Emergency cricothyrotomy is the final step in managing an otherwise inaccessible airway.1 The Quick Trach II (QT; VBM Medizintechnik GmbH, Sulz am Neckar, Germany) was developed for direct placement in the trachea with a catheter-over-needle technique. In contrast, the Melker Set (Melker; Cook Group Incorporated, Bloomington, Indiana, USA) uses a guide-wire for actual placement of the cannula with the Seldinger method. Despite previous studies,2,3 we lack a head-to-head comparison of the Quick Trach II and Melker devices as far as rapidity and efficacy is concerned during cardiopulmonary resuscitation (CPR) manoeuvres.
In case of difficult airway management during CPR, cricothyrotomy is a validated option.2 The European Resuscitation Council (ERC) CPR guidelines emphasise the importance of minimising interruptions during chest compression to maximise coronary and cerebral perfusion pressure.4 In the present study, we compared performance of the Quick Trach II and Melker devices with respect to the efficacy of cricothyrotomy during chest compressions on manikins.
Ethical approval for this study (Ethical Committee No. 1327) was provided by the Ethical Committee of Osaka Medical College, Takatsuki, Japan (Chairperson Prof R. Saura) on 6 January, and written consent was obtained from each participant. twenty-three doctors who specialise in critical care such as emergency medicine or anaesthesiology were recruited from anaesthesiology training course participants at the Osaka Medical College. The participants had 7.0 ± 4.0 years of clinical anaesthesia training but no experience with cricothyrotomy in clinical or simulated situations.
The SimMan3G (Laerdal, Sentrum, Stavenger, Norway) manikin with a new cricothyroid membrane for every attempt was used. Chest compressions were demonstrated by the same Advanced Life Support instructor at a depth of about 5 cm and a rate of 100 compressions per minute in accordance with the present guidelines.4 In the Melker trial, participants used the Melker Set consisting of a needle, a syringe, a guide-wire, a scalpel, a dilator, a 5-mm cannula with an inflatable cuff and a syringe for blocking the cuff. In the Quick Trach II trial, participants used the Quick Trach II set, consisting of a syringe, a conical-shaped needle, a plastic 4-mm cannula with an inflatable cuff and a stopper. Participants were given 30 min to practice these techniques, with the instructor available for advice. The trial started when the participant picked up the Quick Trach II or Melker and ended at the point of manual ventilation after cricothyrotomy. Cricothyrotomy times were recorded for both tracheal and failed airway management. Failed cricothyrotomy was defined as outside the trachea placement. The study was designed as a randomised crossover trial to minimise learning effect. Each participant performed four trials and the order was randomised utilizing a random number table.
Results were compared using two-way analysis of variance (ANOVA) for repeated measures for intubation time, and Fisher's exact test for the success rate. Data are presented as mean ± SD. A P value of less than 0.05 was considered statistically significant. A preliminary study showed that the time required to ventilate lungs after insertion of the Quick Trach II was 14 ± 4 s. To detect a 33% difference, 21 participants are needed for two independent groups using α = 0.05 and β = 0.2.
The success rate with each device is summarised in Table 1. In the Melker trials, no participant failed to secure the airway without chest compressions, while six failed with compressions (P < 0.05). In Quick Trach II trials, no participant failed to secure the airway without chest compressions, while two failed with compressions (N.S.). Cricothyrotomy time was significantly longer with chest compressions when using either the Melker or the Quick Trach II (Melker trial; without chest compressions, 19.7 ± 3.5 s, during chest compressions 29.4 ± 3.4 s; P < 0.05, QT trial; without chest compressions, 15.8 ± 3.3 s, during chest compressions 23.5 ± 3.6 s; P < 0.05). Cricothyrotomy time with chest compressions was significantly shorter in the Quick Trach II trial than in the Melker trial (P < 0.05).
In previous investigations in pig larynxes without chest compression, cricothyrotomy time was shorter with the Quick Trach II than with the Melker device, with fewer complications.5 In our study in manikins with chest compression, neither cricothyrotomy time nor success rate differed between the devices without chest compression. However, cricothyrotomy time was significantly shorter in the Quick Trach II trial than in the Melker trial. During chest compression, direct puncture with the cannula-over-needle method may be more rapid. The probable reason for this is that the smooth guide-wire and catheter insertion is interfered with by chest compressions during Melker trial. In contrast, continuous application of firm pressure to the skin during Quick Trach II trial may facilitate airway management, even during chest compressions.
This study has several limitations. First, the simulations do not account for factors such as bleeding during attempts at invasive airway management. Second, use of the Quick Trach II or Melker may be impaired in patients with difficulty extending the neck or large thyroid tumours. The accumulation of clinical experience and controlled randomised clinical trials are needed to confirm our results.
In our CPR simulation setting with chest compressions, the Quick Trach II device allowed for faster cricothyrotomy than the Melker device.
Acknowledgements relating to this article
Assistance with the study: none.
Financial support and sponsorship: Financial support was provided by our institution.
Conflicts of interest: none.
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