Relation between incidence of pneumonia and protective reflexes in post-stroke patients with oral or tube feeding

Abstract

Objectives: Although attenuated protective reflexes have been implicated in the development of aspiration pneumonia, the relation between the incidence of pneumonia and the state of these reflexes has not been investigated. Furthermore, the role of feeding tube placement in preventing pneumonia in patients with attenuated protective reflexes is unknown. We studied the relationship between the incidence of pneumonia and the state of cough and swallowing reflexes in post-stroke patients with oral or tube feeding.

Design: The incidence of pneumonia was prospectively analysed for 1 year in three groups of post-stroke patients on the basis of the following clinical conditions: oral feeding without dysphagia (n = 43); oral feeding with dysphagia (n = 48); and nasogastric tube feeding with dysphagia (n = 52). We also studied the incidence of pneumonia in bedridden patients with nasogastric tube feeding (n = 14). Before the start of the study, the swallowing and cough reflexes of each patient were measured. The swallowing reflex was evaluated according to latency of response, which was timed from the injection of 1 mL of distilled water into the pharynx through a nasal catheter to the onset of swallowing. The cough threshold of citric acid aerosols was defined as the concentration at which the patient coughed five times. RESULTS.;: The incidence of pneumonia was observed in patients having both a latency of response longer than 5 s and a cough threshold for citric acid higher than a concentration of 1.35 (log mg mL-1). The incidence of pneumonia was significantly higher in patients with oral feeding than in those with tube feeding (54.3 vs. 13.2%, P < 0.001). In bedridden patients with tube feeding, the latency of response was longer than 20 s and no patient coughed at the highest concentration of citric acid. The incidence of pneumonia was 64.3% in such patients.

Conclusions: The state of protective reflexes had a significant relation to the incidence of pneumonia. Feeding tube placement may have a beneficial role in preventing aspiration pneumonia in mildly or moderately disabled post-stroke patients with attenuated protective reflexes. Bedridden patients who were tube-fed had the highest incidence of pneumonia.