What is the fine-grained topic of the following text: During this experiment, the sea level Pa02 was most predictive of resting altitude Pa02, but this measurement in isolation is not sufficient to predict symptomatic responses, cardiac arrhythmias, or efficacy of oxygen supplementation, which can be obtained via an HAST. Only return the topic.
Predictive capability of sea level Pa02 for resting altitude Pa02 and its limitations