Direct Arterial Pressure Monitoring: Pattern Recognition in the Management of Circulatory Failure

Abstract

Direct arterial blood pressure monitoring is frequently undertaken in operating rooms, critical care units, emergency departments and coronary care units where rapid alterations in hemodynamic status may occur in response to the underlying disease and/or treatment. In addition to providing a beat-to beat measurement of blood pressure, a careful study of the individual components of the arterial pressure waveform will also enable a more comprehensive assessment of several other hemodynamic parameters that may influence treatment [1, 2, 3, 4]. Changes in circulating volume (or ventricular preload), stroke volume (an important determinant of cardiac output), volume responsiveness and peripheral vascular resistance (or afterload) are some of the more important variables that may be inferred from the arterial pressure trace. Understanding the significance of all the components of an arterial pressure waveform is, therefore, an essential skill for hospital doctors involved in the care of acutely ill patients. In this case-based discussion we will present a series of arterial pressure recordings that illustrate some of the clinically important concepts.