Clinical features to predict hypoxia and/or hypercapnia in acute asthma attacks.

Arterial blood gas data were correlated with clinical variables including patients' perception of dyspnea and spirometry in 79 episodes of acute asthma attacks. Among several variables that showed univariate significance with severity, only subjective degree of dyspnea rated on a modified Borg scale (MBS) remained predictive to discriminate the presence or absence of hypoxia/hypercapnia in multivariate analyses. MBS alone could predict the arterial blood gas status with accuracy of approximately 75%. Therefore, patients' sensation of dyspnea seemed to be an important factor in the evaluation of acute asthma in an emergency room.