Validity of pulse pressure and systolic blood pressure variation data obtained from a Datex Ohmeda S/5 monitor for predicting fluid responsiveness during surgery

A simple, inexpensive method is needed for predicting fluid responsiveness in patients during surgery. A previously described method using the Datex Ohmeda S/5 monitor to record arterial and pulse pressure might be accurate enough to use for this purpose. In this study, 26 patients undergoing scheduled craniotomy surgery, we compared measurement of systolic pressure variation (SPV) (measured as both mm Hg and %) and pulse pressure variation (PPV%) using the Ohmeda monitor method to simultaneously measurement of a reference standard, stroke volume variation (SVV) determined with an Edwards FloTrac/Vigileo monitor, during volume loading. Variation in systolic pressure, pulse pressure, and stroke volume all decreased proportionally as fluid volume increased. The 3 test parameters, SPV (%), SPV (mm Hg), and PPV (%) were highly correlated to SVV, the reference standard. Bland-Altman plots comparing SPV (%) and PPV with SVV showed agreement with this standard. Receiver operating characteristic curves showed no significant difference between the 3 test parameters for predicting the vascular response to fluid infusion. There were no significant differences between SPV and PPV estimation using the Ohmeda monitor method and the reference SVV measurement for predicting vascular changes in response to fluid loading. The Ohmeda monitor method requires less sophisticated technology and is much less expensive than other methods.