Background & aims: Nasogastric feeding may result in gastro-oesophageal reflux and, therefore, increase the risk of aspiration. This may be greater when feeds are administered via a bolus than by infusion. We aimed to measure gastric emptying time and quantify gastro-oesophageal reflux in healthy volunteers given a liquid feed via an oral bolus (OB), a nasogastric tube bolus (TB) and a nasogastric tube drip (TD).
Methods: Twelve male volunteers participated in three separate studies (OB, TB and TD) in random order, each 3 days apart. The feed consisted of 220 ml Ensure Plus (1.5 kcal/ml), labelled with 12 MBq (99m)Tc DTPA. The OB and TB were given over 5 min and the infusion rate for the TD was 55 ml/h. Gastric emptying time was measured using gamma scintigraphy. Gastro-oesophageal reflux was observed continuously until the stomach was empty, using a multichannel intraluminal impedance catheter.
Results: Mean (95% CI) T(50) gastric emptying times for the OB and TB studies were 41.3 (36.5-46.2) min and 36.2 (30.6-41.8) min respectively (p=0.19). The stomach emptied at a rate equal to the infusion rate in the TD studies. Median (IQR) number of reflux episodes for the OB, TB and TD studies were 4.5 (2.0-6.0), 3.0 (2.0-4.75) and 2.0 (0.25-6.25) respectively. Median (IQR) total duration of reflux for the OB, TB and TD studies were 38 (20-242), 49 (17-71) and 36 (1-125) s respectively (p=NS).
Conclusions: The lack of difference in gastro-oesophageal reflux between bolus and continuous feeding indicates that in healthy volunteers both methods are equally safe with respect to the risk of aspiration.