The intubating laryngeal mask. Clinical appraisal of ventilation and blind tracheal intubation in 110 patients

An Unusual Cause of Intubating Laryngeal Mask Obstruction Preventing Successful Intubation in the Emergency Department

BACKGROUND

The intubating laryngeal mask airway (ILMA) allows providers to blindly intubate through the device. We report a case of foreign material obstructing passage of an endotracheal tube (ET) through an ILMA.

CASE REPORT

A 45-year-old man with unknown past medical history was found obtunded with an apparent intentional drug and alcohol overdose, and required tracheal intubation. We opted to use an ILMA to optimize preoxygenation prior to intubation. His upper dentures were removed and an ILMA was inserted without complication; ventilation was easily performed. Blind tracheal intubation was attempted; the ET was inserted through the ILMA and was unable to be advanced past 15 cm despite multiple attempts, including repositioning the ILMA and rotating the ET. The ILMA was removed to prepare for video laryngoscopy. He was subsequently successfully intubated using a standard geometry video laryngoscope, which showed no anatomical abnormalities. After the case, the ILMA was inspected and the bowl of the ILMA was found to be occluded with denture adhesive. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case report demonstrates that it is possible that foreign material within the ILMA can make successful intubation impossible, despite successful placement and ventilation through the device. Maneuvers may be performed to attempt successful ET intubation, but when unsuccessful, removal of the ILMA and alternate airway management must be performed.

Clinical evaluation of Ambu® Aura-i™ - A new intubating laryngeal mask airway as an independent ventilatory device and a conduit for tracheal intubation in pediatric patients

Background:

Ambu® Aura-i™, a recently introduced second generation supraglottic airway device has been designed to function as an independent ventilatory device as well as a conduit for passage of conventional cuffed tracheal tubes through it. There is dearth of literature on experience of tracheal intubation through intubating laryngeal mask airway (ILMA) in paediatric age group. This study was conducted to study the ventilatory effectiveness and the intubating characteristics of Ambu® Aura-i™ in paediatric patients.

Aim:

To study the effectiveness of Ambu ® Aura-i ™ as a supraglottic device for its ventilatory effectiveness and intubation characteristics in paediatric patients.

Objectives:

To study the Ventilatory effectiveness of Ambu ® Aura-i ™ in terms of: 1) Time taken in insertion of Ambu ® Aura-i ™. 2) No of attempts made for successful insertion of Ambu ® Aura-i™. 3) Tidal volume attained on positive pressure ventilation. 4) Etco2, Spo2 and Leak pressure achieved. To study the Intubating characterstics of Ambu ® Aura-i ™ in terms of :- 1) Grade of alignment of the ventilating orifice achieved in relation to the larynx in the fibre optic view. 2) Time taken in intubation through Ambu ® Aura-i ™. 3) Number of attempts made in intubation. 4) Time taken for removal of the Ambu ® Aura-i ™ after intubation through it has been accomplished.

Method:

Sixty three children undergoing elective surgery under general anaesthesia requiring intubation of trachea, weighing between 5-30 kg were stratified into 3 groups (n= 21) each. Ambu® Aura-i™ size 1.5 , 2.0 ,2.5 were used based on their body weight for airway management. Ventilatory effectiveness was studied in terms of success rate, number of attempts made at insertion, time taken in insertion, tidal volume delivered and leak pressure achieved. Intubating characterstics studied during fibreoptic guided tracheal intubation included grade of alignment of the ventilating orifice achieved in relation to the larynx in fibre optic view, time taken in fibreoptic guided tracheal intubation, success rate and number of attempts made at intubation. Time taken in removal of the device and complications observed were also recorded.

Results:

Ambu® Aura-i™ insertion, fibreoptic guided tracheal intubation and device removal were successful in all the patients in first attempt. The mean time taken in successful device insertion was 10.83±2.04 sec. The mean tidal volume delivered was 7.88±1.33 ml/kg body weight and mean leak pressure achieved was 16.27±5.2 cm H2O. The fibreoptic guided intubation was possible in first attempt in 100% of the patients (n=63). The Fibre optic view was grade 1 in 82.55% patients (n=52 /63) and grade 2 in 17.46% (n=11/ 63) patients. The mean time taken in fibre optic guided intubation was 12.68 ±2.82 sec. The mean time taken in removal of the device over the tracheal tube was 12.27 sec. There was no significant incidence of trauma to soft tissues, sore throat, laryngospasm or hoarseness of voice.

Conclusion:

On the basis of observations of this study, we conclude that Ambu ® Aura-i ™ is not only an effective ventilatoy device, but also an excellent conduit for fibre optic guided intubation using conventional uncuffed endotracheal tube in paediatric patients. Ambu ® Aura-i ™ , is also valuable for establishing rapid airway access in emergent difficult paediatric airway.

Effectiveness of Intubating Laryngeal Mask Airway in managing out-of-hospital cardiac arrest by non-physicians

AIM OF THE STUDY

The role of supraglottic devices in airway management in out-of-hospital cardiac arrest (OHCA) remains controversial. The aim of this study was to evaluate the feasibility and effectiveness of intubation through the Intubating Laryngeal Mask Airway (ILMA) when used by prehospital emergency nurses in the setting of OHCA.

METHODS

We conducted a prospective, observational trial during 12 years by the Fire Department and prehospital emergency service of the health district of Strasbourg, France. The primary outcome was the success rate of ventilation after intubation through the ILMA, while the secondary outcomes were the success rate of ventilation after insertion of the ILMA and complications related to ILMA placement and intubation. Factors associated with successful intubation were also studied.

RESULTS

During the study period, 1464 ILMA placements were attempted by emergency nurses during OHCA. Ventilation was possible in 1250 patients (85.38%) after ILMA placement and in 1078 patients (73.63%) after intubation. Regurgitation of gastric contents occurred in 237 (16.18%) patients, mostly during basic life support. Two factors were predictive of a successful tracheal intubation: the performance of the Chandy maneuver OR = 2.91 (CI: 2.07-3.97) and the number of attempts at intubation OR = 1.95 (CI: 1.43-2.61). Conversely, the number of attempts at ILMA insertion was predictive of an intubation failure OR = 0.11 (CI: 0.07-0.17).

CONCLUSION

The success rate of intubation through the ILMA was high. After ILMA placement, ventilation was possible in 1250 patients (85.38%) and in 1078 patients (73.63%) after intubation.

Evaluation of Fastrach Laryngeal Mask Airway as an Alternative to Fiberoptic Bronchoscope to Manage Difficult Airway: A Comparative Study

INTRODUCTION

Awake intubation via Fiberoptic Bronchoscope (FB) is the gold standard for management of difficult airway but patients had to face problems like oxygen desaturation, tachycardia, hypertension and anxiety due to awake state. This study was conducted to assess feasibility of Fastrach Laryngeal Mask Airway (FLMA) to manage difficult airway as a conduit for intubation as well as for ventilation.

MATERIALS AND METHODS

After ethical approval and informed consent, 60 patients with difficult airway were randomly enrolled in FB group and FLMA group. In FB group, patients were sedated with midazolam/fentanyl. Airway anaesthetization of oropharynx was done with xylocaine spray and viscous and larynx and trachea by superior laryngeal nerve block and transtracheal block respectively. In FLMA group, initially patients were induced with propofol for FLMA insertion then succinylcholine was given for Tracheal Intubation (TI). The first TI attempt was done blindly via the FLMA and all subsequent attempts were performed with fiberoptic guidance. Haemodynamic monitoring was done during induction, intubation, immediately post insertion and there after at five minutes interval for 30 minutes.

RESULTS

All patients in the FLMA group were successfully ventilated (100%). In both the groups 28 (93.33%) patients were successfully intubated. However, first/second/third attempt intubation rate in FLMA vs FB group was 15 (50%) vs 13 (43.3%), 8 (26.66%) vs 10 (33.33%) and 5 (16.66%) in both groups respectively. Patients in the FLMA group were more satisfied with their method of TI and had lesser complications (p<0.05).

CONCLUSION

So the FLMA may be a better technique for management of patients with difficult airways.

Effect of head position on the success rate of blind intubation using intubating supraglottic airway devices

BACKGROUND

To evaluate the effect of head position on the performance of intubating supraglottic airway devices, we compared the success rate of blind intubation in the head-elevated and the pillowless head positions with the LMA Fastrach and the air-Q, and the change of glottic visualization through the air-Q.

METHODS

We assigned 193 patients to two groups according to the device used and subgrouped by head position used for intubation: Fastrach/pillowless, Fastrach/head-elevated, air-Q/pillowless, and air-Q/head-elevated. Blind intubation through the Fastrach or the air-Q was attempted up to twice after induction of general anesthesia. Before the attempt at blind intubation with the air-Q, the percentage of glottic opening (POGO) score was also fiberscopically evaluated at the outlet of the device in both head positions in a cross-over fashion.

RESULTS

The Fastrach significantly facilitated blind intubation compared with the air-Q in both the pillowless and head-elevated positions: 87.2% in Fastrach/pillowless vs 65.9% in air-Q/pillowless (P=.048), 90% in Fastrach/head-elevated vs 53.7% in air-Q/head-elevated (P<.001). The head-elevated position did not significantly affect the success rate of blind intubation for either device (P=.97 in Fastrach, P=.37 in air-Q). Although the head-elevated position significantly improved the POGO score from the median (10-90 percentile) 60% (0-100%) in the pillowless position to 80% (0-100%) (P=.008), it did not contribute to successful blind intubation with the air-Q.

CONCLUSION

Although the head-elevated position improved glottic visualization in the air-Q, the head position had minimal influence on the success rate of blind intubation with either the Fastrach or the air-Q.

Endotracheal intubation with intubating laryngeal mask airway (ILMA), C-Trach, and Cobra PLA in simulated cervical spine injury patients: a comparative study

PURPOSE

The aim of our study was to evaluate the success rate of fiberoptic-guided endotracheal intubation through an Intubating Laryngeal Mask Airway (ILMA), a Cobra Perilaryngeal Airway (Cobra PLA), and a C-Trach Laryngeal Mask Airway (C-Trach) in patients whose necks are stabilized in a hard cervical collar.

METHODS

One hundred and eighty ASA I-II patients were randomized to undergo endotracheal intubation after general anesthesia via an ILMA (group ILMA), a C-Trach (group C-Trach) or a Cobra PLA (group CPLA) with the application of an appropriately-sized hard cervical collar. A fiberoptic bronchoscope was used for intubation via the ILMA and Cobra PLA. Rate of successful insertion of an endotracheal tube through the three devices was the primary aim. Other parameters compared were time taken for device insertion, endotracheal intubation, hemodynamic changes, incidence of hypoxia, and mucosal injury during the procedure. The incidence of postoperative sore throat was also compared between the three groups.

RESULTS

The success rates of intubation in the ILMA, C-Trach, and CPLA groups were 100, 100, and 98% respectively. The first-attempt success rate was significantly better with the C-Trach compared to Cobra PLA (100 vs. 85%, p < 0.05). The time taken for device insertion was significantly more with the Cobra PLA as compared to that taken with an ILMA or a C-Trach (35.7 vs. 30.3 and 27.5 s, respectively). Intubation through a C-Trach took the least amount of time (84.4 s) as compared to an ILMA (117.9 s) or a Cobra PLA (139.2 s). The incidence of hypoxia and airway morbidity was similar between the groups.

CONCLUSION

The success rates of fiberoptic-guided endotracheal intubation through an ILMA and a Cobra PLA are similar to the success rate of intubation using a C-Trach in patients whose cervical spines are immobilized with a hard cervical collar.

Intraocular Pressure Changes Associated with Intubation with the Intubating Laryngeal Mask Airway Compared with Conventional Laryngoscopy

This open, prospective, randomised study was designed to evaluate the changes in intraocular pressure and haemodynamics after tracheal intubation using either the intubating laryngeal mask airway (ILMA) or direct laryngoscopy. Sixty adult patients, ASA physical status 1 or 2 with normal intraocular pressure were randomly allocated to one of the two techniques. Anaesthesia was induced with propofol followed by rocuronium. Tracheal intubation was performed using either the ILMA or Macintosh laryngoscope. Intraocular pressure, heart rate and blood pressure were measured immediately before and after tracheal intubation and then minutely for five minutes. In the laryngoscopy group there was a significant increase in intraocular pressure (from 7.2 ± 1.4 to 16.8 ± 5.3 mmHg, P <0.01), which did not return to pre-intubation levels within five minutes, and also in mean arterial pressure after tracheal intubation, which returned to baseline levels after five minutes. In the ILMA group there were no significant changes in intraocular pressure (from 7.6±1.8 to 10.4±2.8 mmHg, P >0.05) or mean arterial pressure after tracheal intubation. Time to successful intubation was longer with the ILMA, 56.8 ± 7.8 seconds, compared with the laryngoscopy group, 33±3.6 seconds (P <0.01). Mucosal trauma was more frequent with the ILMA (eight of 30) compared with the laryngoscopy group (three of 30) (P <0.01). The postoperative complications were comparable. In terms of minimising increases in intraocular pressure and blood pressure, we conclude that the ILMA has an advantage over direct laryngoscopy for tracheal intubation.

[Tracheal intubation through the intubating laryngeal mask airway training on manikin: comparison of single use and reusable devices from the same manufacturer]

INTRODUCTION

Recently, the French Society for Anaesthesia and Intensive Care (SFAR) has updated algorithms for difficult airway management, in which, the place of the intubating laryngeal mask (ILMA) is well defined. Moreover, in the guidelines, the SFAR recommended that the training for the different techniques for difficult intubation should initially be achieved on manikins. However, few data are available for disposable ILMA learning process on manikins.

STUDY DESIGN

To compare, on manikin, the learning curves of the disposable and reusable ILMA.

MATERIALS AND METHOD

Forty operators (anaesthesiologist, nurse, resident), experienced with conventional tracheal intubation but novice to commercially available ILMAs (Sebac, Pantin, France), underwent videotape learning and manikin training. After randomisation, each participant had to perform 10 timed consecutive tracheal intubations with either reusable or disposable ILMA. The learning curve was built according to the duration of successful procedure. Failure was considered if tracheal intubation could not be achieved or if the procedure lasted more than five minutes.

RESULTS

No difference was noted between the two groups in terms of learning curves, number and repartition of the failed attempts during the learning process.

CONCLUSION

This study shows that both disposable and reusable ILMA share similar learning process on manikins. Further studies are needed to evaluate the efficiency of the disposable ILMA in the clinical field of difficult intubation.

Comparison of the GlideScope video laryngoscope vs. the intubating laryngeal mask for females with normal airways

BACKGROUND AND OBJECTIVE

In this randomized clinical study, we compared the intubation success rates of the intubating laryngeal mask airway with the GlideScope in patients with normal airways. The primary hypothesis was that the intubating laryngeal mask airway was equally effective as the GlideScope in terms of successful intubation times.

METHODS

Sixty ASA I and II adult patients undergoing elective gynaecological surgery were randomly allocated into either the intubating laryngeal mask airway group or the GlideScope group. After a standard anaesthetic intravenous induction, orotracheal intubation was performed. Time taken for successful tracheal intubation, ease of device insertion, difficulty of tracheal intubation, manoeuvres needed to aid tracheal intubation, number of intubation attempts, haemodynamic changes every 2.5 min interval for 5 min and complications during tracheal intubation were recorded.

RESULTS

Time to successful intubation was longer (mean 68.4 s +/- 23.5 vs. 35.7 s +/- 10.7; P < 0.05), mean difficulty score was higher (mean 16.7 +/- 16.3 vs. 7.3 +/- 13.1; P < 0.05) and more intubation attempts were required in the intubating laryngeal mask airway group.

CONCLUSION

The GlideScope improved intubation time and difficulty score for tracheal intubation when compared with the intubating laryngeal mask airway in our patients. Blind intubation through the intubating laryngeal mask airway offers no advantages over the GlideScope in patients with normal airways. Despite its limitations, the intubating laryngeal mask airway is a valuable adjunct, especially in cases of difficult airway management when it can provide ventilation in between intubation attempts.

Tracheal intubation using the ILMA, C-TrachTM or McCoy laryngoscope in patients with simulated cervical spine injury

A study of 90 patients was undertaken to compare intubation success rates of using either ILMA, C-Trach or McCoy laryngoscope in patients with simulated cervical spine injury. Insertion and intubation success rates, time taken to achieve intubation, airway complications and haemodynamic parameters were recorded. Insertion of ILMA and C-Trach was successful at the first attempt in all patients. Intubation success rates were higher in the C-Trach (100%) and McCoy (100%) groups than in the ILMA (87%) group. Total intubation time was significantly longer in the ILMA (63 s, SD 36.5) group than in the C-Trach (41 s, SD 15.8) and McCoy (30 s, SD 7.4) groups (p < 0.05, p < 0.05, respectively). There were no significant differences in haemodynamic parameters among the groups at any time.

Intubating laryngeal mask for airway management in lateral decubitus state: comparative study of right and left lateral positions

BACKGROUND

The intubating laryngeal mask has been used for the emergency management of the airway in patients placed in the lateral decubitus position. We have conducted this prospective study to compare the feasibility of placement of an intubating laryngeal mask and blind tracheal intubation guided by the intubating laryngeal mask in patients placed in the right and the left lateral positions.

METHODS

A total of 82 adults of both sexes with normal airways, scheduled for cholecystectomy, were allocated randomly to be placed in either the right (n=41) or left (n=41) lateral position for the insertion of an intubating laryngeal mask and blind tracheal intubation guided by the intubating laryngeal mask under balanced general anaesthesia. A sequence of standard manoeuvres was performed after each failed attempt at intubating laryngeal mask placement and intubation.

RESULTS

The intubating laryngeal mask was placed in all patients at the first attempt. Ventilation of the lungs through the intubating laryngeal mask was possible in 40 patients (97.5%) from each group after the first attempt at insertion (P=1). Following adjustments, adequate ventilation could be achieved in all patients. The first attempt success rates of blind tracheal intubation were 85.3% (35/41) and 87.8% (36/41) in the right and left lateral groups, respectively (P=1). The remaining patients from both groups (except for one patient in the left lateral group who had a failed intubation) were intubated at the second attempt.

CONCLUSION

Insertion of the intubating laryngeal mask and blind tracheal intubation through it in the lateral position is feasible in patients with normal airways. These procedures have a high and comparable success rate when patients are placed in the right and left lateral positions.

Impact du grade de Cormack et Lehane sur l'utilisation du masque laryngé Fastrach™ : étude en chirurgie gynécologique

OBJECTIVE

To evaluate the impact of Cormack and Lehane grade on the Intubating Laryngeal Mask Airway (LMA-Fastrach) using in women.

STUDY DESIGN

Open prospective study.

PATIENTS

The study included 115 scheduled gynaecologic surgery women.

METHODS

An LMA-Fastrach was systematically performed in patients with a Cormack's grade > or =3 or when Arne's score was > or =7 whatever the Cormack. After induction of anaesthesia and neuromuscular blockade, Cormack's grade was assessed and LMA-Fastrach was inserted. Proper insertion was confirmed by the easiness of assisted ventilation and the normal aspect of the capnographic curve. Intubation through the LMA-Fastrach was carried out with the specific kit's endotracheal tube. More than two attempts were considered as a failure of the technique and an alternative method was performed. The following parameters were noted: age, weight, height, clinical predictors for difficult intubation (Arne et al.'s score), number of LMA-Fastrach insertion, ventilation efficiency through LMA-Fastrach, successful intubation with LMA-Fastrach and oesophageal intubation.

RESULTS

Ventilation through the LMA-Fastrach was efficient in 97%. The success rate of intubation was 94.8% (86% on the first attempt). The success rate of ventilation and intubation were not statistically different according to the different Cormack's grades. The obesity (BMI>30) did not change the success rate of ventilation and intubation through the LMA-Fastrach.

CONCLUSION

In women with either predicted or unpredicted difficult intubation, the success rates of ventilation and intubation through the LMA-Fastrach don't seem to be influenced by Cormack grade and obesity.

Stress response to tracheal intubation in patients undergoing coronary artery surgery: direct laryngoscopy versus an intubating laryngeal mask airway

OBJECTIVE

Stress response caused by endotracheal intubation may be harmful for the coronary or cerebral circulation of high-risk patients. This study evaluated the hypothesis that tracheal intubation via an intubating laryngeal mask airway is associated with less cardiovascular and endocrine stress response than the conventional technique using direct laryngoscopy.

DESIGN

Randomized, patient-blinded trial.

SETTING

University department (single center).

PARTICIPANTS

Eighty-six patients undergoing elective coronary artery surgery.

INTERVENTION

Tracheal intubation was performed via an intubating laryngeal mask or by conventional direct laryngoscopy after standardized induction of anesthesia.

MEASUREMENTS AND MAIN RESULTS

Electrocardiogram with automatic ST-segment analysis and invasive measured blood pressure were recorded continuously and blood samples to analyze norepinephrine plasma levels were taken at 4 times. Catecholamine concentrations and the pressure-rate product were analyzed by using an analysis of variance for repeated measures. In both groups, the pressure-rate product (p = 0.003) and norepinephrine concentrations (p < 0.0001) significantly decreased after induction of anesthesia. However, the fall was more marked in the patients intubated via the laryngeal mask (p = 0.031) than in patients receiving direct laryngoscopy. There were neither signs of cardiac ischemia nor major adverse events during induction of anesthesia.

CONCLUSIONS

Reduction of cardiovascular and endocrine stress response associated with endotracheal intubation is more pronounced when performed via the intubating laryngeal mask. Thus, this technique can be helpful in high-risk cardiac patients.

Difficult Airway Society guidelines for management of the unanticipated difficult intubation

Problems with tracheal intubation are infrequent but are the most common cause of anaesthetic death or brain damage. The clinical situation is not always managed well. The Difficult Airway Society (DAS) has developed guidelines for management of the unanticipated difficult tracheal intubation in the non-obstetric adult patient without upper airway obstruction. These guidelines have been developed by consensus and are based on evidence and experience. We have produced flow-charts for three scenarios: routine induction; rapid sequence induction; and failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed, anaesthetised patient. The flow-charts are simple, clear and definitive. They can be fully implemented only when the necessary equipment and training are available. The guidelines received overwhelming support from the membership of the DAS.

DISCLAIMER

It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.

Detection and Correction of Accidental Oesophageal Intubation during Flexible Lightwand-Guided Intubation via the Intubating Laryngeal Mask

In the following two-part study, we determined the efficacy of observation of the light glow to detect correct placement of the tracheal tube after lightwand-guided tracheal intubation via the intubating laryngeal mask (ILM). We also determined the efficacy of a protocol to correct oesophageal intubation in this situation. In study 1, 80 ASA 1–3, anaesthetized, paralysed patients were randomly assigned to have a tracheal tube, preloaded with a flexible lightwand, placed into either the trachea (n=40) or oesophagus (n=40) under laryngoscope guidance. A blinded observer experienced with the lightwand technique determined whether oesophageal or tracheal intubation had occurred by observation of the light glow. In study 2, 1000 patients, 400 of whom were included in a previous study, underwent flexible lightwand-guided intubation via the ILM. Placement of the tracheal tube in oesophagus or trachea was determined by observation of the glow and verified by capnography. Oesophageal intubation was corrected by adjusting the ILM position using a protocol comprising two adjusting manoeuvres. Observation, verification and correction were by experienced anaesthetists conducting the case. In study 1, oesophageal and tracheal intubation was correctly detected in 38/40 (95%) and 37/40 (92.5%) patients respectively. In study 2, oesophageal and tracheal intubation was correctly detected in 55/55 (100%) and 945/945 (100%) patients respectively. In 40/55 (73%) patients, tracheal intubation was successful at the second attempt and in 13/55 (24%) at the third or fourth attempt. In 2/55 (4%) patients, persistent oesophageal intubation occurred. The sensitivity, specificity and positive predictive value were 95%, 92.5% and 92.7% respectively in study 1, and were all 100% in study 2.

The intubating laryngeal-mask airway may be an ideal device for airway control in the rural trauma patient

A review of the literature on advanced airway management indicates that the intubating laryngeal-mask airway (ILMA) may be an ideal device for airway control in the rural trauma patient. The ILMA is an advanced laryngeal-mask airway designed to allow oxygenation of the unconscious patient as well as blind tracheal intubation with an endotracheal tube. The ILMA is an easy-to-use airway with a high success rate of insertion, and requires little training. For the rural physician managing a difficult airway in a trauma patient, the ILMA has been found to be reliable and successful when other techniques fail, such as fiberoptic intubation and direct laryngoscopy. The ILMA has also been reported to cause less hemodynamic change and less injury to the teeth and lips than direct laryngoscopy. Further, the ILMA was found to be easier and faster to use with a higher success rate than either the combitube or endotracheal tube for unskilled healthcare providers. Limitations and complications of the ILMA may include aspiration, esophageal intubation, damage to the larynx or other tissues during blind passage of a tracheal tube, and edema of the epiglottis.

Intubating laryngeal mask airway

The Intubating Laryngeal Mask Airway (ILMA) was introduced into clinical practice in 1997 following numerous clinical trials involving 1110 patients. The success rate of blind intubation via the device after two attempts is 88% in "routine" cases. Successful intubation in a variety of difficult airway scenarios, including awake intubation, has been described, with the overall success rate in the 377 patients reported being approximately 98%. The use of the ILMA by the novice operator has also been investigated with conflicting reports as to its suitability for emergency intubation in this setting. Blind versus visualized intubation techniques have also been investigated. These techniques may provide some benefits in improved safety and success rates, although the evidence is not definitive. The use of a visualizing technique is recommended, especially whilst experience with intubation via the ILMA is being gained. The risk of oesophageal intubation is reported as 5% and one death has been described secondary to the complications of oesophageal perforation during blind intubation. Morbidity described with the use of the ILMA includes sore throat, hoarse voice and epiglottic oedema. Haemodynamic changes associated with intubation via the ILMA are of minimal clinical consequence. The ILMA is a valuable adjunct to the airway management armamentarium, especially in cases of difficult airway management. Success with the device is more likely if the head of the patient is maintained in the neutral position, when the operator has practised at least 20 previous insertions and when the accompanying lubricated armoured tube is used.

Intubating laryngeal mask airway size selection: a randomized triple crossover study in paralyzed, anesthetized male and female adult patients

We determined the optimal size of intubating laryngeal mask airway (ILM) for ventilation and blind tracheal intubation in men and women. We also determined the distance the tracheal tube needs to protrude beyond the distal aperture to ensure that the cuff is through the vocal cords. Fifty male and 50 female anesthetized, paralyzed patients (ASA physical status I or II, aged 18-80 yr) were studied. Three operators (A, B, and C) were involved for the purposes of blinding. The size 3, 4, or 5 ILM was inserted into each patient in random order by Operator A, and the quality of ventilation was scored (adequate, suboptimal, or failed) by Operator B. The fiberoptic position (correct, too shallow, or too deep) and the distance between the distal aperture and the vocal cords was determined by Operator B. A single attempt at blind intubation was made by Operator C. Operators B and C were blinded to the size of the ILM. Operator C was also blinded to the information recorded by Operator B. All ILMs were inserted into the laryngopharynx at the first attempt. For men and women, the ventilation score was smaller for the Size 3 than the Size 4 or 5 (all: P < 0.002). For men, correct positioning was less common with the Size 3 than the Size 4 or 5 (both: P < 0.02). For women, correct positioning was similar among sizes. For men, tracheal intubation was successful less frequently with the Size 3 (84%) than the Size 4 (100%) or 5 (98%) (both: P < or = 0.01). For women, tracheal intubation success was similar among sizes (Size 3, 4, and 5: 86%, 96%, and 92%, respectively). Intubation was always successful if the ILM was correctly positioned and always failed if it was too shallow or deep. In both male and female patients, the distance between the distal aperture and the vocal cords increased with increasing ILM size (all: P < 0.04) and patient height (P < 0.0001) and was always longer for men (all: P < 0.0001). The overall mean distance (95% confidence interval) that the tracheal tube needed to protrude was 10-12 cm (8-13 cm) in men and 8-11 cm (8-12 cm) in women. We conclude that for men, the Size 4 and 5 ILMs are better than the Size 3 for ventilation and blind intubation. For women, the Size 4 and 5 ILMs are better than the Size 3 for ventilation, but there is no difference among sizes for blind intubation. The length the tracheal tube must protrude from the distal aperture to ensure that the cuff is completely through the vocal cords is 8-13 cm, depending on ILM size, the tracheal tube size, and the sex and height of the patient.

IMPLICATIONS

For men, the Size 4 and 5 intubating laryngeal mask airways are better than the Size 3 for ventilation and blind tracheal intubation. For women, the Size 4 and 5 are better than the Size 3 for ventilation, but there is no difference among sizes for blind intubation. The length the tracheal tube must protrude from the distal aperture of the intubating laryngeal mask airway to ensure that the cuff is completely through the vocal cords is 8-13 cm, depending on the size of the mask and tracheal tube and on the sex and height of the patient.

Difficult airway management in the emergency department

Most airway management in the emergency department is straightforward and readily accomplished by the emergency physician. The exact incidence of difficult intubations is difficult to discern from available evidence, but these are probably more frequent in the Emergency Department than in the operating room, given the urgent nature of the procedure and the lack of preparation of the patient population. A variety of adjuncts for airway management are available to assist in both intubation and ventilation. The utility of these adjuncts is detailed in this review, with emphasis on techniques most useful to the emergency physician.

Initial experience of emergency physicians using the intubating laryngeal mask airway: a case series

OBJECTIVE

Although the intubating laryngeal mask airway (ILMA) is widely available, its use by emergency physicians (EPs) has not been reported. The authors report the initial experience of EPs using the ILMA. A review of their experience and the relevant anesthesia literature provides a basis for EPs to use the ILMA more confidently and effectively.

METHODS

Between January 2000 and January 2001, the ILMA was used on a convenience sample of emergency department (ED) patients undergoing "routine" intubations, and "rescue" situations, after failed rapid-sequence intubation (RSI). Patients were identified from the ED resuscitation case database. Chart review and intubating physician interviews focused on success of the device, complications encountered, and "pearls" of the device's use as perceived by the intubating physician.

RESULTS

Ventilation with the appropriate-size ILMA occurred in less than 15 seconds in all "routine" intubations; tracheal intubation was subsequently accomplished in less than 1 minute. Eight of nine "routine" patients had blind tracheal intubation through the ILMA. One patient required fiberoptic bronchoscopy to guide the endotracheal tube into the trachea. Of the "rescue" intubations, all patients (n = 7) were successfully ventilated and five were successfully intubated using the ILMA.

CONCLUSIONS

In this case series, the ILMA was easy to use in acute resuscitations, and proved to be invaluable in cases of failed RSI.

The intubating laryngeal mask airway: suggestions for use in the emergency department

With the increased use of rapid-sequence induction and its potential complications, emergency physicians need a rescue device for unexpected difficult intubations. The intubating laryngeal mask airway (ILMA) is an ideal rescue airway since it can be placed quickly and can provide adequate ventilation in nearly all patients. It can then be used as conduit for endotracheal intubation, while ventilation is ongoing. The authors review the current literature on the ILMA. In conjunction with their experience using the ILMA in the emergency department (ED), a modification of the American Society of Anesthesiologists difficult airway algorithm was derived for use in the ED. The ILMA appears to be valuable for managing difficult airways.

Intubation through intubating laryngeal mask with and without a lightwand: a randomized comparison

The combined use of a lightwand and the intubating laryngeal mask airway (ILMA) was compared with the use of the ILMA alone to determine whether the combination was a more efficient method of endotracheal intubation. One hundred healthy patients were randomly assigned to two groups. After induction of anaesthesia, Group A patients were intubated blindly through the ILMA while in Group B, intubation was guided by a lightwand. A sequence of standard manoeuvres was followed it attempts at intubation failed. The number of manoeuvres used, the time taken for successful intubation and complications associated with intubation were recorded. Intubations were successful in all patients, but the mean endotracheal intubation time was longer in Group A than in Group B (38.3 +/- 10.4 s versus 26.4 +/- 9.1 s, P < 0.001). The number of patients who needed one or more manoeuvres was significantly higher in Group A than in Group B (76% versus 42%, P = 0.001). We conclude that the lightwand is a useful adjunct in endotracheal intubation through an ILMA.

The laryngeal mask airway: a comprehensive review for the Emergency Physician

The Laryngeal Mask Airway (LMA) was developed in the 1980s, but has only recently begun to be used in Emergency Medicine. The LMA affords effective assisted ventilation without requiring endotracheal intubation or visualization of the glottis. In doing so, it is more efficacious than a bag-valve-mask apparatus, although the risk of aspiration of gastric contents persists, particularly if the device is not properly placed. The LMA also has significant potential utility in management of the difficult airway. Most reported clinical experience with the LMA has come from the operating room. This article provides an overview of the extensive potential utility of the LMA in the Emergency Department and prehospital settings as well as a comprehensive review of the pertinent advantages, disadvantages, and complications associated with its use.

A comparative study of tracheal intubation using an intubating laryngeal mask (Fastrach) alone or together with a lightwand (Trachlight)

STUDY OBJECTIVE

To determine if the Trachlight lightwand can facilitate Fastrach intubation by guiding the tip of the endotracheal tube into the trachea.

DESIGN

Open-label, prospective, randomized, comparative study.

SETTING

General operating suites of a tertiary teaching hospital.

PATIENTS

172 elective surgical patients requiring general anesthesia with endotracheal intubation.

INTERVENTIONS

With general anesthesia, the Fastrach, which is a new intubating laryngeal mask airway, was inserted into the oropharynx. Ventilation was ensured before the insertion of an endotracheal tube via the Fastrach. Tracheal intubation was then performed randomly (coin toss) using either the endotracheal tube alone (Fastrach group), or endotracheal tube with the Trachlight, a lightwand (Fastrach/Trachlight group). The time to place the Fastrach and endotracheal tube, to remove the Fastrach, and the total time to intubate were recorded. The number of attempts, failures, trauma, sore throats, and hemodynamic changes were also recorded. Data were analyzed using unpaired t-test, ANOVA with repeated measures, or Chi-squares contingency table where appropriate.

MEASUREMENTS AND MAIN RESULTS

Although there were no differences in the times to place the Fastrach, and endotracheal tube, the hemodynamic changes, and postoperative complications, there were significantly more attempts and failures in the Fastrach group compared to the Fastrach/Trachlight group. There were no differences in the incidence of sore throat and trauma in between the groups.

CONCLUSIONS

Although tracheal intubation is effective using a Fastrach alone (76% success rate), it is more effective when the Fastrach is used in conjunction with the Trachlight (95%). These results suggest that the lightwand is a useful adjunct for Fastrach intubation. However, the role of Fastrach intubation together with the Trachlight in the management of patients with a potential difficult airway remains to be determined.

Light-guided intubation via the intubating laryngeal mask using a prototype illuminated flexible catheter. Clinical experience in 400 patients

BACKGROUND

The transillumination of the soft tissues of the neck using lighted stylets has been used as an aid for tracheal intubation. We evaluated the efficacy and safety of a prototype illuminated flexible catheter to facilitate light-guided intubation through the intubating laryngeal mask.

METHODS

The illuminated flexible catheter consists of a completely flexible thin plastic catheter with a bulb attached to its distal end. The device was placed into a silicone tracheal tube in such a way that the bulb was adjusted at the distal end of the tracheal tube. The tracheal tube preloaded with the device was inserted through the intubating laryngeal mask and, by observing the glow on the neck, was advanced into the trachea. We report our experience with light-guided intubation through the intubating laryngeal mask in 400 ASA grade 1-3 patients undergoing general anaesthesia.

RESULTS

The intubating laryngeal mask was inserted successfully in all patients. The overall intubating success rate was 99.8% (399/400); in 367 (91.8%) cases at the first attempt, in 28 (7%) at the second, in 4 (1%) at the third and in one case (0.2%) at the fifth attempt. There were 27 patients with potentially difficult airways. All these cases were intubated successfully; in 23 of 27 (85.2%) at the first attempt, in 3 of 27 (11.1%) at the second and one of 27 patients (3.7%) at the third attempt.

CONCLUSION

We conclude that the use of the illuminated flexible catheter facilitates the intubation through the intubating laryngeal mask. The suggested light-guided intubating method proved to be a simple, safe and effective technique.

Intubating laryngeal mask for fibreoptic intubation--particularly useful during neck stabilization

PURPOSE

To assess the ease of fibrescope-assisted tracheal intubation while the patient's head and neck were placed in the neutral or the manual in-line position, and to determine if the intubating laryngeal mask facilitated fibreoptic intubation in these positions.

METHODS

In 84 patients, the patient's head and neck were placed in the neutral position (pillow placed under occiput), and in another 40 patients the head and neck were stabilized by the manual in-line method (no pillows under occiput). In both groups, after induction of anesthesia with 2.0-2.5 mgxkg(-1) propofol, 50-100 microg fentanyl and 1.0 mgxkg(-1) vecuronium, patients were allocated randomly into two groups: in Group C tracheal intubation was attempted using only a fibrescope, whereas in Group L fibreoptic intubation through the intubating laryngeal mask was attempted.

RESULTS

In group C the success rate of fibreoptic tracheal intubation within two minutes was higher in the neutral position (31 of 42 patients (73%)) than in the manual in-line position (8 of 20 patients (40%)). In contrast, in group L the success rate was similar between the two positions. Tracheal intubation was easier in group L than in group C (P < 0.01 or 0.001) and the time for intubation was shorter in group L than in group C in both head and neck positions.

CONCLUSIONS

Fibreoptic tracheal intubation was more difficult in the manual in-line position than in the neutral position. The intubating laryngeal mask facilitated fibreoptic intubation in both positions.

The intubating laryngeal mask airway: effect of handle elevation on efficacy of seal, fibreoptic position, blind intubation and airway protection

We conducted three studies to test the hypothesis that elevation of the intubating laryngeal mask (ILM) handle increases efficacy of seal, changes fibreoptic position, prevents aspiration of regurgitated fluid and improves intubation. In study 1, the ILM was inserted into 20 paralysed, anaesthetized patients and 20 cadavers. Oropharyngeal leak pressure and fibreoptic position were measured at an intracuff pressure of 0, 60 and 120 cm H2O with 0, 20 and 40 N of elevation force. In study 2, the oesophageal pressure at which regurgitation and aspiration occurred was measured in 20 cadavers with the ILM at the above intracuff pressures and elevation forces and 10 cadavers without the ILM (controls). In study 3, ease of blind intubation (first attempt only) was determined in 20 paralysed, anaesthetized patients at 0 and 40 N elevation force. In study 1, there was a significant increase in oropharyngeal leak pressure with increasing elevation force at an intracuff pressure of 0 and 60 cm H2O. There were no changes in fibreoptic position. Oropharyngeal leak pressure and fibreoptic position were similar between patients and cadavers. In study 2, oesophageal pressure for regurgitation and aspiration was usually greater for the ILM than controls (all: P < 0.05. Aspiration and regurgitation usually occurred at the same oesophageal pressure. In study 3, blind intubation was more successful at 0 N than 40 N (15/20 v 8/20, P = 0.03). We conclude that elevation of the ILM handle has little clinical utility other than as a temporary measure to improve the efficacy of the seal.

Segmental cervical spine movement with the intubating laryngeal mask during manual in-line stabilization in patients with cervical pathology undergoing cervical spine surgery

We quantified the extent and distribution of segmental cervical movement produced by the intubating laryngeal mask (ILM) during manual in-line stabilization in 20 anesthetized patients with cervical pathology undergoing cervical spine surgery. All patients had neurological symptoms preoperatively. The ILM was inserted with the head and neck in the neutral position. Intubation was facilitated by transillumination of the neck with a lightwand. Cervical movement was recorded with single-frame lateral radiographic images taken 1) immediately before induction (baseline); 2) during ILM insertion (insertion); 3) when transillumination was first seen at the cricothyroid membrane (intubation A); 4) when the tube was being advanced into the trachea (intubation B); and 5) during ILM removal (removal). Radiographic images were digitized and the degree of flexion/extension and posterior movement measured for the occiput (C0) through to C5. During ILM insertion, C0-5 were flexed by an average of 1-1.6 degrees (all P < 0.05). During intubation A/B, C0-4 were flexed by an average of 1.4-3.0 degrees (all P < 0.01), but C5 was unchanged. During ILM removal, C0-3 were flexed by an average of 1 degree (all: P < 0.05), but C3-5 were unchanged. During insertion and intubation A/B, C2-5 were displaced posteriorly by an average of 0.5-1.0 mm (all: P < 0.05). During removal, there was no change at C1-5. Neurological symptoms improved in all patients. We conclude that the ILM produces segmental movement of the cervical spine despite manual in-line stabilization in patients with cervical spine pathology undergoing cervical spine surgery. This motion is in the opposite direction to direct laryngoscopy, suggesting that different approaches to airway management may be more appropriate depending on the nature of the cervical instability.

IMPLICATIONS

The intubating laryngeal mask produces segmental movement of the cervical spine, despite manual in-line stabilization in patients with cervical spine pathology undergoing cervical spine surgery. This motion is in the opposite direction to direct laryngoscopy, suggesting that different approaches to airway management may be more appropriate depending on the nature of the cervical instability.

Tracheal intubation with the Macintosh laryngoscope versus intubating laryngeal mask airway in adults with normal airways

We tested the hypothesis that haemodynamic changes to intubation and postoperative pharyngolaryngeal morbidity are similar for blind intubating laryngeal mask (ILM)-guided compared with laryngoscope-guided tracheal intubation in adults with normal airways. We also compared intubation success rates and airway complications. One-hundred and fifty paralysed, anaesthetized adult patients undergoing elective surgery were randomly assigned to one of three equal-sized groups: 1. blind intubation via the ILM using a straight, silicone tube; 2. intubation with a Macintosh laryngoscope using a straight silicone tube and 3. intubation with a Macintosh laryngoscope using a polyvinyl chloride tube (controls). A standard sequence of adjusting manoeuvres was followed if intubation was difficult. The number of adjusting manoeuvres and intubation attempts, time to intubation, intubation success rate (first attempt and within 3 min), haemodynamic changes (pre-induction, post-induction, post-intubation), oesophageal intubation, mucosal trauma (blood detected), hypoxia (SpO2 < 95%) and postoperative pharyngolaryngeal morbidity (double-blinded) were documented. Time to successful intubation was longer (57 vs 35 s), and more intubation attempts were required in the ILM group (P < 0.0001). The intubation success rate was 100% (all first attempt) for the laryngoscope groups and 94% (56% first attempt) for the ILM group. There were no significant differences in heart rate or blood pressure among groups. Oesophageal intubation (26 v 0%) and mucosal trauma (19 v 2%) were more common in the ILM group. Hypoxia and postoperative pharyngolaryngeal morbidity were similar among groups. Blind intubation through the ILM offers no advantages over the Macintosh laryngoscope for adult patients requiring intubation for elective surgery with normal airways, but it is a feasible alternative.

A comparison of blind and lightwand-guided tracheal intubation through the intubating laryngeal mask

We have tested the hypothesis that intubation success rates, haemodynamic changes, airway complications and postoperative pharyngolaryngeal morbidity differ between blind and lightwand-guided intubation through the intubating laryngeal mask airway. One hundred and twenty paralysed anasthetised adult patients (ASA I-II, no known or predicted difficult airways) were assigned in a random manner to one of two equal-sized groups. In the blind group, patients were intubated blindly through the intubating laryngeal mask airway. In the lightwand group, patients were intubated through the intubating laryngeal mask airway assisted by transillumination of the neck with a lightwand. A standard sequence of adjusting manoeuvres was followed if resistance occurred during intubation or if transillumination was incorrect. The number of adjusting manoeuvres, time to intubation, intubation success rates, haemodynamic changes (pre-induction, pre-intubation, postintubation), oesophageal intubation, mucosal trauma (blood detected), hypoxia (oxygen saturation < 95%) and postoperative pharyngolaryngeal morbidity (double-blinded) were documented. Overall intubation success was similar (blind, 93%; lightwand, 100%), but time to successful intubation was significantly shorter (67 vs. 46 s, p = 0. 027) and the number of adjusting manoeuvres was significantly fewer (p = 0.024) in the lightwand group. There were no significant differences in blood pressure or heart rate between the groups at any time. Oesophageal intubation occurred more frequently in the blind group (18 vs. 0%, p = 0.002). The incidence and severity of mucosal injury, sore throat and hoarseness were similar between the groups. We conclude that lightwand-guided intubation through the intubating laryngeal mask is superior to the blind technique.

Modern airway management for the trauma patient

Over the last decade there has been significant advancement in airway management and a recent closed claims analysis indicates a decrease in claims since the 1980s. Studies and new airway devices have focused on managing the difficult airway and the failed intubation, problems which are common to the trauma patient. Although new airway devices have improved our ability to ventilate these patients, they are not 100% reliable nor do they provide a definitive airway. Formal training in airway management and the use of these airway devices has much room for improvement. With increased emphasis on training and the development of improved intubating aids, modern management of the difficult airway may approach 100% success.

[Fastrach laryngeal mask and difficult intubation]

OBJECTIVE

To evaluate the success rate of intubation through the intubating laryngeal mask airway (LMA-Fastrach) in patients with predictive signs of difficult airway or after intubation failure.

STUDY DESIGN

Open prospective study.

PATIENTS

The study included 33 adults, 21 with predictive signs of difficult airway and 12 after intubation failure.

METHODS

After induction of anaesthesia, the intubating LMA was inserted. Proper insertion was confirmed by easy bag ventilation and capnography. Intubation through the intubating LMA was then carried out with an armoured endotracheal tube. If intubation failed, a second attempt was carried out after a gentle manipulation of the intubating LMA. After two attempts, if intubation remained impossible, fibrescopic intubation through the intubating LMA was carried out. In case of failure the usual tracheal intubation algorithms were used.

RESULTS

Tracheal intubation through the intubating LMA was successful in all patients, in 32 on the first attempt and in one on the second. Successful tracheal intubation was possible on the first attempt in 25 patients (76%), on the second in four (12%) and after fibrescopic intubation through the intubating LMA in the four remaining (12%).

CONCLUSION

The results of this study confirm that tracheal intubation through the intubating LMA can be recommended in patients with a difficult airway, whether foreseen or not.