Effect of percutaneous endoscopic gastrostomy on gastrointestinal motility: evaluation by gastric-emptying scintigraphy

Purpose Firstly, to assess the effect of percutaneous endoscopic gastrostomy (PEG) tube placement on gastric emptying, gastrointestinal (GO tract motility and the rate of gastroesophageal reflux (GER). Secondly, to confirm whether correlations exist between drug absorption behaviour and GI tract motility using the combination method of absorption function analysis with the motility study. Methods Subjects comprised 11 patients with neurological dysphagia. Gastric-emptying scintigraphy was performed both before PEG via nasogastric tube feeding and after PEG placement. After fasting for more than 8 h, each patient was administered 111 MBq of Tc-99m-labelled diethylenetriaminepentaacetic acid (DTPA) with a 100 ml liquid meal via a nutrition tube. Dynamic imaging was performed immediately after administration of a radiolabelled liquid meal for a 1 h period and static imaging was performed after 1, 2, 3 and 6 h. Gastric emptying half-time (T-50) was calculated in each patient, and GER ratio and GI transit rate were also evaluated. Simultaneously, we administered 10 mg of famotidine in six of the 11 patients and measured serum concentrations of famotidine at 0, 1, 2, 3 and 6 h. Using the time-concentration curve of famotidine, the maximum concentration of famotidine (C-max) and area under the curve of famotidine (AUC(f)) were calculated for each patient. Results In seven of 11 patients, T-50 changed after PEG placement, but not significantly. The GER ratio was significantly decreased and complicated pneumonia improved after PEG placement. GI transit rate for each GI segment was unchanged after PEG placement. Significant linear correlations were identified between T-50 and both C-max and AUC(f). Conclusion Gastric-emptying scintigraphy with Tc-99m-DTPA was effective in the evaluation of GI transit before and after PEG, as well as in assessing GER. Motility and famotidine absorption were maintained after PEG placement. Significant linear correlations were found between T-50 and both Cmax and AUC(f). These findings suggest that drug absorption may have some relationship between T-50. The result may be more reliable with a larger population.