Cheong Y P, Park S K, Son Y, Lee K C, Song Y K, Yoon J S, Kim T Y
Department of Anesthesiology, Wonkwang University School of Medicine, Iksan, Cheonbuk, South Korea.
J Clin Anesth. 1999 Dec;11(8):657-62. doi: 10.1016/s0952-8180(99)00117-8.
To compare the incidence of gastroesophageal reflux and regurgitation associated with laryngeal mask airway (LMA) removal when signs of rejecting the LMA, such as swallowing, struggling, and restlessness, were observed and when the patient could open his or her mouth on command.
Randomized clinical trial.
Operating room and recovery room of a tertiary care referral hospital.
63 ASA physical status I and II adult patients scheduled for elective orthopedic surgery.
Using a standardized general anesthetic technique, patients were allocated randomly to Group A (n = 34; LMA removed when signs of rejection, such as swallowing, struggling, and restlessness, were observed) or Group B (n = 29; LMA removed when the patient could open his or her mouth on command).
To detect gastroesophageal reflux throughout anesthesia, a pH monitoring probe was positioned in the lower esophagus on the day before surgery. To assess regurgitation during emergence, a gelatin capsule of methylene blue (50 mg) was swallowed prior to induction. At the end of anesthesia, episodes of reflux and regurgitation of gastric contents were analyzed/determined by pH below 4 and bluish staining of the pharynx and/or LMA, respectively. Physical events such as bucking, straining, and coughing during the arousal phase were recorded in both groups by an independent observer. The incidence of reflux (pH < 4) from the time of the appearance of rejection signs to LMA removal and the total incidence of reflux in Group B were significantly higher than in Group A (p < 0.05). Staining of the LMA and the pharynx by methylene blue was not observed in patients from either experimental group. The number of physical events in Group B during the arousal phase was significantly increased compared to Group A (p < 0.05). Considering all patients in Group A and Group B, physical events were associated with the occurrence of reflux (p < 0.05). Desaturation (SpO2 < 95%) and clinical evidence of aspiration of gastric contents did not occur in either group.
Maintenance of the LMA until the patient can open his or her mouth on command increases the incidence of gastroesophageal reflux.
比较在观察到患者出现如吞咽、挣扎和躁动等拒绝喉罩（LMA）的迹象时以及患者能按指令张口时拔除LMA后发生胃食管反流和反流的发生率。
随机临床试验。
一家三级医疗转诊医院的手术室和恢复室。
63例美国麻醉医师协会（ASA）身体状况为I级和II级的成年患者，计划进行择期骨科手术。
采用标准化的全身麻醉技术，将患者随机分为A组（n = 34；当观察到吞咽、挣扎和躁动等拒绝迹象时拔除LMA）或B组（n = 29；当患者能按指令张口时拔除LMA）。
为了在整个麻醉过程中检测胃食管反流，在手术前一天将pH监测探头置于食管下部。为了评估苏醒期的反流情况，在诱导前让患者吞服一粒含50mg亚甲蓝的明胶胶囊。麻醉结束时，分别通过pH值低于4以及咽部和/或LMA出现蓝色染色来分析/确定胃内容物的反流和反流发作情况。由一名独立观察者记录两组患者在苏醒期的诸如呛咳、用力和咳嗽等身体反应。从出现拒绝迹象到拔除LMA期间的反流发生率（pH < 4）以及B组的反流总发生率均显著高于A组（p < 0.05）。两个试验组的患者均未观察到LMA和咽部被亚甲蓝染色。与A组相比，B组在苏醒期的身体反应次数显著增加（p < 0.05）。综合考虑A组和B组的所有患者，身体反应与反流的发生相关（p < 0.05）。两组均未发生血氧饱和度降低（SpO2 < 95%）和胃内容物误吸的临床证据。
在患者能按指令张口之前维持LMA会增加胃食管反流的发生率。
