There are many instances in veterinary medicine where your pet may require blood pressure measurement. At Vet4life we monitor many of our patients’ blood pressure during anaesthesia and surgery. This helps in the assessment of the plane of anaesthesia; low blood pressure is often the first sign of a deep plane of anaesthesia. We can then match the anaesthetic management closely to the patient’s needs throughout their operation and correct low blood pressure before complications occurs. Emergency patients, such as road traffic accidents, may also have their blood pressure assessed for signs of low blood pressure (hypotension) which may indicate shock or blood loss.
During routine examinations or the annual vaccine appointment the vet may wish to assess your pet’s blood pressure to check for hypertension (high systolic blood pressure).This is particularly the case in senior patients, as high blood pressure (hypertension) is a common cause of illness in geriatric (old) cats.
Blood pressure can be simply and quickly measured in the clinic. A small cuff is placed on the patient’s leg or tail. The cuff is then inflated until the peripheral pulse is heard to stop. Slow deflation of the cuff while listening for return of the pulse allows the systolic blood pressure to be measured. A patient with blood pressure of 150mmHg or higher is considered hypertensive. Anxiety may lead to mild to moderately elevated blood pressure readings. This is known as the ‘white coat effect’. To help avoid this, the patient is given time to quietly relax and acclimatise to the environment at the clinic prior to the blood pressure being measured. In pets that are particularly stressed, multiple blood pressure readings may be taken to ensure a true diagnosis of hypertension is made.
Careful examination for signs of hypertension may also be required to support the diagnosis of hypertension. In hypertensive patients the persistently high blood pressure will lead to injury of certain organs that are particularly susceptible due to their fine blood supply. These organs are known ‘target organs’ and include the eye, brain, cardiovascular system and kidneys. All hypertensive patients should be examined for target organ damage. This often involves fundoscopic examination of the eye to assess the retinas. Hypertensive injury may be seen as fine bleeds on the retina, or in more severe cases retinal detachment. Pets may become blind due to retinal detachment, which may be noticed as sudden onset blindness or blood trapped within the eye.
Blood and urine tests may also be required to assess the patient’s general health and kidney function. Patients with chronic kidney disease (CKD) are frequently affected with high blood pressure. As the kidneys are target organs, the hypertension in CKD will lead to further insult to the kidney and potential worsening of already diminished kidney function. Thyroidal disease, certain hormonal diseases, such as Conn’s syndrome, as well as chronic kidney disease are associated with hypertension.
If an underlying cause for the hypertension is diagnosed then this should be addressed and, where possible, corrected. Therapy with anti-hypertensive medications will also often be initiated. The dose of these medications often requires adjustment based on multiple blood pressure readings. The aim is to slowly bring the blood pressure back toward the normal range (<150mmHg) and prevent further target organ injury. In emergency cases, such as patients with retinal detachments or neurological complications, the blood pressure will require rapid correction. There is not as strong of a link between high salt foods and hypertension as with humans, however in most cases the avoidance of high salt diets is recommended.
As high blood pressure is often a silent illness with few – if any – visible signs, it may be difficult for owners to notice at home. Therefore blood pressure readings are regularly taken in senior patients and those with higher risk due to certain conditions. Once diagnosed, hypertension often requires lifelong management with regular monitoring to ensure that the blood pressure stays well controlled and the serious potential complications of uncontrolled hypertension, such as blindness, are avoided.