“…Other approaches to the problem of assessment of adequacy of circulatory filling volume have relied on cardiovascular performance indices, and thus attempted to derive the likely responsiveness of the circulation to volume therapy. Various aspects of systolic pressure variation as a marker of volume performance have been advocated by numerous authors [11][12][13][14][15][16] , and, while this measure seems to provide a reasonable guide to the fact that volume is deficient, it does not, currently, provide a quantitative assessment. Furthermore, the technique is not valuable in detecting volume overload.…”