Ultrasonographic Measurement Of Antral Area For Estimating Gastric Content And Volume In Parturients

Objective: The bedside ultrasound was used to assess the gastric fullness and predict the risk of reflux and aspiration.Methods: Pregnant women were recruited in the First Affiliated Hospital of Chongqing Medical University from May 2020 to January 2021,gestational age ≥ 36 weeks,18 years ≤ age ≤ 45 years,ASA ≤grade Ⅲ,and BMI ≤ 35 kg/cm~2.An ultrasound assessment of the long diameter,short diameter,and cross-sectional area of the gastric antrum in the right decubitus position was performed at different time.The cross-sectional area of the right side decubitus> 10.30cm~2 is defined as a full stomach under ultrasound.The fasting time <6h is regarded as the full stomach by fasting guidelines of the American Society of Anesthesiologists in 2017.Age,height,weight,and gestational age were conducted.Results: 169 women were enrolled.There were 18(39.13%)parturients defined as full stomach by ultrasound in the 46 parturients whose fasting time was less than 6h.There was 1(0.81%)parturient defined as full stomach by ultrasond in the 123 parturients whose fasting time were more than 6h.The kappa coefficient of the two methods of diagnosis of a full stomach was 0.469,p<0.001.95% pregnant cohort with empty stomach by ultrasond for antral short diameter,long diameter,and short diameter × long diameter were 2.84cm(95%CI,2.60～3.19cm),4.41cm(95%CI,4.26～4.64cm)and 11.68cm~2(95%CI,10.12～12.77cm~2)in the right lateral decubitus position.No correlation was seen between the CSARLD of women with empty stomach under ultrasound and the item such as age,gestational age,height,weight,and BMI.The degree of maternal satiety was statistically significant with the food weight at the last meal,but not statistically significant with gestational diabetes.Conclusions: The current ASA fasting guidelines to assess the gastric fullness is not reliable.It is more reasonable to judge the degree of gastric fullness by measuring the cross-sectional area of gastric antrum by ultrasound.Ultrasound measurement of the short diameter × long diameter of the gastric antrum is simpler,and the value greater than12.77cm~2 can be treated as a full stomach.Food weight can affect gastric emptying,and maternal gestational diabetes does not affect gastric emptying.Bedside ultrasound has a high clinical application value in real-time judgment of the fullness of the women’s stomach,and can be used to predict the risk of reflux and aspiration and guide the placement of the gastric tube.