Arterial tension is the pressure exerted on the walls of the arteries by blood moving away from the heart. When doctors measure blood pressure in patients, they commonly take the measurement at the brachial artery in the arm, using the arterial tension in this artery as a frame of reference. There are a variety of other ways to measure blood pressure, including the use of invasive techniques like monitors placed in the arteries, an option sometimes used in hospital settings.
Every time the heart beats, it creates arterial tension as blood is pushed out into the arteries. The circulatory system is a vast pump working under pressure to move blood throughout the body. As blood gets further away from the heart, the arterial tension declines, dropping rapidly in smaller arteries as it works its way to the corners of the body before returning along the network of the patient's veins.
Taking a pressure measurement at a single artery provides information about the arterial tension at that artery. This information can be used to extrapolate a mean arterial pressure and to collect other information about the patient's circulatory system and heart health. Pressure measurements are taken during systole and diastole, the high and low points of pressure. Normal ranges for arterial tension vary, depending on age and level of fitness.
Patients with unusually high or low arterial tension may be at risk of medical complications. Variations in blood pressure levels can also be a sign of disease in a patient, indicative of a problem in the cardiovascular system. Chronic high pressure can strain the arteries and may be associated with increased risk of conditions like stroke. When high pressure is identified, a doctor may recommend diagnostic testing to determine why and methods for controlling or reducing it may be explored.
Many patients are familiar with the process of measuring arterial tension at the brachial artery in the arm, where a cuff is applied and a doctor listens for the flow of blood through the artery or uses an automated device to collect a blood pressure measurement. If invasive measurement is needed, a doctor has a choice between several arteries for the placement of a cannula used to monitor pressure. Because this method has risks for the patient, it is only used when a doctor feels it is necessary and it is applied primarily in hospital settings, where patients can be closely monitored.