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Observation noninferior to intervention for spontaneous pneumothorax

New data published in The New England Journal of Medicine indicates that conservative management of spontaneous pneumothorax may be noninferior to an interventional approach in healthy, young patients.

The randomized, open-label, noninferiority trial, conducted at 39 hospitals in Australia and New Zealand, included 316 patients aged 14 to 50 years with a first-known, unilateral, moderate-to-large primary spontaneous pneumothorax who were randomly assigned immediate intervention (n = 154) or a conservative observational approach (n = 162).

Conservative management consisted of at least 4 hours of observation in the ED followed by discharge with written instructions and analgesia if repeat chest radiographs showed no pneumothorax enlargement and the patient did not require oxygen and could walk without difficulty. For the intervention, clinicians placed a small-bore Seldinger-type chest tube and attached a water seal for 1 hour. If the lung had re-expanded and the underwater drain no longer bubbled, the drain was closed with a stopcock for 4 hours. If the lung remained fully expanded, the chest tube was removed and the patient was discharged.

Patients were followed for 12 months.

Noninferiority of conservative approach

Among patients assigned conservative management, 15.4% underwent interventions for reasons prespecified in the protocol, including enlarging pneumothorax or persistence of clinically significant symptoms, and 84.6% did not undergo any intervention, according to the study results.

The primary outcome was lung re-expansion at 8 weeks. In a complete-case analysis that excluded data from patients who completed 8-week follow-up — 23 in the intervention group and 37 in the conservative-management group — lung re-expansion occurred in most patients in both groups (98.5% and 94.4%, respectively; risk difference, –4.1 percentage points; 95% CI, –8.6 to 0.5; P = .02 for noninferiority). However, in a sensitivity analysis that imputed all missing data after 56 days as treatment failure, re-expansion occurred in 93.5% of the intervention group and 82.5% of the conservative-management group, with a risk difference of –11 percentage points (95% CI, –18.4 to –3.5) that was outside the noninferiority margin of –9 percentage points, according to the results.

Complete symptom resolution by 8 weeks occurred in 93.4% of the intervention group and 94.6% of the conservative-management group (risk difference, 1.1 percentage points; 95% CI, –4.4 to 6.7), with no significant difference in median time to resolution between groups (15.5 vs. 14 days; HR = 1.11; 95% CI, 0.88-1.4). Additionally, in the per-protocol analysis, radiographic resolution occurred within 8 weeks in 98.4% of the intervention group and 94.6% of the conservative-management group (risk difference, –3.8 percentage points; 95% CI, –8.3 to 0.7).

Notably, patients assigned intervention vs. conservative management were more likely to experience recurrence during 12-month follow-up (16.8% vs. 8.8%) and have a serious adverse event (RR = 3.3; 95% CI, 0.34-1.02).

Clinical implications

In light of the new data, the researchers concluded that this “trial challenges the fundamental concept of whether initial routine drainage is required in all patients with primary spontaneous pneumothorax.”

The authors also noted, however, that the results were “statistically fragile” due to difficulty in accounting for all patients at 8 weeks.

Nevertheless, the essential finding that patients fared well with conservative management remains the focus, according to V. Courtney Broaddus, MD, from the department of medicine at the University of California, San Francisco.

“Their symptoms resolved as quickly as the symptoms in the intervention group, and they had fewer days in the hospital, fewer days off from work and less need for surgery. The conservative-management group also had fewer adverse events. It turns out, not surprisingly, that most of the complications came from the chest drains themselves. The conservative approach was quite safe,” she wrote in an accompanying editorial.

These results, coupled with previous studies, suggest use of a conservative approach may now be warranted in clinical practice, Broaddus noted.

“On the basis of this randomized 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 hemodynamic compromise and with the following provisos: the patient is informed and agrees to the approach, is readily available for outpatient follow-up, and is not planning air travel or scuba diving. It is time to incorporate these findings into new guidelines to help standardize 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,” she wrote. – by Melissa Foster

Disclosures: Brown reports he has received grants from Emergency Medicine Foundation (QLD), Green Lane Research and Education Fund (NZ), Health Research Council of New Zealand, National Health Medical Research Council – Department of Health, Australian Government, Royal Perth Hospital Research Foundation and State Health Research Advisory Council. Please see the study for all other authors’ relevant financial disclosures. Broaddus reports no relevant financial disclosures.