Background Currently, no specific medicine is available for silicosis complicated with chronic obstructive pulmonary disease (COPD).

Objective This study investigates the effects of tetrandrine combined with a modified pursed lip breathing method on the blood oxygen level, respiratory function, and the ability of self care among silicosis patients complicated with COPD.

Methods A total of 81 patients with silicosis and stable COPD admitted to the outpatient department of Jiangxi Province Institute of Occupational Disease Prevention and Control between June 2018 and January 2020 were selected as study subjects and divided into a drug therapy group (40 cases) and a combined treatment group (41 cases) by random number table method. The drug therapy group were treated with tetrandrine only, while the combined treatment group were treated with tetrandrine and a modified pursed lip breathing method. The arterial blood gas indicatorsarterial oxygen saturation (SaO₂), arterial partial pressure of oxygen (PaO₂), and arterial partial pressure of carbon dioxide (PaCO₂), lung function indicatorsforced vital capacity (FVC), the percentage of predicted forced expiratory volume in 1 second (FEV1%), the percentage of predicted maximum ventilatory volume (MVV%), and FEV1/FVC, respiratory rate, 6-minute walking distance, modified Medical Research Council Dyspnea Scale (mMRC) scores, and activities of daily living (ADL) in both groups were detected and compared before and after the assigned treatment.

Results The study included 81 male silicosis patients complicated with stable COPD. No differences were found between the drug therapy group and the combined treatment group in age, body mass index, silicosis duration, COPD duration, and silicosis stages. At baseline, there were also no differences in the observations such as arterial blood gas indicators and lung function indicators. After the designed treatment, the PaCO₂ level, mMRC score, and respiratory rate of the drug therapy group were (43.99±5.01) mmHg, 1.97±0.21, and (23.09±2.02) times·min^-1, respectively, and those of the combined treatment group were (38.09±3.04) mmHg, 1.52±0.19, and (17.99±1.05) times·min^-1, respectively; these indicators were reduced after treatment compared with before, and the combined treatment group showed lower levels than the drug therapy group (P < 0.05). After the treatment, the SaO₂, PaO₂, FVC, FEV1%, MVV%, and FEV1/FVC of the drug therapy group were (86.69±8.57)%, (70.57±7.17) mmHg, (2.59±0.30) L, (77.69±7.47)%, (69.17±7.02)%, and (56.24±5.69)%, respectively, and those of the combined group were (98.49±9.15)%, (80.02±8.59) mmHg, (3.15±0.35) L, (86.29±8.05)%, (80.02±8.09)%, and (63.01±6.52)%, respectively; these indicators were increased after treatment compared with before, and the combined treatment group showed higher levels than the drug therapy group (P < 0.05). After the treatment, the 6-minute walking distance of the drug therapy group was (337.65±35.41) m, significantly shorter than (388.29±39.05) m of the combined treatment group (P < 0.05); the respiratory rate and the mMRC of the drug therapy group were (23.09±2.02) m and 1.97±0.21, significantly higher than (17.99±1.05) m and 1.52±0.19 of the combined treatment group (P < 0.05). At 3, 6, and 9 months after the treatment, the ADL scores of the drug therapy group were 55.34±5.57, 65.14±6.57, and 80.11±7.99, respectively, and those of the combined treatment group were 59.14±6.02, 71.38±7.05, and 89.24±9.42, respectively; the ADL scores were significantly different between the two groups at different time points after treatment, showing patterns like higher ADL scores after treatment than before, and higher ADL scores in the combined treatment group than in the drug therapy group (P < 0.05).

Conclusion Tetrandrine combined with modified pursed lip breathing can remarkably improve the blood oxygen level in patients with silicosis complicated with stable COPD, as well as their respiratory function and self-care ability; therefore, the combined treatment deserves wide application.