Which clinical factors are predictive of outcome in primary spontaneous pneumothorax management?

Background Primary spontaneous pneumothorax (PSP) occurs when air leaks into the pleural space in patients without known underlying lung disease, causing pain and breathlessness. Optimal management of PSP is not defined and we are unable to predict who will fail medical treatment (ongoing pneumothorax with prolonged air leak). We hypothesised that patients with longer symptom duration and higher symptom scores would be more likely to fail treatment. Methods Prospectively collected data from the Randomised Ambulatory Management of Primary Pneumothorax randomised controlled trial of ambulatory management were used to determine which clinical factors are associated with treatment failure including symptom scores, time from symptom onset to presentation, treatment allocation, vital signs, history of prior pneumothorax and size of initial pneumothorax. Results Overall, 63/236 patients (26.7%) failed treatment. On average, symptoms started 1 day before admission. Multivariable analysis found that patients who presented at least 1 day after symptoms began had a lower risk of treatment failure than those presenting on the day symptoms began (ORs 0.39 (0.18 to 0.81)). Conclusion Further work is required to determine psychological drivers of PSP presentation and risks of prolonged air leak.