Conservative observational management is an acceptable alternative to interventional management for uncomplicated, moderate-to-large primary spontaneous pneumothorax, an Australian study has shown.

In a study involving 316 patients with a pneumothorax (≥32% on chest radiography) at 39 hospitals, those who were randomised to conservative management had non-inferior outcomes compared to patients managed with interventions for the primary outcome of radiographic resolution within 8 weeks.

Conservative management resulted in a lower risk of pneumothorax recurrence than interventional management, and the time until complete resolution of symptoms did not differ substantially between the two approaches.

The study investigators, led by Dr Simon Brown of the Royal Perth Hospital and the University of Western Australia, noted that the conservative management approach spared 85% of the patients from an invasive intervention and resulted in fewer hospitalisation days and days off work, a lower likelihood of prolonged chest-tube drainage, less need for surgery, and fewer adverse events than interventional management.

“Our trial challenges the fundamental concept of whether initial routine drainage is required in all patients with primary spontaneous pneumothorax,” they wrote in the NEJM.

Patients assigned to conservative management were observed for a minimum of four hours before a repeat chest radiograph was obtained. If they did not receive supplementary oxygen and were walking comfortably,they were discharged with analgesia and written instructions.

Interventional management involved insertion of a small-bore chest tube, attached to an underwater seal, with a chest radiograph conducted after one hour. If the lung had re-expanded and there was no air leak, the tube was clamped for 4 hours and, if the lung remained fully expanded, the chest tube was removed and the patient was discharged.

In the conservative management group, 25 patients (15.4%) underwent interventions to manage the pneumothorax, as per pre-specified protocols.

Reexpansion within eight weeks occurred in 129 of 131 patients (98.5%) with interventional management and in 118 of 125 (94.4%) with conservative management, with the -4.1 point difference being within the prespecified noninferiority margin of −9 percentage points.

“This randomised, controlled trial of conservative as compared with interventional management of moderate-to-large primary spontaneous pneumothorax provides modest, but statistically fragile, evidence that conservative management was noninferior to interventional management,” the study authors concluded.

An accompanying commentary by Dr Courtney Broaddus of  the Department of Medicine, University of California San Francisco, said the trial raised questions about why clinicians were so ready to intervene in pneumothorax when almost all patients did well with a watchful waiting approach – and with fewer adverse events from chest drains.

“On the basis of this randomised trial and the earlier reports, we should now be prepared to offer this conservative approach to the young, healthy person with a large primary spontaneous pneumothorax if there is no haemodynamic compromise,” she wrote.

“It is time to incorporate these findings into new guidelines to help standardise the approach across continents. With this trial, we can include a conservative approach as a reasonable management option for moderate-to-large pneumothoraxes in otherwise healthy young people.”