British journal of anaesthesia
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We studied how head and neck position affect the cuff position and oropharyngeal sealing pressures of the laryngeal mask airways (LMAs) in children. We studied 39 non-paralyzed healthy children aged 1.5-8.0 yr, weighing 10.3-27.0 kg, managed with size 2 or 2.5 LMAs during elective surgery. ⋯ Oropharyngeal sealing pressure was significantly greater during neck flexion compared with the neutral position (P<0.02). Fibreoptic examination revealed that the epiglottis covered a larger area of the LMA aperture during neck flexion, compared with the neutral position (P<0.02).
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Thirty volunteers underwent intradermal skin testing with increasing concentrations of rocuronium and cisatracurium to evaluate weal and flare responses, and whether either agent would cause mast cell degranulation and sensitization upon re-exposure. We found that intradermal injection of rocuronium and cisatracurium at concentrations > 10(-4) M resulted in positive weal (>8 mm) responses, and positive flare responses at > 10(-4) and > 10(-5) M respectively. ⋯ Skin testing with rocuronium and cisatracurium should be performed at concentrations < 10(-4) and < 10(-5) M respectively to avoid false-positive responses. The ability of these agents to produce positive weal and flare responses at relatively low concentrations may explain the high incidence of potential reactions reported.