Intra-Arterial Monitoring of Blood Pressure

firmer to the surgeon's fingers. But how strong are the beats? The anesthesiologist scans a manometer dial for the oscillations coming from the blood pressure cuff that might give the answer. But is the pressure really good enough to assure that the patient is getting the circulation he requires? Another patient has suffered a ruptured viscus and the toxins in his blood are threatening the vascular bed. His nurse must administer intravenous vasopressors at a rate adequate to maintain a systolic pressure over 80 mm. Hg. She wraps a cuff around the brachial artery and listens carefully for the Korotkoff sounds. How faint they are. Did she hear them correctly? Does the cuff measurement represent the central arterial pressure, or is she being misled by the peripheral vasodilatation or vasoconstriction that may accompany sepsis? Uncertainty in cardiovascular crises like these is common enough to warrant employing an alternative technique to evaluate blood pressure-a technique that is continuous and direct. By passing a catheter into the artery and attaching it to an electronic measuring system, one can measure arterial pressure as it is transmitted directly to an electronic pressure sensor called a transducer. The transducer converts the me-