Size of small pneumothorax on chest radiograph as a predictor for failure of conservative management in thoracic stab wounds - A critical analysis of 284 cases at a major trauma centre in South Africa.

Introduction: Selective conservative management of asymptomatic patients with small pneumothorax (PTX) in the setting of thoracic stab wounds (SWs) appears safe, but the correlation between the size of PTX and rate of failure of conservative management remains largely unknown.

Materials and methods: A prospective study was conducted over a 14-year period on patients with isolated thoracic SWs who were asymptomatic with small PTX on CXR (<2 cm) and underwent clinical observation at a major trauma centre in South Africa.

Results: 284 patients were included (91 % male, mean age: 24 yrs). Eight (3 %) eventually required TT, and all other patients were managed successfully with clinical observation alone. There was no morbidity or mortality as a direct result of our selective conservative management approach. The need for TT was based on the size of initial PTX; Group A: <0.5 cm (0 %), Group B: ≥0.5 to < 1 cm (0 %), Group C: ≥1 cm to < 1.5 cm (3 %) and Group D: ≥1.5 cm to < 2 cm (13 %). For every 0.5 cm increase in PTX size, there was a five-fold (95 % CI, 1.73 to 16.67, p = 0.004) increased risk for the need for TT.

Conclusion: Selective conservative management of patients with asymptomatic small PTX of < 2 cm on CXR following thoracic SWs appears safe although the greater the size of the initial PTX, there was a higher risk of failure of conservative management. This should alert clinicians to remain vigilant and have a low threshold for intervention.