ABSTRACT
The "gold standard" for blood pressure (BP) measurement is the invasive measurement done by inserting a large bore hypodermic needle into the desired artery or vein, and coupling this needle with a saline-filled catheter to a physiological BP sensor, generally of the unbonded strain gauge type. BP monitoring under clinical circumstances can either be by catheter/transducer, or be performed noninvasively by a caregiver with a sphygmomanometer and stethoscope, or by a calibrated plethysmographic device that sends its output data to a nursing station. BP is sometimes given as mean arterial pressure (MAP), which is simply the time average of BP(t) measured with an invasive sensor. This chapter describes how the sphygmomanometer works, and how finger plethysmographs can be used to continuously monitor BP. Another approach to BP measurement with the pressure cuff that avoids listening for Korotkow sounds is oscillometry.
