Bob, I'm sorry to hear that you seemed to have suffered another bout of delayed hypersensitivity reactions to your chemo/immuno-oncology regimens which triggered your ARDS (acute respiratory distress syndrome)

ARDS occurs as a result of the disruption of the alveolar-capillary bronchio-alveolar endothelial barrier that allows inflammation associated protein-rich fluids to enters the alveoli, causing pulmonary edema. This interferes with respiratory gas exchange and reduced blood oxygen saturation which in turn reduces oxygen supply to the organs of your body. With impaired cardiac function i.e reduced pumping ability this lowers systemic flow of low oxygenated blood to your organ systems (heart, lungs, kidneys, liver and brain). The hypo-perfusion of your various organ systems triggers additional hypoxia related degradation of their normal functioning.

Lower blood oxygenation may initially cause your symtoms of breathlessness (dypsnea). As your blood oxygen levels continue to drop, you may will experience "air hunger" or the inability to catch your breath. As mentioned above, continued oxygen desaturation triggers a catastrophic cascade of multi-organ failure i.e ARDS.

The most common clinical disorders associated with the development of ARDS include sepsis, pneumonia, aspiration of gastric contents, delayed medication hypersensitivity reactions, and major trauma.

In your case, based on your description of the time line of the onset of your symptoms, I strongly suspect that you've suffered a delayed hypersensitivity reactions to your chemo/immuno-oncology regimens.

There are a number of recent reports in the clinical literature re the development of ARDS due to patients' delayed hypersensitivity reactions to FOLFOX/FOLFIRI, Herceptin, and Keytruda and other PD- L inhibitors which have triggered episosodes of sub-phenotype 2 ARDS, which is characterized by hyperinflammation and hypotension.

It seems your pulmonolgist has a handle on your case and is providing you with appropriate supportive care which should include appropriate ventilatory support (I assume you've had a respiratory therapist involved in your care team) wide spectrum antibiotics to address your pneumonia and generally, a tapering steroid regimen to tamp down your inflammatory reactions and other interventions to manage your body's fluid balance and diuresis.

I'm sure he is doing so in consultation with your oncologist.

I hope you feel better soon. Regardless of how crappy you may feel, any day above ground beats the alternative.

Dave