Predictive Factors of Early Autologous Blood Pleurodesis for Postoperative Air Leak

Autologous blood pleurodesis (ABP) is an effective, safe, and minimally invasive treatment for air leaks following lung resection. This article provides a brief overview of ABP and focuses on predicting treatment based on air leak volumes detected by a digital drainage system, highlighting the benefits of early intervention.

Introduction

Postoperative prolonged air leaks (PALs) following lung resection is a significant complication, occurring in approximately 5 to 15% of cases. PALs are typically defined as persistent air leaks from the lung into the pleural cavity lasting more than five days post-surgery. This condition can adversely affect patient recovery, leading to prolonged hospital stays, increased healthcare costs, and a higher risk of infections. Autologous blood pleurodesis (ABP) was first introduced by Robinson CL in 1987 as a treatment for PALs and is recognised as a cost-effective, safe, and simple procedure. ABP is primarily performed when conservative treatments, such as chest drainage, fail to resolve PALs. The basic principle of ABP is the "patch effect" of coagulated blood, but it is also said to induce a mild inflammatory response that promotes pleural adhesion. While much discussion has centred on the optimal blood volume and factors that enhance the success rate of ABP, no definitive conclusions have been reached regarding the best volume or timing for the procedure.

Another key factor is the timing of ABP. Many thoracic surgeons use "five days post-surgery" as the cut-off for classifying PALs, but there has been little discussion about whether this criterion is ideal. It has been suggested that early ABP intervention within 1 to 4 days postoperatively could reduce the risk of PALs and shorten hospital stays. This article explores the predictors of ABP success, particularly when performed earlier than the standard intervention period, and discusses the clinical implications of these findings along with future directions.

Mechanism of Autologous Blood Pleurodesis

Understanding the mechanism of ABP is crucial for optimising its therapeutic effect. The primary function of ABP is the physical "patch effect," which covers defects in the visceral pleura. Additionally, it induces a mild inflammatory response that promotes pleural surface adhesion, effectively sealing the air leaks. As the inflammatory response is minimal, ABP carries a lower risk of causing severe pain or respiratory distress, unlike chemical pleurodesis. This makes ABP a safer option for patients with interstitial pneumonia or acute respiratory distress syndrome (ARDS).

Procedure for Autologous Blood Pleurodesis

For patients who have undergone lung resection, autologous blood is administered through the already-inserted chest drain. First, 50 to 150 mL of autologous blood is collected from the patient’s vein or artery, with venous blood being more commonly used in most studies. Whether anticoagulants such as heparin are added to the collected blood depends on the attending physician’s judgement. Since the goal of ABP is to create a patch effect through blood coagulation, most studies opt not to add heparin. The collected blood is promptly injected through the chest drain under sterile conditions. In some cases, the patient is kept at rest, while in others, the patient’s position is adjusted to ensure that the administered blood spreads evenly. Although rare, there is a concern that the blood may block the drain and cause tension pneumothorax. To prevent drain obstruction, it is recommended to flush the drain with saline or similar solutions after administering the blood. Additionally, to prevent the outflow of the injected blood, the chest drain is managed by elevating it, and once the air leaks stops, the chest drain is removed.

Predictors of Autologous Blood Pleurodesis Success and Optimal Timing

Identifying predictors of ABP success is an important step towards improving patient outcomes. One particularly noteworthy factor is the volume of air leakage. In a digital drainage system, air leakage is measured in millilitres per minute. According to a study, when this value is below 60 mL/min, the success rate of ABP increases, and the risk of requiring additional interventions decreases. Conversely, when the value exceeds 60 mL/min, there is a higher likelihood of requiring multiple ABP procedures or other chemical pleurodesis, and the recurrence rate of pneumothorax also rises. However, even if multiple procedures are necessary, early ABP—performed within 1 to 4 days postoperatively—has been shown to shorten drainage time and reduce hospital stays. Traditionally, a cut-off point of 5 days has often been set for PALs. However, the British Thoracic Society guidelines state that "A cutoff point of 5 days has been widely advocated in the past but is arbitrary." In other words, by intervening early rather than adhering to the traditional "5-day rule", it may be possible to reduce the risk of complications arising from PALs. The use of a digital drainage system for managing air leaks following lung resection is widely recognised as useful among thoracic surgeons. However, the fact that it also provides valuable data through specific numerical measurements to predict the success of ABP treatment is a new discovery.

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Samir Redzepagic, MD, Public Health Officer, Monash Public Health