Abstract: Objective:To analyze the clinical effect of high flow humidified oxygen therapy in patients with acute heart failure complicated by respiratory failure and difficulty in weaning.Methods:This study was a retrospective study.From January 2020 to January 2022, 80 patients with acute heart failure and difficulty in weaning from respiratory failure admitted to the emergency department of the Emergency in Eighth Medical Center of the PLA General Hospital were selected.There were 49 males and 31 females, aged(52.86 ± 4.31)years old, ranging from 38 to 76 years old.The patients were randomly divided into low flow group and high flow group with 40 patients in each group.All patients were given routine treatment after admission.On this basis, the low flow group was given low flow oxygen treatment, and the high flow group was given high flow humidified oxygen treatment.The treatment effect, weaning success rate, vital signs, blood gas indicators[arterial partial pressure of oxygen(PaO 2), blood oxygen saturation(SaO 2), arterial partial pressure of carbon dioxide(PaCO 2)]Lung function[forced expiratory volume per second(FEV 1), forced vital capacity(FVC), forced expiratory volume per second(FEV 1/FVC)], serological indicators[C-reactive protein(CRP), B-type natriuretic peptide(BNP), interleukin-6(IL-6)]. Results:The weaning success rate[95.0%(38/40)]in the high flow group was higher than that in the low flow group[75.0%(30/40)], and the effective rate[95.0%(38/40)]in the high flow group was higher than that in the low flow group[75.0%(30/40)], and the differences were statistically significant( P<0.05). After 7 days of treatment, the mean arterial pressure[(75.45±3.86)mmHg, 1 mmHg=0.133 kPa], heart rate[(82.18±6.62)times/min], respiratory rate[(19.89±3.65)times/min]in the high flow group were lower than those in the low flow group[(80.86±4.13)mmHg, (89.67±7.48)times/min, (22.34±4.17)times/min]; PaO 2[(83.49±7.93)mmHg], SaO 2[(93.84±7.45)%]were higher than those in low flow group[(76.52±6.48)mmHg, (86.93±6.78)%], PaCO 2[(40.78±4.36)mmHg]were lower than those in low flow group[(46.45±4.82)mmHg]; FEV 1[(1.95±0.51)L], FVC[(3.08±0.47)L], FEV 1/FVC[(63.31±6.43)%]were higher than those in low flow group[(1.65±0.42)L, (2.87±0.42)L, (57.49±5.81)%]; CRP[(28.59±4.71)mg/L], BNP[(285.74±26.81)pg/ml], IL-6[(12.79±3.23)ng/L]were lower than those in the low flow group[(35.82±5.63)mg/L, (342.81±35.69)pg/ml, (15.42±4.98)ng/L], and the differences were statistically significant( P<0.05). Conclusions:The implementation of high flow humidified oxygen treatment program can effectively improve the success rate of weaning of patients with high flow humidified oxygen treatment program, improve the vital signs and blood gas indicators of patients, promote the recovery of pulmonary function of patients, and improve the treatment effect of patients.