NONINVASIVE COlHuntsman et al.perfusion imaging using surfactant stabilized microbubbles. (abstr) Circulation 64 (suppl IV): IV-203, 1981 infarctions are not recognizable by standard clinical criteria. ' Current criteria for the clinical evaluation of circulation in myocardial infarction are often timeconsuming, subjective and prone to error. Clinicians are urged to rely on "monitoring of heart rate and rhythm, measurement of systemic and arterial pressure by cuff, obtaining chest roentgenograms to detect heart failure, careful and repeated auscultation of lung fields for pulmonary congestion and edema, measurement of urine flow, examination of the skin and mucous membranes for evidence of the adequacy of perfusion, and arterial sampling of Po2, Pco2, and pH when hypoxemia or metabolic acidosis is suspected."3 Physicians are often reluctant to use invasive CO determinations, except in selected patients, because they cause discomfort and may result in complications.4 I Given the importance of CO assessment, a noninvasive, easily

Background Functional hemodynamic indicators (systolic pressure variation [SPV and SPV%] and pulse pressure variation [PPV%]) are sensitive and specific indicators of fluid responsiveness. It was unknown if these indicators could be accurately measured directly from the bedside monitor. Objective Determine the accuracy of SPV, SPV%, and PPV% measurements by using a stop-cursor method compared with a digitized analog strip (gold standard). Methods A prospective observational study using a convenience sample of 30 adult patients in a medical-surgical intensive care unit who were receiving mechanical ventilation and had no spontaneous breaths during 3 sequential ventilator breaths and had an optimized arterial catheter. The peak and nadir arterial pressure values for a ventilator cycle were simultaneously obtained by using the stop-cursor method on the bedside monitor and a hardcopy strip. The indicators were averaged over 3 breaths, and the difference between methods was calculated. Results Data were analyzed from 29 patients (1 patient excluded) on assist control ventilation (mean [SD] for tidal volume, 7.5 [2] mL/kg; positive end-expiratory pressure, 7 [4] cm H 2 O). For SPV, the mean bias was 0.4 (SD, 0.9) mm Hg (95% limits of agreement [LOA], -1.4 to 2.2 mm Hg); for SPV%, 0.3 (SD, 0.9; 95% LOA, -1.5% to 2.1%); for PPV%, 1.0 (SD, 3.3; 95% LOA, -5.5% to 7.5%). In only 1 case (PPV%) was there disagreement on fluid response characterization. Conclusions Statistically significant small differences in SPV and SPV% were detected. The differences in SPV, SPV%, and PPV% were not clinically significant, suggesting that functional hemodynamic indicators can be obtained accurately with the stop-cursor method.

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