Hourly systolic blood pressure and heart rate versus initiation of dexmedetomidine therapy. Systolic blood pressure and heart rate values were averaged each hour for all 16 patients with data available. Measurements were recorded from 24 h prior to dexmedetomidine therapy through the first 24 h on dexmedetomidine. Negative numbers represent data prior to the initiation of the study drug and the time point 0 represents the initiation of dexmedetomidine. Error bars reflect the standard error around each mean value.