Lønvik et al. BMC Emergency Medicine (2021) 21:51 https://doi.org/10.1186/s12873-021-00444-0 RESEARCH Open Access A prospective observational study comparing two supraglottic airway devices in out-of-hospital cardiac arrest Maja Pålsdatter Lønvik1,2, Odd Eirik Elden3,4,5, Mats Joakimsen Lunde5, Trond Nordseth6,7, Karin Elvenes Bakkelund3 and Oddvar Uleberg3,8* Abstract Background: Airway management in patients with out of hospital cardiac arrest (OHCA) is important and several methods are used. The establishment of a supraglottic airway device (SAD) is a common technique used during OHCA. Two types of SAD are routinely used in Norway; the Kings LTS-D™ and the I-gel®. The aim of this study was to compare the clinical performance of these two devices in terms of difficulty, number of attempts before successful insertion and overall success rate of insertion. Methods: All adult patients with OHCA, in whom ambulance personnel used a SAD over a one-year period in the ambulance services of Central Norway, were included. After the event, a questionnaire was completed and the personnel responsible for the airway management were interviewed. Primary outcomes were number of attempts until successful insertion, by either same or different ambulance personnel, and the difficulty of insertion graded by easy, medium or hard. Secondary outcomes were reported complications with inserting the SAD’s. Results: Two hundred and fifty patients were included, of whom 191 received I-gel and 59 received LTS-D. Overall success rate was significantly higher in I-gel (86%) compared to LTS-D (75%, p = 0.043). The rates of successful placements were higher when using I-gel compared to LTS-D, and there was a significant increased risk that the insertion of the LTS-D was unsuccessful compared to the I-gel (risk ratio 1.8, p = 0.04). I-gel was assessed to be easy to insert in 80% of the patients, as opposed to LTS-D which was easy to insert in 51% of the patients. Conclusions: Overall success rate was significantly higher and the difficulty in insertion was significantly lower in the I-gel group compared to the LTS-D in patients with OHCA. Keywords: Airway management, Airway research, Cardiac arrest, OHCA, Emergency medical services, Supraglottic airway device, I-gel, LTS-D, Laryngeal tube, LT, Resuscitation * Correspondence: [email protected] 3Department of Emergency Medicine and Pre-Hospital Services, St. Olav’s University Hospital, NO-7030 Trondheim, Norway 8Department of Research and Development, Norwegian Air Ambulance Foundation, NO-0103 Oslo, Norway Full list of author information is available at the end of the article © The Author(s). 2021 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. 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BMC Emergency Medicine (2021) 21:51 Page 2 of 7 Background challenges of insertion in I-gel and LTS-D, when being Establishment of a patent airway in order to perform used by ambulance personnel during out-of-hospital car- ventilations and chest compressions in addition to early diac arrest in Central Norway. defibrillation are important interventions during the re- suscitation of a patient with out-of-hospital cardiac Methods (OHCA) [1]. To establish a patent airway, health care The study is a prospective observational study. The providers commonly use bag-valve-mask ventilation study follows the ‘Strengthening the reporting of obser- (BVM), or an advanced airway such as supraglottic air- vational studies in epidemiology’ (STROBE) recommen- way device (SAD) or endotracheal intubation (ETI). Ani- dations for reporting of observational cohort studies mal studies have shown that a combination of [12]. ventilation and chest compressions is more effective than compressions only to preserve oxygenation and to Study setting limit hypercapnia [2, 3]. Even though the time spent on The Central Norway Regional Health Authority has the ventilation during BVM is not necessarily long, the total overall responsibility for the three ambulance services hands-off time is significantly longer than the time re- within the health trusts of Møre- og Romsdal (HMR), quired for each ventilation [4]. While BVM requires in- Nord-Trøndelag (HNT) and St. Olav’s hospital (SOH), terruptions in compression to perform ventilation, SAD/ covering a total patient population of approximately ETI allows continuous compressions combined with 721.000 persons. The three ambulance services are sep- ventilations between compressions. Another advantage arate administrative units, but the Joint Commission of is that a fixed airway gives the manual availability for Ambulance Services in Central Norway provide the same other practical tasks, and no-flow time is reduced when guidelines and protocols, and the training and certifica- an advanced airway is established [5]. tion of personnel within the three services. The only dif- An advantage of the SAD is that it can be inserted ference in protocols during this study was the type of without visual inspection, and that it provides a relative SAD used during OHCA. In HMR and SOH the I-gel air seal tightness around the larynx, which reduces the was used, whereas in HNT the LTS-D was used. passing of air into the stomach. Even though some stud- ies show higher survival with the use of ETI compared Data collection to SAD [6], SAD is performed quicker and with a higher All cardiovascular and / or respiratory arrests in adult success rate than ETI when used out of hospital and by patients where ambulance personnel attempted insertion less experienced personnel [7–9]. SAD is associated with of a SAD during the 12-month period from March 2016 a lower hands-off time than ETI [10]. European guide- to February 2017 were included. These patients were lines regarding CPR by ambulance personnel recom- registered according to the Utstein template of uniform mends the use of SAD rather than ETI during out of reporting for OHCA and by using the updated definition hospital cardiac arrest (OHCA) [1]. of a resuscitation attempt: “the act of trying to maintain Neither the Norwegian nor the European Resuscitation or restore life by establishing and/or maintaining breath- Councils have specific recommendations on the selec- ing and circulation through CPR, defibrillation, and tion of type of SAD, which may explain the use of sev- other related emergency care” [13]. The inclusion process eral different devices among local health trusts [11]. In is shown in Fig. 1. Ambulance staff recorded patient data the three local health trusts in Central Norway two dif- electronically in the electronic patient chart (Ambustat®). ferent types are used, the I-gel® (Intersurgical, Woking- Additional study variables were added to further de- ham, UK) and the King LTS-D™ (North American scribe characteristics of the performed airway manage- Rescue, Greer, SC, US). LTS-D is a laryngeal tube, con- ment (Additional file 1). To validate recorded data, every sisting of a tube with a distal oesophagus cuff and a ambulance personnel responsible for airway manage- proximal pharyngeal cuff, which are inflated after inser- ment was interviewed after every case. This was done to tion in oesophagus. I-gel is an anatomical shaped laryn- ensure that the form was interpreted and filed correctly. geal mask, covering all of glottis when placed. Both The objective was to do all the interviews within a week devices contain a gastric tube port, to decompress the after each case, but due to practical reasons, it could stomach for air or fluids, and thereby reduce the risk of take up to a month before the interviews were gastric reflux. In our region, ETI is only performed by conducted. helicopter emergency medical services, which are The included OHCA were divided into groups accord- manned by anaesthesiologists. ing to which SAD was used. Whenever a need for SAD The aim of the study was to investigate the number of was identified and the ambulance personnel tried to in- attempts before successful insertion and assessment of sert a SAD, it was defined as an attempt. When EMS Lønvik et al. BMC Emergency Medicine (2021) 21:51 Page 3 of 7 Fig. 1 Inclusion and exclusion flowchart. The figure illustrates the numbers and reasons for patient exclusion and the number included patients. Utstein registration and resuscitation attempt definition refer to the Utstein template of uniform reporting for OHCA [13]. EMS: Emergency Medical System, ROSC: Return of Spontaneous Circulation, SAD: Supraglottic Airway Device7 took the SAD out of the patient’sairwaytotrya Statistics renewed insertion, it was defined as a new attempt. A Data was analysed in SPSS and R version 4.0.3, applying successful insertion of a SAD was defined as properly the R-package “fmsb” [14]. Relevant outcomes were positioned and working, as clinically assessed by the assessed with the Chi-square test, or estimation of risk ambulance personnel on site.