UMEM Educational Pearls

Title: Hemothorax, chest tubes, and volume calculation

Category: Trauma

Keywords: chest tube, tube thoracostomy, hemothorax, volume (PubMed Search)

Posted: 8/23/2025 by Robert Flint, MD (Updated: 8/24/2025)
Click here to contact Robert Flint, MD

Question

Over 300 ml of blood on a chest CT in a traumatically injured patient requires a tube thoracostomy.  How do you calculate 300 ml of blood on a chest CT?

Answer

You use Mergo's formula. 

Image B the AP line is what would represent d

References

1. Blank JJ, de Moya MA. Traumatic pneumothorax and hemothorax: What you need to know. J Trauma Acute Care Surg. 2025 Jul 3. doi: 10.1097/TA.0000000000004692. Epub ahead of print. PMID: 40604368.

2. CT-based pleural effusion volume estimation formula demonstrates low accuracy and reproducibility for traumatic hemothorax

Tewkesbury, Grace et al. Injury, Volume 55, Issue 1, 111112