Maltby J Roger, Pytka Saul, Watson Neil C, Cowan Robert A McTaggart, Fick Gordon H
Department of Anesthesia, University of Calgary, Calgary, Alberta, Canada.
Can J Anaesth. 2004 Feb;51(2):111-5. doi: 10.1007/BF03018767.
To determine whether, in obese [body mass index (BMI) > 30 kg.m(2)] patients, oral intake of 300 mL clear liquid two hours before elective surgery affects the volume and pH of gastric contents at induction of anesthesia.
A single-blind, randomized study of 126 adult patients, age > or = 18 yr, ASA physical status I or II, BMI > 30 kg.m(2) who were scheduled for elective surgery under general anesthesia. Patients were excluded if they had diabetes mellitus, symptoms of gastroesophageal reflux, or had taken medication within 24 hr that affects gastric secretion, gastric fluid pH or gastric emptying. All patients fasted from midnight and were randomly assigned to fasting or fluid group. Two hours before their scheduled time of surgery, all patients drank 10 mL of water containing phenol red 50 mg. Those in the fluid group followed with 300 mL clear liquid of their choice. Immediately following induction of general anesthesia and tracheal intubation, gastric contents were aspirated through a multiorifice Salem sump tube. The fluid volume, pH and phenol red concentration were recorded.
Median (range) values in fasting vs fluid groups were: gastric fluid volume 26 (3-107) mL vs 30 (3-187) mL, pH 1.78 (1.31-7.08) vs 1.77 (1.27-7.34) and phenol red retrieval 0.1 (0-30)% vs 0.2 (0-15)%. Differences between groups were not statistically significant.
Obese patients without comorbid conditions should follow the same fasting guidelines as non-obese patients and be allowed to drink clear liquid until two hours before elective surgery, inasmuch as obesity per se is not considered a risk factor for pulmonary aspiration.
确定肥胖[体重指数（BMI）>30kg·m²]患者在择期手术前两小时口服300mL清液是否会影响麻醉诱导时胃内容物的容量和pH值。
一项针对126例年龄≥18岁、美国麻醉医师协会（ASA）身体状况分级为I或II级、BMI>30kg·m²且计划接受全身麻醉下择期手术的成年患者的单盲随机研究。如果患者患有糖尿病、胃食管反流症状或在24小时内服用过影响胃液分泌、胃液pH值或胃排空的药物，则将其排除。所有患者从午夜开始禁食，并随机分为禁食组或液体组。在预定手术时间前两小时，所有患者饮用10mL含50mg酚红的水。液体组患者随后饮用300mL其选择的清液。在全身麻醉诱导和气管插管后，立即通过多孔塞勒姆引流管抽吸胃内容物。记录液体容量、pH值和酚红浓度。
禁食组与液体组的中位数（范围）值分别为：胃液容量26（3-107）mL对30（3-187）mL，pH值1.78（1.31-7.08）对1.77（1.27-7.34），酚红回收率0.1（0-30）%对0.2（0-15）%。两组之间的差异无统计学意义。
无合并症的肥胖患者应遵循与非肥胖患者相同的禁食指南，并且在择期手术前两小时可饮用清液，因为肥胖本身不被视为肺误吸的危险因素。
