Laypersons can successfully place supraglottic airways with 3 minutes of training. A comparison of four different devices in the manikin

Comparison of Laryngeal Mask Airway Seal Between Anesthesiologists and Individuals Without Previous Airway Experience

BACKGROUND

Tracheal intubation is the gold standard for airway management in emergency medicine, but more difficult to apply for inexperienced individuals than laryngeal mask airway (LMA).

OBJECTIVE

The aim of our study was to investigate if inexperienced individuals are able to secure the airway with the help of LMA after a short introduction. A second aim was to evaluate Thiel-fixed specimens against unfixed ones.

METHODS

In a body donor model, LMA application was evaluated between medical students without previous airway experience and anesthesiologists by comparing the sealing of the larynx using a water column applied to the esophagus.

RESULTS

LMAs were successfully applied in 46 out of 55 (83.6%) attempts by medical students and in 30 out of 39 (76.9%) attempts by anesthesiologists. Among medical students, 14.1% of all LMA applications were primarily leaky, compared with 18.8% in anesthesiologists. Esophageal sealing was better in Thiel-fixed specimens (leakage 10.9%) compared with unfixed specimens (leakage 22.9%). Our data showed no significant difference between anesthesiologists and medical students in terms of sealing of LMA. Therefore, we conclude that medical students without previous airway experience can quickly learn to apply LMA sufficiently and thus, achieve aspiration protection similar to anesthesiologists.

CONCLUSION

Medical students without previous airway experience can successfully insert LMAs after a short introduction. Thiel-fixed specimens are suitable for studies as well as for training in LMA application.

The effect of class 3 obesity on the functionality of supraglottic airway devices: a historical cohort analysis with propensity score matching

PURPOSE

Supraglottic airway devices (SGAs) have been increasingly used as a primary airway in patients undergoing anesthesia as an alternative to endotracheal tubes. Second-generation devices have expanded their applicability to include uses in patients with obesity. Nevertheless, there is limited evidence of SGA suitability for patients with class 3 obesity (body mass index [BMI] ≥ 40 kg·m-2). As such, we compared rates of SGA functionality between patients with class 3 obesity and patients without class 3 obesity undergoing general anesthesia.

METHODS

We performed a propensity score matching analysis using inverse probability of treatment weighting to compare the functionality of SGAs in adult patients with class 3 obesity vs without class 3 obesity. These patients underwent surgery at a hospital in Queensland, Australia from November 2017 to September 2020 and had a SGA inserted as part of their anesthetic care. All data were collected from patients' electronic medical records. We included 321 patients in the cohort with class 3 obesity and 471 in the cohort without class 3 obesity (control/comparison). The estimated effect of class 3 obesity on SGAs was calculated using adjusted odds ratios (AORs) with their 95% confidence intervals (CIs).

RESULTS

The overall weighted prevalence of nonfunctional SGAs was 3.2%, with a significantly higher rate in the class 3 obesity cohort compared with the control cohort (4.7% vs 2.1%) (P = 0.04). This adjusted analysis illustrates that class 3 obesity was associated with an almost four times higher odds of a nonfunctional SGA (odds ratio [OR], 2.3; 95% CI, 1.0 to 5.1; AOR, 3.9; 95% CI, 1.4 to 10.6) than patients without class 3 obesity.

CONCLUSION

Patients with class 3 obesity (BMI ≥ 40 kg·m-2) had greater than three-fold odds of nonfunctional intraoperative SGAs than patients without class 3 obesity.

[Manikin-based comparison of the use of different supraglottic airways by laypersons]

BACKGROUND

Supraglottic airways (SGA) are an established method of airway management both in prehospital medicine and clinical settings. Endotracheal intubation is the gold standard, but SGA offer advantages in terms of faster application learnability.

OBJECTIVES

In the present study it was investigated whether the time until the first sufficient ventilation in the three examined SGAs applied by bystander differed significantly.

MATERIALS AND METHODS

A total of 160 visitors to a shopping mall were assigned to one of the three SGA after permutative block randomization. The primary endpoint of the present study was the required placement time until the first sufficient ventilation.

RESULTS

Participants managed to place the i‑gel laryngeal mask airway (i-gel, Intersurgical Beatmungsprodukte GmbH, Sankt Augustin, Germany) after a median time of 11 s, whereas the median time until the first sufficient ventilation using a classic laryngeal mask airway (LMA; 26 s) or a laryngeal tube (LT; 28 s) was significantly longer. Thus, the time savings when using the i‑gel compared to the LT and LMA were each significant (p < 0.001), whereas the times between LT and LMA did not differ significantly (p 0.65).

CONCLUSION

The results show that laypersons are able to successfully apply various supraglottic airways to the phantom after a short learning period. The i‑gel laryngeal mask could be placed with the highest success rate and speed.

Does the revised intubating laryngeal tube (ILTS-D2) perform better than the intubating laryngeal mask (Fastrach)? - a randomised simulation research study

BACKGROUND

The intubating laryngeal tube (ILTS-D™) and the intubating laryngeal mask (Fastrach™) are devices that facilitate both extraglottic application and blind tracheal intubation. A revised model of the iLTS-D (for scientific reasons called ILTS-D2) has been designed but not yet evaluated. Therefore, we compared the ILTS-D2 with the established Fastrach under controlled conditions in a prospective randomised controlled simulation research study.

METHODS

After ethical approval, we randomised 126 medical students into two groups. Each participant received either Fastrach or ILTS-D2 to perform five consecutive ventilation attempts in a manikin. The primary endpoint was the time to ventilation in the last attempt of using the devices as extraglottic devices. Secondary endpoints were the time to tracheal intubation and the success rates.

RESULTS

There was no relevant difference between the two devices in the time to ventilation in the last of five attempts (Fastrach: median 14 s [IQR: 12-15]; ILTS-D2: median 13 s [IQR: 12-15], p = 0.592). Secondary endpoints showed a 2 s faster blind tracheal intubation using the Fastrach than using the ILTS-D2 (Fastrach: median 14 s [IQR: 13-17]; ILTS-D2: median 16 s [IQR: 15-20] p < 0.001). For both devices, the success rates were 100% in the last attempt.

CONCLUSIONS

Concerning extraglottic airway management, we could not detect a relevant difference between the revised ILTS-D2 and the Fastrach under laboratory conditions. We advocate for an evaluation of the ILTS-D2 in randomised controlled clinical trials.

TRIAL REGISTRATION

Identifier at clinicaltrials.gov: NCT03542747. May 31, 2018.

[Systematic analysis of airway registries in emergency medicine]

BACKGROUND

A myriad of publications have contributed to an evidence-based approach to airway management in emergency services and admissions in recent years; however, it remains unclear which international registries on airway management in emergency medicine currently exist and how they are characterized concerning inclusion criteria, patient characteristics and definition of complications.

METHODS

A systematic literature research was carried out in PubMed with respect to publications from 2007-2017. All publications from airway registries collecting data on prehospital or emergency department (ED) airway management were included. Publications from pediatric intensive care units (PICU) were also included as long as they were the primary place of pediatric emergency care.

RESULTS

A total of eleven emergency airway registries (EAR) were identified that were primarily concerned with airway management. Furthermore, reported data on emergency airway management were extracted from different, national resuscitation registries. There was only one multinational EAR which exclusively collects data on pediatric emergency airway management (NEAR4KIDS, National Emergency Airway Registry for Kids). Additionally, all emergency department airway registries identified include data on pediatric emergency airway management to varying degrees (0.2-10.5%). Published observation periods were also highly variable with a minimum of 18 months and a maximum of 156 months. The ANZEDAR (Australia and New Zealand Emergency Airway Registry) is currently the largest EAR with data from 43 participating institutions in 2 different countries, while the NEAR III (National Emergency Airway Registry) includes data on 21,374 emergency intubations over a 10-year period and thus has the largest number of emergency interventions. Reported rapid sequence induction (RSI) rates in the registries are between 27.5% and 100%. First-pass success rates vary between 69% and 89%, while the reported use of video laryngoscopy is 0-73%.

CONCLUSION

This study identified eleven EARs that sometimes widely differed concerning inclusion periods, inclusion criteria, definition of complications and application of newer methods of emergency airway management. Thus, comparability of the reported results and first-pass success rates is only possible to a limited extent. The authors therefore advocate the initiation of an airway registry in emergency medicine in German-speaking countries.

The novel video-assisted intubating laryngeal mask Totaltrack compared to the intubating laryngeal mask Fastrach - a controlled randomized manikin study

BACKGROUND

The novel Totaltrack combines a supraglottic airway device with video laryngoscopic tracheal intubation. The intubation laryngeal mask Fastrach is an established device without visual control of intubation. We hypothesized that supraglottic ventilation success with Totaltrack would be similar to Fastrach, but intubation would be performed faster due to visual control of the procedure.

METHODS

Fifty-five anaesthesiologists were randomized into one of two study arms: Fastrach Totaltrack. After a standardized introduction, six consecutive attempts of supraglottic ventilation and intubation attempts with each of one of the devices were performed on an airway manikin. The combined primary outcome was: time to supraglottic ventilation and time to ventilation after intubation. Additionally, success rate and learning curves were evaluated.

RESULTS

Supraglottic time to ventilation was shorter when using the Fastrach compared to the Totaltrack (median: 7.8 s [confidence interval [CI]: 7.0-8.6 s] vs. 11 s [CI: 7.8-14.2 s], P < 0.001). Intubation was faster using the Fastrach compared to Totaltrack (median: 12.5 s, [CI: 10.1-14.9 s] vs. 23.3 s [CI: 21.5-25.1 s], P < 0.001). Success rate for supraglottic ventilation was comparable between Fastrach and Totaltrack (86-96%). Successful intubation via the device was 100% in Fastrach and ranged from 61% to 93% in Totaltrack, with a higher probability of successful intubation after four applications.

CONCLUSION

In this manikin-based study the novel Totaltrack did not prove superior to Fastrach despite a similar design. Video laryngoscopic control of supraglottic ventilation and endotracheal intubation was prolonged using the Totaltrack. Clinical trials are mandatory to evaluate the role of the Totaltrack in airway management.

Layperson mouth-to-mask ventilation using a modified I-gel laryngeal mask after brief onsite instruction: a manikin-based feasibility trial

OBJECTIVE

The intention of this manikin-based trial was to evaluate whether laypersons are able to operate an I-gel laryngeal mask (I-gel) modified for mouth-to-mask ventilation after receiving brief on-site instruction.

SETTING

Entrance hall of a university hospital and the city campus of a public technical university, using a protected manikin scenario.

METHODS

Laypersons were handed a labelled, mouthpiece-integrated I-gel laryngeal mask and a corresponding instruction chart and were asked to follow the printed instructions.

OUTCOME MEASURES

The overall process was analysed and evaluated according to quality and duration.

RESULTS

Data from 100 participants were analysed. Overall, 79% of participants were able to effectively ventilate the manikin, 90% placed the laryngeal mask with the correct turn and direction, 19% did not position the mask deep enough and 85% believed that their inhibition threshold for performing resuscitation was lowered. A significant reduction in reluctance before and after the trial was found (p<0.0001). A total of 35% of participants had concerns about applying first aid in an emergency. Former basic life support (BLS) training significantly reduced the time of insertion (19.6 s, 95% CI 17.8 to 21.5, p=0.0004) and increased overall success (p=0.0096).

CONCLUSIONS

Laypersons were able to manage mouth-to-mask ventilation in the manikin with a reasonable success rate after receiving brief chart-based on-site instructions using a labelled I-gel mask. Positioning the mask deep enough and identifying whether the manikin was successfully ventilated were the main problems observed. A significant reduction in reluctance towards initialising BLS by using a modified supraglottic airway device (SAD) may lead to better acceptance of bystander resuscitation in laypersons, supporting the introduction of SADs into BLS courses and the stocking of SADs in units with public automatic external defibrillators.

Effect of the laryngeal tube on the no-flow-time in a simulated two rescuer basic life support setting with inexperienced users

INTRODUCTION

Intubation with a laryngeal tube (LT) is a recommended alternative to endotracheal intubation during advanced life support (ALS). LT insertion is easy; therefore, it may also be an alternative to bag-mask ventilation (BMV) for untrained personnel performing basic life support (BLS). Data from manikin studies support the influence of LT on no-flow-time (NFT) during ALS.

METHODS

We performed a prospective, randomized manikin study using a two-rescuer model to compare the effects of ventilation using a LT and BMV on NFT during BLS. Participants were trained in BMV and were inexperienced in the use of a LT.

RESULTS

There was no significant difference in total NFT with the use of a LT and BMV (LT: mean 83.1 ± 37.3 s; BMV: mean 78.7 ± 24.5 s; p = 0.313), but we found significant differences in the progression of the scenario: in the BLS-scenario, the proportion of time spent performing chest compressions was higher when BMV was used compared to when a LT was used. The quality of chest compressions and the ventilation rate did not differ significantly between the two groups. The mean tidal volume and mean minute volume were significantly larger with the use of a LT compared with the use of BMV.

CONCLUSIONS

In conclusion, in a two-rescuer BLS scenario, NFT is longer with the use of a LT (without prior training) than with the use of BMV (with prior training). The probable reasons for this result are higher tidal volumes with the use of a LT leading to longer interruptions without chest compressions.

The novel intubating laryngeal tube (iLTS-D) is comparable to the intubating laryngeal mask (Fastrach) - a prospective randomised manikin study

Background

Supraglottic devices are helpful for inexperienced providers who perform ventilation in emergency situations. Most supraglottic devices do not allow secondary tracheal intubation through the device. The novel intubating laryngeal tube (iLTS-D®) and the intubating laryngeal mask (Fastrach™) are devices that offer supraglottic ventilation and secondary tracheal intubation.

Methods

We evaluated the novel iLTS-D and compared it to the established Fastrach using a manikin-based study. Participants used both devices in a randomised order. The participants conducted four consecutive trials on a manikin. One trial was composed of the following procedures. First, participants ventilated the manikin using either iLTS-D or Fastrach. ‘Time to ventilation’, success rates and number of attempts were recorded for the supraglottic device. Second, participants intubated the manikin through the previously inserted supraglottic device. ‘Time to tracheal ventilation’, success rate and tube localisation were recorded. The primary endpoint was the results of the final fourth trial, which mirrored the standardised training of trials 1, 2 and 3.

Results

A total of 64 participants were enrolled. All of the participants successfully inserted both devices on their first attempt in trial 4. Fastrach was applied 1 s faster in trial 4 than the iLTS-D (median ‘time to ventilation’ Fastrach: 13.5 s., iLTS-D: 14.5 s., p = 0.04). All participants successfully intubated through both devices in trial 4. There was no difference in ‘time to tracheal ventilation’ by tracheal intubation between either device (median ‘time to tracheal ventilation’: Fastrach: 14.0 s., iLTS-D: 14.0 s., p = 0.16).

Conclusion

The iLTS-D performed similarly to the ILMA in insertion and intubation times in a manikin setting.

Laryngeal mask, laryngeal tube, and Frova introducer in simulated difficult airway

BACKGROUND

The use of supraglottic devices is rising in the prehospital management of difficult airway; moreover, we think that patients with multiple trauma or cervical instability can take advantage of these devices without opening or retiring the cervical collar.

OBJECTIVE

To compare speed and ease of use between Laryngeal Tube S (LTS) and the Ambu AuraOnce laryngeal mask (LMA).Our second objective was to evaluate changing these devices to an endotracheal tube (ETT) using a Frova introducer.

METHODS

We studied the use of LTS and LMA in an experimental model, represented by a manikin with a rigid cervical collar and a limited mouth opening. This study was carried out in Complutense University of Madrid with 145 2(nd)-year students for the degree in Dentistry who have knowledge of the airway but lack experience in intubation. Number of attempts and time for the device's insertion were measured, as well as time for the exchange maneuver using the Frova introducer.

RESULTS

Insertion of all devices was possible on the first attempt; time for insertion was LTS 12.2 ± 1.28 s and LMA 6.87 ± 0.97 s. Once these devices were inserted, a Frova introducer is used to perform an exchange by an endotracheal tube; all devices could be exchanged on the first attempt, and exchange time was LTS 26.9 ± 1.2 s and LMA 16.79 ± 1.32 s. Results for both time for insertion and exchange of the LMA were significantly lower than those for the LTS (p < 0.001).

CONCLUSION

The method used can be considered quick and easy, even for personnel inexperienced in intubation. This exchange maneuver has not been described previously, so we can consider it as a new application of the Frova introducer.

Concluding results from the first phase of the Zurich Unexpected Difficult Airway course based on exercise of technical skills

We analysed the results of the first phase of the Zurich Unexpected Difficult Airway course. Two hundred and twenty-eight staff members performed a total of 2712 standardised airway rescue procedures with four airway devices: SensaScope™, LMA Fastrach™, Laryngeal Tube and needle cricothyrodotomy. Four consecutive attempts were performed using each device. We analysed the success rate and the time needed for successful completion for each attempt and device. The success rates and mean (SD) completion times for all participants were 96.2% and 30.2 (15.3) s for the SensaScope, 88.1% and 40.4 (17.2) s for the LMA Fastrach, 99.0% and 12.1 (10.6) s for the Laryngeal Tube and 99.0% and 12.3 (6.1) s for needle cricothyroidotomy. The learning curves resulting from the four consecutive attempts with each device showed a clear pattern of improvement. This institutional airway training course represents a promising method to improve the capability of practitioners to cope with unexpected difficult airway situations.

A randomised crossover comparison of manikin ventilation through Soft Seal®, i-gel™ and AuraOnce™ supraglottic airway devices by surf lifeguards

Forty surf lifeguards attempted to ventilate a manikin through one out of three supraglottic airways inserted in random order: the Portex® Soft Seal®; the Intersurgical® i-gel™; and the Ambu® AuraOnce™. We recorded the time to ventilate and the proportion of inflations that were successful, without and then with concurrent chest compressions. The mean (SD) time to ventilate with the Soft Seal, i-gel and AuraOnce was 35.2 (7.2)s, 15.6 (3.3)s and 35.1 (8.5) s, respectively, p < 0.0001. Concurrent chest compression prolonged the time to ventilate by 5.0 (1.3-8.1)%, p = 0.0072. The rate of successful ventilations through the Soft Seal (100%) was more than through the AuraOnce (92%), p < 0.0001, neither of which was different from the i-gel (97%). The mean (SD) tidal volumes through the Soft Seal, i-gel and AuraOnce were 0.65 (0.14) l, 0.50 (0.16) l and 0.39 (0.19) l, respectively. Most lifeguards (85%) preferred the i-gel. Ventilation through supraglottic airway devices may be considered for resuscitation by surf lifeguards.

Supreme Laryngeal Mask Airway achieves faster insertion times than Classic LMA during chest compressions in manikins

BACKGROUND

According to the 2010 European Resuscitation Council guidelines on cardiopulmonary resuscitation (CPR), one can appreciate that the classic laryngeal mask airway (CLMA) is acceptable as an alternative airway device to endotracheal intubation for airway management in cardiac arrest victims.

OBJECTIVE

To compare a relatively new supraglottic airway device, the Supreme Laryngeal Mask Airway (SLMA), with the CLMA in a cardiac arrest scenario.

METHODS

Fifty healthcare professionals inexperienced in advanced airway management attempted to insert both airway devices in a manikin in 2 scenarios: in the first, chest compressions were not performed (non-CPR scenario), and in the second, uninterrupted chest compressions were performed (CPR scenario). The primary end points were insertion time and success rate at first attempt. The level of self-confidence of each participant was recorded.

RESULTS

SLMA achieves faster insertion times both in the non-CPR (SLMA: 10.4 ± 2.7 seconds vs CLMA: 13.4 ± 3.2 seconds, P < .05) and in the CPR scenario (SLMA: 9.9 ± 2.0 seconds Vs CLMA: 11.9 ± 2.3 seconds, P < .05). The difference between first attempt success rates was not statistically significant both in the non-CPR (SLMA: 96% vs CLMA: 90%, P = .18) and in the CPR scenario (SLMA: 98% vs CLMA: 94%, P = .32). The participants are more self-confident using SLMA instead of CLMA (P < .001) and 94% of them would prefer SLMA for future use.

CONCLUSION

SLMA could be a useful alternative to CLMA during CPR in the hands of healthcare professionals with minimal experience in airway management.

Transfer of airway skills from manikin training to patient: success of ventilation with facemask or LMA-Supreme(TM) by medical students

During emergency care, the ability to ventilate the patient's lungs is a crucial skill. Supraglottic airway devices have an established role in emergency care, and manikin trials have shown that placement is easy even for inexperienced users. However, there is current discussion as to what extent these results can be transferred to patients. We studied the transfer of skills learnt on a manikin to the clinical situation in novice medical students during their anaesthesia rotation. They were required to ventilate the lungs of a manikin using a facemask and then position a supraglottic airway device (LMA-Supreme™) and ventilate the lungs. This process was then repeated on anaesthetised patients, with standard ventilator settings to assess adequacy of ventilation. Sixty-three students participated in the manikin study. The success rate for ventilating the lungs was 100% for both devices, but the mean (SD) time to achieve successful ventilation was 27.8 (24.4) s with the facemask compared with 38.6 (22.0) s with the LMA-Supreme (p = 0.008). Fifty-one of the students progressed to the second part of the study. In anaesthetised patients, the success rate for ventilating the lungs was lower for the facemask, 27/41 (66%) compared with the LMA-Supreme 37/41 (90%, p = 0.006). For 26 students who succeeded with both devices, the tidal volume was lower using the facemask, 431 (192) ml compared with the LMA-Supreme 751 (221) ml (p = 0.001), but the time to successful ventilation did not differ, 60.0 (26.2) s vs 57.3 (26.6) s (p = 0.71). We conclude that the results obtained in manikin studies cannot be transferred directly to the clinical situation and that guidelines should take this into account. Based on our findings, a supraglottic airway device may be preferable to a facemask as the first choice for inexperienced emergency caregivers.

Critical airway skills and procedures

Airway management is a critical procedure and essential skill necessary for all physicians working in the emergency department. Optimal resuscitative treatment of medical and trauma patients often revolves around timely and effective airway interventions that can be challenging in the acute setting, especially in critical patients. Time-honored airway techniques and procedures combined with recent advances in rapid sequence intubation, video laryngoscopy, and further advanced airway techniques now offer emergency clinicians a wide range of exciting new options for improving this crucial component of acute care and management.

Laryngeal tube use in out-of-hospital cardiac arrest by paramedics in Norway

Background

Although there are numerous supraglottic airway alternatives to endotracheal intubation, it remains unclear which airway technique is optimal for use in prehospital cardiac arrests. We evaluated the use of the laryngeal tube (LT) as an airway management tool among adult out-of-hospital cardiac arrest (OHCA) patients treated by our ambulance services in the Haukeland and Innlandet hospital districts.

Methods

Post-resuscitation forms and data concerning airway management in 347 adult OHCA victims were retrospectively assessed with regard to LT insertion success rates, ease and speed of insertion and insertion-related problems.

Results

A total of 402 insertions were performed on 347 OHCA patients. Overall, LT insertion was successful in 85.3% of the patients, with a 74.4% first-attempt success rate. In the minority of patients (n = 46, 13.3%), the LT insertion time exceeded 30 seconds. Insertion-related problems were recorded in 52.7% of the patients. Lack of respiratory sounds on auscultation (n = 100, 28.8%), problematic initial tube positioning (n = 85, 24.5%), air leakage (n = 61, 17.6%), vomitus/aspiration (n = 44, 12.7%), and tube dislocation (n = 17, 4.9%) were the most common problems reported. Insertion difficulty was graded and documented for 95.4% of the patients, with the majority of insertions assessed as being “Easy” (62.5%) or “Intermediate” (24.8%). Only 8.1% of the insertions were considered to be “Difficult”.

Conclusions

We found a high number of insertion related problems, indicating that supraglottic airway devices offering promising results in manikin studies may be less reliable in real-life resuscitations. Still, we consider the laryngeal tube to be an important alternative for airway management in prehospital cardiac arrest victims.

Does a 4 diagram manual enable laypersons to operate the Laryngeal Mask Supreme®? A pilot study in the manikin

Background

Bystander resuscitation plays an important role in lifesaving cardiopulmonary resuscitation (CPR). A significant reduction in the "no-flow-time", quantitatively better chest compressions and an improved quality of ventilation can be demonstrated during CPR using supraglottic airway devices (SADs). Previous studies have demonstrated the ability of inexperienced persons to operate SADs after brief instruction. The aim of this pilot study was to determine whether an instruction manual consisting of four diagrams enables laypersons to operate a Laryngeal Mask Supreme^® (LMAS) in the manikin.

Methods

An instruction manual of four illustrations with speech bubbles displaying the correct use of the LMAS was designed. Laypersons were handed a bag containing a LMAS, a bag mask valve device (BMV), a syringe prefilled with air and the instruction sheet, and were asked to perform and ventilate the manikin as displayed. Time to ventilation was recorded and degree of success evaluated.

Results

A total of 150 laypersons took part. Overall 145 participants (96.7%) inserted the LMAS in the manikin in the right direction. The device was inserted inverted or twisted in 13 (8.7%) attempts. Eight (5.3%) individuals recognized this and corrected the position. Within the first 2 minutes 119 (79.3%) applicants were able to insert the LMAS and provide tidal volumes greater than 150 ml (estimated dead space). Time to insertion and first ventilation was 83.2 ± 29 s. No significant difference related to previous BLS training (P = 0.85), technical education (P = 0.07) or gender could be demonstrated (P = 0.25).

Conclusion

In manikin laypersons could insert LMAS in the correct direction after onsite instruction by a simple manual with a high success rate. This indicates some basic procedural understanding and intellectual transfer in principle. Operating errors (n = 91) were frequently not recognized and corrected (n = 77). Improvements in labeling and the quality of instructional photographs may reduce individual error and may optimize understanding.