Electromyographic swallowing study during high flow oxygen therapy compared with low flow oxygen therapy in post-extubated patients

Abstract

Background: High flow nasal cannula (HFNC) is increasingly used during a post-extubation period. Its interface allows patients to drink or eat but there are limited data of HFNC’s effects on patient’s swallowing. Objectives: Our study aimed to compare swallowing latency time in post-extubated patients using HFNC 50 LPM and oxygen cannula 5 LPM. We hypothesized that a positive pressure effect of HFNC might decrease the latency time and improve swallowing function. Additionally, we analyzed factors affecting the latency time. Methods: We performed a crossover study in the post-extubated patients within a 48-hour period. We randomly assigned the patients to receive HFNC 50 LPM or oxygen cannula 5 LPM. The oxygen therapy lasted for 5 minutes. Then the patients swallowed 3 ml. of water. The latency times were recorded three times using surface electromyography and were interpreted by blinded assessors. Subsequently, the patients were switched into the other treatment and the tests were repeated. After the crossover phase, we also measured the latency times in patients using HFNC 30 and 40 LPM. Results: Totally, 20 patients were included. The mean swallowing latency time in the HFNC 50 LPM group was significantly shorter than the latency time in simple oxygen group (1.11 (0.56) VS 1.29 (0.70) seconds, p = 0.027). The mean latency times in patients using HFNC 30 LPM (1.24 (0.80) seconds) and HFNC 40 LPM (1.23 (0.70) seconds) were not different from the simple oxygen group. According to multivariate analysis, diabetes mellitus was the only factor affecting the swallowing latency time. Conclusion: The post-extubated patients using HFNC 50 LPM had better swallowing reflex.