Blood pressure is an important factor that influences your dog's overall health. Serious, even life-threatening, complications can occur if your pup's pressure climbs too high, a condition called hypertension, or drops too low, a condition called hypotension. Measuring a dog's blood pressure is a little more difficult than measuring your own, so it's best to take your dog to the vet for monitoring.
Measuring Blood Pressure
Your veterinarian likely will measure your dog's blood pressure by using a device called a sphygmomanometer and a technique known as the auscultatory method. First, the vet will tighten an inflatable cuff around your dog's tail or paw. Then, by reading the blood pressure while listening to how the blood flow changes as the pressure is reduced, he can determine the maximum and minimum blood pressure, known as systolic and diastolic, respectively.
Veterinarians also use other techniques to measure blood pressure, such as Doppler flow detection and the oscillometric methods, which rely on electronic devices that measure blood pressure through sound or analyze the changes in blood pressure over time. These methods are less accurate than the auscultatory method. Doppler flow detection cannot determine diastolic pressure. Blood pressure also can be measured directly, by introducing a pressure-sensitive device into the vein.
Signs and Symptoms of Hypertension
Part of the danger of high blood pressure is that it may go undetected for a length of time, which is part of the reason vets monitor it regularly. The eyes of dogs are often the first place to suffer damage, which can manifest as decreased vision or partial blindness. Accordingly, it is important to report any vision changes to your vet so he can measure your pet's pressure; additionally, in some cases, it is possible to reverse eye damage with early detection.
As untreated hypertension also can lead to kidney, heart or nervous system damage, veterinary attention is crucial. If your dog's blood pressure is below 150/95, she is not suffering from hypertension and probably does requires no treatment. Blood pressures above 160/119 or 179/100 are troubling and your veterinarian will try to determine and treat the cause. Blood pressures in excess of 180/120 necessitate immediate treatment to avoid long-term consequences.
Signs and Symptoms of Hypotension
Hypotension -- usually defined as pressure lower than 133/75 -- may precipitate from electrolyte imbalances, dehydration, heart disease or medications, as well as acute disorders, such as shock or sepsis. Clinical signs of low blood pressure include decreased urine output, weakness, mental dullness and low body temperature. Additionally, you may notice that your dog's gums are paler than normal. Unlike hypertension, which may persist for prolonged periods without causing acute problems, severe hypotension is a medical emergency.
Causes of Blood Pressure Problems
While many cases of hypotension relate to a traumatic event or injury, a number of diseases, including chronic renal failure, diabetes and hyperthyroidism, among others, can cause your dog's blood pressure to rise. When this occurs, veterinarians call it secondary hypertension. The term primary hypertension refers to high blood pressure that is not caused by other diseases; in such cases, the cause is often unknown. However, many veterinarians suspect that primary hypertension is strongly related to heredity. According to petMD, researchers estimate between 0.5 percent and 10 percent of all dogs suffer from hypertension. The vast majority of these cases -- approximately 80 percent or all dogs with hypertension -- are secondary hypertension.