Small Bore vs Large Bore Thoracostomy for Traumatic Haemothorax.

Background

We see a lot of traumatic haemothoraces here in Virchester. It’s a range of patients with both blunt and penetrating injuries, and the standard practice for managing these patients has been the insertion of a large bore tube thoracostomy to drain the blood and relieve any complications. However, there’s an ongoing debate about the optimal tube size, and we’ve covered this at St Emlyn’s before with various trials suggesting that smaller tubes may well work. Traditional large-bore tubes (LBTT) are often preferred by our surgeons as they are believed to offer better drainage and reduce complications. Small bore tube thoracostomy (SBTT), however, is easier to put in, is less painful, and patients often prefer them. As someone who has had several chest drains, I totally get the patient discomfort element and would prefer small ones if possible, but what does the evidence say? This week we have a systematic review and meta-analysis in the Journal of Trauma and Acute Care Surgery that explores whether SBTT (≤14F) provides similar outcomes to LBTT (≥20F) for HTX patients. The abstract is below, but as always we recommend you read the paper yourself and come to your own conclusions.

Background: Traumatic hemothorax (HTX) is common, and while it is recommended to drain it with a tube thoracostomy, there is no consensus on the optimal catheter size. We performed a systematic review to test the hypothesis that small bore tube thoracostomy (SBTT) (≤14 F) is as effective as large-bore tube thoracostomy (LBTT) (≥20F) for the treatment of HTX.
Methods: Pubmed, EMBASE, Scopus, and Cochrane review were searched from inception to November 2022 for randomized controlled trials or cohort studies that included adult trauma patients with HTX who received a tube thoracostomy. Data was extracted and Critical Appraisal Skills Program checklists were used for study appraisal. The primary outcome was failure rate, defined as incompletely drained or retained HTX requiring a second intervention. Cumulative analysis was performed with x 2 test for dichotomous variables and an unpaired t-test for continuous variables. Meta-analysis was performed using a random effects model.
Results: There were 2,008 articles screened, of which nine were included in the analysis. The studies included 1,847 patients (714 SBTT and 1,233 LBTT). The mean age of patients was 46 years, 75% were male, average ISS was 20, and 81% had blunt trauma. Failure rate was not significantly different between SBTT (17.8%) and LBTT (21.5%) (p = 0.166). Additionally, there were no significant differences between SBTT vs. LBTT in mortality (2.9% vs. 6.1%, p = 0.062) or complication rate (12.3% vs. 12.5%, p = 0.941), however SBTT had significantly higher initial drainage volumes (753 vs. 398 mL, p < 0.001) and fewer tube days (4.3 vs. 6.2, p < 0.001). There are several limitations. Some studies did not report all the outcomes of interest, and many of the studies are subject to selection bias.
Conclusion: SBTT may be as effective as LBTT for the treatment of traumatic HTX.

Lyons, N. B., et al. (2024). Small versus large-bore thoracostomy for traumatic hemothorax: A systematic review and meta-analysis. Journal of Trauma and Acute Care Surgery, 97(4), 631-638.

What Kind of Study is This?

This is a systematic review and meta-analysis. These studies bring together data from several studies, including cohort studies and randomized controlled trials (RCTs), comparing small bore tube thoracostomy and large bore tube thorocostomy for haemothorax management in adult trauma patients. Methodologically, these studies can be very powerful and are often considered high levels of evidence, BUT they are dependent on the quality of the studies they use, and they must follow appropriate methodological practice. In this case the authors PRISMA guidelines (good), and assessed the quality of the studies using the Critical Appraisal Skills Program (CASP) checklists for quality and assessing risk of bias (also good).

In terms of searching, they looked at a range of databases, including Pubmed, EMBASE, Scopus, and Cochrane databases, including articles up to November 2022, to identify studies evaluating outcomes of small bore tube thorocostomy vs. large bore tube thorocostomy in HTX patients. The review included studies that examined adults who received either a small or large-bore thoracostomy tube for HTX or hemopneumothorax (HPTX). This is a reasonable search strategy. It could be expanded to look at the grey literature, such as conference abstracts, but there are unlikely to have been significant trials missed up to 2022 with this approach.

Tell Me About the Data (patients and studies)

A total of 1,847 patients across 11 studies were included in the analysis, with a predominance of male patients (approximately 75%) and an average age of 46. The patient population represented a range of injury severities, with an average Injury Severity Score (ISS) of 20. Of these patients, 81% had experienced blunt trauma, which aligns with the typical clinical presentation of HTX.

Notably, there was variability in the urgency of tube placement between groups: only 15% of the SBTTs were placed emergently, compared to 64% of the LBTTs, highlighting a trend where smaller tubes are often chosen in stable, less acute settings. The study divided patients by tube size, with SBTT defined as tubes of ≤14F and LBTT as those of ≥20F, though specific diameters varied across the included studies.

What Were the Measured Outcomes in This Study?

The study primarily focused on failure rate as the main outcome, defined as the need for a secondary intervention to manage a retained or incompletely drained HTX. Secondary outcomes included:

• Mortality
• Initial drainage volume
• Total tube days
• Overall complication rates, including insertion-related complications, retained HTX, pneumonia, and empyema
• Hospital and ICU length of stay (LOS)
• Pain scores at insertion and during tube presence

These are all reasonable measures, although not all studies will report all outcomes.

What Are the Main Results?

The main findings are:

• Failure Rate: No significant difference was observed between small bore tube thoracostomy and large bore tube thoracostomy in failure rate (17.8% vs. 21.5%, p=0.166). So a non-statistically significant difference, that even if it was a 3% difference would arguably not be clinically significant either.
• Mortality: Mortality rates were also comparable, with no significant difference (2.9% for SBTT vs. 6.1% for LBTT, p=0.062). Mortality in trauma patients is rarely due to a single intervention so not great surprise in no difference here. However, LBTT are more likely to be placed in the more seriously injured patient and so that may account for the raw data here.
• Complication Rates: Total complication rates were nearly identical between the two groups (12.3% for SBTT vs. 12.5% for LBTT).
• Drainage Volume and Tube Days: SBTTs achieved higher initial drainage volumes (753 vs. 398 mL, p<0.001) and had fewer tube days overall (4.3 vs. 6.2 days, p<0.001). This is a bit of a surprise and I can’t really explain this.
• Pain Scores: SBTT patients generally reported lower pain scores at insertion, likely due to the less invasive nature of the smaller-bore catheter.

So overall, it looks as though SBTTs may be as effective as LBTTs in managing HTX while potentially offering improved comfort and quicker resolution.

Should we believe the results?

As mentioned previously, systematic reviews are great, but they do have limitations, and this one is no exceptio.n

• Selection Bias: Many included studies were observational, non-randomised cohort studies, increasing susceptibility to selection bias. In my practice we are more likely to place an LBTT in the sicker patients. An RCT might avoid this selection bias (not always), but observational trials are notorious for this bias creeping into treatment selection.
• Heterogeneity: Significant heterogeneity existed across the studies, especially in terms of patient characteristics and tube placement timing. SBTT was often placed later than LBTT, which may have influenced initial drainage volumes. Later placement also fits with fewer sick patients.
• Lack of Consistency in Failure Definition: The studies did not completely agree on the definition of failure.
• Limited Pain Data: While some studies measured pain, the scales used were not standardised, and pain reporting varied, limiting the ability to draw general conclusions.

Despite these limitations, the meta-analysis was reasonably well conducted, with low heterogeneity for most outcomes. Further high-quality RCTs would strengthen the evidence.

Should We Change Practice Based on This Study?

I’m not sure. I do have some concerns about selection bias, but that said, there is a consistency of evidence across a range of studies that we are probably using larger drains than we need to. My personal practice has changed and I’ve been comfortable going down to 24F, from the 36F or even 40F that we used to put in around the early days of ATLS. Based on the evidence here, I think we could go smaller still with the use of small bore tube thoracostomy considered for stable patients with haemothorax, especially those where pain reduction and shorter tube duration are key considerations. I would also be more comfortable with smaller tubes in non-emergent cases or less severe trauma. However, due to limited data on SBTT use in emergent settings, I’m going to stick with the larger tubes as the standard in urgent scenarios, particularly for patients with severe or complex injuries.

Final thoughts

This systematic review and meta-analysis suggest that small-bore tube thoracostomy may be a viable option for traumatic haemothorax, offering comparable effectiveness to large-bore tubes in stable settings. I’m happy with a nuanced approach favouring SBTT in stable patients while continuing to rely on LBTT for emergent situations. However, I’d love to see some better-designed RCTs to support this conclusion.

References

1. Lyons, N. B., Abdelhamid, M. O., Collie, B. L., Ramsey, W. A., O’Neil, C. F., Delamater, J. M., et al. (2024). Small versus large-bore thoracostomy for traumatic hemothorax: A systematic review and meta-analysis. Journal of Trauma and Acute Care Surgery, 97(4), 631-638.
2. Simon Carley, “Chest drains & aspiration: Do it better with St.Emlyn’s,” in St.Emlyn’s, November 19, 2016
3. Simon Carley, “JC: Can we use smaller pigtail drains in traumatic haemothorax?,” in St.Emlyn’s, November 11, 2021
4. Simon Carley, “JC: Conservative management of chest trauma. St Emlyn’s,” in St.Emlyn’s, December 7, 2018
5. Simon Carley, “JC: Conservative management of pneumothoraces.,” in St.Emlyn’s, February 10, 2020
6. PRISMA statements.
7. Critical Appraisal Skills Program (CASP)
8. Patel, N. J., Dultz, L., Ladhani, H. A., et al. (2021). Management of simple and retained hemothorax: A practice management guideline from the Eastern Association for the Surgery of Trauma. American Journal of Surgery, 221(5), 873-884.
9. Chang, S. H., Kang, Y. N., Chiu, H. Y., & Chiu, Y. H. (2018). A systematic review and meta-analysis comparing pigtail catheter and chest tube as the initial treatment for pneumothorax. Chest, 153(5), 1201-1212.
10. Kulvatunyou, N., Erickson, L., Vijayasekaran, A., et al. (2014). Randomized clinical trial of pigtail catheter versus chest tube in injured patients with uncomplicated traumatic pneumothorax. British Journal of Surgery, 101(2), 17-22.
11. Bauman, Z. M., Kulvatunyou, N., Joseph, B., et al. (2021). Randomized clinical trial of 14-French (14F) pigtail catheters versus 28-32F chest tubes in the management of patients with traumatic hemothorax and hemopneumothorax. World Journal of Surgery, 45(3), 880-886.
12. Inaba, K., Lustenberger, T., Recinos, G., et al. (2012). Does size matter? A prospective analysis of 28-32 versus 36-40 French chest tube size in trauma. Journal of Trauma and Acute Care Surgery, 72(2), 422-427.
13. Maezawa, T., Yanai, M., Huh, J. Y., & Ariyoshi, K. (2020). Effectiveness and safety of small-bore tube thoracostomy (≤20 Fr) for chest trauma patients: A retrospective observational study. American Journal of Emergency Medicine, 38(12), 2658-2660.
14. Rivera, L., O’Reilly, E. B., Sise, M. J., et al. (2009). Small catheter tube thoracostomy: Effective in managing chest trauma in stable patients. Journal of Trauma, 66(2), 393-399.