Small Hemothoraces Not Drained on Admission: Initial Volume Predicts Need for Intervention

Unlike large hemothoraces (HTX), small HTX after blunt trauma may be observed without drainage. We aimed to study if there were risk factors that would predict the need for intervention in initially observed small HTX.

A retrospective review of patients with blunt traumatic HTX from 2016 to 2022 was performed. Patients with small HTX (pleural fluid volume <400 mL on admission chest computerized tomography [CT]) were included. Patients were considered as being "initially observed" if there was no intervention for the HTX within 48 hours after admission. Primary outcome was any HTX-related intervention (open, thoracoscopic or percutaneous procedures) occurring after 48 hours and up to 6 months after injury. Univariable and multivariable statistical analyses were employed. A P-value of <.05 was considered significant.

Of 335 patients with HTX, 188 (59.6%) met inclusion criteria. Median (interquartile range) HTX volume was 90 (36-134) ml. One hundred and twenty-seven (68%) were initially observed. Of these, 31 (24%) had the primary outcome. These patients had a larger HTX volume (median, 129 vs 68 mL, P = .0001), and number of rib fractures (median, 7 vs 4, P = .0002) compared to those without the primary outcome. Chest-related readmission occurred in 8 (6%) with a median of 20 days from injury. Of these, 7 required an HTX-related intervention. Logistic regression analysis found that both the number of rib fractures and HTX volume independently predicted the primary outcome.

For small HTX initially observed, number of rib fractures and initial volume predicted delayed HTX-related intervention.