全凭静脉麻醉时双相气道正压面罩通气下胃食管反流的监测

Monitoring the gastroesophageal reflux during bi-level positive airway pressure mask ventilation under total intravenous anesthesia

目的监测全凭静脉麻醉（TIVA）下双相气道正压（BiPAP）面罩通气时的胃食管反流情况，评估该通气方法在全身麻醉中应用的安全性。方法选择择期行腹腔镜胆囊切除手术的成年患者40例，美国麻醉师协会（ASA）分级Ⅰ～Ⅱ级，无胃食管反流危险因素，随机分为面罩通气组（Ⅰ组）和气管内插管通气组（Ⅱ组），每组20例。麻醉前经鼻置入胃食管双探头pH电极，使远端探头位于食管下段（A点），近端探头置于食管中上段（B点）。麻醉诱导后，两组分别应用BiPAP面罩通气和间歇正压机械通气（IPPV），连续实时监测围术期食管下段及中上段pH值变化直至患者清醒。以pH值小于4．0作为胃食管反流的诊断标准。结果麻醉后30min、气腹后30min、麻醉结束后pH值监测结果显示，Ⅰ组食管下段pH值分别为5．43±0．51、5．24±0．47、5．36±0．53；Ⅱ组食管下段pH值分别为5．37±0．67、5．29±0．68、5．36±0．78。Ⅰ组和Ⅱ组食管下段及食管中上段各时点pH值监测无1例小于4．0，反流发生率均为0，两组比较pH值差异无统计学意义（P〉0．05）。结论在无胃食管反流病史的患者行腹腔镜胆囊切除术时，应用BiPAP面罩通气全身麻醉不增加胃食管反流概率，是较安全的方法之一。

Objective To evaluate the safety by monitoring the gastroesophageal reflux during bi-level positive airway pressure （BiPAP） mask ventilation under total intravenous anesthesia （TIVA）. Methods Forty adult patients, scheduled for elective laparoscopic cholecystectomy, ASA Ⅰ to Ⅱ, were randomly divided into group Ⅰ （ventilated by mask, n = 20） and Ⅱ （ventilated by endotracheal tube, n = 20）. Risk factors of gastroesophageal reflux were excluded in all the patients. Before anesthesia, gastroesophageal hiprobe pH electrode was inserted through nostril, and ensure that the distal probe was located in the lower part of esophagus （site A ）, and the proximal probe in the middle or upper part （site B ）. After anesthesia induction, the patients of two groups received BiPAP mask ventilation or endotracheal intermittent positive pressure ventilation（ IPPV）, respectively. The pH value of the lower and middle or upper part of esophagus was monitored continuously and real-timely till the patients awake. Diagnosis of gastroesophageal reflux was confirmed when pH 〈 4.0. Results At 30 min after anesthesia, 30 min after artificial pneumoperitoneum and instantly after the end of anesthesia, the pH values of lower part of esophagus were 5.43 ± 0.51,5.24 ± 0.47 and 5.36 ± 0.53 in group Ⅰ ,and 5.37 ± 0.67, 5.29 ± 0.68 and 5.36 ± 0. 78 in group Ⅱ , respectively. In two groups, no pH value of the lower and middle or upper part of esophagus under 4.0 was observed at all time points, and no reflux nianifested in all the patients. There was no significant difference of pH value and incidence of reflux between two groups （P 〉 0.05 ）. Conclusion BiPAP mask ventilation does not increase the incidence of gastroesophgeal reflux in patient without history of gastroesophageal reflux undergoing laparoscopic cholecystectomy during general anesthesia, therefore, it should be a safe ventilation technique.