Comparative efficacy of doxycycline and its analogues with autologous blood patch pleurodesis for persistent air leak following secondary spontaneous pneumothorax in adults-a systematic review

Background: The presence of free air in the pleural space of lungs is termed pneumothorax and in individuals with underlying lung disease, it is known as secondary spontaneous pneumothorax. The incidence of spontaneous pneumothorax is 16 to 18 per lakh population. The most common causes for secondary spontaneous pneumothorax are chronic obstructive pulmonary disease (COPD), tuberculosis (TB), human immunodeficiency virus (HIV), cystic fibrosis of lung, and history of smoking. The clinical signs and symptoms include acute dyspnea, thoracic pain and cough. Persistent air leaks are frequently seen in secondary spontaneous pneumothorax. The incidence of persistent air leaks in post-surgical patients varies from 8% to 43%. The aim of the study is to compare the efficacy of doxycycline, tetracycline, and minocycline to other pleurodesis agents in the cessation of air leaks and reducing the recurrence of pneumothorax in adults with persistent air leaks following secondary spontaneous pneumothorax. Methods: A systematic search from PubMed, Cochrane, Embase, Web of Science, and clinical trials.gov was performed. After screening, three studies were selected which includes 2 randomized controlled trials (RCTs) and 1 prospective study with a pooled sample size of 168. Results: The mean age and standard deviation of the study participants was 50.57 +/- 13.23 years. The success rate of autologous blood patch pleurodesis (ABPP) was reported as 94.70% followed by doxycycline with 84.20%, talc with 84% and tetracycline 63%. The mean time of cessation of air leaks was lowest with doxycycline (11 and 36 hours) and ABPP (24 and 27 hours). Furthermore, ABPP is reported having fewer complications when compared with other agents. Conclusions: Among chemical pleurodesis agents, doxycycline is reported to be having higher success rate and less recurrences. However, it is found to be inferior when compared directly to ABPP.