Vomiting during body surface gastric mapping testing

BackgroundVomiting is a symptom of various gastrointestinal (GI) disorders and may invalidate gastric emptying tests. Body surface gastric mapping (BSGM) is a clinical test to assess motor vs. sensory contributors to GI symptoms. AimsWhile previous studies have observed myoelectrical dysrhythmias associated with vomiting, the effects of vomiting on BSGM testing have not been defined. MethodsA large clinical database of de-identified BSGM tests was queried for vomiting events, noted by symptom markers via an integrated symptom reporting App. Tests with pre-meal or >2 vomiting events were excluded. Spectrograms and clinical reports were qualitatively assessed. Key BSGM metrics, including the Gastric Alimetry Rhythm Index (GA-RI) and BMI-adjusted amplitude, were interrogated in 5 min epochs for quantitative analysis. ResultsA total of 49 vomit events were included. Vomiting typically had little effect, though was sometimes characterised by small, temporary decreases in BMI-adjusted amplitude or GA-RI. Prolonged periods (> 10 mins) of low amplitude were observed in 4 cases (8%). A mixed effects model revealed a transient decrease in GA-RI in the 5 mins before ({Delta} = -0.27; p < 0.001) and after vomiting ({Delta} = -0.21; p = 0.014), but not in subsequent periods (all p > 0.05). Other metrics were unaffected. Nausea, bloating, and excessive fullness symptoms decreased following vomiting (all p < 0.05). ConclusionsTransient amplitude and rhythm decreases were observed concurrent to vomiting, but subsequently normalised. While additional considerations may be required during test interpretation, the overall impact of vomiting on BSGM test interpretation is minimal.