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Letter by Bellomo et al Regarding Article,“Relationship Between Supranormal Oxygen Tension and Outcome After Resuscitation From Cardiac Arrest”

R Bellomo, M Bailey... - Circulation, 2012 - Am Heart Assoc We read the paper by Kilgannon and colleagues 1 with interest. In a recent study involving 12 108 intensive care unit survivors of cardiac arrest in Australia and New Zealand, 2 we found that the relationship between hyperoxia and mortality was significantly altered by ...

We read the paper by Kilgannon and colleagues1 with interest. In a recent study involving 12 108 intensive care unit survivors of cardiac arrest in Australia and New Zealand,2 we found that the relationship between hyperoxia and mortality was significantly altered by the introduction of Fio2 into the predictive multivariable model such that Pao2 was no longer associated with hospital mortality. Such findings and clinical experience suggest that a high Pao2 may thus simply reflect a high Fio2. A high Fio2 would, in turn, reflect a clinical attempt to compensate for greater physiological instability. If this were the case, the relationship between higher Pao2 and greater mortality would simply represent the fact that Pao2 is a marker of illness severity instead of a mediator of injury. Accordingly, we think that the authors should report their analysis after correction for Fio2. Similarly, we found that the APACHE III (Acute Physiology and Chronic Health Evaluation III) score also significantly decreased the associated between Pao2 and mortality. Given such findings in a large cohort, we similarly suggest that adjustment for APACHE III score is crucial to any analysis of the relationship between Pao2 and mortality. We have checked with colleagues in the United States, and they have confirmed that such information is recorded and stored as part of the Project IMPACT database; thus, it should be ...