Laryngeal mask, laryngeal tube, and Frova introducer in simulated difficult airway.

BACKGROUND: The use of supraglottic devices is rising in the prehospital management of difficult airway; moreover, we think that patients with multiple trauma or cervical instability can take advantage of these devices without opening or retiring the cervical collar. OBJECTIVE: To compare speed and ease of use between Laryngeal Tube S (LTS) and the Ambu AuraOnce laryngeal mask (LMA).Our second objective was to evaluate changing these devices to an endotracheal tube (ETT) using a Frova introducer. METHODS: We studied the use of LTS and LMA in an experimental model, represented by a manikin with a rigid cervical collar and a limited mouth opening. This study was carried out in Complutense University of Madrid with 145 2(nd)-year students for the degree in Dentistry who have knowledge of the airway but lack experience in intubation. Number of attempts and time for the device's insertion were measured, as well as time for the exchange maneuver using the Frova introducer. RESULTS: Insertion of all devices was possible on the first attempt; time for insertion was LTS 12.2 ± 1.28 s and LMA 6.87 ± 0.97 s. Once these devices were inserted, a Frova introducer is used to perform an exchange by an endotracheal tube; all devices could be exchanged on the first attempt, and exchange time was LTS 26.9 ± 1.2 s and LMA 16.79 ± 1.32 s. Results for both time for insertion and exchange of the LMA were significantly lower than those for the LTS (p < 0.001). CONCLUSION: The method used can be considered quick and easy, even for personnel inexperienced in intubation. This exchange maneuver has not been described previously, so we can consider it as a new application of the Frova introducer.

Straight blades improve visualization of the larynx while curved blades increase ease of intubation: a comparison of the Macintosh, Miller, McCoy, Belscope and Lee-Fiberview blades.

PURPOSE: To compare the Macintosh (M), McCoy (MC), Miller (MIL), Belscope (BP) and Lee-Fiberview (LF) laryngoscopes with respect to the grade of laryngeal visualization and the difficulty of intubation. METHODS: We included 500 patients scheduled to undergo elective surgery and who required tracheal intubation. Patients were randomly assigned to five groups of 100 patients each. Anesthesia was induced intravenously using 1-3 mg.kg(-1) of propofol, fentanyl 1.5 microg.kg(-1) and atracurium 0.5 mg.kg(-1) or suxamethonium 1 mg.kg(-1). The laryngeal view was classified according to Cormack and Lehane. The degree of difficulty with intubation was rated as: Grade 1, intubation easy; Grade 2, intubation requiring an increased anterior lifting force and assistance to pull the right corner of the mouth upwards to increase space; Grade 3, intubation requiring multiple attempts and a curved stylet; Grade 4, failure to intubate with the assigned laryngoscope. Data were examined using analysis of variance, chi(2) or Fisher test, Student's t test and odds ratio. P < 0.05 was considered statistically significant. RESULTS: Laryngoscopic views obtained with the BP and MIL laryngoscopes were similar, and better than with the other types of laryngoscopes (P < 0.001). The levering tip of the MC blade (P = 0.02) and the fibreoptic device of the LF (P < 0.001) significantly improved the laryngoscopic view. Regarding the degree of difficulty with intubation, the best results were obtained with the MC and M blades (P < 0.001). CONCLUSION: Laryngoscopy was better with straight blades but curved blades provided better intubating conditions.