How to detect a positive response to a fluid bolus when cardiac output is not measured?

Annals of Intensive Care

Table 2 Changes in haemodynamic variables induced by volume expansion

	Before volume expansion	After volume expansion
Heart rate (mean ± SD, beats/min)
Non-responders	92 ± 21	91 ± 21*
Responders	99 ± 22^#	97 ± 20*^#
Systolic arterial pressure (mean ± SD, mmHg)
Non-responders	110 ± 22	117 ± 25*
Responders	109 ± 22	128 ± 25*^#
Diastolic arterial pressure (mean ± SD, mmHg)
Non-responders	55 ± 12	57 ± 13*
Responders	53 ± 11	59 ± 13*
Mean arterial pressure (mean ± SD, mmHg)
Non-responders	71 ± 16	75 ± 18*
Responders	69 ± 14	79 ± 17*
Arterial pulse pressure (mean ± SD, mmHg)
Non-responders	55 ± 17	60 ± 19*
Responders	56 ± 18	69 ± 21*^#
Shock index (mean ± SD, beats/min/mmHg)
Non-responders	0.87 ± 0.28	0.81 ± 0.25*
Responders	0.95 ± 0.36^#	0.79 ± 0.22*
Cardiac index (mean ± SD, L/min/m²)
Non-responders	3.4 ± 1.2	3.6 ± 1.3*
Responders	2.8 ± 1.0^#	3.7 ± 1.2*
Arterial elastance (mean ± SD, mmHg/mL)
Non-responders	1.71 ± 0.74	1.64 ± 0.73*
Responders	2.27 ± 1.08^#	1.61 ± 0.61*

N = 275 in responders and 216 in non-responders
* p < 0.05 vs. Before volume expansion (comparisons in rows); ^# p < 0.05 vs. Non-responders (comparisons in columns)