Electronic sphygmomanometers noninvasively measure and display a patient's arterial blood pressure. The use of these units may help to overcome some of the problems associated with manual sphygmomanometry, such as variations in user techniques, hearing acuity, and the difficulty of obtaining measurements on hypotensive patients. In addition, many automatic blood pressure units can be programmed for readings at regular intervals and will sound an alarm if a patient's blood pressure exceeds preset limits. Most units display heart rates based on the blood pressure waveform. These monitors are frequently included in vital signs monitors that may also be used to measure a patient's temperature and/or oxygen saturation