Turning tube feeding off while repositioning patients in bed.

Norma Metheny is a professor and the Dorothy A. Votsmier Endowed Chair in Nursing at Saint Louis University in St Louis, Missouri. because standard care mandates frequent position changes to prevent pressure ulcers as well as pooling of respiratory secretions. When missed calories due to position changes are added to those associated with feeding interruptions for other reasons (eg, preparation for surgery or diagnostic procedures), it is clear that a critically ill patient’s nutrient intake may be significantly decreased. For example, in a study of 39 critically ill patients followed for 276 tube feeding days, Elpern et al reported that patients received a mean of 64% of the goal energy intake (largely because of feeding interruptions). The mean length of feeding interruptions in the study was 5.23 hours per patient per day; 15% of the interruptions were associated with changes in the patient’s body position. To evaluate the potential benefit of reduced gastric volume after a brief feeding interruption, it is necessary to consider the rate at which the stomach empties. In a study of 10 healthy males, a mean of 89.5 minutes was required for 50% of a specially marked 200-mL liquid meal to empty from the subjects’ stomachs when they were sitting up. Gastric emptying is even slower in many critically ill patients. For example, another group of investigators found that the mean gastric half-emptying time was 155 minutes ANorma Metheny, RN, PhD, replies: