The Efficacy and Safety of Autologous Blood Patch for Persistent Air Leaks: A Systematic Review and Meta-Analysis

Persistent air leaks (PALs) are associated with prolonged hospital stays, contamination and sustained infection of the pleural space, and significant morbidity. A fistulous tract between the alveoli and the pleural space is referred to as an alveolar-pleural fistula (APF), whereas a fistulous tract between the bronchiole and the pleural space is referred to as a bronchopleural fistula (BPF). There is no consensus on the treatment, and multiple modalities exist for the management of persistent air leak (PAL). Autologous blood patch (ABP) is a relatively safe and inexpensive method that has been used for many years for the treatment of PALs. We conducted an electronic database search between 08/24/2022 and 08/27/2022 in PubMed, Embase, and Cochrane using keywords. The following keywords were used: "Blood patch" OR "Autologous blood patch" AND "pleurodesis." Our study included all original studies with the prime focus on the etiology of PALs, clinical characteristics, procedural details of ABP, and outcomes of the proposed treatment. The primary outcomes that were the focus of our study were the time to seal the air leak, the time to remove the chest tube after air leak cessation, and the time to discharge from the hospital. To determine the safety of ABP, we also evaluated the procedural outcomes. Our findings suggest a statistically significant decrease in the time to air leak cessation when compared to the control group (mean difference of -3.75 {95% CI: -5.65 to -1.85; P=0.001}) with considerable heterogeneity of I2=85% and P=0.001. However, the difference was not statistically significant when a lower dose of ABP (50 mL) was compared to a higher dose (100 mL) (mean difference of 1.48 {95% CI: -0.07 to 3.02; P=0.06}) and considerable heterogeneity of I2=80% and P=0.03. There was no statistically significant difference in the time to discharge when compared to the control group (mean difference of -2.12 {95% CI: -4.83 to 0.59; P=0.13}) and considerable heterogeneity (I2=95% and P<0.001). When compared to the control group, ABP did not provide any statistically significant difference in the risk ratio for infection (1.18 {95% CI: 0.52 to 2.65; P=0.70} and moderate heterogeneity {I2=33% and P=0.20}), pain (1.18 {95% CI: 0.52 to 2.65; P=0.70} and moderate heterogeneity {I2=33% and P=0.20}), and fever (0.54 {95% CI: 0.27 to 1.10; P=0.09} and no heterogeneity {I2=0% and P=0.50}). Our study concludes that using ABP caused a statistically significant decrease in the time to air leak cessation when compared to the control group. However, the procedure does not provide a statistically significant difference in the time to discharge from the hospital when compared to conservative treatment. Similarly, there was no statistically significant difference in the risk ratio for complications such as infection, pain, and fever when compared to conservative management. More studies need to be conducted to fully understand the efficacy and safety of ABP in the management of PALs.