Effect of high-flow nasal cannula oxygen therapy on diaphragmatic function in patients with acute exacerbation of chronic obstructive pulmonary disease: a prospective randomized controlled trial

Abstract

To investigate the effect of high-flow nasal cannula oxygen therapy (HFNC) on the clinical efficacy and diaphragm function of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). The patients with mild to moderate AECOPD (clinical classification I-II) admitted to Huxi Hospital Affiliated to Jining Medical College from January to October in 2018 were enrolled. The patients were divided into HFNC treatment group and routine oxygen therapy control group (each n = 37) by randomly number table method. The two groups were given bronchiectasis drugs, corticosteroids, expectorant, anti-infection treatment, at the same time, the HFNC treatment group was given HFNC with the initial flow rate of 40 L/min. The routine oxygen therapy control group was given low flow oxygen, and the initial flow rate was 3 L/min. General data such as gender, age, clinical grade, acute physiology and chronic health evaluation II (APACHE II) score were recorded. Bedside ultrasound was used to measure the diaphragmatic excursions during quiet breathing (DEq), diaphragmatic excursions during deep breathing (DEd), and diaphragmatic shallow fast breathing index (D-RSBI) before and 2, 24 and 48 hours after treatment in both groups and compared, meanwhile, arterial blood gas analysis was performed, and arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2) were recorded. Two patients in the HFNC treatment group withdrew from the study because they could not tolerate HFNC, while other patients were enrolled in the analysis. There was no statistically significant difference in gender, age, proportion of AECOPD II grade or APACHE II score between the two groups, indicating that the general data of the two groups were comparable and balanced. There was no statistically significant difference in DEq, DEd, D-RSBI, PaO2 or PaCO2 before treatment between the two groups. After treatment, DEp in both groups was decreased gradually with time, it was decreased earlier in the HFNC treatment group, and it showed significant difference as compared with that before treatment at 2 hours after treatment (mm: 18.3±3.1 vs. 20.1±4.2, P < 0.01), and it was significantly lower than that in the routine oxygen therapy control group (mm: 18.3±3.1 vs. 20.3±3.7, P < 0.05); DEd was gradually increased in both groups, it was significantly increased in the HFNC treatment group, and it was significantly higher than that in the routine oxygen therapy control group at 24 hours and 48 hours after treatment (mm: 55.2±7.6 vs. 50.8±9.2 at 24 hours, 59.4±7.7 vs. 53.6±9.1 at 48 hours, both P < 0.05); D-RSBI was decreased gradually in both groups, it was decreased earlier and more significant in the HFNC treatment group, and it was significantly lower than that in routine oxygen therapy control group at 24 hours and 48 hours after treatment (times×min-1×mm-1: 0.41±0.13 vs. 0.51±0.20 at 24 hours, 0.31±0.12 vs. 0.43±0.17 at 48 hours, both P < 0.05). After treatment, there was no statistically significant difference in PaO2 or PaCO2 between the two groups. HFNC can effectively relieve diaphragm fatigue in patients with mild to moderate AECOPD, but it had no effect on carbon dioxide retention.