[i] Arterial blood pressure: The mean pressure is the average pressure throughout the cardiac cycle. Because systole is shorter than diastole, the mean arterial pressure (MAP) is slightly less than the value halfway between systolic and diastolic pressure. MAP can be determined by integrating a pressure signal over the duration of one cycle. The mean pressure is then given by the value of this integral divided by time.
[ii] The slope of the upstroke of the wave reflects myocardial contractility (dP/dt).
[iii] The stroke volume can be calculated by measuring the area from the beginning of the upstroke to the dicrotic notch. If this is multiplied by the heart rate, then cardiac output can be estimated.
[iv] The position of the dicrotic notch on the down stroke. A low dicrotic notch is seen in hypovolaemic patients.
[v] The slope of the diastolic decay indicates resistance to outflow. A slow fall is seen in vasoconstriction.
Thromboembolism/vasospasm/thrombosis resulting in:
[i] Compromise of circulation leading to blanching and possible necrosis or gangrene of tissues and extremities.
[iii] Damage to peripheral nerves.
[i] Incidents relating to arterial cannulation as identified in 7,525 reports submitted to the Australian incident monitoring study (AIMS-ICU).
Durie M et al.
Anaesth Intensive Care 2002; 30(1): 60-5.
[ii] Invasive arterial BP monitoring in trauma and critical care: effect of variable transducer level, catheter access, and patient position.
McCann UG 2nd et al.
Chest 2001; 120(4): 1322-6.