Small versus large bore chest tube in traumatic hemothorax, hemopneumothorax, and pneumothorax: a meta-analysis of randomized controlled trials with trial sequential analysis

Background: The optimal tube size for managing traumatic hemothorax, pneumothorax, or hemopneumothorax remains debated. While large-bore chest tubes (LCTs—≥ 28 Ch) are traditionally favored, emerging evidence suggests that small-caliber tubes (SCTs—≤ 14 Ch), such as pigtail catheters and small straight tubes, may offer similar efficacy with fewer complications. This study aimed to evaluate the comparative effectiveness and safety of SCTs versus LCTs from Randomized Controlled Trials (RCTs) in adult trauma patients and to assess the conclusiveness of the current evidence using trial sequential analysis (TSA). Methods: The study was conducted according to the Cochrane recommendations, searching the PubMed, Scopus, and EMBASE datasets up to 25th March 2025 without language restrictions (PROSPERO ID: CRD420251023165). The primary outcome was treatment failure; secondary outcomes included insertion-related complications, duration of drainage, and length of hospital stay. Random effects models based on restricted maximum likelihood and Hartung-Knapp correction were developed. Sensitivity analysis was conducted to detect sources of heterogeneity. The risk of bias was assessed using the Cochrane RoB 2 tool. TSA was used to evaluate the risk of random error and to determine whether the required information size (RIS) had been reached. Results: Four RCTs (n = 676 patients) were included. Pooled analysis showed no significant difference in failure rates between SCTs and LCTs (RR 0.95, 95% CI 0.66–1.35, I2 = 0%). No significant differences were observed in complication rates or hospital stay. Duration of tube placement was significantly shorter in the SCT group (MD − 0.49 days, p = 0.02). TSA indicated that the cumulative evidence was underpowered, achieving only 22% of the RIS (3110 patients). The Z-curve did not cross thresholds for benefit, harm, or futility. Conclusion: SCTs appear to be as effective and safe as LCTs for selected trauma patients with uncomplicated thoracic injuries. However, due to limited sample size and heterogeneity across trials, current evidence is inconclusive. Larger, high-quality RCTs are warranted to confirm these findings and guide clinical practice.