Extraglottic Airway Research Articles

Chest Compression Fraction in Simulated Cardiac Arrest Management by Primary Care Paramedics: King Laryngeal Tube Airway Versus Basic Airway Management

Objective. The objective of this randomized simulation study was to determine whether use of the King laryngeal tube (KLT) airway resulted in differences in chest compression fraction (CCF) during simulated cardiac arrest managed by primary care paramedics (PCPs), as compared with basic airway management (bag–mask ventilation [BMV]). Methods. The KLT was introduced to all providers in our system at the time of study initiation. All participants received the same training, and were not aware that the primary outcome of the study was CCF. Standard airway management by PCPs prior to this was BMV. Pairs of PCPs were randomized to use KLT or BMV during a scripted 6-minute cardiac arrest scenario. The scenarios were videotaped, and data were abstracted by a single investigator. The CCF was calculated (fraction of time chest compressions were done/total scenario time). The CCF, number of seconds to first ventilation, and number of seconds to first compression were compared using the Mann-Whitney U test. Results. Sixty-seven pairs of PCPs participated: 30 in the KLT arm and 37 in the BMV arm. Demographics were similar in each group: KLT 68.3% males, BMV 55.4% males; KLT mean age 33.52 years (standard deviation [SD]: 11.95), BMV mean age 32.07 years (SD: 8.78); and KLT mean years of experience 9.03 (SD: 9.86), BMV mean years of experience 6.59 (SD: 6.58). The CCF was higher in the KLT group: median 0.82 (interquartile range [IQR] 0.71–0.88) compared with the BMV group: median 0.70 (IQR 0.66–0.73), p < 0.001. Time to first ventilation was longer in the KLT group: median 83.00 sec (IQR 43.75–139.25 sec) than in the BMV group: median 48.00 sec (IQR 37.00–71.00 sec), p = 0.004. Times to first compression were similar: KLT median 13.00 sec (IQR 8.00–17.00 sec), BMV median 14.00 sec (IQR 11.00–18.50 sec), p = 0.331. Conclusion. In this randomized simulation study, KLT use by PCPs during simulated standard cardiac arrest scenarios was found to significantly increase CCF compared with basic airway management with BMV. Key words: emergency medical services; paramedics; airway; extraglottic airway device; cardiac arrest

Use of extraglottic airways in patients undergoing ambulatory laparoscopic surgery without the need for tracheal intubation

Background:Second generation extraglottic airway devices with gastric access and separate breathing channels have ushered in a new era where their use is increasingly prevalent in surgical patients who would have been traditionally intubated for general anesthesia. New innovations like the i-gel, which is constructed of a thermoplastic elastomer, provide an airtight seal around patient's perilaryngeal anatomy without the inflatable cuff mechanism found in the laryngeal mask airway supreme (LMAS).Methods:We conducted a randomized controlled trial comparing the LMAS with the i-gel in 70 anesthetized paralyzed patients undergoing laparoscopic female sterilization. Our primary outcome measure was the oropharyngeal leak pressure (OLP). We studied secondary outcomes of successful first attempt insertion rates, time and ease of the airway and gastric tube insertion, leak fractions and pharyngeal morbidity.Results:We found no difference in the OLP between LMAS and i-gel, 25.9 (4.2) versus 24.4 (4.3) s, P=0.153. Both devices had similar first attempt insertion rates (LMAS 94% vs. i-gel 91%) with similar ease and comparable times to achieve an effective airway, LMAS 14.7 (2.7) versus i-gel 16.5 (9.6) s, P=0.306, although gastric tube insertion was easier and faster for the LMAS, 7.9 (1.9) versus i-gel 14.8 (7.7) s, P<0.005. Intraoperatively, there was a significantly greater leak fraction with the i-gel of 0.06 (0.03) versus 0.04 (0.02) with the LMAS, P=0.013. Three patients (8.6%) with LMAS had mild sore throat; one patient (2.9%) had mucosal injury. No complications were documented in the i-gel group.Conclusions:Both these extraglottic airway devices offer similar OLPs, high insertion success rates at the first attempt with similar ease and insertion times (albeit longer gastric tube insertion with i-gel). Both provided effective ventilation despite a higher leak fraction with i-gel that was clinically inconsequential.

Magnetic resonance imaging study of the in vivo position of the extraglottic airway devices i-gel™ and LMA-Supreme™ in anaesthetized human volunteers

Exact information on the anatomical in situ position of extraglottic airway (EGA) devices is lacking. We used magnetic resonance imaging (MRI) to visualize the positions of the i-gel™ and the LMA-Supreme™ (LMA-S) relative to skeletal and soft-tissue structures. Twelve volunteers participated in this randomized, prospective, cross-over study. Native MRI scans were performed before induction of anaesthesia. Anaesthesia was induced, and the two EGAs were inserted in a randomized sequence. Their positions were assessed functionally, optically by fibrescope, and with MRI scans of the head and neck. The LMA-S protruded deeper into the upper oesophageal sphincter than the i-gel™ (P<0.001). Both devices reduced the area of the glottic aperture (P<0.001), and the LMA-S had the largest effect (P=0.049). The i-gel™ significantly compressed the tongue (P<0.001). Both devices displaced the hyoid bone ventrally (P<0.001); the i-gel™ to a greater degree (P=0.029). The fibreoptically determined position of the bowl of the devices was identical. The LMA-S and i-gel™ differ significantly with regard to in situ position and spatial relationship with adjacent structures assessed by MRI, despite similar clinical and fibreoptical findings. This could be relevant with regard to risk of aspiration, glottic narrowing, and airway resistance and soft-tissue morbidity.

The LMA‐SupremeTM as an intubation conduit in patients with known difficult airways: a prospective evaluation study

Many extraglottic airway devices allow the direct passage of an adult-sized tracheal tube, but this is not possible with the LMA-Supreme(TM) . We evaluated the feasibility of using the LMA-Supreme(TM) as a conduit for intubation in patients with known difficult airways. Sixty-eight adult patients, with preoperative predictors of difficult intubation, were scheduled for elective surgery under general anaesthesia. After assessing the direct laryngoscopy view, 23 patients with Cormack-Lehane III/IV were included in the study. An LMA-Supreme(TM) was inserted, followed by the passage of a flexible bronchoscope loaded with an Aintree Intubation Catheter into the trachea. The bronchoscope and LMA-Supreme(TM) were removed, and a tracheal tube was railroaded over the Aintree Intubation Catheter into the trachea. Tracheal intubation was successful in all patients using the above technique. SpO(2) was >95% during the intubation procedure. We conclude that the LMA-Supreme(TM) is a successful conduit for bronchoscopic/Aintree Intubation Catheter-guided intubation in patients with known difficult airway.

Directly measured mucosal pressures produced by the i‐gelTM and laryngeal mask airway SupremeTM in paralysed anaesthetised patients

The i-gel™ and LMA Supreme™ are extraglottic airway devices with non-inflatable and inflatable cuffs, respectively. We hypothesised that directly measured mucosal pressures would differ between these devices in anesthetised paralysed patients. Thirty patients were randomly allocated to receive one of these two devices. Four pressure sensors were attached to all airway devices used to measure mucosal pressure at the base of the tongue, the distal oropharynx, the hypopharynx and the pyriform fossa. At these four places, median (IQR [range]) i-gel mucosal pressures were 8.0 (2.7-10.7 [0-26.7]), 5.0 (2.7-7 [1.0-37.3]), 9.3 (2.7-13.3 [0-22.7] and 8.0 (2.7-10.7 [0-25.3]) cmH(2)O, respectively, and for the LMA Supreme, these were 5.0 (0.5-8.0 [0-33]), 4.0 (1.3-9.3 [0-24]), 10.7 (4-17.3 [0-26.7]) and 8.0 (0-10.7 [0-36]) cmH(2)O, respectively. Mucosal pressures were low and similar for both devices. The LMA Supreme mucosal pressures were higher in the hypopharynx than in the distal oropharynx (p = 0.04) and base of the tongue (p = 0.011). There were no pressure differences between the locations for the i-gel.

Anesthesia Patient Safety Foundation

In Brief The development of the laryngeal mask airway in 1981 was an important first step toward widespread use and acceptance of the extraglottic airway (EGA). The term extraglottic is used in this review to encompass those airways that do not violate the larynx, in addition to those with a supraglottic position. Although the term extraglottic may be broad and include airways such as tracheostomy tubes, the term supraglottic does not describe a large number of devices with subglottic components and is too narrow for a discussion of modern devices. EGAs have flourished in practice, and now a wide variety of devices are available for an ever-expanding array of applications. In this review we attempt to clarify the current state of EGA devices new and old, and to illustrate their use in numerous settings. Particular attention is paid to the use of EGAs in special situations such as obstetric, pediatric, prehospital, and nontraditional “out of the operating room” settings. The role of the EGA in difficult airway management is discussed. EGA devices have saved countless lives because they facilitate ventilation when facemask ventilation and tracheal intubation were not possible. Traditionally, difficult airway management focused on successful tracheal intubation. The EGA has allowed a paradigm shift, changing the emphasis of difficult airway management from tracheal intubation to ventilation and oxygenation. EGA devices have proved to be useful adjuncts to tracheal intubation; in particular, the combination of EGA devices and fiberoptic guidance is a powerful technique for difficult airway management. Despite their utility, EGAs do have disadvantages. For example, they typically do not provide the same protection from pulmonary aspiration of regurgitated gastric material as a cuffed tracheal tube. The risk of aspiration of gastric contents persists despite advances in EGA design that have sought to address the issue. The association between excessive EGA cuff pressure and potential morbidity is becoming increasingly recognized. The widespread success and adoption of the EGA into clinical practice has revolutionized airway management and anesthetic care. Although the role of EGAs is well established, the user must know each device's particular strengths and limitations and understand that limited data are available for guidance until a new device has been well studied. Published ahead of print December 16, 2011

The Baska Mask® -A new concept in Self-sealing membrane cuff extraglottic airway devices, using a sump and two gastric drains: A critical evaluation

Background: In this study, we evaluated the performance of the Baska Mask® , a new extraglottic airway device (EAD) for use in anesthesia in adult patients undergoing a variety of surgical interventions. Materials and Methods: The self-recoiling membrane distally open cuff silicone mask consists of an anatomically curved airway tube with: (1) a bite block over the full length of the airway; (2) a self-sealing membranous variable-pressure cuff which adjusts to the contours of the mouth and pharynx; (3) a large sump cavity with two aspiratable gastric drain tubes; together with a number of special features such as (4) a tab for manually curving the mask to ease insertion; and (5) a suction elbow integral to one port with a second port acting as a free air flow access. The cuff of the Baska Mask® is not an inflatable balloon, but a membrane which inflates on every breath during intermittent positive pressure ventilation (IPPV) to achieve a superior seal when opposed to the larynx. An increase in IPPV pressure increases the oropharyngeal seal. With existing extraglottic airway devices, an increase in IPPV merely increases the leak. Results: Fifty patients with American Society of Anesthesiologists (ASA) physical status I-III were enrolled. We evaluated the first attempt and overall insertion success rates, insertion time, ease of insertion and removal of the device, oropharyngeal leak pressure, and anatomical position at fiberoptic view. The first attempt success rate was high (88%) and overall insertion success rates was considered easy to very easy by the operators in 92% of patients. Removal of the device was considered easy in all cases. The oropharyngeal leak pressure was above 30 cm H 2 O in all patients and the maximum of 40 cm H 2 O was achieved in 82% of the patients. In two patients, no adequate capnogram was obtained, so a smaller size mask was inserted with correction to adequate function. At fiberoptic evaluation of the anatomical position of the masks, the vocal cords could be seen, except in six patients (12%), where only the epiglottis could be visualized. Conclusion: The new EAD Baska Mask® has many novel features which should improve safety when used in both spontaneously breathing and IPPV anesthesia.

Evolution of the Extraglottic Airway

The development of the laryngeal mask airway in 1981 was an important first step toward widespread use and acceptance of the extraglottic airway (EGA). The term extraglottic is used in this review to encompass those airways that do not violate the larynx, in addition to those with a supraglottic position. Although the term extraglottic may be broad and include airways such as tracheostomy tubes, the term supraglottic does not describe a large number of devices with subglottic components and is too narrow for a discussion of modern devices. EGAs have flourished in practice, and now a wide variety of devices are available for an ever-expanding array of applications. In this review we attempt to clarify the current state of EGA devices new and old, and to illustrate their use in numerous settings. Particular attention is paid to the use of EGAs in special situations such as obstetric, pediatric, prehospital, and nontraditional "out of the operating room" settings. The role of the EGA in difficult airway management is discussed. EGA devices have saved countless lives because they facilitate ventilation when facemask ventilation and tracheal intubation were not possible. Traditionally, difficult airway management focused on successful tracheal intubation. The EGA has allowed a paradigm shift, changing the emphasis of difficult airway management from tracheal intubation to ventilation and oxygenation. EGA devices have proved to be useful adjuncts to tracheal intubation; in particular, the combination of EGA devices and fiberoptic guidance is a powerful technique for difficult airway management. Despite their utility, EGAs do have disadvantages. For example, they typically do not provide the same protection from pulmonary aspiration of regurgitated gastric material as a cuffed tracheal tube. The risk of aspiration of gastric contents persists despite advances in EGA design that have sought to address the issue. The association between excessive EGA cuff pressure and potential morbidity is becoming increasingly recognized. The widespread success and adoption of the EGA into clinical practice has revolutionized airway management and anesthetic care. Although the role of EGAs is well established, the user must know each device's particular strengths and limitations and understand that limited data are available for guidance until a new device has been well studied.

No contact of epiglottis with mask aperture bars of extraglottic airway devices: Prevention of occluding the airway questioned

No contact of epiglottis with mask aperture bars of extraglottic airway devices: Prevention of occluding the airway questioned

The Emergency Airway: Noteworthy Airway Articles: From DSI to Extraglottic Airway Devices

The Emergency Airway: Noteworthy Airway Articles: From DSI to Extraglottic Airway Devices

Larynxtubus II

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 LTSII/LTS-D, which provides an additional channel for the insertion of a gastric drain tube. This article reports on the successful use of the LTSII in 12 children aged from 2 days to 6 years when endotracheal intubation, alternative mask or laryngeal mask ventilation failed. Use of the LTSII was associated with a high level of success, securing the airway when other techniques had failed. The potential advantage of the LTSII 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 LTSII 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.

Comparison of Three Extraglottic Airway Devices

Extraglottic airway devices (EGDs) are valuable tools for emergency medical services providers during cardiopulmonary resuscitation (CPR). Researchers

Colour coding: a must for extraglottic airway devices

We read with interest the recent letters highlighting the problems associated with ambiguous or inaccurate colour coding of gas cylinders [1, 2]. When correctly applied, colour coding plays an important role in avoiding mistakes due to human error [3], as critical information about the device is instantly available. Unfortunately, colour coding has only been introduced for gas cylinders [4], intravenous cannulas and needles [5].We consider that extraglottic airway devices should be added to this woefully short list.

Extraglottische Atemwegshilfen auf der Intensivstation

Extraglottic airway devices (EGA) are not only used in routine anaesthesia practice, they also have a distinct value for in-hospital and out-of-hospital difficult airway management. In the environment of the intensive care unit (ICU) EGA are not used on a regular basis. However, expertise and knowledge regarding EGA coming from the operating theatre or the out-of-hospital setting may also be of value for the ICU setting. This review presents the potential indications for EGA on the ICU for the management of difficult airway situations as well as during percutaneous tracheotomy. Furthermore, the possible advantages of EGA during postoperative recovery from anaesthesia as well as termination of controlled ventilation for intensive care patients are discussed.

Pilot Study of the Air-Q Intubating Laryngeal Airway in Clinical Use

The air-Q Intubating Laryngeal Airway (ILA) is a newly introduced extraglottic airway device. In this pilot study, we evaluated its use as a routine airway device during positive pressure ventilation. Ease of endotracheal intubation through the device was also assessed. Fifty-nine ASA I and II patients undergoing elective surgery received an air-Q ILA and an endotracheal tube where indicated. Insertion, ventilation and intubation characteristics were noted, as well as throat morbidity and occurrence of adverse events. An air-Q ILA was successfully inserted in 100% of patients. Mean leak pressure was 19 +/- 5 cmH2O. Endotracheal intubation was indicated in 19 patients and successful in 58% on the first attempt and 74% in total. Ten percent of the study patients were noted to have dysphagia. One patient was diagnosed with bilateral lingual nerve injury but made a complete recovery in four weeks. The air-Q ILA is an adequate extraglottic airway device in terms of insertion and ventilation. However the proposed advantage of ease of endotracheal intubation requires further investigation.

Rapid sequence airway vs rapid sequence intubation in a simulated trauma airway by flight crew

Background Rapid sequence airway (RSA) utilizes rapid sequence intubation (RSI) pharmacology followed by the placement of an extraglottic airway without direct laryngoscopy. Study objective To evaluate the difference in time to airway placement and lowest oxygen saturations in a simulated trauma patient using RSI or RSA with a Laryngeal Mask Airway—Supreme (LMAS). Methods This randomized, prospective, non-blinded, IRB-approved observational study used a SimMan ® human simulator in an ambulance. FC were randomly assigned to initially manage the patient with RSI or RSA. They then completed the same scenario with the other modality to serve as their own control. Trained assistants performed directed tasks. SimMan ® had an initial grade III view and desaturated along a standardized curve until intubation, LMAS, or bag-valve-mask ventilation (BVMV) was initiated. When BVMV was used, oxygen saturation increased along a standardized curve. The simulator's airway converted to a grade II view after the first attempt if difficult airway maneuvers were applied. Time, oxygen saturation, number of attempts and back-up airway placement were recorded. Results Nineteen FC completed both paired modalities. Paired T-test was used for statistical analysis. Average time to secure the airway was 145 s shorter in the RSA group (95% CI: 100.4–189.7). Lowest oxygen saturation was 4.8% higher (95% CI: 2.8–6.8) in the RSA group. During RSI, FC placed a back-up airway 47% of the time. Conclusion In a simulated moderately difficult trauma airway managed by FC, RSA results in a significantly shorter time to secure the airway and less hypoxemia compared to RSI.

Lingual Nerve Injury: a complication associated with the classic laryngeal mask airway?

Cranial nerve injuries are well-recognized complications of laryngoscopy and tracheal intubation and face mask ventilation. Recently, these have also been reported in association with extraglottic airway devices. Its diagnosis is clinical and it has a good prognosis, with resolution of the symptoms within a few weeks to months. The frequency of cranial nerve injuries can be reduced by avoiding insertion trauma, using appropriate sizes, minimizing cuff volume, and early identification and correction of malposition. We present a case of lingual nerve injury that was associated with use of the classic laryngeal mask airway during bilateral varicose vein stripping and perforator ligation under general, balanced anesthesia.

Gastro-oesophageal reflux disease (GORD)—To tube or not?

SummaryGastro-oesophageal reflux and aspiration in the general healthy population is a rare complication of anaesthesia. Gastro-oesophageal reflux disease (GORD) is a common disease with extremely variable severity. Airway management in this subset of patients with GORD is controversial. Increasing confidence of anaesthetists in the safety of extraglottic airways is leading to the expansion of their use into patients with a history of, or risk of gastro-oesophageal reflux without published trials supporting this practice. This practice is likely to be due to the possible risks and complications of endotracheal intubation.Disadvantages of extraglottic airway devices over endotracheal tubes include lack of airway protection against aspiration, difficulty in ventilation with malposition, air leak or decreased chest/lung compliance, and the risk of gastric aspiration as a result of high inspiratory pressures.The use of extraglottic airway devices in patients with GORD should be preceeded by a good history and examination, directed premedication, and limited to those patients that are controlled on medication with mild disease, short duration surgery with the continuous possibility of visualisation and access to the patient's airway, surgery in the supine position, and only by experienced users with directional extraglottic airway devices with separate gastrointestinal and airway tracts. Absolute indications for endotracheal intubation must be absent. The overriding principle of choosing the appropriate airway management device must be that the patient should not be compromised by the choice of airway device, and that the ultimate decision is more likely to benefit the patient than cause harm. If there is any doubt or hesitation with respect to this or possible regurgitation—endotracheal intubation is indicated and the endotracheal tube MUST be the airway of choice.

Students insert the laryngeal tube quicker and more often successful than the esophageal–tracheal combitube in a manikin

Background Endotracheal intubation remains the standard of airway management. Because intubation skills are difficult to acquire, for medical students teaching of easier to learn techniques should be considered. Methods We retrospectively analyzed data that were collected in a University teaching facility. 264 medical students were taught how to use laryngeal tube (LT) and Esophageal Tracheal Combitube ® (ETC) in a manikin. The students underwent one of two different types of extraglottic airway management training consisting of either long lecture (30 min) and intensive training (2 h) (group IT, n = 48), or brief (10 min) lecture and 20 min of training (group BT, n = 216). Both groups underwent a test 6 weeks after training, group IT had an additional test 24 h after training. Results After 24 h students in group IT were faster using the LT than the ETC (31.7 s ± 2.1 vs. 51.9 s ± 5.8, p < 0.001). Up to 6 weeks after training students were able to place the LT significantly faster than the ETC in both groups (26.5 s ± 2.1 vs. 53.9 s ± 5.8 group IT and 43.4 s ± 1.6 vs. 103.8 s ± 4.4 group BT, p < 0.001). At 24 h and 6 weeks following intensive training, there was no statistical difference in the time required for insertion of either device. Conclusion Following different training scenarios in a manikin, students were able to place the LT much faster than the ETC. Even brief training was sufficient to generate short insertion times for the LT.

Present-day prehospital airway management in the former Eastern German state of Thuringia: equipment and education of emergency physicians

We describe the condition of education and equipment regarding prehospital airway management in the German federal state of Thuringia, representing a part of former Eastern Germany. In 2006 a postal survey of the 39 emergency medical stations (EMS) in Thuringia was carried out. The response rate was 100%. In 72% of the EMS, a device for extraglottic airway management and in all EMS a device for cricothyrotomy was available. A device to monitor end-tidal CO2 was available in 41%. Difficulties in airway management in the past two years were reported from 74% of the EMS. Ongoing training and education in airway management is provided in 82% of the emergency districts. This survey reveals wide variations in the equipment for airway management available to prehospital emergency physicians in Thuringia. Given the reported difficulties in airway management, availability of a more standardized set of airway management devices in Thuringia may be helpful.