In medicine, the mean arterial pressure (MAP) is an average blood pressure in an individual during a single cardiac cycle. MAP is altered by cardiac output and systemic vascular resistance. Testing Mean arterial pressure can be measured directly or estimate from systolic and diastolic blood pressure by using a formula. The least invasive method is the use of an blood pressure cuff which gives the values to calculate an estimate of the mean pressure. A similar method is to use a oscillometric blood pressure device that works by a cuff only method where a microprocessor determines the systolic and diastolic blood pressure. Invasively, an arterial catheter with a transducer is placed and the mean pressure is determined by the subsequent waveform. Estimating MAP While MAP can only be measured directly by invasive monitoring it can be estimated by using a formula in which the lower (diastolic) blood pressure is doubled and added to the higher (systolic) blood pressure and that composite sum then is divided by 3 to estimate MAP. Thus, a common way to estimate mean arterial pressure is: where: DP = diastolic pressure SP = systolic pressure MAP = mean arterial pressure Systolic pressure minus diastolic pressure equals the pulse pressure which may be substituted in. Another way to find the MAP is to use the Systemic Vascular Resistance equated (), which is represented mathematically by the formula where is the change in pressure across the systemic circulation from its beginning to its end and is the flow through the vasculature (equal to cardiac output). In other words: Therefore, Mean arterial pressure can be determined by rearranging the equation to: where: is cardiac output is systemic vascular resistance is central venous pressure and usually is small enough to be neglected in this formula. This is only valid at normal resting heart rates during which can be approximated using the measured systolic () and diastolic () blood pressures: Elevated heart rate At high heart rates is more closely approximated by the arithmetic mean of systolic and diastolic pressures because of the change in shape of the arterial pressure pulse. For a more accurate formula of for elevated heart rates use: Where HR = heart rate. DP = diastolic pressure MAP = mean arterial pressure PP = pulse pressure which is systolic minus diastolic pressure Most accurate The version of the MAP equation multiplying 0.412 by pulse pressure and adding