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Conservative management of spontaneous pneumothorax was noninferior to interventional management in patients with moderate-to-large primary lung collapse at low risk for serious adverse events (AE), according to multicenter clinical trial.

The vast majority (84.6%) of patients randomized to receive conservative management did not require any intervention, and almost all who were not lost to follow-up had full lung re-expansion within eight weeks, which was the primary study outcome, reported Simon G.A. Brown, PhD, of Royal Perth Hospital and the University of Western Australia, and colleagues.

The intervention group had roughly three-fold higher incidences of experiencing at least one AE (relative risk 3.32, 95% CI 1.85-5.95) and a serious AE (RR 3.30, 95% CI 1.37-8.10) compared with patients who were conservatively managed, the researchers wrote in the .

The study "challenges the fundamental concept of whether initial routine drainage is required in all patients with primary spontaneous pneumothorax," Brown and colleagues stated.

In an , V. Courtney Broaddus, MD, of the University of California San Francisco and San Francisco General Hospital, said based on the trial findings and earlier reports, watchful waiting should be considered for certain patients with uncomplicated primary spontaneous lung collapse who are informed and agree to the approach, and are willing and able to follow-up with the medical team.

She noted that in the U.S., patients who present to the emergency department with spontaneous, uncomplicated moderate-to-large pneumothorax generally have chest tubes placed to drain air from the lung, and they are hospitalized.

"This study give us reassurance that patients who are candidates for conservative management will be safe and should do well," Broaddus told 番茄社区. "In some cases, they will do better than if we put in tubes and admit them to the hospital."

The study was conducted at 39 metropolitan and rural hospitals in Australia and New Zealand.

The intervention protocol involved the placement of a small-bore chest tube, attached to an underwater seal, with a chest radiograph conducted one hour after insertion. If the lung had re-expanded and the underwater drain no longer bubbled, the drain was closed and a repeat chest radiograph was conducted four hours later if the patient's condition was stable. If the radiograph showed that the pneumothorax had not recurred, the drain was removed and the patient was discharged.

Patients were admitted to the hospital if the initial drain insertion did not resolve on radiography or if the pneumothorax recurred under observation.

The conservative protocol involved observation of the patient for a minimum of four hours before a repeat chest radiograph was obtained. Following observation, patients were discharged with analgesia if they did not require supplemental oxygen during their stay and were walking comfortably.

Interventions could be considered in the conservative management group when clinically significant symptoms persisted despite analgesic treatment; when chest pain or dyspnea prevented mobilization; when a patient was unwilling to continue conservative treatment; and when the patient's condition became unstable or a repeat chest radiograph showed an enlarging pneumothorax and physiological instability.

A total of 154 patients were randomized to the intervention and 162 to conservative management. In a complete-case analysis, which lacked data for 23 patients in the intervention group and 37 in the conservative-management group, the authors found that re-expansion within eight weeks occurred in 129 of 131 patients (98.5%) with interventional management and in 118 of 125 (94.4%) with conservative management (risk difference -4.1 percentage points, 95% CI −8.6 to 0.5, P=0.02 for noninferiority).

In a sensitivity analysis, in which all missing data after 56 days were considered treatment failure -- with re-expansion in 93.5% (129/138) in the intervention group and 82.5% (118/143) in the conservative management -- the risk difference of −11.0 percentage points (95% CI −18.4 to −3.5) was outside the prespecified noninferiority margin.

Conservative management was associated with a lower risk of serious AEs and almost half the risk for pneumothorax recurrence during the first 12 months (recurrences occurred in 16.8% of the intervention group and 8.8% of the conservative management group).

Study limitations included the necessity of an open-label design, and the failure in the original statistical analysis plan to specify the window for the 8-week visit "nor define how missing radiographic data were to be handled for the primary outcome."

Despite these and other limitations, Broaddus told 番茄社区 the findings provide valuable new information and should help change clinical practice.

"This paper may not be perfect, but I challenge anyone to come up with a better study," she said. "They are giving us the data to show that we can manage certain patients conservatively, without tubes and needles."

In the editorial, Broaddus called for new guidelines that incorporate the findings, and help standardize the approach to treating uncomplicated spontaneous primary pneumothorax.

"We are all over the map with treatment," she said. "These patients are managed very differently in the U.S., the U.K., Canada, and Australia. That tells us that until now there has simply not been enough data to standardize treatment."

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