Mean arterial pressure (MAP)
Mean arterial pressure (MAP) is a crucial measurement of blood pressure, particularly utilized in emergency medical settings such as hospitals' emergency rooms or intensive care units. It reflects the average pressure in a person's arteries during one cardiac cycle, which is significant for assessing blood flow to vital organs and tissues. MAP is determined using systolic and diastolic blood pressure readings, with a normal range typically between 70 to 110 mm Hg. Extreme values of MAP can indicate severe health risks; readings above 110 mm Hg may suggest cardiovascular stress and potential organ damage, while readings below 60 mm Hg can lead to inadequate blood supply to organs, risking organ failure. Healthcare practitioners closely monitor MAP in cases of trauma, shock, or other life-threatening conditions, as it provides a more comprehensive view of a patient's circulatory health. Management of abnormal MAP levels often involves medications or interventions to restore appropriate blood pressure. Understanding MAP is essential for ensuring adequate perfusion and preventing serious complications in critically ill patients.
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Mean arterial pressure (MAP)
Mean arterial pressure (MAP) is a type of blood pressure reading generally taken in emergency settings such as the emergency room or intensive care unit (ICU) of a hospital. Blood pressure is the measure of the strength of the blood pushing against the blood vessels as the heart pumps blood throughout the body. High or low blood pressure can have negative health effects. MAP helps medical professionals determine the actual pressure of the blood pressing against the walls of the arteries, which are a type of fibrous and muscular blood vessel that carries oxygenated blood away from the heart and throughout the body. The MAP reading helps health practitioners determine if a person's blood flow is strong enough to push adequate amounts of blood to the tissues and organs of the body. It helps those in the medical field determine if a person's blood pressure needs to be raised or lowered to increase the perfusion, or delivery, of blood. Regulation of MAP is critical in most cases to prevent serious health conditions or even death.
Background
Blood pressure is an important indicator of health. The central nervous system monitors a person's blood pressure continuously to ensure it remains constant. The baroreceptor reflexes aid in keeping blood pressure at a constant rate because they are able to decipher how far the arterial walls, heart, and veins expand as blood passes through them. When the blood pressure is high, the more they are stretched, which signals the brain to relax and tighten them. This helps to restore blood pressure to normal levels.
Certain medical conditions, a poor diet combined with an unhealthy lifestyle, and genetics can cause high or low blood pressure. The most common form of blood pressure reading is taken by a device with a cuff and a gauge to measure the systolic blood pressure over the diastolic blood pressure; however, automated blood pressure machines also exist. This reading is a measurement of two numbers written like a fraction. The systolic is on top, and the diastolic is on the bottom. The systolic, or top, number is used to measure the amount of pressure in the arteries when the heart muscle contracts. The diastolic, or bottom, number is used to measure the blood pressure between heartbeats. These numbers are expressed in millimeters of mercury (mm Hg).
The American Heart Association (AHA) considers a normal blood pressure reading of systolic pressure between 90 and 120 mm Hg and diastolic pressure between 60 and 80 mm Hg. Readings above 120/80 mm Hg are considered high blood pressure, or hypertension. High blood pressure can have a dire effect on health and cause serious conditions such as heart disease or stroke. Medications and a healthy lifestyle that includes a proper diet and exercise can help to control high blood pressure. Readings below 90/60 mm Hg are considered low blood pressure, or hypotension. Low blood pressure can also have a negative effect on health because it can cause inadequate amounts of oxygenated blood to circulate throughout the body.
Overview
A MAP reading is generally needed in serious medical emergencies, such as trauma, septic shock, head injury, stroke, heart attack, and hemorrhage, because it provides a more accurate measure of blood delivery to the tissues and organs in the body. This reading can help a medical professional determine if a person is in danger of having his or her organs shut down due to low blood flow caused by severe injury. Blood pressure machines in medical facilities are used to calculate MAP. MAP can also be monitored by inserting a thin catheter (small flexible tube) into an artery; this is called an arterial line. Arterial lines are the most accurate way to measure MAP, but they are invasive.
MAP is calculated by using systolic blood pressure and diastolic blood pressure figures. After these figures are determined, the diastolic number is doubled. Then, this number is added to the systolic figure. Next, that number is divided by 3, which results in the MAP. For example, a person has a blood pressure reading of 115/85 mm Hg. Take the diastolic reading and double it: 85 + 85 = 170. Next, add the systolic reading to this total: 115 + 170 = 285. Last, divide the total by 3, so 285/3 = 95. The MAP for a person with a blood pressure reading of 115/85 mm Hg = 95 mm Hg. The normal range for MAP is about 70 to 110 mm Hg, so this person has a MAP in the normal range and should have adequate blood flood to his tissues and organs.
Health practitioners should take care to calculate MAP on all patients with serious illness and injury because the patients might have a slightly low to normal systolic pressure figure, which can lead to a wrong diagnosis. A MAP reading above 110 mm Hg shows that the heart is stressed because it is working harder than it should to pump blood to the other parts of the body. When this happens, fatty deposits known as atheroma build up in the arteries. These deposits can cause heart disease, blood clots, heart attacks, or stroke. High MAP can also cause the heart muscle to enlarge, thicken, and weaken. High MAP generally shortens a person's life span; very high MAP can cause organ failure and lead to death—especially a MAP reading that spikes in a short period. High MAP can be treated by lowering the blood pressure as with medications.
A MAP reading below 60 mm Hg can be fatal because not enough blood is getting to the organs and tissues. This lack of blood can cause organ failure, which then leads to shock. Low MAP can be treated by medications that cause the blood vessels to constrict, which aids in increasing blood pressure. Sometimes, blood transfusions and intravenous fluids may be needed in addition to medications to bring up the blood pressure.
Bibliography
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