Feasibility and safety of argon plasma coagulation as hemostatic tool during medical thoracoscopy

Introduction

Medical Thoracoscopy (MT) is the second a commonly performed procedure in interventional pulmonology (IP) (1), primarily used for the diagnosis and management of undiagnosed pleural effusion (2). As a minimally invasive technique, MT allows direct visualization of the pleural cavity using a rigid or semi-rigid thoracoscope. This enables proceduralists to assess pleural lesions and obtain biopsies, facilitating a definite diagnosis of pleural effusion of unclear cause (3). Additionally, MT, also referred to as pleuroscopy, enables therapeutic interventions, particularly in complicated parapneumonic effusions or empyema (4-6).

MT offers a diagnostic yield comparable to video-assisted thoracoscopic surgery (VATS) but with the advantage of a shorter hospital stay and reduced cost (7). This is particularly important in cases of pleural effusion of unclear etiology and for diagnosing any underlying malignancy. The safety profile of MT is well established, with low rates of major complications. Recent evidence has demonstrated that MT can also be safely performed in critically ill patients within intensive care unit (ICU) settings (8,9). The most common adverse events include varying degrees of bleeding and pneumothorax (10,11). Bleeding is typically managed with electrocautery tools, with the limitation that contact electrosurgical techniques need direct contact of the probe with the bleeding surface.

Argon plasma coagulation (APC) is a monopolar, non-contact electrosurgery technique that uses ionized, electrically conductive argon gas, known as argon plasma (12). APC can be applied both en-face and tangentially, making it especially useful for reaching difficult anatomical areas (13). While APC has been widely adopted in the gastrointestinal field for hemostasis, ablation, tissue devitalization, and tissue reduction (13,14), its application in IP is more recent. It has gained attention in bronchoscopic procedures and endobronchial ablative therapies (15), as well as in the management of refractory and spontaneous pneumothorax (16,17). In addition, APC has recently been investigated as a thermoablative modality for the treatment of tracheobronchomalacia and excessive dynamic airway collapse (18,19). However, the use of APC in MT remains limited and underreported.

Here, we describe the APC technique applied during MT as the predominant tool to achieve hemostasis following rigid forceps pleural biopsy and report procedural complications from a retrospective cohort. We present this article in accordance with the STROBE and SUPER reporting checklists (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-696/rc).

Methods

This is an observational descriptive study conducted at Mayo Clinic, Jacksonville FL, USA. Data were recorded in an encrypted database, and the study was approved by the corresponding Institutional Review Board. The primary outcome of this study is to describe the APC technique during MT. Secondary outcomes focus on the descriptive analysis of a retrospective cohort undergoing MT with APC. This study was approved by the Mayo Clinic Institutional Review Board (IRB No. 25010866), and was conducted in accordance with the principles of the Declaration of Helsinki and its subsequent amendments. The requirement for informed consent was waived by the IRB due to the retrospective nature of the study and the use of de-identified data.

Population

We selected patients who underwent MT at our institution between December 1^st, 2022 and April 4^th, 2024. We included all patients who underwent APC during MT with the rigid APC applicator (35 and 350 mm, ERBE^® Elektromedizin GmbH, Tübingen, Germany) (Figure 1). Patients who did not receive APC were excluded. Demographics, comorbidities, smoking status, and cancer history were documented (Table 1).

Figure 1 Medical thoracoscopy with argon plasma coagulation used for hemostasis.

Procedure description

Parietal pleural biopsies were obtained with a rigid forceps with a ‘peel off technique’. Once obtained, we use the above detailed probe at a setting of Forced APC, 40 Watts, 0.8 lpm of argon flow. Watt levels were adjusted depending on desired effect (Figure 1).

Procedure details

Details of the pleuroscopy were recorded, including motive and side of the procedure, adhesion lysis, the volume of pleural fluid removed, chest tube placement, and French (Fr) size utilized (14, 20, and 24 Fr), as well as tunnel pleural catheter insertion, pleurodesis, biopsy, and bleeding complications. For talc pleurodesis, the talc dosage in grams was noted. Bleeding complications were assessed with the Validated Intraoperative Bleeding Scale (VIOPS) (20). A VIOPS score ≥2 was considered a complication, as it requires additional intervention. Although the scale has not yet been applied in MT, it has demonstrated strong interobserver reliability in clinical trials of hemostatic agents and has been associated with postoperative bleeding outcomes in surgical settings (21). For these reasons, we considered it an appropriate and standardized tool to evaluate intraoperative bleeding in our cohort. All the patients were admitted following the procedure (Table 2).

Pleural fluid analysis

Pleural fluid analysis was performed on samples obtained during pleuroscopy. The gross appearance of the fluid was documented by colors. We recorded the total white blood cell count, the predominance of cells, and the chemistry analysis of the fluid (proteins, glucose, Lactate dehydrogenase, cholesterol, albumin, and pH). Cell predominance was defined as lymphocytic if the fluid contained more than 50% of lymphocytes, polymorphonuclear if more than 50% of neutrophils, and eosinophilic if more than 10% of eosinophils. If none of these criteria were met, the fluid was categorized as normal. We used Lights’s criteria to classify the fluid as a transudate or exudate (22).

Statistical analysis

We performed descriptive statistics of the study population and procedural details. For continuous variables, data were summarized using the median and interquartile range (IQR). Categorical variables were documented as frequencies and percentages. Given the sample size, more advanced statistical techniques may have limited applicability and were therefore not performed. All statistical analyses were conducted using IBM statistical software SPSS V28.0.

Results

Twenty patients were included in this study. The median age was 72 years (IQR, 63–77 years), and 55% (n=11) were males. Eleven patients (55%) were former smokers, while 8 (40%) had never smoked. Hypertension was the most common comorbidity, present in 75% (n=15) of patients, followed by obstructive sleep apnea in 35% (n=7). The patients’ demographics are summarized in Table 1.

Twenty procedures were performed, with 14 (60%) on the right side of the chest. All procedures utilized APC, and 60% (n=12) underwent adhesion lysis. Recurrent pleural effusion (95%) was the most common indication for the procedure. One procedure (5%) was performed solely to obtain a biopsy of pleural nodularities. The median volume of pleural fluid removed was 642.5 mL (IQR, 24.37–1,450 mL). A chest tube was placed on 14 (70%) occasions, with the 24 Fr tube being the most commonly used (45%). In 95% (n=19) of the cases, a tunnel pleural catheter was placed. Pleurodesis was performed on 45% (n=9) of the procedures, with the most common talc dose being 4 g (35%). A VIOPS score of 1 was reported on 95% (n=19) of the cases, with bleeding complications occurring in 5% (n=1) of the procedures (Table 2). No air embolism cases were noted in our cohort.

Pleural fluid analysis was performed on 19 samples, 42% (n=8) of which had a grossly yellow appearance. The median total white blood cell count was 469/µL (IQR, 184–850.25/µL). Lymphocytic predominance was observed in 50% (n=10) of the cases, with a median lymphocyte percentage of 73% (IQR, 25.75–85.5%). The analysis showed that 94.7% (n=18) of the pleural fluid samples were exudates, while 5.3% (n=1) were transudates (Table 3).

Biopsies were obtained in 19 (95%) cases, with 4 (21.1%) cases showing malignant results. Lung cancer abutting the pleura was diagnosed in 2 patients (10.5%), mesothelioma in 1 (5.3%) patient, and metastasis in 1 (5.3%) case (Table 4).

Discussion

APC uses ionized argon gas to deliver a high-frequency monopolar current that coagulates tissue. It is a non-contact technique, typically applied with a 2–10 mm distance between the electrode and the tissue (14). The current is applied until a white coagulum forms, and the coagulated area is expanded using vertical and circumferential maneuvers (23). As the tissue coagulates, its increased resistance reduces the electric current, maintaining an injury depth of 1 to 2 mm (24). APC is primarily used in endoscopic procedures for hemostasis, devitalization, tissue reduction, and ablation. Three different modes are available: (I) forced APC, which provides continuous energy output developed in earlier systems; (II) pulsed APC, which delivers intermittent current in two modes (1 pulse per second with higher energy or 16 times per second with lower energy), while maintaining a constant voltage; (III) precise APC which utilizes an integrated system that regulates the argon plasma intensity while providing a continuous energy application, allowing a more superficial depth of injury at the target tissue (13,23).

While three APC modes exist—forced, pulsed, and precise—the choice of mode depends on the clinical context and desired coagulation depth. We utilized forced APC at 40 W and 0.8 L/min argon flow due to its continuous energy delivery, which allows for rapid and effective hemostasis during thoracoscopy. This mode is particularly advantageous when immediate bleeding control is required, as it provides greater tissue penetration compared with pulsed or precise settings. Although pulsed and precise APC can achieve more superficial coagulation with potentially reduced thermal injury, prior reviews have highlighted Forced APC as the most established and versatile modality for achieving reliable hemostasis in endoscopic practice (13). Our findings of a low bleeding complication rate (5%) are consistent with this evidence and support the safety of forced APC in pleural procedures. Furthermore, comparative studies in gastrointestinal settings have demonstrated that forced APC achieves equivalent hemostasis to pulsed APC but in shorter procedure times, without increasing complication rates (23). These data reinforce the rationale for our use of forced APC as the primary mode for hemostasis in MT.

APC is widely used in the gastrointestinal field, with studies reporting it as a safe and effective strategy for various conditions, including ablation of Barrett’s esophagus, proctopathies, colonic mucosal resection, and bleeding (25-27). APC has also proven to be feasible, safe, and effective in central airway stenosis surgery (28), lung decortication in patients with chronic pleural empyema (29), in the management of pneumothorax (16,30), and endobronchial ablative therapies for airway obstruction (15) or excessive central airway collapse (31). In bronchoscopic procedures, complications such as airway perforation and bleeding are unlikely. Gas embolism is an infrequent complication, yet it can cause hemodynamic instability, cardiac arrest, stroke and death (15,32). Airway fire is another possible complication, which can be avoided by maintaining the fractional inspired oxygen (FiO₂) <0.4 and preventing proximity to inflammable material (24).

In 2019, Guo et al. assessed the effects and prognosis of MT assisted with APC, combined with electrosurgical unit surgery, compared to VATS and pleurodesis surgery in elderly patients with refractory pneumothorax. APC helps reduce pneumothorax recurrence by promoting basal granulation coagulation of bullae, as the argon ion beam can locate the air leaks and automatically coagulate them. The APC group demonstrated lower pleural effusion drainage levels, lower visual analog scores and fewer hospitalization-related costs than VATS, with no differences in procedure-related complications (fever, subcutaneous emphysema, wound infection, lung infection, tube dissociation, chest pain, atelectasis and abnormal vital signs). This supports APC as a safe, effective, and affordable treatment in this setting (16).

APC remains underreported and underutilized in MT, likely due to the lack of large-scale studies in this field. However, the results in surgical, endoscopic and bronchoscopic procedures such as the ones mentioned above, provide a strong rationale for conducting studies to establish its efficacy in pleuroscopy. While the use of APC in MT for recurrent pneumothorax has been described, our study reports a cohort of patients with recurrent pleural effusion and pleural nodularity, expanding the range of conditions in which APC may prove beneficial as the main tool to achieve hemostasis.

In our cohort, MT with APC was performed to achieve hemostasis after pleural biopsy for undiagnosed pleural effusion in 95% of the cases, and adhesiolysis was performed in 60% of the procedures. Talc pleurodesis was conducted on 9 (45%) occasions, and 19 patients underwent pleural biopsy. Only one patient (5%) experienced a bleeding complication, defined as VIOPS score ≥2. Although this rate appears higher than that reported in large retrospective series, such as Wan et al. (11). who analyzed 1,926 MT procedures and found only seven cases of clinically significant bleeding (0.36%), the apparent discrepancy is likely explained by the small sample size of our study, which makes the percentage more sensitive to single events, as well as by our systematic use of the VIOPS scale to document intraoperative bleeding. In contrast, most retrospective series, including Wan et al., report bleeding only when clinically significant or requiring intervention. Therefore, while our observed incidence appears higher, we consider it consistent with the overall safety profile of MT, and larger cohorts will be required to validate our findings.

This study is one of the few reporting the use of APC in MT. Despite the sample size, we believe this descriptive analysis of the procedure and the description of the technique provide a foundation for larger-scale cohorts and more methodological studies, aimed at proving and comparing the therapeutic and diagnostic value of MT with APC to other practices to enhance care for patients with pleural cavity diseases.

Conclusions

APC is a feasible and safe hemostatic technique during MT, providing effective bleeding control with a low complication rate. Its standardized application may enhance procedural consistency and expand therapeutic options in pleural disease management. Larger studies are needed to validate these findings and further define the role of APC in pleuroscopy.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE and SUPER reporting checklists. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-696/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-696/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-696/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-696/coif). S.F.B. serves as an unpaid editorial board member of Journal of Thoracic Disease from September 2024 to August 2026. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Mayo Clinic Institutional Review Board (IRB No. 25010866). The requirement for informed consent was waived by the IRB due to the retrospective nature of the study and the use of de-identified data.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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