Blood pressure - why is is abnormal?
Blood pressure measurement
Blood pressure measurement
In a healthy animal, blood pressure is maintained within a narrow range. When blood pressure is too high (hypertension) or too low (hypotension), serious health problems can occur.
What is blood pressure?
Blood pressure is the force exerted by the blood as it is pumped around the vessels in the body. Most people are familiar with the concept of high blood pressure as a disease that humans can get, but it is also seen in animals.
Hypertension occurs when the rabbit's arterial blood pressure is persistently higher than normal. Hypertension is a normal and expected result of increased stress levels or a high level of activity, but it can also be caused by an underlying disease (known as secondary hypertension) or it can actually be the disease itself (primary hypertension) where the blood pressure is dangerously high with no apparent reason.
Long-term hypertension can seriously damage the organs, including the heart, kidneys, eyes, and the nervous system.
Conversely, low blood pressure can cause serious health problems if not controlled, so quick veterinary treatment is essential.
How will my vet measure my rabbit's blood pressure?
Unlike in humans, only the systolic blood pressure is measured in animals, so the blood pressure reading is only a single number reflecting the highest pressure (in mmHg) found as the heart pumps blood out to the body.
Measuring the blood pressure is usually a painless and stress free procedure. It uses a blood pressure cuff just like the ones used in human hospitals, only much smaller! The blood pressure cuff is placed around the limb and inflated while the pulse is listened to with a Doppler machine. The pressure is then read on a pressure gauge attached to the cuff. The entire procedure only takes a minute or two.
What is normal blood pressure for a rabbit?
As a general rule, normal blood pressure for a rabbit is between 120-180 mmHg.
What causes hypertension?
Stress is a major cause of hypertension, so it is important that blood pressure is taken in a quiet room, away from other people and animals. It is important to keep the rabbit as calm and still as possible before and during the procedure so that the most accurate resting blood pressure reading can be obtained.
Other causes of hypertension include obesity or a diet high in salt, which is unlikely to be a problem unless the rabbit is fed an inappropriate diet. Chronic disease, eg heart or kidney failure, can also contribute to the development of hypertension.
Signs of hypertension include disorientation, weakness, seizures, circling, nose bleeds, dilated pupils, eyes rolling back, blindness, red/blood in the whites of the eyes, blood in the urine.
What causes hypotension?
Some medications, and especially sedative drugs, can cause hypotension. Other reasons for hypotension include dehydration, shock (eg from trauma), blood loss, sepsis/infection, and hormone imbalance.
Sings of hypotension include disorientation, weakness, collapse, lack of activity, shallow breathing, increased thirst and pale gums/eyelids.
Can my rabbit be treated?
Medication may be prescribed and if any predisposing factors are sighted, such as obesity, this needs to be corrected. In cases of hypotension, your rabbit may need to be put on intravenous fluids.
In either case, your vet will want to monitor your rabbit and perform repeated blood pressure checks to ensure the blood pressure returns to normal.