a b s t r a c t

Introduction: The main cause of cardiac arrest in pediatric patients is respiratory failure. Objective: To test the ability of paramedics to intubate the trachea of a child by means of the standard Macintosh [MAC] laryngoscope vs the Clarus Leviatan fiberoptic stylet (FPS) during 3-airway scenarios.

Methods: This was a randomized crossover manikin study involving 89 paramedics. The participants performed tracheal intubations using the MAC laryngoscope and the Clarus Leviatan FPS in 3 pediatric airway scenarios: scenario A, normal airway without chest compression ; scenario B, normal airway with CC; and scenario C, difficult airway with CC. Results: A total of 89 paramedics participated in this study. In scenario A, the FPS maintained a better success rate at first attempt (97.8% vs 88.9%; P = .73) and time required to intubate (17 [interquartile range, 15-21) seconds vs 18 [interquartile range, 16-22] seconds; P = .67) when compared with MAC. In scenariosB and C, the results with FPS were significantly better than those with MAC (P b .05) for all analyzed variables.

Conclusions: This study suggested that the FPS could be used as an option for airway management even for paramedics

with little experience. Future studies should explore the efficacy of FPS in pediatric clinical emergency settings.

(C) 2015

Introduction

The main cause of cardiac arrest in pediatric patients is respiratory failure [1,2]. During advanced life support, Adequate airway manage- ment, oxygenation, and ventilation are of crucial importance [3,4]. The 2010 European Resuscitation Council Guidelines for Cardiopulmonary Resuscitation (CPR) emphasize the delivery of continuous CPR Chest compressions with as few interruptions as possible, including pauses for airway management efforts [3]. Those guidelines include a section on adjuncts for oxygenation, ventilation, and airway control [3], recommending the use of Endotracheal intubation as a criterion standard for securing the airway during CPR. Endotracheal intubation offered an alternative method for the optimization of care, efficient ventilation, and promising superior airway protection and a

? Author’s contributions: Conception and design: L.S., L.C., L.B., A.K., P.Z., Z.T.; analysis and interpretation: L.S., A.K.; drafting the manuscript for important intellectual content: L.S., L.C., L.B., A.K., P.Z., Z.T.

?? Source of support: None declared.

* Corresponding author at: Department of Emergency Medicine, Medical University of Warsaw, Lindleya 4, 02-005 Warsaw, Poland. Tel.: +48 502258562.

E-mail address: [email protected] (Z. Truszewski).

route for delivering endobronchial medications. However, Prehospital ETI in children challenges the skills of an emergency medical provider as it is potentially hazardous and often performed in awkward condi- tions [5]. Several studies have examined prehospital pediatric tracheal intubation performed by paramedics or emergency physicians from dif- ferent clinical backgrounds They show that child intubation effective- ness in prehospital settings is insufficient and ranges from only 63.4% to 77% [6,7]. Some studies also suggest that multiple intubation attempts are associated with adverse events such as aspiration, hypoxemia, hypotension, and cardiac arrest [8-10]. In order to limit the number of times a child can be intubated, alternative methods of intubation using devices such as the Clarus Leviatan fiberoptic stylet (FPS; Clarus Medical, Minneapolis, MN) are recommended.

We hypothesized that the FPS is beneficial for the intubation of pedi- atric manikins while performing CPR. In the current study, we com- pared the effectiveness of FPS and the Macintosh (MAC) laryngoscope in 3 airway scenarios.

Methods

A prospective, randomized, crossover manikin trial was chosen for this study. This study has been approved by the institutional review board of the International Institute of Rescue Research and Education

http://dx.doi.org/10.1016/j.ajem.2015.06.003

0735-6757/(C) 2015

in Warsaw (approval 01.2015.11.17 was given on January 5, 2015) and was conducted in January 2015. Exclusion criteria included wrist or lower back problems, or pregnancy.

After written informed consent was obtained, 89 paramedics volunteered to participate in this study. All participants were routinely involved in the management and initial treatment for patients with cardiac arrest at emer- gency departments or with emergency medical service teams.

All participants were competent with standard techniques following the laryngoscope with Miller or MAC blades, but none of the partici- pants had prior experience of using the FPS. All participants attended a 2-hour workshop to gain practical manikin-based experience using the MAC and the FPS. Participants performed all intubation unaided, using a size 2 MAC laryngoscope and a pediatric Clarus Leviatan FPS (Fig. 1). A lubricated 5.5 ID cuffed endotracheal tube was used for all in- tubations, and an appropriate-sized rigid stylet was used with the MAC. Each participant performed intubations on a PediaSIM CPR training manikin (FCAE HealthCare, Sarasota, FL), which is designed to represent a 6-year-old child. The PediaSIM features a relatively “easy airway” at rest but can be programmed to generate a “difficult airway.” Just before each attempt, the participants were reminded that the “patient” needed emergency ETI, to give them a certain feeling of time pressure that would have been present in a real emergency. Subjects participated in

3 airway scenarios:

Scenario A: normal airway without CC was applied during intubation.

Scenario B: normal airway with CC, where continuous CCs were applied using the mechanical chest compressor LUCAS-2 (Physio- Control, Redmond, WA, USA). LUCAS-2 provided the same quality of CC independent of the rescuer’s fatigue. Chest compression was provided at a rate of 100 min^-1 to a depth of 4 to 5 cm.

Scenario 3: CC with difficult airway, where both CC using Lucas-2 and difficult airway were applied. The difficult airway was created by tongue edema to generate a Mallapati grade 3. Tongue edema was simulated by inflating the tongue to a pressure of 110 mm Hg.

In each scenario, the manikin was placed on the floor in a neutral position in a bright room. Elevation of the head or the upper body was not allowed.

The Research Randomizer program was used [www.randomizer. com] to split the volunteers into 4 groups and to determine the order of laryngoscope use (Fig. 2). The first group started intubation with a MAC in scenario A, the second using a MAC in scenario B, the third using Leviatan in scenario A, and the fourth using Leviatan in scenario

B. After completing the first ETI procedure, participants had a 10- minute break before attempting to perform ETI using another method. Participants had a maximum of 3 attempts at ETI for each intubation method. Participants were not allowed to watch each other during any of the intubation attempts in order to avoid learning from other participants’ mistakes or successes throughout the procedure.

The primary end point was the time taken to intubate for each device. The time required for intubation was defined as the initial inser- tion of the blade between the teeth until the first effective manual

ventilation of the manikin’s lungs. All processes were video recorded, and such records were used to precisely identify each time variable. The ability to ventilate the manikin with a mask-bag-value was consid- ered to be a successful attempt. A failed intubation attempt was defined as an attempt in which the trachea was not intubated or an insertion at- tempt lasted more than 60 seconds. The secondary end points were suc- cess of intubation and the glottic view according to the Cormack-Lehane grade reported by each participant [11]. We surveyed dental compres- sion by means of a Visual analog scale , which graded the pressure applied to the upper teeth (n = none, mild = 1, moderate = 2, severe = 3). To discover the subjective opinion about the difficulty of each intubation method, participants were asked to rate it on a VAS with a score from 1 (extremely easy) to 5 (extremely difficult). Partici- pants were also asked which laryngoscope they would prefer to use in a real life intubation.

Sample size calculations indicated that 89 participants would be a

sufficient number to detect moderate differences in intubation times between the MAC and the Leviatan (using 5% level of significance and 80% power). Results are shown as follows: median and interquartile range (IQR), mean +- SD, or absolute numbers and percentages (%). Statistical analysis was performed using Statistica version 12 for Windows (StatSoft Inc, Tulusa, OK). A P values less than .05 was considered as statistically significant. The times required for successful intubation were compared using the Wilcoxon Signed Rank Test. To detect possible differences in success rates for ETI, the McNemar test was used. For comparisons of VAS, and Cormack-Lehane grade 1-way analysis of variance, a post hoc (Scheffe) test, was used.

Results

Eighty-nine paramedics (59 female; 55.1%) participated in this trial. Twenty-seven subjects (11 female; 40.7%) worked in hospital emergency units and 62 (48 female; 77.4%) in teams of emergency medical services. The mean age was 34.2 +- 9.4 years, and the mean work experience was 9.2 +- 5.7 years.

In scenario A (normal airway without CC), the median times for in- tubation were similar when using MAC and FPS (Fig. 3). All participants performed successful intubation with MAC and FPS (Table 1).

In scenario B (normal airway with uninterrupted CC), the results with FPS were significantly better than those with MAC (P b .05) for success of first attempt, overall success rate, time for intu- bation, Dental compression, Cormack-Lehane grade, and ease of intuba- tion scores (Table 2).

In scenario C (difficult airway with uninterrupted CC), the analysis showed that the median time for intubation with FPS was 23 (IQR, 21- 26) seconds and was a statistically significant shorter time than with MAC (39 [IQR, 35-44] seconds; P b .001). The results with FPS were significantly better than those with MAC for: success of first attempt, overall success rate, time for intubation, dental compression, Cormack- Lehane grade, and ease of intubation scores (Table 3).

Fig. 1. Laryngoscopes used for this study were MAC laryngoscope (A) and Clarus Leviatan FPS (B).

Fig. 2. Flowchart of design and recruitment of participants according to CONSORT statement.

Discussion

So far, no randomized controlled trial has compared FPS to MAC in a Pediatric manikin in 3 airway scenarios. In the present study, the time required for intubation was shorter when using FPS. Endotracheal intubation is considered a standard in securing the airway of patients with cardiac arrest [3,12].

An interruption in CCs during CPR is associated with a negative impact of survival from CA [3,12,13]. When difficulties in airway

Fig. 3. time to intubation.

management arise, patients die from failure to oxygenate. Ensuring ad- equate airway management and adequate oxygenation is integral to successful CPR [3,4]. Direct laryngoscopy using a laryngoscope with Miller or MAC blades is still considered the “gold standard” of intubation in pediatric patients. However, first-attempt success using direct laryngoscopy in an emergency setting (prehospital and some EDs) is reported to be 44% to 83% [14,15].

In the current study, we demonstrated that the success rate of intu- bation with the MAC decreased during uninterrupted CC, with a signif- icant increase of time. Intubation time did not significantly increase using the FPS, and all participants were successful in intubating using

Table 1

Data from normal airway without CC scenario

Data reported as median (IQR) or number (%). NS, not statistically significant.

Table 2

Data from normal airway with uninterrupted CC scenario

Parameter assessed MAC FPS P

Data reported as median (IQR) or number (%). NS, not statistically significant.

the FPS during CC. The study by Komasawa et al [16] evaluating the ef- ficacy of infant intubation using a Miller laryngoscope and Airtraq laryn- goscope performed by 20 staff doctors in intensive care and emergency medicine indicated that the efficacy of intubating using direct laryngos- copy decreases when ETI is performed during CC. This dependence is also confirmed by other studies [17,18]. The decrease in the efficiency of intubation using direct laryngoscopy during uninterrupted CC may be due to the fact that the glottis moved during CCs, and the relative positions of the glottis as well as the tube were considered unstable.

The concept of difficult airway management includes physical diffi- culties associated with the patient, such as subglottic narrowing. In many studies, we can observe a decreasED efficiency in intubation in cases of Difficult airways [19,20]. As a result of intubating a difficult air- way, the intubator may have to perform multiple intubation attempts before obtaining Effective airway management by endotracheal tube. Nonetheless, as some studies have indicated, failed attempts in placing the endotracheal tube can lead to bleeding and epiglottis edema. This can lead to a “vicious circle” of events wherein each intubation attempt leads to an increased risk of failure of another attempt at intubation and finally difficulties in patient ventilation [10,21,22]. Therefore, the Diffi- cult Airway Society has recognized the need for placement in “plan A” for difficult airways and alternative Intubation devices including video

Table 3

Data from difficult airway with uninterrupted CC scenario

Data reported as median (IQR) or number (%). NS, not statistically significant.

laryngoscopes. Other devices such as FPS may also be helpful, as they allow you to visualize the image of the end of the tracheal tube, which translates into higher efficiency intubation. Several studies indicate that FPS can be used successfully in many clinical situations [23-26]. This study, however, is the first study evaluating the effectiveness of child intubation using the FPS. In our study, although the participants had significantly less clinical experience with the FPS than the MAC, they had a high success rate of first attempt intubation, overall success rate, shorter times of intubation, better Cormack-Lehane grades, and less dental compression, indicating that the FPS was relatively easy to use. Our study had several limitations. First, this study was performed using a high-fidelity simulator, not on Live patients. However, according to recommendations from the International Liaison Committee on Resuscitation, randomized clinical trials for cases of cardiac arrest are unethical and cannot determine the expected benefits of CPR [27]. Sec- ond, the simulated clinical environment creates a safe, controllable, and reproducible area. Some studies about the use of airway simulators have been published [28-30]. The third limitation of our study was that the paramedics who assessed the Intubation times were not novices, unsure about the methods used. The study, however, also has its strengths. The study was a randomized crossover. Furthermore, for simulation of a CC

system, the Lucas2 was used.

Conclusions

Clinical accumulation and randomized trials of FPS vs MAC use in patients in clinical situations are needed in the future. We concluded that in child situations managed by paramedics, the FPS performed better than the standard MAC for ETI in children–normal and difficult airway during CC.

Conflict of interest statement

The authors declare that they have no conflicts of interests.

Acknowledgments

None of authors involved in this study have any financial relation- ship with any manufacturers of intubation devices.

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