Comparative effects on glucose absorption of intragastric and post-pyloric nutrient delivery in the critically ill
1 Discipline of Acute Care Medicine, University of Adelaide, North Terrace, Adelaide, SA 5000, Australia
2 National Health and Medical Research Council of Australia, Centre for Clinical Research Excellence in Nutritional Physiology and Outcomes, Level 6, Eleanor Harrald Building, North Terrace, Adelaide, SA 5000, Australia
3 Intensive Care Unit, Level 4, Emergency Services Building, Royal Adelaide Hospital, North Terrace, Adelaide, SA 5000, Australia
4 Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Level 6, Eleanor Harrald Building, North Terrace, Adelaide, SA 5000, Australia
5 Department of Gastroenterology, Level 4, Emergency Services Building, Royal Adelaide Hospital, North Terrace, Adelaide, SA 5000, Australia
Critical Care 2012, 16:R167 doi:10.1186/cc11522Published: 17 September 2012
Studies in the critically ill that evaluate intragastric and post-pyloric delivery of nutrient have yielded conflicting data. A limitation of these studies is that the influence in the route of feeding on glucose absorption and glycaemia has not been determined.
In 68 mechanically ventilated critically ill patients, liquid nutrient (100 ml; 1 kcal/ml containing 3 g of 3-O-Methyl-D-glucopyranose (3-OMG), as a marker of glucose absorption), was infused into either the stomach (n = 24) or small intestine (n = 44) over six minutes. Blood glucose and serum 3-OMG concentrations were measured at regular intervals for 240 minutes and the area under the curves (AUCs) calculated for 'early' (AUC60) and 'overall' (AUC240) time periods. Data are presented as mean (95% confidence intervals).
Glucose absorption was initially more rapid following post-pyloric, when compared with intragastric, feeding (3-OMG AUC60: intragastric 7.3 (4.3, 10.2) vs. post-pyloric 12.5 (10.1, 14.8) mmol/l.min; P = 0.008); however, 'overall' glucose absorption was similar (AUC240: 49.1 (34.8, 63.5) vs. 56.6 (48.9, 64.3) mmol/l.min; P = 0.31). Post-pyloric administration of nutrients was also associated with greater increases in blood glucose concentrations in the 'early' period (AUC60: 472 (425, 519) vs. 534 (501, 569) mmol/l.min; P = 0.03), but 'overall' glycaemia was also similar (AUC240: 1,875 (1,674, 2,075) vs. 1,898 (1,755, 2,041) mmol/l.min; P = 0.85).
In the critically ill, glucose absorption was similar whether nutrient was administered via a gastric or post-pyloric catheter. These data may have implications for the perceived benefit of post-pyloric feeding on nutritional outcomes and warrant further investigation.