Influence of airway management strategy on “no-flow-time” in a standardized single rescuer manikin scenario (a comparison between LTS-D™ and I-gel)

A prospective observational study comparing two supraglottic airway devices in out-of-hospital cardiac arrest

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-021-00444-0.

Effect of endotracheal intubation and supraglottic airway device placement during cardiopulmonary resuscitation on carotid blood flow over resuscitation time: An experimental porcine cardiac arrest study

BACKGROUND

Supraglottic airway devices (SGDs) are widely used during the resuscitation of out-of-hospital cardiac arrest (OHCA). The effect of SGDs on carotid blood flow (CBF) as resuscitation time passes is controversial. We assessed the effects of endotracheal intubation (ETI) and 3 types of SGD placement on CBF over time in prolonged resuscitation through an experimental porcine cardiac arrest study.

METHODS

We conducted a randomized crossover study using 12 female pigs. After 4 min of untreated ventricular fibrillation, 3 pairs of ETI for 3 min and each type of SGD placement, including Combitube, I-gel, and laryngeal mask airway, for 3 min were conducted. The order of the 3 pairs of ETI and SGD were randomly assigned for each pig. We measured physiological parameters including CBF and mean arterial pressure (MAP). We compared CBF and MAP between the last 1 min of the insertion period for each of the 3 types of SGD and the preceding ETI period. Trends of CBF and MAP according to ETI and SGD transition were also plotted during the prolonged resuscitation duration.

RESULTS

CBF decreased after inserting I-gel and Combitube compared to ETI (mean difference (95% CI): -685 ml (-1052 to -318) for Combitube, -369 ml (-623 to -114) for I-gel). MAP subsequently decreased after transitioning airway devices as resuscitation was prolonged, regardless of the device type. The mean CBF during the transition from ETI to SGD decreased by -480 ml (95% CI: -675 to -286), but the decrease in CBF during the transition from SGD to ETI was only -4 ml (95% CI: -182 to 175).

CONCLUSION

SGD placement was associated with decreased carotid blood flow during cardiopulmonary resuscitation in an experimental porcine model. As time passed during prolonged resuscitation, reduction in CBF was aggravated after the transition to SGD placement compared to the reduction after the transition to ETI. This study was approved by the study institution IACUC 16-0140-S1A0.

Comparison of the UEScope videolaryngoscope with the Macintosh laryngoscope during simulated cardiopulmonary resuscitation: A randomized, cross-over, multi-center manikin study

BACKGROUND

Endotracheal intubation (ETI) can be challenging, especially in life-threatening situations such as cardiopulmonary resuscitation (CPR). Videolaryngoscopes aim to ease ETI, but effort is still widely discussed. This study intended to investigate 2 different airway devices regarding the success rate of ETI during ongoing chest compressions.

METHODS

This randomized, cross-over, multi-center manikin trial included 85 experienced paramedics actively working in the emergency medicine service. After a standardized training session, all paramedics underwent 3 airway scenarios using both, direct laryngoscopy using a Macintosh blade and videolaryngoscope (the UEScope): normal airway without chest compressions, normal airway with uninterrupted chest compressions, and difficult airway with uninterrupted chest compressions. The primary outcome was successful ETI, defined as successful placement of the endotracheal tube within the manikin's trachea. Secondary outcomes were number of intubation attempts, time to successful ETI, time to best glottis view, best percent of glottic opening, best glottic view score (Cormack and Lehane), occurrence of dental trauma, ease of use, and willing to reuse in real-life situations.

RESULTS

The UEScope provided a better glottis visualization, and higher first pass intubation success rate compared to direct laryngoscopy in all 3 scenarios. The overall intubation success was higher, and the intubation time was shorter with the UEScope in scenario B and scenario C, but was comparable in scenario A. Dental compression occurred less often using the UEScope and paramedics rated intubation using the UEScope easier compared to direct laryngoscopy in all 3 airway scenarios.

CONCLUSION

In simulated CPR scenarios, intubation with the UEScope resulted in a better glottis visualization, a higher intubation success, and a shorter intubation time compared to Macintosh laryngoscope (MAC). Moreover, in situations where the airway is difficult for ETI especially by the paramedic, the UEScope would be a better choice than the MAC. Further studies are needed to confirm these results in real-life patients.

Comparison of learning performance of 2 intubating laryngeal mask airways in novice: A randomized crossover manikin study

BACKGROUND

Intubating laryngeal mask airways (LMAs) such as i-gel and Aura-i could serve as rescue devices in resuscitation and further ensure the airway by facilitating trachea intubation without ventilation interruption. But data regarding intubating LMAs in novice are limited and skill degeneration without regular training has not been evaluated. So we designed this prospective randomized crossover manikin study to compare the learning performance of 2 intubating LMAs (i-gel and Aura-i).

METHODS

In total, 46 novice doctors participated in this study. After standardized training and finishing 3 consecutive successful intubations with both LMAs on manikin, each participant applied intubation with both LMAs in random order for initial evaluation. To evaluate skill retention, participants were reassessed 90 days later on the same manikin without retraining between times. Primary outcome was time to successful ventilation (TTV).

RESULTS

The TTV for i-gel was significantly shorter than Aura-i (initial evaluation 11.8 ± 2.9 seconds vs 22.4 ± 5.2 seconds, 90-days reevaluation 14.9 ± 3.6 seconds vs 28.9 ± 10.0 seconds, initial evaluation, P = .001; second evaluation, P < .001); during re-evaluation, TTV taken for i-gel and Aura-i were both significantly longer (initial evaluation, P = .001; second evaluation, P < .001) and ease score of insertion both increased profoundly (i-gel P = .025; Aura-i P < .001). In both assessments, participants preferred i-gel as easier alternative (initial evaluation, P = .001; second evaluation, P < .001). There was no difference in successful intubation rate, first attempt success rate, bronchoscopy assessment, and insertion score for 2 LMAs.

CONCLUSION

Compared with Aura-i, i-gel showed a faster and easier intubation by novice doctors in this manikin study; the skill retention of intubation performance after 3 months was acceptable for both intubating LMAs, but TTV prolonged significantly.

Comparison of the i-gel and other supraglottic airways in adult manikin studies: Systematic review and meta-analysis

BACKGROUND

The i-gel has a gel-like cuff composed of thermoplastic elastomer that does not require cuff inflation. As the elimination of cuff inflation may shorten insertion time, the i-gel might be a useful tool in emergency situations requiring prompt airway care. This systematic review and meta-analysis of previous adult manikin studies for inexperienced personnel was performed to compare the i-gel with other supraglottic airways.

METHODS

We searched PubMed, the Cochrane Library, and EMBASE for eligible randomized controlled trials (RCTs) published before June 2015, including with a crossover design, using the following search terms: "i-gel," "igel," "simulation," "manikin," "manikins," "mannequin," and "mannequins." The primary outcomes of this review were device insertion time and the first-attempt success rate of insertion.

RESULTS

A total of 14 RCTs were included. At the initial assessment without difficult circumstances, the i-gel had a significantly shorter insertion time than the LMA Classic, LMA Fastrach, LMA Proseal, LMA Unique, laryngeal tube, Combitube, and EasyTube. However, a faster insertion time of the i-gel was not observed in comparisons with the LMA Supreme, aura-i, and air-Q. In addition, the i-gel did not show the better results for the insertion success rate when compared to other devices.

CONCLUSION

The findings of this meta-analysis indicated that inexperienced volunteers placed the i-gel more rapidly than other supraglottic airways with the exception of the LMA Supreme, aura-i, and air-Q in manikin studies. However, the quicker insertion time is clinically not relevant. The unapparent advantage regarding the insertion success rate and the inherent limitations of the simulation setting indicated that additional evidence is necessary to confirm these advantages of the i-gel in an emergency setting.

The laryngeal tube - a helpful tool for cardiopulmonary resuscitation in the dental office?

BACKGROUND

Supraglottic airway adjuncts such as the laryngeal tube (LT) have been recommended to be used by cardiopulmonary resuscitation (CPR) first responders.Objective This study aims to evaluate the performance characteristics of dental students and dentists using the LT in comparison to a conventional bag valve mask device (BVM) within manikin CPR training.

METHOD

A group of eight dentists and 12 dental students performed randomised crossover CPR training using LT and BVM. Time intervals needed to perform five CPR cycles were recorded, as well as tidal and total gastric inflation volumes.

RESULTS

Median tidal volumes 0-1025 ml (median 462.5 ml) were observed using BVM and 100-500 ml (median 237.5 ml) with LT (p = 0.02). Total gastric inflation of 0-2900 ml was measured using BVM, no gastric inflation using LT (p = 0.0005). Time intervals needed to perform five CPR cycles did not differ between BVM (range 87.5-354.5 s, median 112 s) and LT (range 84.7-322.3 s, median 114 s) (p = 0.55). A median delay of 37.6 s (range 0-82.1 s) before starting CPR was observed using LT.

CONCLUSIONS

Lower tidal volumes but also lower or even no gastric inflation may be observed when dentists use a laryngeal tube during CPR. Respective training must focus on chest compressions. These must be started before inserting the LT or a different supraglottic airway adjunct and be delivered continuously during insertion. It is recommended to use a supraglottic airway such as an LT only after having been trained in its use.

Performance of intubation with 4 different airway devices by unskilled rescuers: manikin study

INTRODUCTION

This study was designed to compare the performances of 4 airway devices in achieving successful ventilation.

METHODS

A randomized crossover trial was conducted to evaluate 4 airway devices: laryngeal mask airway (LMA), i-gel (iGEL), PENTAX Airway Scope (AWS), and Macintosh laryngoscope (MCL). Thirty-eight unskilled rescuers performed intubation on a manikin during chest compressions in normal and difficult airway scenarios. The time to ventilation, intubation success rate, and difficulty of intubation were measured.

RESULTS

The time to ventilation of the airway devices in the normal scenario had a median value of 8.8 seconds (interquartile range, 7.3-10.5 seconds) for iGEL, 16.1 seconds (13.9-19.3 seconds) for LMA, 30.6 seconds (24.6-37.6 seconds) for AWS, and 35.0 seconds (29.5-45.9 seconds) for MCL. In the difficult airway scenario, the respective time to ventilation was 8.6 seconds (7.8-10.0 seconds), 15.3 seconds (14.3-20.2 seconds), 29.4 seconds (25.7-36.3 seconds) and 59.0 seconds (46.1-103.3 seconds). The success rates were 100% and 100% for LMA, 100% and 100% for iGEL, 97.4% and 94.7% for AWS, and 78.9% and 47.4% for MCL in the normal and difficult airway scenarios. The difficulties of intubation expressed as numerical rating scale were 2.0 and 2.0 (median values) for LMA, 1.0 and 2.0 for iGEL, 3.0 and 3.0 for AWS, and 4.0 and 5.0 for MCL in the normal and difficult airway scenarios, respectively.

CONCLUSION

With novice intubators who were unfamiliar with the airway devices, the LMA, iGEL, and AWS were superior to the MCL for establishing an airway without interruption of chest compressions in a manikin study. Intubation with the iGEL was faster and easier than with the other airway devices.

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.

Supraglottic airway device use as a primary airway during rapid sequence intubation

INTRODUCTION

This study compared first-attempt placement success rates of the King LTS-D as a primary airway for patients requiring medication-assisted airway management (MAAM) against historical controls.

SETTING

Rotor-wing division of a single critical care transportation company

METHODS

53 providers (RNs/EMT-P) consented to participation and were trained in the use of the King LTS-D. All patients in need of MAAM per agency treatment guidelines were screened for inclusion and exclusion criteria. After each placement attempt, providers completed data collection via telephone. The primary endpoint was comparison of first-attempt placement success rate between the King LTS-D and historical control endotracheal intubation (ETI) MAAM patients. Overall placement success, time to placement, pre- and post-placement SaO2, ETCO2 at 2 minutes after placement, and complications were also analyzed.

RESULTS

38 patients received rapid sequence intubation with the King LTS-D by 23 of 58 consented providers. First-attempt success rate was 76% (29/38), with an overall success rate of 84% (32/38). The primary endpoint analysis showed no difference in first-attempt success rate between historical control ETI MAAM data and King LTS-D (71% vs 76%; OR = 0.1.34 [95% CI Intubation time to insertion was 26 seconds (IQR = 12-46). Pre- and post-insertion SaO(1)2 values were 88.9 ± 12.6% and 92.1 ± 12.7%, respectively. Mean ETCO2 at 2 minutes after placement was 34.8 ± 4.0. Vomit in the patient's airway was the most frequently reported complication (46%).

CONCLUSION

Success rates with the King LTS-D were not significantly different from historical control ETI data. Time to placement was comparable to previous reports.

Performance of the i-gel™ during pre-hospital cardiopulmonary resuscitation

BACKGROUND

Current cardiopulmonary resuscitation (CPR) guidelines recommend airway management and ventilation whilst minimising interruptions to chest compressions. We have assessed i-gel™ use during CPR.

METHODS

In an observational study of i-gel™ use during CPR we assessed the ease of i-gel™ insertion, adequacy of ventilation, the presence of a leak during ventilation, and whether ventilation was possible without interrupting chest compressions.

RESULTS

We analysed i-gel™ insertion by paramedics (n=63) and emergency physicians (n=7) in 70 pre-hospital CPR attempts. There was a 90% first attempt insertion success rate, 7% on the second attempt, and 3% on the third attempt. Insertion was reported as easy in 80% (n=56), moderately difficult in 16% (n=11), and difficult in 4% (n=3). Providers reported no leak on ventilation in 80% (n=56), a moderate leak in 17% (n=12), and a major leak with no chest rise in 3% (n=2). There was a significant association between ease of insertion and the quality of the seal (r=0.99, p=0.02). The i-gel™ enabled continuous chest compressions without pauses for ventilation in 74% (n=52) of CPR attempts. There was no difference in the incidence of leaks on ventilation between patients having continuous chest compressions and patients who had pauses in chest compressions for ventilation (83% versus 72%, p=0.33, 95% CI [-0.1282, 0.4037]). Ventilation during CPR was adequate during 96% of all CPR attempts.

CONCLUSIONS

The i-gel™ is an easy supraglottic airway device to insert and enables adequate ventilation during CPR.

Evaluation of airway management associated hands-off time during cardiopulmonary resuscitation: a randomised manikin follow-up study

INTRODUCTION

Airway management is an important component of cardiopulmonary resuscitation (CPR). Recent guidelines recommend keeping any interruptions of chest compressions as short as possible and not lasting more than 10 seconds. Endotracheal intubation seems to be the ideal method for establishing a secure airway by experienced providers, but emergency medical technicians (EMT) often lack training and practice. For the EMTs supraglottic devices might serve as alternatives.

METHODS

40 EMTs were trained in a 1-hour standardised audio-visual lesson to handle six different airway devices including endotracheal intubation, Combitube, EasyTube, I-Gel, Laryngeal Mask Airway and Laryngeal tube. EMTs performances were evaluated immediately after a brief practical demonstration, as well as after 1 and 3 months without any practice in between, in a randomised order. Hands-off time was pair-wise compared between airway devices using a repeated-measures mixed-effects model.

RESULTS

Overall mean hands-off time was significantly (p<0.01) lower for Laryngeal tube (6.1s; confidence interval 5.2-6.9s), Combitube (7.9s; 95% CI 6.9-9.0s), EasyTube (8.8s; CI 7.3-10.3s), LMA (10.2s; CI 8.6-11.7s), and I-Gel (11.9s; CI 10.2-13.7s) compared to endotracheal intubation (39.4s; CI 34.0-44.9s). Hands-off time was within the recommended limit of 10s for Combitube, EasyTube and Laryngeal tube after 1 month and for all supraglottic devices after 3 months without any training, but far beyond recommended limits in all three evaluations for endotracheal intubation.

CONCLUSION

Using supraglottic airway devices, EMTs achieved a hands-off time within the recommended time limit of 10s, even after three months without any training or practice. Supraglottic airway devices are recommended tools for EMTs with lack of experience in advanced airway management.

Comparison of manually triggered ventilation and bag-valve-mask ventilation during cardiopulmonary resuscitation in a manikin model

BACKGROUND

To compare a novel, pressure-limited, flow adaptive ventilator that enables manual triggering of ventilations (MEDUMAT Easy CPR, Weinmann, Germany) with a bag-valve-mask (BVM) device during simulated cardiac arrest.

METHODS

Overall 74 third-year medical students received brief video instructions (BVM: 57s, ventilator: 126s), standardised theoretical instructions and practical training for both devices. Four days later, the students were randomised into 37 two-rescuer teams and were asked to perform 8min of cardiopulmonary resuscitation (CPR) on a manikin using either the ventilator or the BVM (randomisation list). Applied tidal volumes (V(T)), inspiratory times and hands-off times were recorded. Maximum airway pressures (P(max)) were measured with a sensor connected to the artificial lung. Questionnaires concerning levels of fatigue, stress and handling were evaluated. V(T), pressures and hands-off times were compared using t-tests, questionnaire data were analysed using the Wilcoxon test.

RESULTS

BVM vs. ventilator (mean±SD): the mean V(T) (408±164ml vs. 315±165ml, p=0.10) and the maximum V(T) did not differ, but the number of recorded V(T)<200ml differed (8.1±11.3 vs. 17.0±14.4 ventilations, p=0.04). P(max) did not differ, but inspiratory times (0.80±0.23s vs. 1.39±0.31s, p<0.001) and total hands-off times (133.5±17.8s vs. 162.0±11.1s, p<0.001) did. The estimated levels of fatigue and stress were comparable; however, the BVM was rated to be easier to use (p=0.03).

CONCLUSION

For the user group investigated here, this ventilator exhibits no advantages in the setting of simulated CPR and carries a risk of prolonged no-flow time.

Hands-off time during insertion of six airway devices during cardiopulmonary resuscitation: a randomised manikin trial

INTRODUCTION

Cardiopulmonary resuscitation (CPR) guidelines recommend limiting interruptions of chest compressions because prolonged hands-off (i.e., non-compression) time compromises tissue perfusion. 2010 European Resuscitation Council guidelines suggest that chest compressions should be paused less than 10 s during airway device insertion.

METHODS

With approval of the local ethics committee of the Medical University of Vienna and written informed consent, we recruited 40 voluntary emergency medical technicians, none of whom had advanced airway management experience. After a standardised audio-visual lecture and practical demonstration, technicians performed airway management with each six airway devices (endotracheal tube, Combitube, EasyTube, laryngeal tube, Laryngeal Mask Airway, and I-Gel) during on-going chest compressions in a randomised sequence on a Resusci Anne Advanced Simulator. Data were analysed using a mixed-effects model accounting for the repeated measurements and pair-wise comparisons among the airway devices.

RESULTS

The hands-off time associated with airway management using an endotracheal tube (including all intubation attempts) was 48 s (95% confidence interval: 43-53). The hands-off time for airway management using a laryngeal tube was 8.4 (3.4-16.4) s, Combitube 10.0 (4.9-15.1) s, EasyTube 11.4 (6.4-16.4) s, LMA 13.3 (8.2-18.3) s and for I-Gel 15.9 (10.8-20.9) s. Hands-off time was significantly longer with the conventional endotracheal tube than with any of the other airway systems. Only a third of the technicians successfully inserted an endotracheal tube whereas all of them successfully positioned each supraglottic device.

CONCLUSION

Supraglottic devices appear to be a reasonable emergency airway management strategy, even for inexperienced personnel.

Performance and skill retention of intubation by paramedics using seven different airway devices--a manikin study

INTRODUCTION

Endotracheal intubation (ETI) is the most widespread method for emergency airway management. Several studies reported that ETI requires considerable skill and experience and if performed incorrectly, may result in serious adverse events. Unrecognized tube misplacement or oesophageal intubation is associated with high prehospital morbidity. This study investigates the usability of supraglottic airway devices compared to ETI and the skill retention of 41 previously inexperienced paramedics following training using a manikin model.

METHODS

41 paramedics participated in this study. None had prior experience in airway management, apart from bag-valve ventilation. After a standardised audio-visual lecture lasting 45min, the paramedics participated in a practical demonstration using the advanced patient simulator SimMan(®) (Laerdal Medical, Stavanger, Norway). Afterwards, paramedics were instructed to perform airway-management using seven different techniques to secure the airway (ETI, Laryngeal mask unique [LMA], Proseal, Laryngeal tube disposable [LT-D(®)], I-Gel(®), Combitube(®), and EasyTube(®)) following a randomized sequence. Participants underwent reassessment after 3 months without any further training or practice in airway-management.

RESULTS

During the initial training session, ETI was successfully performed in 78% of cases, while 3 months later the success rate was 58%. For the supraglottic airway devices, five out of six were successfully used by all paramedics at both time points, the exception being Proseal(®). Our data show successful skill retention (success rate: 100%) after 3 months for five out of six supraglottic airway devices. Time to ventilation (T3) was significantly less for LMA, LT-D(®) and I-Gel(®) at all time points compared to ETI.

CONCLUSION

ETI performed by inexperienced paramedics is associated with a low success rate. In contrast, supraglottic airway devices like LMA, LT-D(®), I-Gel(®), Combitube(®) and EasyTube(®) are fast, safe and easy-to-use. Within the limitations of a manikin-study, this study suggests that inexperienced medical staff might benefit from using supraglottic airway devices for emergency airway management.