Table 2.

Sensitivity, specificity and Youden’s J index of traditional vital signs and hemodynamic responses for prediction of the onset of decompensated shock secondary to progressive central hypovolemia. Modified from Convertino et al. [14,22,23,25].

Vital Sign	Sensitivity	Specificity	Youden’s ‘J’ Index
Systolic Blood Pressure	0.80	0.17	0.03
Diastolic Blood Pressure	0.40	0.53	0.07
Mean Blood Pressure	0.60	0.33	0.07
Heart Rate	0.80	0.02	0.18
Stroke Volume	0.60	0.33	0.07
Cardiac Output	0.80	0.02	0.18
Pulse Pressure Variability	0.78	0.69	0.47
Peripheral Capillary Oxygen Saturation (SpO2)	0.60	0.00	0.40
Deep Muscle Oxygen Saturation (SmO2)	0.65	0.63	0.28
Compensatory Reserve	0.84–0.87	0.78–0.86	0.62–0.73

Note: For Youden’s Index, a value of 1 represents a perfect diagnostic test, while a value of 0 represents a test with poor diagnostic accuracy. Stroke volume (SV), systolic, diastolic and mean blood pressures were measured by finger photoplethysmograpy; heart rate (HR) was measured by standard electrocardiogram; cardiac output was calculated as SV times HR; Pulse pressure variability and SpO₂ was measured with standard pulse oximetry; SmO₂ was measured with near-infrared spectroscopy; compensatory reserve was measured by pulse oximetry.