Table 1 Inclusion and exclusion criteria

Age ≥ 18 years

Elective surgery

General anesthesia

ASA physical status > 3

Dyspnea

Systolic blood pressure ≥ 180 mmHg

Systolic blood pressure < 90 mmHg

Decompensated heart failure

Elevated pulmonary arterial pressure > 40 mmHg

Significant valvular disease

Significant carotid stenosis

Documented negative fluid balance > 1.000 ml on preceding day

Pheochromocytoma

SOFA score > 1

Agitation (RASS > 1)

IVC non visualized

Epidural catheter in use