Comparison of the Anesthetic Requirement for Tolerance of Laryngeal Mask Airway and Endotracheal Tube

Abstract

We tested the hypothesis that the laryngeal mask airway (LMA) is tolerated at lighter levels of anesthesia than an endotracheal tube (ET). We studied 20 unpremedicated, nonsmoking ASA physical status I or II patients aged 18-40 yr whose surgery lasted > 1 h. Subjects were randomly assigned to receive either an ET or LMA. Anesthesia was induced with intravenous propofol and the LMA or ET was inserted. The ET-group patients received 1.5 mg/kg of succinylcholine, preceded by vecuronium (0.015 mg/kg IV). Maintenance of anesthesia was with only isoflurane and approximately 66% N2O in O2 by spontaneous ventilation. All gas concentrations were measured by a Raman spectrometer sampling from the breathing circuit end of the LMA or ET. Toward the end of the procedure, the end-tidal N2O and isoflurane concentrations were allowed to decrease to < 3 vol% and 0.8 +/- 0.05 vol%, respectively. The end-tidal isoflurane concentration was then decreased in 0.1% +/- 0.05% decrements, each stable value being held for 5 min. The patient was observed for signs of reaction to the presence of the LMA or ET. The mean (range) end-tidal isoflurane concentrations for reaction to ET and LMA were 0.55% (0.4-0.7) and 0.35% (0.2-0.51), respectively (P < 0.001). These data confirm the original hypothesis of the study.

Prolonged Use of the Laryngeal Mask Airway ProSealTM: A Report of Seven Cases Lasting 5-11 h

“…However, positive pressure ventilation is readily accomplished with the LMA Classic TM [12], the correctly positioned LMA Classic TM will provide some protection against aspiration [13] and the increased risk of aspiration with time is hypothetical, as it has only been the subject of one study [4]. In fact, the LMA Classic TM may offer advantages over the tracheal tube since: (i) spontaneous ventilation is easier due to a reduced work of breathing [14,15]; (ii) positive pressure ventilation can be performed without muscle relaxation due to better tolerance [16]; (iii) the risk of pulmonary infection may be reduced due to non-interference with pulmonary airway resistance [17] and ciliary motility [18]; and (iv) pharyngolaryngeal morbidity may be reduced as the vocal cords are not penetrated and mucosal pressures are lower [19]. A meta-analysis into prolonged use of the LMA Classic TM (based on 16 anecdotal reports, 4 descriptive [20,21] and 7 comparative studies) concluded that there was reasonable evidence supporting its use for 2-4 h, some evidence for 4-8 h, but little evidence for more than 8 h [22].…”

The reinforced laryngeal mask airway (RLMA) protects the airway in patients undergoing nasal surgery — an observational study of 200 patients

“…It is tolerated better at lighter levels of anesthesia. 7 During emergence from anesthesia for nasal surgery, the laryngeal mask maintains an unobstructed airway better than the Guedel airway. 8 It is potentially beneficial therefore to leave it in place until full emergence from anesthesia.…”

Comparison of The Complications With Laryngeal Mask And Endotracheal Intubation

“…tanın (10) 12 (60) 6 (30) 2 (10) 17 (85) 3 (15) (1-3) .. anestezi pratiğinde LM kullanımı, EE ve yüz maskesine ora:rıla daha kolay ve güvenlidir. (1)(2)(3)(4)(5).…”