Objective: To investigate the effect of gastric antrum ultrasonography in evaluating gastric emptying after oral administration of 300 mL carbohydrates two hours before cesarean section, and to analyze the risk factors of gastric emptying in pregnant women.
Methods: From August 2020 to February 2021, a total of 80 patients, aged 22-43 years, body mass index (BMI) < 35 kg/m2, gestational age≥36 weeks, falling into American Society of Anesthesiologists (ASA) physical status Ⅰ or Ⅱ, scheduled for cesarean sections in Peking University International Hospital were recruited and divided into two groups: the intervention group (n=40)and the control group (n=40). In the intervention group, solid food was restricted after 22:00, the patients were required to take 300 mL carbohydrates two hours before cesarean section. In the control group, solid food and liquid intake were restricted after 22:00 the night before surgery. All the patients received assessment of preoperative feeling of thirst and starvation with visual analogue scale (VAS). The cross-sectional area (CSA)of gastric antrum was measured in supine position and right supine position before anesthesia, the gastric volume (GV)and the gastric volume/weight(GV/W)of the two groups was further calculated. Perlas A semi-quantitative grading assessments were performed in each patient. The blood pressure and heart rate were recorded at admission(T0), 5 minutes after anesthesia (T1), immediately after fetal delivery (T2) and at the end of the surgery (T3). The occurrence of nausea and vomiting during the operation and 24 hours after the operation were recorded.
Results: One case in each group was excluded because the antrum was not clearly identified during the ultrasound assessments. In the semi-sitting position, the CSA was (5.07±1.73) cm2 in the intervention group vs. (5.24±1.96) cm2 in the control group, respectively; in the right lateral decubitus position, CSA was (7.32±2.17) cm2 in the intervention group vs. (7.25±2.24) cm2 in the control group, GV was (91.74±32.34) mL vs. (90.07±31.68) mL, GV/W was (1.27±0.40) mL/kg vs. (1.22±0.41) mL/kg, respectively; all the above showed no significant difference between the two groups (P > 0.05). Perlas A semi-quantitative grading showed 0 in 20 patients (51.3%), 1 in 16 (41%), 2 in 3 (7.7%)in the intervention group and 0 in 22 (56.4%), 1 in 15 (38.5%), 2 in 2 (5.1%)in the control group, the proportion of Perlas A semi-quantitative grading showed no significant difference between the two groups (P > 0.05). For the patients with Perlas A semi-quantitative grade 2 (3 cases in the intervention group and 2 cases in the control group), metoclopramide 0.2 mg/kg was intravenously injected before anesthesia. No aspiration case was observed in this study. The intervention group was endured less thirst and hunger (P < 0.05). There was no significant difference in blood pressure and heart rate between the two groups at each time point (P > 0.05). There was no significant difference in the incidence of intraoperative hypotension between the two groups (P > 0.05). There was no significant difference in the incidence of nausea intraoperatively and postoperatively between the two groups (P > 0.05).
Conclusion: Ultrasonography of gastric antrum can provide objective basis for evaluating gastric emptying of pregnant women perioperatively. 300 mL carbohydrates intake two hours before surgery, which does not increase GV and the risk of reflux aspiration, and is helpful in minimizing disturbance to the patient's physiological status, therefore leading to better clinical outcome.
目的: 探讨胃窦部超声检查评估剖宫产产妇术前2 h口服300 mL碳水化合物后胃排空的效果, 并分析影响产妇胃排空的风险因素。
方法: 选择2020年8月至2021年2月在北京大学国际医院行择期剖宫产的产妇80例, 年龄22~43岁, 体重指数(body mass index, BMI)＜35 kg/m2, 孕周≥36周, 美国麻醉医师学会(American Society of Anesthesiologists, ASA)分级Ⅰ或Ⅱ级, 随机分为干预组和对照组, 每组40例。干预组产妇于术前一日22:00后禁食, 术日在预期手术开始前2 h口服碳水化合物300 mL; 对照组产妇于术前一日22:00后禁食禁饮。两组患者入手术室后行术前干渴感及饥饿感的视觉模拟评分(visual analogue scale, VAS)。麻醉前行胃窦部超声检查, 分别在半坐位和右侧卧位下测量胃窦横截面积(cross-sectional area, CSA), 并进一步计算两组患者胃容量(gastric volume, GV)及胃容量/体质量(gastric volume /weight, GV/W), 并进行Perlas A半定量评级。记录患者入室(T0)、麻醉后5 min(T1)、胎儿剖出即刻(T2)、手术结束(T3)时的血压和心率。记录术中、术后24 h恶心呕吐的发生情况。
结果: 两组各有1例患者无法清晰显示胃窦部, 余78例患者可以进行CSA测量及Perlas A半定量评级。半坐位下, 干预组和对照组的CSA分别为(5.07±1.73) cm2和(5.24±1.96) cm2; 右侧卧位下, 干预组和对照组的CSA分别为(7.32±2.17) cm2和(7.25±2.24) cm2, GV分别为(91.74±32.34) mL和(90.07±31.68) mL, GV/W分别为(1.27±0.40) mL/kg和(1.22±0.41) mL/kg, 上述指标两组间差异均无统计学意义(P＞0.05)。Perlas A半定量评级: 干预组0级20例(51.3%), 1级16例(41%), 2级3例(7.7%); 对照组0级22例(56.4%), 1级15例(38.5%), 2级2例(5.1%), 两组评级构成比差异无统计学意义(P＞0.05)。Perlas A半定量评级为2级的患者(干预组3例及对照组2例), 麻醉前静脉注射甲氧氯普胺0.2 mg/kg, 均未发生反流误吸。与对照组比较, 干预组术前干渴感、饥饿感VAS明显降低(P＜0.05)。术中各观察时点血压、心率两组差异无统计学意义(P＞0.05), 术中低血压发生率两组差异无统计学意义(P＞0.05)。术中、术后24 h恶心的发生率两组差异无统计学意义(P＞0.05)。
结论: 胃窦部超声检查能为剖宫产围术期产妇判断胃排空情况提供客观依据。剖宫产产妇术前2 h饮用300 mL碳水化合物, 可减少患者不适, 同时不增加麻醉前GV和反流误吸风险, 临床效果更好。
Keywords: Gastric cross-sectional area; Gastric ultrasonography; Gastric volume; Pregnant women.