The Role of Hemoglobin in the Oxygen Cascade

There was a contention that oxygen saturation, especially as reported by a pulse oximeter, is inadequate to many of the tasks of critical care. We're going to investigate some of the commonalities in yours and my practice and maybe some of the areas we may disagree with this original tweet or maybe we disagree with each other. But I guess the first question along those lines is an ABG useful and when do you get them to assess the cause or severity of lung disorders?