Inclusion Criteria:  Patients with no known intracranial pathology. Patients with systolic blood pressure < 90 mmHg Patients with mean blood pressure < 65 mmHg Patients with tachycardia (heart rate 100 beats/min) Patients with mottled skin, oliguria (diuresis of less than 20 ml/hr or 0.5 ml/kg/hr for two hours), and acute renal failure. Patients with arterial lactate concentration > 2 mmol/L  Exclusion Criteria:  Patients with known intracranial hypertension Patients in the early postpartum period Patients with severe mitral or aortic regurgitation Patients with cardiac arrhythmia Patients unable to be evaluated due to poor echogenicity