDc

aDarnall Army Community Hospital, Fort Hood, TX 76544, USA

bLeonard Wood Army Community Hospital

cEisenhower Army Medical Center

Received 13 December 2005; revised 28 February 2006; accepted 1 March 2006

Abstract

Objectives: This study was designed to determine whether digital intubation is a valid option for definitive airway control by emergency physicians.

Methods: Digital intubation was performed by 18 emergency medicine residents and 4 staff emergency medicine physicians on 6 different cadavers. Placement was confirmed by direct laryngoscopy. The total time for all attempts used, as well as the number of attempts, was recorded. Each participant attempted intubation on all 6 cadavers.

Results: For 5 of the 6 cadavers, successful intubation occurred 90.9% of the time (confidence interval [CI], 85.5%-96.3%) for all participants. The average number of attempts for these 5 cadavers was

1.5 (CI, 1.4-1.7), and the average time required for success or failure was 20.8 seconds (CI, 16.9-24.8). The sixth cadaver developed soft tissue damage and a false passage near the vocal cords resulting in multiple failed attempts.

Conclusions: Although the gold standard for routine endotracheal intubation remains to be direct laryngoscopy, its effectiveness in certain situations may be limited. We believe that digital intubation provides emergency physicians with another option in securing the unprotected airway.

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Introduction

The ability to provide definitive management of the unstable airway is one of the most important facets of the emergency physician’s skill set. The gold standard in airway management remains to be endotracheal intubation facili-

This study was presented as a moderated poster at the ACEP Scientific Assembly in Washington, DC, September 2005.

* Corresponding author. Tel.: +1 254 288 8303.

E-mail address: [email protected] (S.E. Young).

tated by direct laryngoscopy (DL). Although this is clearly the most ideal way to establish airway control, the wide array of Rescue devices available on the market demonstrates how this method may not always be the most successful [1]. Many of these products, including the Gum elastic bougie, laryngeal mask airway, Combitube, and others can be helpful, successful implementation relies on both the provider’s skill and the availability of the product [2,3]. On occasion, the use of a laryngoscope may not be feasible, such as in the setting of massive facial trauma, during tactical operations when the need for light discipline is

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paramount, or in multiple prehospital scenarios where a patient is entrapped in such a position to prevent Traditional methods of managing the unstable airway. Digital intubation (DI) is a potentially valuable tool for definitive airway control, requiring less equipment and patient positioning than any of the other major methods of airway management [4].

In DI, the practitioner uses the index and middle fingers in the same fashion as a Miller Laryngoscope blade, lifting the epiglottis and guiding the endotracheal tube between the fingers and into the trachea. Ideally, the practitioner stands on the side of the patient, caudal to the head, facing the patient’s head. One prior study looked at the success rate of paramedics performing this technique in the field, demonstrating that DI is a reasonable failed airway technique when used by experienced paramedics [5]. A cadaveric pilot study was conducted to determine whether DI is a valid option for definitive airway control by emergency medicine staff and resident physicians. The primary outcome measures evaluated were success rate, number of attempts, and time needed for endotracheal

intubation in cadavers after a brief instructional session.

Methods

Study design and setting

This study was a prospective pilot study conducted as part of an annual airway management curriculum at a medical school’s gross anatomy laboratory. Six (4 men and 2 women) nonembalmed fresh-frozen human cadavers with an average age of 78 years were used. Approval for the study was granted by the Institutional Anatomical Oversight Review Committee.

Study protocol

A total of 18 emergency medicine residents and 4 emergency medicine staff physicians performed DI on all 6 cadavers. Experience levels of the physicians ranged from

5 months of emergency medicine training to 7 years of faculty experience. Only 1 of the participants, a resident with previous paramedic training, had performed DI on a living patient. After a brief instructional session, which consisted of a demonstration and verbal directions, all the

Table 1 All 6 cadavers

Categorical variable

Primary

Second

Final

attempt

attempt

attempt

No. of DI performed

132

58

34

No. of successful DI

74

24

11

Success rate (%)

56.1

41.4

32.4

Cumulative

56.1

74.2

82.6

success rate (%)

Average time to

11.5

28.0

41.1

completion (s)

Table 2 Five of six cadavers

Categorical variable

No. of DI performed No. of successful DI Success rate (%)

Cumulative success rate (%)

Average time to completion (s)

Primary

attempt

110

71

64.5

64.5

Second

attempt

39

21

53.8

83.6

Final

attempt

18

8

44.4

90.9

11.4

17.5

21.7

participants were divided into small groups and were randomly placed at 1 of 6 cadavers.

Three attempts were allowed for each cadaver, with 30 seconds maximum given for each attempt. Individual participants attempted DI without assistance (eg, Sellick maneuver, head positioning, and tube handling were not performed). Participants attempted intubation on all 6 cadavers. A stylet was consistently used in the lumen of the ETT. A 7.5-mm ETT was used at first attempt at DI, and subsequent attempts involved the use of a 6.5-mm ETT. Staff emergency physicians confirmed placement using DL. Time was started when the operator was ready and stopped after each attempt. The total time for all attempts was recorded, as well as the number of attempts needed to successfully intubate the trachea.

Data analysis

The primary end points of the study were to determine the success rate, number of attempts, and time needed to digitally intubate cadaveric models. Descriptive analyses were performed for all variables. Values for categorical variables were reported as proportions with 95% confi- dence intervals (95% CIs). All data were entered into an electronic database, and statistical analysis was per- formed using Microsoft Excel (version 10.2614.2625; Microsoft Corporation).

Results

Successful intubation occurred 82.6% (95% CI, 76.1%- 89.1%) of the time for all participants. For all 6 cadavers, the average number of attempts for all participants was 1.7 (95% CI, 1.6-1.8), and the average time required for success or failure was 24.1 seconds (95% CI, 20.1-28.2). One cadaver developed soft tissue damage and a false passage near the vocal cords during the airway curriculum laboratory presented before the performance of the study, resulting in multiple failed attempts. If this cadaver were to be excluded, successful DI occurred 90.9% (95% CI, 85.5%-96.3%) of the time for all participants. The average number of attempts for all participants on these 5 cadavers was 1.5 (95% CI, 1.4-1.7), and the average total time required for success or failure was 20.8 seconds (95% CI, 16.9-24.8). Tables 1 and 2

show the success rates and times for each attempt across all 6 cadavers and 5 of the 6 cadavers, respectively.

Limitations

Study size and participants

The multitude of different airways encountered in a real- life setting cannot be accounted for with only 6 different cadavers. In addition, although the average age of the cadavers may allow the results to be generalized to adults, it does not allow any conclusions to the application of DI to the pediatric population.

Most participants were residents with varying airway experience, which theoretically could have altered the success rate. However, DI is not like other common methods of airway management, and it is unlikely that an experienced staff physician would be significantly better than a novice resident. That having been said, no comparison was made between residents and staff physi- cians because of the small number of total participants; it is possible that previous airway management experience may increase the skills of the provider at DI. Likewise, the advanced knowledge of anatomy and the airway may increase the likelihood of a physician succeeding with this technique when compared with personnel responding to a real-life scenario requiring this intervention.

Setting

The stress inherent to the setting in which DI is most likely to be beneficial could not be created with the use of cadavers. Although cadavers provide a more realistic model than simulated mannequins, the true pressure of providing a life-saving airway was unobtainable in this training airway laboratory. The influence of environmental stressors on success rates of a given practitioner cannot be determined from this study.

Timing

Recorded times for this study show the amount of time required to perform the procedure. They do not include placement verification with end-tidal carbon dioxide mea- surement, breath sound auscultation, chest x-ray, or any other means of ETT placement confirmation. It is reason- able to assume that several seconds would be added to each attempt for assessment of ETT placement, but certainly no more than other methods of advanced airway management.

Cadaver characteristics

The cadavers had been allowed to thaw 7 days before commencement of the study, and multiple intubations with traditional techniques had been performed during the airway curriculum presented before the study. As previously discussed, 1 cadaver developed a false passage near the

vocal cords that altered the results, likely in the negative direction. The effect of these factors on the success rate of DI could not be accounted for or controlled. The effect of the cold on the cadaveric tissue may have made them excessively stiff, which also affected the results.

Discussion

DI is a technique often discussed in prehospital education and routinely taught in the tactical emergency medical support setting [6]. It is, however, mentioned briefly or not at all in the major emergency medicine textbooks and is rarely included in advanced airway methods taught to emergency medicine physicians [7,8]. Although the gold standard for routine endotracheal intubation remains to be DL, it may fail or be impractical in certain situations. The results of this study demonstrate that DI provides emergency physicians with another option in securing the unprotected airway. DI may be particularly useful in the setting where the providers’ experience with or access to rescue airway devices is lacking, or where traditional patient positioning is not easily accomplished.

In general, DI can be accomplished with the practitioner not truly at the bheadQ of the patient’s bed and with little to no manipulation of the cervical spine [4]. The main potential complications of DI are upper airway trauma, Esophageal intubation, and bronchial mainstem intubation [9]. This study did not look at cervical spine manipulation or bronchial mainstem Intubation rates during the perfor- mance of this procedure, but further studies should be conducted comparing cervical spine movement during DI to conventional DL.

This study was performed by naive physicians after only a short training session. It is unknown whether continued training or significant a priori experience with DI would alter success rates. Further investigation would help to evaluate whether continued training in DI would improve success rates. Future research would also help to compare naive participants with more experienced physicians.

Conclusions

Emergency medicine physicians can perform DI rapidly and effectively in a human cadaveric model. This technique may represent a valid alternative to other methods of defini- tive airway management in specific, challenging settings.

References

  1. Sagarin MJ, Barton ED, Chng Y-M, Walls RM. Airway management by US and Canadian Emergency Medicine Residents: a multicenter analysis of more than 6,000 endotracheal intubation attempts. Ann Emerg Med 2005;46:328 – 36.
  2. Graham CA. Advanced airway management in the emergency department: what are the training and skills maintenance needs for UK emergency physicians? Emerg Med J 2004;21(1):14 – 9.
  3. Ander DS, Hanson A, Pitts S. Assessing resident skills in the use of rescue airway devices. Ann Emerg Med 2004;44(4):314 – 9.
  4. Stewart RD. Tactile orotracheal intubation. Ann Emerg Med 1984;13(3):175 – 8.
  5. Hardwick WC, Bluhm D. Digital intubation. J Emerg Med 1984;1(4): 317 – 20.
  6. Bledsoe B, Shade B, Porter R. Paramedic emergency care. 3rd ed. Upper Saddle River (NJ)7 Brady; 1996.
  7. Marx JA, editor. Rosen’s emergency medicine. 5th ed. St. Louis (MO)7 Mosby; 2002. p. 1 – 21.
  8. Tintinalli JE, editor. Emergency medicine, a comprehensive study guide. 6th ed. NewYork (NY)7 McGraw-Hill; 2004. p. 111.
  9. White SJ. Left mainstem intubation with digital intubation technique: an unrecognized risk. Am J Emerg Med 1994;12(4):466 – 8.

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