The diagnostic accuracy of ultrasonography over manual aspiration for gastric reserve volume estimation in critically ill patients

Abstract

Background: Although gastric reserve volume (GRV) is a surrogate marker for gastrointestinal dysfunction and feeding intolerance. There is ambiguity in its estimation in most of the international guidelines due to problems associated with its measurement. Ever since point of care ultrasound has entered into the armamentarium of anesthetists, it has kindled interest for its efficient use for this estimation. Methods: In this prospective observational study we recruited 57 critically ill patients and thus analyzed 586 samples of GRV obtained by both ultrasonographic (USG) and manual aspiration method done simultaneously on these patients.Results: USG-guided GRV was significantly correlated (r=0.788, P<0.0001)and in positive agreement with manual aspiration technique by Bland-Altman plot with mean average of difference of 8.5±14.84 (95% confidence interval [CI], 7.389–9.798) The upper and lower limit of agreement were 37.7 and –20.5 which too were within the ±1.96 standard deviation (P<0.0001).The sensitivity and positive predictive value, specificity and negative predictive value, AUC (95% CI) of the USG for finding out the feed intolerance was (66.67%, 98.15%, 0.8) in our study with 96.49% diagnostic accuracy.Conclusions: Ultrasonographic estimation of GRV was positively, significantly correlated and was in agreement with manual aspiration method. It estimated feed intolerance earlier than manual aspiration technique. With routine use of gastric USG, its use could possibly be extrapolated in clinical situations where feeding status is unclear and there is high risk of aspiration and we hope it will eventually become a standard practice of critical care.