In Reply.—Dr Park raises important issues relevant to the interpretation of oscillometric BP readings. It is true that the Dinamap Monitor derives values from analysis of multiple pulses waveforms during the inflation-deflation cycle. Since the precise period of sampling is unknown to the user, Dr Park argues that the highest and lowest BP encountered during the entire Dinamap cycle should be the appropriate range for comparison with intra-arterial BP recording. We agree that this would be a desirable method for the rigorous evaluation of an oscillometric device. However, it was our intention to examine the Dinamap Monitor as it is used in a clinical setting. We believe that most physicians would consider the oscillometric and direct arterial pressure values to be interchangeable and would make the same clinical decision regardless of the method employed. Consequently, we think that it is important to emphasize the occasionally large differences between oscillometric