Pneumothoraces on VV ECMO, particularly early in the course of ECMO for respiratory failure, MUST NOT be drained unless they cause tension resulting in haemodynamic compromise. Further reduction in lung ventilation (and increased ECMO support) may control or reverse air leaks and allow inter-costal catheters to be avoided, or inserted later when lung injury is less severe. Early patients support with VV ECMO had fatal complications from bleeding and the most common site was pleural space bleeding related to inter-costal catheter insertion.
The need to drain pleural effusion whilst on ECMO is commonly debated. Pleural effusions however are generally benign and potential worsening of oxygenation is taken care of by the ECMO circulation. Effusions are commonly parapneumonic and/or result from the initial fluid resuscitation. Drainage generally should be avoided and focus on conservative measures such as optimising the fluid balance. The threshold to drain is very high given the well known potential for bleeding complications.
Drainage may be favoured if there is:
- Evidence of a tension hydrothorax with haemodynamic effects
- High suspicion of pleural empyema
- Excessive effusion in significant hypoxia that has failed to be managed otherwise
Lung abscess can be a major problem including
- Bronchopleural fistulas
- Uncontrolled sepsis
- Bronchial toileting
Regardless of the level of lung destruction that seems evident on HRCT, there is a quite remarkable possibility of lung function recovery during and after support with VV ECMO. Caution should be applied intubating these patients as well as avoiding excessive pressures during ventilation and in the weaning process.