Comments on parenchymal blood patching in CT-guided lung biopsy

Dear Editor, We read with great interest the article by Chakraborty, Pratik titled ‘Parenchymal blood patching in percutaneous computed tomography-guided lung biopsy: A retrospective analysis of pneumothorax management’ published in Lung India.[1] The authors are to be commended for addressing pneumothorax, a common and clinically relevant complication of CT-guided lung biopsy. In this retrospective analysis, the authors report a significantly lower incidence of pneumothorax in the blood patch group compared with the non-blood patch group (8.5% vs. 30.7%, P = 0.04). However, certain methodological aspects merit further clarification. As the study involved two temporally separated cohorts, the criteria used for case selection during the non-blood patch and blood patch periods are not clearly described. It is unclear whether lesion related characteristics (e.g. size, depth, or location), perceived procedural risks, or operator preference influenced the decision to use blood patching. This raises the possibility of selection bias, which may have contributed to the observed reduction in pneumothorax rates. Additionally, the temporal separation of the two cohorts raises possibility for time trend bias. Procedural expertise, imaging technology, and peri procedural practices may evolve over time and independently influence complication rates. Information regarding whether a uniform institutional protocol for case selection for CT guided lung biopsy,[2] the he choice between transthoracic biopsy over transbronchial lung biopsy, and post procedure monitoring across the study period would help in interpreting the results more accurately. The validity of the comparison group also warrants discussion. In the non-blood patch arm, no tract sealing technique was employed. Prior studies have explored alternative techniques such as saline injection and other sealants to reduce pneumothorax rates.[3,4] The absence of an active comparator group, may therefore overestimated the apparent benefit of blood patching. Moreover, the relatively higher pneumothorax rates in the control group raises questions regarding, whether it fully reflects current practice, particularly considering evolving biopsy techniques and pneumothorax risk prediction models.[4] It is also relevant that autologous blood patching technique was introduced few decades ago, yet it has not been widely adopted in daily clinical practice.[2] This may reflect unresolved concerns regarding procedural feasibility, variability in effectiveness, or safety. While the present study focuses on pneumothorax reduction, procedure related adverse events such as infection, empyema, inflammatory reactions, or delayed complications related to intraparenchymal blood injection are not discussed. Although published literature on intraparenchymal blood patching after CT guided lung biopsy have not documented procedure specific complications, the lack of dedicated safety analyses highlights the need for future studies to systematically assess and report potential adverse effects.[5,6] Explicit reporting of safety endpoints would strengthen confidence in the broader applicability of this technique. Additionally, follow-up in the present study was limited to the immediate post procedural duration. Data about delayed pneumothorax, late infections, or post discharge outcomes would have increased the clinical relevance of the results. Despite these limitations, the study provides valuable real-world data from an Indian tertiary care centre and highlights a potentially cost-effective intervention with clinical utility. We concur with the authors that prospective, multicentre studies incorporating standardized case selection criteria, active comparator groups, dedicated safety endpoints, and longer follow-up are required to clearly define the efficacy and safety profile of parenchymal blood patching. We congratulate the authors on their contribution and believe this work will stimulate further discussion and research into biopsy tract-sealing strategies. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.