Qualitative and quantitative ultrasound assessment of gastric content

Abstract

Objective: Pulmonary aspiration of the gastric contents is one of the most feared complications in anesthesia. Its prevention depends on preoperative fasting as well as identification of risky patients. A reliable diagnostic tool to assess gastric volume is currently lacking. The aim of this study performed on volunteers was to evaluate the feasibility of ultrasonography to identify qualitative and quantitative gastric content. Method: A standardized gastric scanning protocol was applied on 67 healthy volunteers to assess the gastric antrum in four different situations: fasting, after ingesting clear fluid, milk and a solid meal. A qualitative and quantitative assessment of the gastric content in the antrum was performed by a blinded sonographer. The antrum was considered either as empty, or containing clear or thick fluid, or solids. Total gastric volume was predicted based on a cross-sectional area of the antrum. A p-value less than 0.05 was considered statistically significant. Results: For each type of gastric content, the sonographic characteristics of the antrum and its content were described and illustrated. Sonographic qualitative assessment allowed to distinguish between an empty stomach and one with different kinds of meal. The predicted gastric volume was significantly larger after the consumption of any food source compared to fasting. Conclusion: Bedside sonography can determine the nature of gastric content. It is also possible to estimate the difference between an empty gastric antrum and one that has some food in it. Such information may be useful to estimate the risk of aspiration, particularly in situations when prandial status is unknown or uncertain.

A randomized, double-blind study of the ultrasound assessment of the effect of pharyngeal packing on perioperative gastric volume in nasal surgery

“…However, the critical cut-off value for GV with regard to an aspiration risk must be discussed. The critical threshold for this risk has been reported to be 0.4–0.8 ml/kg (28–56 ml/70 kg) [20, 25], but the 0.8 ml/kg threshold is probably insufficient because regurgitation and aspiration of a minimum of 200 ml GV are required for pulmonary damage [26]. Residual GVs in healthy, hungry patients can be ≥1.5 ml/kg [27].…”

A randomized, double-blind study of the ultrasound assessment of the effect of pharyngeal packing on perioperative gastric volume in nasal surgery

“…However, the critical cut-off value for GV with regard to an aspiration risk must be discussed. The critical threshold for this risk has been reported to be 0.4-0.8 ml/kg (28-56 ml/70 kg) [25,20], but the 0.8 ml/kg threshold is probably insufficient because regurgitation and aspiration of a minimum of 200 ml GV are required for pulmonary damage [26]. Residual GVs in healthy, hungry patients can be ≥1.5 ml/kg [27].…”

Ultrasound assessment of the effect of pharyngeal packing on perioperative gastric volume in nasal surgery

“…The gastric antrum is the optimal region for GV evaluation by ultrasonography [18]. The success rates of stomach evaluation via investigation of the gastric antrum with patients in the supine and right lateral decubitus positions are almost 100% [19,20]. For this reason, we used this approach, with ultrasonographic measurements performed with patients supine to avoid postoperative prolongation of the general anaesthesia period and complications related to position change.…”