EPIDEMIOLOGIC-STUDY OF BLOOD-PRESSURE IN DOMESTIC DOGS

Previous experience has shown that a noninvasive (indirect) technique using an oscillometric monitor in conjunction with a tail cuff makes r outine clinical blood pressure measurement practicable in dogs. The re lationship between indirect and direct readings has been evaluated in both anaesthetised and conscious dogs (Bodey and others 1994, 1996). I n this study, more than 2000 pressure measurements were taken from 190 3 dogs. It was found that systolic is the most variable pressure param eter and that it depends on age, breed, sex, temperament, disease stat e, exercise regime and, to a minor extent, diet. Diet was not a signif icant determinant of diastolic and mean arterial pressure. Age and bre ed were the major predictors for all parameters. Heart rate was primar ily affected by the temperament of the animal, though other factors al so play a part in prediction. The distribution of systolic, diastolic, mean arterial pressure and heart rate across the dog population appro ximates to a log normal distribution. On the basis of these results it is possible to describe normal ranges for canine blood pressure; defi nition of hypertension, though, demands attention to age and breed nor mal values. The existence of statistically defined hypertension in an individual or breed does not imply adverse effects justifying therapy. Among the secondary causes of hypertension, such as diabetes, obesity and hyperadrenocorticism, hepatic disease was a new addition also und ocumented in humans. The hypothesis that dogs, though classic model an imals for hypertension, are resistant to its development found support from the modest increase in mean pressure values observed among dogs with renal disease, notably those with substantial reduction of glomer ular filtration rate. The existence of breeds such as deerhounds with average pressures in the borderline range for hypertension in humans ( and many individuals, therefore, well above) suggests that dogs may al so be resistant to some of the adverse effects of high blood pressure.