Two groups of 80 patients requiring laryngeal mask size 3 and 4 during general anesthesia were randomized into 4 subgroups for each size of the laryngeal mask: Soft Seal® (Portex®), AuraOnce™ (Ambu®), LMA-Classic™ (Teleflex®) and LMA-ProSeal™ (Teleflex®). After insertion, the cuff was inflated with 5-ml increments of air up to the maximum recommended volume. After each 5-ml intracuff pressure was measured, the volume of air that generated the intracuff pressure of 60 cmH2O was recorded.
Mean (SD) volume of air required to achieve the intracuff pressure of 60 cmH2O in Soft Seal®, AuraOnce™, LMA-Classic™, LMA-ProSeal™ laryngeal mask size 3 were 11.80(1.88), 9.20(1.88), 8.95(1.50) and 13.50(2.48) ml, respectively, and these volumes in laryngeal mask size 4 were 14.45(4.12), 12.55(1.85), 11.30(1.95) and 18.20(3.47) ml, respectively. The maximum recommended volume resulted in high intracuff pressures (> 60 cmH2O) in all laryngeal mask types and sizes studied.
Pressure-volume curves of adult laryngeal masks are all in sigmoidal shape. Cuff designs and materials can effect pressure and volume correlation. Approximately half of the maximum recommended volume is required to achieve the intracuff pressure of 60 cmH2O except LMA-ProSeal™ which required two-thirds of the maximum recommended volume.
Thai Clinical Trials Registry, TCTR20150602001, May 28, 2015.
在全身麻醉期间需要3号和4号喉罩的两组患者被随机分为4个亚组,每个尺寸的喉罩:SoftSeal®(Portex®),AuraOnce™(Ambu®),LMA-Classic™(Teleflex®)和LMA-ProSeal™(Teleflex®)。插入后,将袖带充入5ml增量的空气,直至最大推荐体积.在测量每个5毫升的内压后,记录了产生60cmH2O内压的空气量。
在SoftSeal®中达到60cmH2O的内部压力所需的空气平均(SD)体积,AuraOnce™,LMA-Classic™,LMA-ProSeal™喉罩尺寸3为11.80(1.88),9.20(1.88),8.95(1.50)和13.50(2.48)毫升,分别,喉罩尺寸为4的这些体积为14.45(4.12),12.55(1.85),11.30(1.95)和18.20(3.47)毫升,分别。在所研究的所有喉罩类型和尺寸中,最大推荐体积导致高的腔内压力(>60cmH2O)。
成人喉罩的压力-容积曲线均为S形。袖带设计和材料可以影响压力和体积相关性。除了LMA-ProSeal™需要三分之二的最大推荐体积外,需要大约一半的最大推荐体积才能达到60cmH2O的内部压力。
泰国临床试验注册中心,TCTR20150602001,2015年5月28日。