Do nasogastric tubes affect aspiration risk?
Reviewed by Roganie Govender

A nasogastric tube (NGT) is frequently used for patients who are at risk of endotracheal aspiration of oral diet. However, this cannot eliminate the aspiration of saliva. The incidence of aspiration pneumonia in patients with NGT therefore remains high. Some evidence exists suggesting that the presence of the NGT impairs swallowing function, thus influencing clinical decisions on whether to allow small amounts of oral intake during NGT feeding. The authors of this paper examined whether the presence of an NGT increased the risk of aspiration of a small amount of fluid (1mL). The authors undertook videofluoroscopy on 147 patients with NGT, where patients were examined swallowing 1mL of contrast with the NGT insitu and then with the NGT removed. All patients also had a subsequent assessment of their swallowing physiology that allowed the authors to characterise their dysphagia severity and make recommendations for diet [non-oral feeding (n=59), diet modification (n=75), diet as tolerated (n=13)]. The Rosenbeck Penetration-Aspiration Scale (PAS) was used to quantify aspiration risk before and after NGT removal. They compared the difference in PAS scores with NGT-in vs. NGT-out. The overall mean PAS scores were not statistically different for each condition. A PAS-difference score was also calculated (PAS NGT-in – PAS NGT out.), where a PAS-diff >0 indicated greater aspiration risk in the presence of the NGT. In this study, the authors found no difference in aspiration risk for small volumes with and without an NGT, regardless of dysphagia severity. They provide useful references and discussion for the sources of aspiration pneumonia in NGT fed patients (saliva and gastro-oesophageal reflux material). The authors recommend further studies that consider oral diet of semi-solids in patients who are NGT fed due to aspiration of fluids.

Effect of Nasogastric Tube on Aspiration Risk: Results from 147 Patients with Dysphagia and Literature Review.
Kim G, Baek S, Park H, et al.
DYSPHAGIA
2018;33:731-8.