Patient On Ventilator, Low BP
A sudden drop in blood pressure while undergoing dialysis has long vexed many kidney patients. Side effects associated with this situation over the long term range from stroke to seizure to heart damage to death. Patients also suffer in the short term with gastrointestinal, muscular and neurologic symptoms.
Ventilators normally don't cause pain. The breathing tube in your airway may cause some discomfort. It also affects your ability to talk and eat.
If your breathing tube is a trach tube, you may be able to talk. (A trach tube is put directly into your windpipe through a hole in the front of your neck.)
Instead of food, your health care team may give you nutrients through a tube inserted into a vein. If you're on a ventilator for a long time, you'll likely get food through a nasogastric, or feeding, tube. The tube goes through your nose or mouth or directly into your stomach or small intestine through a surgically made hole.
Changes in blood pressure associated with mechanical ventilation may confound the medical observer. The specific effect of ventilation on the cardiovascular system varies with the patient’s kidney and heart function, as well as vascular tone. In any case, blood pressure changes related to mechanical ventilation will manifest themselves at the beginning or end of the ventilatory support.
Your blood pressure can vary depending on the time of day – it gradually increases throughout the day. What you're doing and how you're feeling can also affect it.
Hypotension is the medical term for low blood pressure (less than 90/60). A blood pressure reading appears as two numbers. The first and higher of the two is a measure of systolic pressure, or the pressure in the arteries when the heart beats and fills them with blood. The second number measures diastolic pressure, or the pressure in the arteries when the heart rests between beats.
How Is Blood Pressure Generated?
The left lower chamber of the heart (ventricle) receives oxygenated blood from the lungs and pumps it throughout the body. The heart fills with blood between heartbeats. This phase in the heart cycle is called diastole. When the heart pumps to push blood throughout the arteries, this phase is called systole. You can place your fingers on your neck or the inside of your wrist to detect your heartbeat. The pulse you feel is the contraction of the heart's left ventricle.
How Is Blood Pressure Determined?
Several factors influence blood pressure. Blood volume and blood vessel wall behavior are two important determinants of blood pressure. The more blood pumped with each heartbeat, the higher the blood pressure. The presence of stiff or narrow artery walls that resist blood flow also increases blood pressure. Having lower blood volume and open, flexible arteries decreases blood pressure.