Afterload Assessment With or Without Central Venous Pressure: A Preliminary Clinical Comparison

A clinical comparison, of two methods of afterload assessment, has been made. The first method, systemic vascular resistance index (SVRi), is based upon the traditional formula for afterload which utilizes central venous pressure (CVP), as well as cardiac index (C-i), and mean arterial blood pressure (MAP). The second method, total systemic vascular resistance index (TSVRi), also uses MAP and C-i. However, TSVRi ignores the contribution of CVP. This preliminary examination, of 10 randomly-selected ICU patients, has shown a high degree of correlation (ranging from 90 to 100%) between SVRi and TSVRi (P < 0.0001). Furthermore, there was also a high degree of correlation (ranging from 94 to 100%) noted between the hour-to-hour change in SVRi with the hour-to-hour change in TSVRi (P < 0.0001). The results, of this pilot study, support the premise that the use of CVP may not always be necessary for afterload evaluation in the clinical setting. Minimally-invasive means of measuring both C-i and MAP, without CVP, may be adequate for use in assessing afterload.