Veterinary session

High blood pressure and its harmful consequences is a proven problem for our pets. To establish this, indirect blood pressure measurement has now become a routine examination in small animal medicine. Based on the research of the Cardiology and Nephrology Working Group of the Department of Internal Medicine and Clinic and the literature, the most accurate way to measure the blood pressure is at the tail with the High Definition Oscillometry (HDO) device, regardless of body position. In our research, we looked for an answer to the question of whether the lenght and quality of the tail fur has an influence on the measured blood pressure values.

A total of 35 dogs participated in the research, of which 7 were excluded. An HDO blood pressure measuring device and the same measurement protocol were used for all animals. The blood pressure of the animals was measured in three different states: in full fur; on the ventral side after 180° shearing; and after a full 360° furcut. Tail circumference was measured before and after shearing. For each animal, at least four measurements were performed in each of the three fur states, so a total of more than 400 measurements were performed. After the measurements, we compared the systolic and diastolic values, the mean arterial pressure and the pulse in different fur states using a paired-samples sign test.

The 28 examined dogs were divided into control and target groups. The control group (n=9) included short-haired dogs, in which the tail circumference reduction after complete fur cutting was ≦ 10%. The group consisted of 6 males and 3 females, their age was 6.8 ± 4.5 years, their body weight was 19.1 ± 5.8 kg. The target group (n=19) included dogs with longer fur, whose tail size reduction was >10%. Among the dogs, 13 were males and 6 were females, their age was 8.2 ± 3.4 years, their body weight was 25.6 ± 13.8 kg.

The blood pressure values of the control group did not show significant changes after fur shearing (p=0.095; median -6 [1st quartile -13, 3rd quartile -3] mmHg, systole). The blood pressure values of the target group were significantly reduced both in the half-sheared state (p=0.001; median -10 [1st quartile -40, 3rd quartile -1.5] mm Hg, systole) and in the fully sheared state (p=0.012; median -9 [1st quartile -41, 3rd quartile -2] mmHg, systole), relative to the whole coat measurement. The greatest drop in blood pressure was observed in dogs with long and/or thick fur after trimming.

Based on our results, fur quality and length affects the results of blood pressure measured at the base of the tail with the HDO device. Falsely high values can be measured in long-haired or shaggy-haired dogs, so we recommend repeating the measurements in these animals after trimming the tail hair.