This shows the response to an intravenous dose of metaraminol (0.5 mg) in a patient (age 75 years, weight 62 kg) during surgery for aortic valve replacement for aortic stenosis. This record was obtained soon after discontinuation of cardiopulmonary bypass. At the start, the arterial pressure and SVR are low and there is an obvious systolic pressure variation indicating hypovolaemia. In response to the metaraminol there is an increase in blood pressure due to an increase in SVR which in turn causes a small reduction in stroke volume.