Reflex responses to insertion of the intubating laryngeal mask airway,intubation and removal of the ILMA

We studied 21 patients (ASA 1 or 2) to investigate the skin vasomotor reflex (SVmR) and haemodynamic responses to insertion of an intubating laryngeal mask airway (ILMA), tracheal intubation using the ILMA and removal of the ILMA. Anaesthesia was induced with fentanyl, midazolam, vecuronium and nitrous oxide. A size 4 ILMA was inserted using the standard technique, and a silicone reinforced tracheal tube (7.5 mm, ID) was passed through it. After confirming successful intubation, the ILMA was removed using the stabilizing rod. The three procedures were performed at approximately one-minute intervals. Insertion of the ILMA, intubation and removal of the ILMA all significantly reduced the skin blood flow on the ring finger in all patients. The mean amplitudes of the SVmR were 0.46 (SD 0.29), 0.54 (0.32) and 0.68 (0.21) respectively. The magnitude of the SVmR and the haemodynamic changes induced by removal of the ILMA were significantly larger than those accompanying the other two procedures. Use of the ILMA for intubation and removal of the ILMA produces three stimuli and the removal of the ILMA produces the greatest response.     

Fibreoptic views through the laryngeal mask and the intubating laryngeal mask.

BACKGROUND AND OBJECTIVE: The intubating laryngeal mask (intubating laryngeal mask airway) was designed to facilitate blind intubation. Its value as an adjunct to fibreoptic laryngoscopy has not been evaluated. This study compares the intubating laryngeal mask airway with the standard laryngeal mask airway as conduits for fibreoptic laryngoscopy. METHODS: The fibreoptic view of the laryngeal inlet was graded via both devices in 60 anaesthetized patients. The fibreoptic view through the intubating laryngeal mask airway was assessed after the central epiglottic elevator bar had been lifted out of the field of vision by an 8-mm Euromedical tracheal tube, which was inserted to a depth of 18 cm. The fibreoptic view from the aperture bars of the laryngeal mask was recorded. RESULTS: The vocal cords were viewed less frequently through the intubating laryngeal mask airway (52%) than through the laryngeal mask airway (92%) [difference = 40% (95% CI = 26% to 54%), P < 0.0001]. CONCLUSION: The view of the laryngeal inlet is better through the laryngeal mask airway than through a tracheal tube inserted to 18 cm in the intubating laryngeal mask.     

An unexpected complication of the intubating laryngeal mask

Fatal oesophageal perforation occurred as a complication of elective general anaesthesia for cataract extraction in a 77-year-old female patient. Tracheal intubation had been achieved, albeit with difficulty, in the course of a clinical trial of the intubating laryngeal mask.     

The use of the intubating laryngeal mask endotracheal tube with intubating devices

IMPLICATIONS: Despite adequate visualization of the vocal cords using specialized airway devices, anatomical factors and the physical characteristics of the tube may cause difficulty when performing endotracheal intubation. The endotracheal tube designed for use with the intubating laryngeal mask airway may facilitate intubation in these circumstances.     

Awake tracheal intubation through the intubating laryngeal mask

PURPOSE: To report successful awake insertion of the intubating laryngeal mask (Fastrach) and subsequent tracheal intubation through it, in a patient with predicted difficult tracheal intubation, due to limited mouth opening, and difficult ventilation through a facemask, due to a large mass at the corner of the mouth. CLINICAL FEATURES: A 53-yr-old woman with a large post-gangrenous mass on the right cheek to the angle of the mouth was scheduled for its resection. The right side of her face was damaged by a bomb attack followed by cancrum oris 50 yr ago. The distance between the incisors during maximum mouth opening was 2 cm and that between the gums on the right side < 1 cm. After preoxygenation and 50 micrograms fentanyl and 30 mg propofol i.v., propofol was infused at 2 mg.kg-1.hr-1. Lidocaine, 8%, was sprayed on the oropharynx. A #4 intubating laryngeal mask was inserted with a little difficulty. A fibrescope was passed through a 7.5-mm ID RAE tracheal tube, and the combination was easily passed through the laryngeal mask into the trachea. General ansthesia was then induced. Finally, the intubating laryngeal mask was removed, while the RAE tube was being stabilized using an uncuffed 6.0-mm ID tracheal tube. CONCLUSION: Awake tracheal intubation through the intubating laryngeal mask is a useful technique in patients with limited mouth opening in whom ventilation via a facemask is expected to be difficult.     

Removal of the connector on the laryngeal mask airway provides a useful alternative to the intubating laryngeal mask

PURPOSE: We describe two cases in which fiberoptic intubation through the standard laryngeal mask airway (LMA) was successful with large-bore tracheal tubes (TTs) when an intubating LMA (ILMA) could not be used. CLINICAL FEATURES: Patient # 1, with obstructive sleep apnea, underwent elective surgical repair. His mouth opening was just under 25 mm, but difficult intubation was not anticipated. We induced general anesthesia, easily ventilated the patient by mask, and established neuromuscular blockade. Direct laryngoscopy and attempts to insert either a #5 or a #4 ILMA into the mouth failed. A standard #4 LMA, with the connector removed, was inserted, through which a 7.0 mm nasal RAE TT, fiberoptically guided, passed into the trachea at the first attempt. Patient #2, with a loosened implant after left hip arthroplasty, underwent revision prosthesis. Her neck movement was limited. We thus planned awake securing of the airway, but the patient refused. We induced anesthesia and established bag-mask-valve ventilation. The limited neck movement prevented direct laryngoscopy. Visualizing the laryngeal inlet with the fiberoptic bronchoscope (FOB) proved impossible as bloody secretions obscured the FOB's tip. Ventilation by mask was easy. As an ILMA was not available, we removed a #5 LMAs connector and passed an 8.0 mm nasal RAE TT through the LMA. Fiberoptic-guided intubation was easy. In both cases, the remainder of the intraoperative course was uneventful. CONCLUSION: A standard LMA whose connector has been removed to allow passage of TTs of >6.0 mm internal diameter may be substituted for the ILMA when necessary.     

The intubating laryngeal mask for maxillo-facial trauma

We report the successful use of the intubating laryngeal mask airway in a patient with maxillo-facial trauma for whom the facemask and laryngoscope were relatively contraindicated and the fibreoptic scope potentially difficult to use.     

The cardiovascular response to insertion of the intubating laryngeal mask airway

Sixty-one patients received a standardised anaesthetic and were randomly assigned to three groups: tracheal intubation via direct laryngoscopy, tracheal intubation via an intubating laryngeal mask airway with immediate removal of the device, and tracheal intubation via an intubating laryngeal mask airway with delayed removal. The cardiovascular response to intubation was of a similar magnitude in all groups, although delayed removal of the intubating laryngeal mask airway was associated with a second pressor response. Norepinephrine changed significantly over time following direct laryngoscopy and following immediate removal of the intubating laryngeal mask airway, but not after delayed removal. The findings of this study do not support using the intubating laryngeal mask instead of direct laryngoscopy purely to decrease the response to intubation.