From the Guidelines
Yes, there can be residual radiological and pulmonary function test (PFT) abnormalities in resolved Acute Respiratory Distress Syndrome (ARDS). Most patients show significant improvement in both radiological findings and lung function over time, but complete normalization doesn't always occur. According to the study published in Intensive Care Medicine 1, the natural history of ALI/ARDS tends to be dominated by the inciting event rather than the lung injury itself, and treatment of the underlying cause and support of the respiratory system remains the standard of care.
Radiological Abnormalities
Radiologically, some patients may have persistent ground-glass opacities, reticular patterns, or fibrotic changes on chest CT scans even months after clinical recovery. The study 1 notes that in patients with more severe ARDS, significant lung fibrosis eventually develops, which contributes to the increase in dead-space ventilation even as alveolar edema and the intrapulmonary shunt resolve.
Pulmonary Function Test Abnormalities
PFT abnormalities commonly include reduced diffusion capacity (DLCO), mild restrictive patterns with decreased total lung capacity, and sometimes mild obstructive patterns. These abnormalities tend to be most severe in the first few months after ARDS and gradually improve over 6-12 months, with the most significant recovery occurring within the first year. However, some patients, particularly those who had severe ARDS or required prolonged mechanical ventilation, may have persistent abnormalities for years.
Underlying Pathophysiology
The underlying pathophysiology involves fibroproliferative repair processes following the acute inflammatory damage, which can lead to permanent structural changes in lung architecture. As noted in the study 1, after the initial improvement in oxygenation, further improvements depend on whether the fibroproliferative response can restore the normal lung architecture for gas exchange.
Recommendations
Regular follow-up with pulmonary function testing and imaging is recommended for ARDS survivors to monitor recovery and identify those who might benefit from pulmonary rehabilitation. This approach allows for the early detection of persistent abnormalities and the implementation of targeted interventions to improve outcomes and quality of life.
From the Research
Residual Radiological Abnormalities
- Residual radiological abnormalities are common in patients who have recovered from Acute Respiratory Distress Syndrome (ARDS) 2, 3, 4, 5
- Studies have shown that these abnormalities can persist for months or even years after hospital discharge 3, 6, 4, 5
- The presence and severity of these abnormalities can be related to the severity of ARDS during hospitalization 3, 5
Pulmonary Function Test (PFT) Abnormalities
- PFT abnormalities are also common in patients who have recovered from ARDS 2, 3, 4, 5
- These abnormalities can include reduced lung volumes, impaired diffusion capacity, and obstructive or restrictive patterns 2, 3, 5
- The severity of PFT abnormalities can be related to the severity of ARDS during hospitalization and the presence of residual radiological abnormalities 3, 5
Predictors of Residual Abnormalities
- Several factors have been identified as predictors of residual radiological and PFT abnormalities, including:
Long-term Follow-up
- Long-term follow-up is necessary to determine the persistence and severity of residual radiological and PFT abnormalities in patients who have recovered from ARDS 3, 6, 4, 5
- This follow-up can help identify patients who may require ongoing care and management to address persistent symptoms and functional limitations 3, 5