Confirming nasogastric feeding tube position versus the need to feed

Abstract

Objective: To review current methods for confirming nasogastric tube position and their efficacy in relation to the need to feed.

Design and methods: This paper reviews current guidelines and techniques to safely confirm tube position balanced against the need to provide nutrition quickly. All new information was incorporated from electronic database searches up to 7.4.2012.

Findings: Tube misplacement per se, feeding through undetected misplaced tubes and the potentially fatal complications that arise from both appear to be underestimated. Misplacement occurs due to failure to confirm tube position, lack of expertise in interpretation or inability of the confirmation method to differentiate safe placement from misplacement. Inability to confirm tube position is a major cause of delay to feeding and risks malnutrition.

Discussion: Theoretically, X-ray is the gold standard for confirming tube position. However, because X-ray is associated with misinterpretation and delays feeding, it should in most cases be the second-line confirmation technique after other methods fail. Currently, pH offers the most practical first-line confirmation method with a threshold of ≤5.0 indicating gastric position. A pH threshold ≤4.0 increases false negatives, excess X-ray use and misinterpretation and delay to feeding whereas a threshold >5.0 can fail to detect lung, oesophageal or intestinal placement. Traumatic injury on misplacement can be pre-empted by use of capnography/capnometry or X-ray at a 35 cm tube depth or an electromagnetic (EM) trace. The EM trace guides real-time placement and re-positioning until gastric position is attained but a larger evidence-base is required to confirm this potential.

Conclusions and recommendations: Research is urgently required on how to avoid tube misplacement. This must be balanced against risk of delayed feeding and cumulative nutritional deficit leading to subsequent complications and mortality.