Longitudinal studies of reproducibility and variability of indirect (oscillometric) blood pressure measurements in dogs: evidence for tracking.

To be clinically reliable, blood pressure readings taken in quiet surroundings with good technique from healthy, unstressed subjects accustomed to the procedure, should be reasonably constant between occasions. Apart from changes attributable to age or stress, sustained rises suggest hypertension. Yet it is increasingly realised that arterial pressure shows great short-term lability. Despite this, 'tracking' occurs in groups of humans, i.e. when ranked by blood pressure they tend to maintain their rank order. This paper examines month-on-month variability of arterial pressure, measured by non-invasive oscillometry (Dinamap) in both pet dogs and kennel populations. 'Tracking' occurred and there was also evidence of 'white coat' effects. Heart rate was more variable than arterial pressure and should not be used to reject pressure readings unless changes are extreme. There was further evidence that canine blood pressure rises with age.