[Prehospital airway management of laryngeal tubes. Should the laryngeal tube S with gastric drain tube be preferred in emergency medicine?]

In-hospital mortality after prehospital endotracheal intubation versus alternative methods of airway management in trauma patients. A cohort study from the TraumaRegister DGU®

PURPOSE

Prehospital airway management in trauma is a key component of care and is associated with particular risks. Endotracheal intubation (ETI) is the gold standard, while extraglottic airway devices (EGAs) are recommended alternatives. There is limited evidence comparing their effectiveness. In this retrospective analysis from the TraumaRegister DGU®, we compared ETI with EGA in prehospital airway management regarding in-hospital mortality in patients with trauma.

METHODS

We included cases only from German hospitals with a minimum Abbreviated Injury Scale score ≥ 2 and age ≥ 16 years. All patients without prehospital airway protection were excluded. We performed a multivariate logistic regression to adjust with the outcome measure of hospital mortality.

RESULTS

We included n = 10,408 cases of whom 92.5% received ETI and 7.5% EGA. The mean injury severity score was higher in the ETI group (28.8 ± 14.2) than in the EGA group (26.3 ± 14.2), and in-hospital mortality was comparable: ETI 33.0%; EGA 30.7% (27.5 to 33.9). After conducting logistic regression, the odds ratio for mortality in the ETI group was 1.091 (0.87 to 1.37). The standardized mortality ratio was 1.04 (1.01 to 1.07) in the ETI group and 1.1 (1.02 to 1.26) in the EGA group.

CONCLUSIONS

There was no significant difference in mortality rates between the use of ETI or EGA, or the ratio of expected versus observed mortality when using ETI.

EMT-led laryngeal tube vs. face-mask ventilation during cardiopulmonary resuscitation - a multicenter prospective randomized trial

Background

Laryngeal tube (LT) application by rescue personnel as an alternate airway during the early stages of out-of-hospital cardiac arrest (OHCA) is still subject of debate. We evaluated ease of handling and efficacy of ventilation administered by emergency medical technicians (EMTs) using LT and bag-valve-mask (BVM) during cardiopulmonary resuscitation of patients with OHCA.

Methods

An open prospective randomized multicenter study was conducted at six emergency medical services centers over 18 months. Patients in OHCA initially resuscitated by EMTs were enrolled. Ease of handling (LT insertion, tight seal) and efficacy of ventilation (chest rises visibly, no air leak) with LT and BVM were subjectively assessed by EMTs during pre-study training and by the attending emergency physician on the scene. Outcome and frequency of complications were compared.

Results

Of 97 eligible patients, 78 were enrolled. During pre-study training EMTs rated efficacy of ventilation with LT higher than with BVM (66.7% vs. 36.2%, p = 0.022), but efficacy of on-site ventilation did not differ between the two groups (71.4% vs. 58.5%, p = 0.686). Frequency of complications (11.4% vs. 19.5%, p = 0.961) did not differ between the two groups.

Conclusions

EMTs preferred LT ventilation to BVM ventilation during pre-study training, but on-site there was no difference with regard to efficacy, ventilation safety, or outcome. The results indicate that LT ventilation by EMTs during OHCA is not superior to BVM and cannot substitute for BVM training. We assume that the main benefit of the LT is the provision of an alternative airway when BVM ventilation fails. Training in BVM ventilation remains paramount in EMT apprenticeship and cannot be substituted by LT ventilation.

Trial registration

ClinicalTrials.gov (NCT01718795).

Electronic supplementary material

The online version of this article (10.1186/s13049-017-0446-1) contains supplementary material, which is available to authorized users.

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.

Overinflation of the cuff and pressure on the neck reduce the preventive effect of supraglottic airways on pulmonary aspiration: an experimental study in human cadavers

BACKGROUND

The oesophageal leak pressure is defined as the pressure which breaks the seal between the cuff of a supraglottic airway and the peri-cuff mucosa, allowing penetration of fluid into the pharynx and the oral cavity. As a consequence, a decrease in this variable increases the risk of reflux and can lead to pulmonary aspiration. The aim of this study was to analyse the effects of cuff overinflation and pressure on the neck on the oesophageal leak pressure of seven supraglottic airways.

METHODS

Three laryngeal masks, two laryngeal tubes, and two oesophageal-tracheal tubes were tested in an experimental setting. In five human cadavers, we simulated a sudden increase in oesophageal pressure. To measure baseline values (control), we used an intracuff pressure as recommended by the manufacturer. The first intervention included overinflation of the cuff by applying twice the amount of pressure recommended. A second intervention was defined as external pressure on the neck.

RESULTS

The oesophageal leak pressure was decreased for laryngeal masks (control, 28 cm H2O; overinflation, 9 cm H2O; pressure on the neck, 8 cm H2O; P<0.01) and for laryngeal tubes (control, 68 cm H2O; overinflation, 37 cm H2O; pressure on the neck, 39 cm H2O; P<0.01) and was unaffected for oesophageal-tracheal tubes (control, 126 cm H2O; overinflation/pressure on the neck, 130 cm H2O; n.s.).

CONCLUSION

Cuff overinflation and pressure on the neck can enhance the risk of gastro-oesophageal reflux when using supraglottic airways. Therefore, both manoeuvres should be avoided in clinical practice.

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.

Difficult intubation and outcome after out-of-hospital cardiac arrest: a registry-based analysis

Background

Airway management during resuscitation attempts is pivotal for treating hypoxia, and endotracheal intubation is the standard procedure. This German Resuscitation Registry analysis investigates the influence of airway management on primary outcomes after out-of-hospital cardiac arrest, in a physician-based emergency system.

Methods

A total of 8512 patients recorded in the German Resuscitation Registry (2007–2011) were analyzed. The Return of Spontaneous Circulation After Cardiac Arrest (RACA) score was used to compare observed return of spontaneous circulation (ROSC) rates with the ROSC predicted by the score and to analyze factors influencing the primary outcome. Patients were classified into three groups: difficult intubation, impossible intubation, and a control group with normal airways.

Results

The observed ROSC matched the predicted ROSC in the group with difficult airways. The impossible intubation group had lower ROSC rates (31.3 % vs. 40.5 %; P < 0.05). Impossible intubation was more frequent in men (OR 2.28; 95 % CI, 1.43–3.63; P = 0.001), young patients (OR 2.18; 95 % CI, 1.26–3.76; P = 0.005) and those with trauma (OR 2.22; 95 % CI, 1.01–4.85; P = 0.046). Fewer impossible intubations were reported when the emergency physicians were anesthesiologists (OR 0.65; 95 % CI, 0.44–0.96; P = 0.028). If a supraglottic airway device was not used in the impossible intubation group, the observed ROSC (18.0 %; 95 % CI, 7.4–28.6 %) was poorer than predicted (38.2 %) (P < 0.05).

Conclusions

Outcomes after resuscitation attempts are poorer when endotracheal intubation is not possible. Predictive factors for impossible intubation are male gender, younger age, and trauma. Supraglottic airway devices should be used at an early stage whenever these negative factors are present.

Electronic supplementary material

The online version of this article (doi:10.1186/s13049-015-0124-0) contains supplementary material, which is available to authorized users.

Complications associated with the prehospital use of laryngeal tubes--a systematic analysis of risk factors and strategies for prevention

OBJECTIVE

With the increasing spread of laryngeal tubes (LT) in emergency medicine, complications and side-effects are observed. We sought to identify complications associated with the use of LTs in emergency medicine, and to develop strategies to prevent these incidents.

METHODS

In a prospective clinical study, all patients who had their airways managed in the field with a LT and who were admitted through the emergency department of the Frankfurt University Hospital during a 6 year period were evaluated using anonymised data collection sheets. A team of experts was available 24/7 and was requested whenever a patient was admitted with a LT in place. This team evaluated the condition of the patients with respect to prehospital airway management and was responsible for further advanced airway management. All complications were analysed, and strategies for prevention developed.

RESULTS

One hundred eighty nine patients were included and analysed. The initial cuff pressure of the LTs was 10 0 cm H₂O on the median. Complications consisted of significant tongue swelling (n=73; 38.6%), resulting in life-threatening cannot ventilate, cannot intubate scenarios in two patients (1.0%) and the need for surgical tracheostomy in another patient, massive distension of the stomach (n=20, 10.6%) with ventilation difficulties when LTs without gastric drainage were used; malposition of the LT in the piriform sinus (n=1, 0.5%) and significant bleeding from soft tissue injuries (n=4, 2.1%).

CONCLUSIONS

The prehospital use of LTs may result in severe and even life-threatening complications. Likely, such complications could have been prevented by using gastric drainage and cuff pressure adjustment. Both, prehospital health care providers and emergency department staff should develop a greater awareness of such complications to best avoid them in the future.

[Taking over a patient with preclinical laryngeal tube]

Endotracheal intubation (ETI) is the most effective method for securing the airway. However, the practice and theory of ETI differ considerably. There is a wide gap between reality and the optimum of quality and quantity required by many specialist organizations, e.g., the European Resuscitation Council. Alternative airway devices, such as a laryngeal tube, can be useful provided the hospital staff know how the device functions and how to avoid or control complications.

[Supraglottic airway devices in emergency medicine : impact of gastric drainage]

This case report describes a life-saving use of a supraglottic airway device (LT-D™-Larynxtubus, VBM Medizintechnik, Sulz, Germany) in an out-of-hospital emergency patient suffering from severe traumatic brain injury. Mechanical ventilation with the laryngeal tube was complicated by repeated airway obstructions and pronounced gastric distension with air as a consequence of oropharyngeal leakage. In this situation pulmonary ventilation of the patient was compromised so that emergency endotracheal intubation became necessary in the resuscitation area with vital indications. In this context the status of supraglottic airway devices in emergency medicine is discussed as well as the reasons for the gastric distension. Besides the immediate drastic consequences of gastric distension with respect to pulmonary ventilation, potential deleterious non-pulmonary consequences of this complication are highlighted. The clinical relevance of the described complications as well as the associated possibility of an optimized position control necessitate the recommendation only to use second generation supraglottic airway devices with integrated gastric access in (out-of-hospital) emergency medicine.

[Implementation of the laryngeal tube for prehospital airway management: training of 1,069 emergency physicians and paramedics]

OBJECTIVE

The European Resuscitation Council recommends that only rescuers experienced and well-trained in airway management should perform endotracheal intubation. Less trained rescuers should use alternative airway devices instead. Therefore, a concept to train almost 1,100 emergency physicians (EP) and emergency medical technicians (EMT) in prehospital airway management using the disposable laryngeal tube suction (LTS-D) is presented.

METHODS

In five operational areas of emergency medicine services in Germany and Switzerland all EPs and EMTs were trained in the use of the LTS-D by means of a standardized curriculum in the years 2006 and 2007. The main focus of the training was on different insertion techniques and LTS-D use in children and infants. Subsequently, all prehospital LTS-D applications from 2008 to 2010'were prospectively recorded.

RESULTS

None of the 762 participating EMTs and less than 20% of the EPs had previous clinical experience with the LTS-D. After the theoretical (practical) part of the training, the participants self-assessed their personal familiarity in using the LTS-D with a median value of 8 (8) and a range of 2-10 (range 1-10) of 10 points (1: worst, 10: best). Within the 3-year follow-up period the LTS-D was used in 303 prehospital cases of which 296 were successfully managed with the device. During the first year the LTS-D was used as primary airway in more than half of the cases, i.e. without previous attempts of endotracheal intubation. In the following years such cases decreased to 40% without reaching statistical significance. However, the mean number of intubation attempts which failed before the LTS-D was used as a rescue device decreased significantly during the study period (2008: 2.2 ± 0.3; 2009: 1.6 ± 0.4; 2010: 1.7 ± 0.3).

CONCLUSION

A standardized training concept enabled almost 1,100 rescuers to be trained in the use of an alternative airway device and to successfully implement the LTS-D into the prehospital airway management algorithm. Because the LTS-D recently became an accepted alternative to endotracheal intubation in difficult airway scenarios, the number of intubation attempts before considering an alternative airway device is steadily decreasing.

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

INTRODUCTION

Supraglottic airway devices have frequently been shown to facilitate airway management and are implemented in the ILCOR resuscitation algorithm. Limited data exists concerning laypersons without any medical or paramedical background. We hypothesized that even laymen would be able to operate supraglottic airway devices after a brief training session.

METHODS

Four different supraglottic airway devices: Laryngeal Mask Classic (LMA), Laryngeal Tube (LT), Intubating Laryngeal Mask (FT) and CobraPLA (Cobra) were tested in 141 volunteers recruited in a technical university cafeteria and in a shopping mall. All volunteers received a brief standardized training session. Primary endpoint was the time required to definitive insertion. In a short questionnaire applicants were asked to assess the devices and to answer some general questions about BLS.

RESULTS

The longest time to insertion was observed for Cobra (31.9 ± 27.9 s, range: 9-120, p < 0.0001; all means ± standard deviation). There was no significant difference between the insertion times of the other three devices. Fewest insertion attempts were needed for the FT (1.07 ± 0.26), followed by the LMA (1.23 ± 0.52, p > 0.05), the LT (1.36 ± 0.61, p < 0.05) and the Cobra (1.45 ± 0.7, p < 0.0001). Ventilation was achieved on the first attempt significantly more often with the FT (p < 0.001) compared to the other devices. Nearly 90% of the participants were in favor of implementing supraglottic airway devices in first aid algorithms and classes.

CONCLUSION

Laypersons are able to operate supraglottic airway devices in manikin with minimal instruction. Ventilation was achieved with all devices tested after a reasonable time and with a high success rate of > 95%. The use of supraglottic airway devices in first aid and BLS algorithms should be considered.

[Laryngeal tube II : alternative airway for children?]

Difficult airway situations both expected and unexpected, present major challenges to every anesthesiologist, especially in pediatric anesthesia. However, the integration of extraglottic airway devices, such as the laryngeal mask, into the algorithm of difficult airways has improved the handling of difficult airway situations. A device for establishing a supraglottic airway, the laryngeal tube (LT), was introduced in 1999. The LT is an extraglottic airway designed to secure a patent airway during either spontaneous breathing or controlled ventilation. The design of the device has been revised several times and a further development is the LTS II/LTS-D, which provides an additional channel for the insertion of a gastric drain tube. This article reports on the successful use of the LTS II in 12 children aged from 2 days to 6 years when endotracheal intubation, alternative mask or laryngeal mask ventilation failed. Use of the LTS II was associated with a high level of success, securing the airway when other techniques had failed. The potential advantage of the LTS II over the standard LT is an additional suction port, which allows gastric tube placement and can be used as an indirect indicator of correct placement. With a modified insertion technique using an Esmarch manoeuvre, placement was simple and fast to perform. In emergency situations when direct laryngoscopy fails or is too time-consuming the LTS II tube is recommended as an alternative device to secure the airway. As with all extraglottic airway devices, familiarity and clinical experience with the respective device and the corresponding insertion technique are essential for safe and successful use, especially in emergency situations.