A Unique Case of Acute Respiratory Distress Syndrome Secondary to Rheumatoid Lung Disease With Administration of Anti-Tumor Necrosis Factor Alpha (TNFα) Agent.

Patients with rheumatoid arthritis (RA) may experience complications directly from the disease process or from immune-modulating agents used to treat RA. Adalimumab is a recombinant human monoclonal antibody directed against tumor necrosis factor alpha (TNFα) which has been increasingly used in the management of inflammatory and autoimmune diseases. Acute lung injury has been associated with the use of anti-TNFα agents, but the association with adalimumab is rare. Here we present a case of a patient with RA-associated lung disease who developed acute respiratory distress syndrome while being treated with adalimumab. Adalimumab-related lung injury is less common than lung injury associated with other anti-TNFα drugs, thus clinicians should be aware of this condition, as prompt recognition and supportive management can help prevent worsening outcomes.

Establishing a gradient between partial pressure of arterial carbon dioxide and end-tidal carbon dioxide in patients with acute respiratory distress syndrome.

End-tidal carbon dioxide (ETCO2) monitoring is useful in many situations. However, ETCO2 monitoring is unreliable in patients with acute respiratory distress syndrome (ARDS) due to widespread lung inflammation. In our study, we attempt to establish the gradient between the arterial pressure of carbon dioxide (PaCO2) and ETCO2 in patients with ARDS, which we defined as the PaETCO2 gradient. The main objective of the study was to establish a PaETCO2 gradient in each severity of ARDS. We analyzed 35 patients with ARDS and a total of 88 arterial blood gases were included. PaCO2, PaO2/FiO2 and ETCO2 were measured. Patients were stratified into mild, moderate and severe ARDS as classified by the Berlin ARDS criteria. PaCO2 and ETCO2 were compared at each severity stratification. The mean PaCO2 was 50.0, the mean ETCO2 was 26.6 and the gradient among all samples was 23.24 (±12.02). The mean gradient for each severity is as follows: mild: 19.3 (±9.9), moderate: 27.9 (±13.2) and severe: 23.9 (±7.8). The difference between the PaETCO2 gradient of the mild to moderate (p=0.001) and mild to severe groups (p=0.01) reached statistical significance. However, the difference between the moderate to severe groups did not reach statistical significance (p=0.48). We found the gradient between PaCO2 and ETCO2 in patients with ARDS is vast and tends to worsen with increasing severity of ARDS. This indicates that the gradient between the 2 may be used as an indicator of increasing severity of ARDS.