Abstract
Recently, less-invasive cardiac output monitors have been paid much attention for better management for critically ill patients instead of conventional thermodilution method with pulmonary artery catheter. However, adequate assessment of accuracy of these less-invasive monitors is warranted. Statistical method described by Bland and Altman should be applied to adequately assess agreement between two different methods for cardiac output measurement. However, several cautions must be paid to undergo or interpret Bland-Altman analysis. First, criteria to accept interchangeability remains to be concretely defined. Since the conventional thermodilution method demonstrates significant variation around 20%, the similar degree of variations is widely accepted. However, more liberal criteria may be acceptable. Another approach that more than 75% of bias measurements were within ±20% of the mean may be used. Second, special statistical handling is required if the repeated measurements per individual were made. In this commentary article, these important aspects of Bland-Altman analysis are reviewed.
