EBQ:Conservative versus interventional treatment for spontaneous pneumothorax

Complete Journal Club Article

Simon G.A. et. al. "Conservative versus Interventional Treatment for Spontaneous Pneumothorax". '. 2020. 382:405-415.
PubMed Full text

Clinical Question

In patients with moderate-to-large primary spontaneous pneumothorax, is conservative management (observation) non-inferior to interventional management (chest tube insertion) with respect to lung re-expansion at 8 weeks?

Conclusion

• Supports conservative therapy vs chest tube.

Major Points

• This landmark RCT (PSP trial) challenged the standard practice of routine chest tube insertion for primary spontaneous pneumothorax
• Conservative management was non-inferior to interventional treatment for complete lung re-expansion at 8 weeks (98.5% vs 99.4%)
• Conservative management resulted in shorter hospital stays (median 0 days vs 2 days)
• Fewer adverse events occurred in the conservative group
• Approximately 15% of patients in the conservative group required eventual chest tube placement due to worsening symptoms

Study Design

• Multicenter, open-label, randomized, non-inferiority trial
• 39 hospitals across Australia and New Zealand
• N = 316 patients (conservative n=162, interventional n=154)
• Non-inferiority margin: 9 percentage points
• Study period: 2011-2017
• Primary Outcome: complete lung re-expansion on chest radiograph at 8 weeks

Population

Patient Demographics

• Mean age: 26 years
• Male: 83%
• Smokers: 35%
• Mean pneumothorax size: 50% (Collins method)

Inclusion Criteria

• 14 to 50 years of age
• unilateral primary spontaneous pneumothorax of 32% or more on chest radiography according to the Collins method (sum of interpleural distances, >6 cm)

Exclusion Criteria

• Secondary pneumothorax, defined as pneumothorax occurring in the setting of acute trauma (including iatrogenic) or underlying lung disease including but not limited to COPD, pulmonary fibrosis, TB, cystic fibrosis, lung cancer and asthma that requires regular preventative medication or has been symptomatic within the last two years
• Previous spontaneous pneumothorax on the same side
• Coexistent hemothorax (i.e. spontaneous hemopneumothorax)
• Bilateral pneumothorax
• Clinical instability suggesting tension pneumothorax; respiratory distress persisting despite oxygen and parenteral narcotic analgesia (RR >30/min or SpO2 <90%), SBP <90 mmHg, HR greater than or equal to SBP.
• Pregnancy at time of enrolment
• Social circumstances whereby the patient either does not have adequate support after discharge to re-attend hospital if required, or is unlikely to present for study follow up.
• Air travel within the next 12 weeks if this cannot be deferred should the pneumothorax be slow to resolve

Interventions

• Observed for a minimum of 4 hours then repeat chest X-ray.
• Discharge if no supplementary oxygen and walking comfortably,
• Chest tubes placed if:
  • clinically significant symptoms persisted despite adequate analgesia
  • chest pain or dyspnea prevented mobilization
  • patient was unwilling to continue with conservative treatment
  • the patient’s condition became physiologically unstable (systolic blood pressure of <90 mm Hg, heart rate in beats per minute greater than or equal to systolic blood pressure in millimeters of mercury, respiratory rate of >30 breaths per minute, or Spo2 of <90% while the patient was breathing ambient air)
  • Repeat chest radiograph showed an enlarging pneumothorax along with physiological instability.

Outcomes

Primary Outcome

• Complete lung re-expansion at 8 weeks:
  • Conservative: 129/131 (98.5%)
  • Interventional: 107/108 (99.4%)
• Risk difference: -0.9% (95% CI -3.3 to 1.5), within non-inferiority margin

Subgroup analysis

• Results were consistent across prespecified subgroups including pneumothorax size, smoking status, and age

Criticisms & Further Discussion

• Significant drop out rate
• Relatively large number of protocol violations
• large inferiority margins and the short intervention time.”

See Also

• Spontaneous pneumothorax

Funding

• National Health and Medical Research Council (NHMRC) of Australia