Ultrasonographic gastric volume before unplanned surgery

Area of Science:

• Medical imaging
• Anesthesiology
• Surgical preparation

Background:

• Accurate gastric volume assessment is crucial for preoperative risk stratification.
• Gastric ultrasound is a non-invasive tool for evaluating gastric content.
• Standard fasting guidelines may not guarantee an empty stomach.

Purpose of the Study:

• To measure gastric antral cross-sectional area using ultrasound.
• To estimate gastric volume in patients undergoing unplanned surgery after a minimum six-hour fast.
• To identify factors associated with increased gastric volume.

Main Methods:

• Ultrasound measurements of gastric antral cross-sectional area were performed in 263 semi-recumbent patients fasted for at least six hours.
• Gastric volume was estimated from the measured area.
• Multivariable linear regression analysis was used to identify associated factors.

Main Results:

• The median gastric antral area was 333 mm² (IQR 241–472 mm²).
• The mean estimated gastric volume was 45.8 ml (SD 34.0 ml).
• Higher body mass index and morphine administration were significantly associated with larger gastric antral areas (p=0.01 and p=0.04, respectively).
• Fasting time was not associated with gastric area.

Conclusions:

• Ultrasound is a feasible method for assessing gastric volume in fasted patients prior to surgery.
• Gastric distension is influenced by factors beyond fasting duration, including BMI and opioid use.
• Ultrasound measurements provide a more reliable assessment of gastric status than fasting time alone.