COMPARISON OF VARIOUS INTUBATION DEVICED DURING RESUSCITATION OF COVID-19-SUSPECTED PATIENTS BY PARAMEDICS WEARING PERSONAL PROTECTIVE EQUIPMENT

for successful intubation by paramedics wearing PPE AGP in a suspected/ confirmed COVID-19 adult patient resuscitation scenario. The study was designed as a single-blind, multicentre, prospective, randomized, crossover Background: Endotracheal intubation is one of the basic methods for airway control during cardiopulmonary resuscitation. In the era of the prevailing pandemic of SARS-CoV-2, medical personnel may face a necessity of resuscitating aninfected patient. Objective: The objective was to compare three intubation methods for suspected/confirmed COVID-19 adult patient resuscitation performed by paramedics wearing personal protective equipment (PPE) for aerosol generating procedures (AGP). Material and Methods: The multicentre, single-blind, prospective, randomized, crossover simulation trial involved 32 paramedics. The participants wearing PPE AGP performed tracheal intubations with the Macintosh, Airtraq, and McGrath MAC laryngoscopes in a patient with suspected COVID-19 in two resuscitation scenarios: scenario A – without chest compressions; scenario B – with continuous chest compressions. The primary outcome was time to intubation.Results: In scenario A, the intubation time for the respective devices equalled 35 s (IQR: 29–46) vs. 44s (IQR: 35–67) vs. 49 (IQR: 34–72) (p = 0.003). The total efficacy of each intubation method was 100%; however, the efficacy of the first intubation attempt was highest for McGrath MAC (90.6%), followed by Macintosh (68.1%) and Airtraq 62.5%) (p<0.001). In scenario B, the results with McGrath MAC were significantly better than those with Macintosh and Airtraq(p<0.05) for all the analysed variables. Conclusions: In conclusion, the McGrath MAC videolaryngoscope offers better intubation conditions as compared with the Macintosh laryngoscope or Airtraq in the resuscitation COVID-19.

Оригинальные исследования simulation study and was approved by the Institutional Review Board of the Polish Society of Disaster Medicine (approval No. 12.01.2020.IRB). The investigation was carried out at the Medical Simulation Centre of Poznan University of Medical Sciences and Lazarski University in February 2020. Paramedics with at least one year of experience were invited to take part in the study, and voluntary written informed consent was obtained from all participants. The inclusion criteria involved at least one year of work experience, a minimum of 10 clinical intubations, as well as no experience with videolaryngoscopy.
Simulation scenario. An advanced SimMan 3G adult patient simulator (Laerdal, Stavanger, Norway) was used to simulate a patient with suspected/ confirmed SARS-CoV-2 infection. Endotracheal intubation was performed in two scenarios: a) scenario A: normal airway without chest compressions; b) scenario B: normal airway with uninterrupted chest compressions; the LUCAS3 mechanical chest compression system (Physio-Control Inc., Lund, Sweden) served to standardize chest compressions.
When intubating the patient, the participants wore an anti-chemical, antiviral, antibacterial suit of class F providing protection against organic and inorganic chemicals in high concentrations and against solid particles of less than 1 µm in diameter. The suit also protects against biological hazards and toxic agents (Maskpol Inc., Panki, Poland). In order to simulate real interventionsin a patient with SARS-CoV-2, the participants wore a protective mask with FFP1 filter, protective goggles, a visor, as well as double nitrile gloves ( Figure 2).

Figure 1. -Devices included in the study: a) standard Macintosh laryngoscope; b) Air traq optical laryngoscope; c) video laryngoscope Mc Grath MAC Рисунок 1. -Устройства, включенные в исследование: а) стандартный ларингоскоп Макинтоша; б) оптический ларингоскоп Air traq; в) видеоларингоскоп Mc Grath MAC
Devices. The following devices were included in the study ( Figure 1) Each endotracheal intubation was performed with a standard 7.5 mm internal diameter, cuffed, plastic endotracheal tube (SUMI, Sulejowek, Poland). For MAC and McGrath MAC intubation, a single-use intubation stylet was applied. Before each intubation attempt, both the guide and the endotracheal tube were moistened with a slide agent dedicated for medical simulators.
Training phase. The participants received a 60-minute theoretical training on the indications for intubation in patients suspected of or infected with SARS-CoV-2 and on protecting medical staff against contact with such patients. Subsequently, the instructor demonstrated the correct technique of endotracheal intubation using all the devices tested. After the demonstration, the participants were allowed to familiarize themselves with the laryngoscopes before commencing the study; this phase included at least one successful tracheal intubation by each participant with each device. Demonstrations and training were all performed with the Laerdal Airway Management Trainer The paramedics had a maximum of three attempts of intubation with each device in each scenario. After the intubation attempts with a given laryngoscope, they had a 10-minute break, and then intubated the patient with the use of another technique. The order of both the participants and the endotracheal intubation methods was random. The Research Randomizer program (randomizer.org) was used for randomization.
Measurements. The primary endpoint was intubation time, which was recorded by an independent researcher, unaware of the study protocol. The intubation time was defined as the time between the laryngoscope passing the manikin's Оригинальные исследования teeth and the participant declaring the trachea to be intubated. Tracheal intubations that lasted more than 120 seconds were classified as unsuccessful. Failed tracheal intubations also included oesophageal intubations (not recognized by the participant) and tracheal intubations that required more thanthree attempts. When the participant recognized the intubation as oesophageal, it was counted as one attempt instead of unsuccessful intubation. If a participant, however, opted against a second or third attempt, the endotracheal intubation was registered as a failed attempt.
The secondary endpoints included the number of tracheal intubation attempts, the Cormack-Lehane grade [10] scored by the participant, as well as the percentage of glottic opening (POGO) score. Following the completion of a scenario, the subjects were asked to grade each device for the ease of its technical use (1 = easy, 100 = difficult) and the willingness to reuse (1 = would never use again, 100 = would like to use) in a relevant scenario, but they were discouraged from overall ranking of the devices. Also recorded were demographic data, which included the participants' experience in emergency medicine.
Statistical analysis. The sample size was based on expected differences of time to intubation and calculated with G*Power 3.1 using a two-tailed t-test (Cohen's d = 0.8, alpha error = 0.05, power = 0.95). We determined that a minimum of 32 participants were required for a pairwise comparison of our samples. All analyses were performed with the statistical package Statistica 13.3EN (Tibco Inc., Tulsa, OK, USA). The data were blinded for the team interpreting the results. Categorical data were presented as raw numbers and as frequencies, and continuous and ordinal data as medians and interquartile ranges (IQR). Non-parametric tests were used because the data distribution was not typically based on Shapiro-Wilk and Kolmogorov-Smirnov tests. The Kruskal-Wallis one-way analysis of variance (ANOVA) with post-hoc Dunn's test wereapplied to assess pairwise differences between the devices for the following variables: intubation time, POGO score, ease of use, and willingness to reuse. Chi-square tests were used to evaluate differences between the devices for the rate of successful tracheal intubation. The values of p ≤ 0.05 were considered statistically significant.
Results A total of 32 paramedics (14 female, 45.2%) participated in the study. All participants worked in teams of emergency medical services. Their mean age was 28.3±5.6 years, and mean work experience time equalled 2.9 ± 1.6 years.
Scenario A: without chest compressions. The intubation results in scenario A are presented in Endotracheal intubation with McGrath was associated with a better glottic view in the Cormack-Lehane scale, as well as in the POGO score in comparison with Macintosh laryngoscope (p < 0.001) and Airtraq (p < 0.001). Intubation with McGrath was also reported as easier to perform in comparison with Macintosh laryngoscope (p < 0.001) and Airtraq (p < 0.001).
Discussion This is the first study comparing endotracheal intubation for suspected/confirmed COVID-19 adult patient resuscitation scenarios performed by paramedics wearing PPE AGP. The current SARS-CoV-2 coronavirus pandemic requires medical personnel to take special measures, including the use of PPE to protect against new virus infection [9,11,12]. Hence, every action, especially in pre-hospital conditions, where paramedics are unaware of the patients' status, should be performed under special precautionary measures. Such precautions are crucial as carelessness may result in self-infection or infection of future patients during subsequent medical interventions [13]. Also, in any case of contact with a patient with suspected/confirmed COVID-19, if PPE AGP was not worn bythe medical personnel, it is necessary to isolate the emergency medical team until the patient confirms or excludes COVID-19 [14]. This, in turn, results in blocking the ambulance and its entire crew and thereby reduces the responsiveness of local emergency services.
Paramedics acting within the framework of emergency medical teams often face the necessityto adequately protect airway patency, including performing endotracheal intubation [15]. In the context of COVID-19 patients in severe condition requiring mechanical ventilation, endotracheal intubation still seems to be the gold standard for airway management [16]. The use of full protection in the form of PPE AGP may limit the effectiveness of medical procedures [17,18]. This is also confirmed by Scott Taylor et al. [19]. In their research, emergency medicine residents and prehospital providers performed endotracheal intubation in a cadaveric model while wearing level C PPE or without any PPE. The success rate of the first intubation attempt with and without PPE Оригинальные исследования equalled 58% vs. 96%. Intubation performed with PPE also affects intubation time, extending the duration of the procedure [19]. Paramedics also feel more temperature-related discomfort during direct laryngoscopy when wearing PPE [20]. In turn, in a study by Wang et al. [21], PPE did not affect physicians' emergency airway placement time.
In the scenario without chest compressions, intubation with the McGrath MAC videolaryngoscope was associated with the shortest duration of the procedure compared with the Airtraq optical laryngoscope and with direct laryngoscopy performed with the Macintosh laryngoscope. Studies also indicate the advantage of videolaryngoscopy over direct laryngoscopy when using chemical, biological, radiation, and nuclear PPE [22,23]. Claret et al. [24] revealed that the Macintosh laryngoscope was superior to the Airtraq laryngoscope in terms of endotracheal intubation speed, effectiveness, and overall ease of use. The above relationshiphas also been confirmed in our study. The total efficacy of MAC, Airtraq, and McGrath laryngoscopes intubation under the conditions of PPE AGP in the scenario where the chest was not compressed during intubation attempts was 100%; however, the efficacy of the first intubation attempt was 68.1% vs. 62.5% vs. 90.6%, respectively. It is worth emphasizing that during cardiopulmonary resuscitation, interruptions in chest compressions should be minimized; therefore, endotracheal intubation should be performed as soon as possible, with compressions resumed immediately after inserting the endotracheal tube between the vocal folds, or completely without interruptions in chest compressions [7]. Endotracheal intubation during continuous chest compressions may result in reduced effectiveness if chest compression is stopped for the duration of the procedure [25][26][27].
The scientific literature lacks studies concerning the efficacy of intubation under cardiopulmonary resuscitation with preserved chest compressions as performed by personnel dressed in PPE. In this study, intubation with the McGrath MAC videolaryngoscope was the most effective in terms of procedure duration and efficacy. In turn, Claret et al. [24] showed that in endotracheal intubation by physicians wearing chemical, biological, radiological, and nuclear PPE during infant resuscitation simulation, the orotracheal intubation success rate with the Airtraq laryngoscope was higher than that with the Miller laryngoscope and that intubation time with the Airtraq laryngoscope was lower than with the Miller laryngoscope. This is confirmed by the results of the study.
Limitations The presented study has its limitations. One of them is the fact that the investigation was carried out under medical simulation conditions and not during real resuscitation activities. However, such a way of designing and conducting the study was purposeful because only medical simulation allows for full standardization of the performed procedures and their repetition without any harm to the health of the potential patient. The second limitation was the inclusion of only paramedics in the research group. This was also a deliberate decision, as it is this professional group operating in prehospital conditions that is in practice often faced with the need to protect airways and conduct cardiopulmonary resuscitation. The study also has its strengths. Among them, we can mention the fact that it was a single-blind multicentre randomized crossover trial. Another strong point is the evaluation of three intubation methods: direct laryngoscopy, optical laryngoscopy, and videolaryngoscopy. Moreover, this is the first study evaluating endotracheal intubation of a suspected/confirmed COVID-19 adult patient during resuscitation performed by paramedics wearing PPE AGP.

Conclusions
In conclusion, McGrath MAC videolaryngoscope offers better intubation conditions than the Macintosh laryngoscope or Airtraqin a suspected/confirmed COVID-19 adult patient resuscitation with and without chest compressions when paramedics wear PPE AGP. Further clinical studies are necessary to confirm these initial positive findings.