Objective:To investigate the inflammatory state and immune function of patients experiencing acute exacerbation of chronic obstructive pulmonary disease complicated by hypercapnia before and after noninvasive mechanical ventilation.Methods:The clinical data of 120 patients experiencing acute exacerbation of chronic obstructive pulmonary disease complicated by hypercapnia who received treatment in Taizhou Central Hospital from August 2018 to August 2019 were retrospectively analyzed. According to different treatment methods, they were divided into a noninvasive ventilation group ( n = 57) and a conventional treatment group ( n = 63). The therapeutic effect was observed in each group. Before and after treatment, serum levels of inflammatory factors (tumor necrosis factor-α, interleukin-6, C-reactive protein), immune indexes (CD 4+, CD 8+, CD 4+/CD 8+), blood gas analysis indexes (PaCO 2, PaO 2, pH) and pulmonary function indexes (forced expiratory volume in 1 second, forced vital capacity, peak expiratory flow) were measured in each group. Adverse reactions such as sputum obstruction and gastric distension during treatment were statistically analyzed. Results:Total effective rate in the noninvasive ventilation group was significantly higher than that in the conventional treatment group ( P < 0.05). After treatment, serum levels of tumor necrosis factor-α, interleukin-6, C-reactive protein were (61.98 ± 5.16) ng/L, (19.77 ± 3.41) ng/L, (15.39 ± 3.22) mg/L respectively in the noninvasive ventilation group, which were significantly lower than those in the conventional treatment group [(68.24 ± 5.12) ng/L, (21.04 ± 3.52) ng/L, (19.28 ± 3.50) mg/L, t = 6.664, 2.003, 6.314, all P < 0.05]. After treatment, CD 4+ and CD 4+/CD 8+ were (29.28 ± 2.81) and (1.18 ± 0.17) respectively in the non-invasive ventilation group, which were significantly higher than (27.34 ± 2.96) and (1.09 ± 0.15) in the conventional treatment group ( t = 3.672, 3.081, both P < 0.05). After treatment, PaCO 2 [(48.34 ± 6.92) mmHg] in the noninvasive ventilation group was lower than that in the conventional treatment group [(53.09 ± 7.07) mmHg, t = 3.712, P < 0.05]. PaO 2, pH, forced expiratory volume in 1 second, forced vital capacity and peak expiratory flow were (70.61 ± 9.82) mmHg, (7.35 ± 0.15), (2.39 ± 0.48) L, (2.50 ± 0.46) L, (4.65 ± 0.75) L/s, respectively in the non-invasive ventilation group, which were significantly higher than those in the conventional treatment group [(65.19 ± 8.23) mmHg, (7.29 ± 0.14), (2.16 ± 0.47) L, (2.21 ± 0.45) L, (4.06 ± 0.69) L/s, t = 3.287, 2.266, 2.650, 3.488, 4.488, all P < 0.05]. There was no significant difference in the incidence of adverse reactions between the two groups ( P > 0.05). Conclusion:Noninvasive mechanical ventilation for patients experiencing acute exacerbation of chronic obstructive pulmonary disease complicated by hypercapnia can improve the inflammatory state and immune function, enhance lung function and reduce the degree of hypoxia.