Patients in ICU who suffer from circulatory insufficiency, regardless the cause that require invasive hemodynamic monitoring. The aim of the study is to correlate stroke volume variation which predicts fluid responsiveness with change of the blood pressure after intravenous admission of propofol. This test could become a surrogate of stroke volume variation in patients with contraindications to minimally invasive hemodynamic monitoring.

This prospective, observational study was conducted after approval of the Independent Bioethics Commitee at Medical University of Gdańsk (numer zgody) and registered in ClinicalTrials.gov. Mechanically ventilated patients of intensive care unit who routinely recieved haemodynamic monitoring with PiCCO™ (Getinge AB, Sweden) technology using Philips IntelliVue PiCCO-Module (Philips Healthcare, Amsterdam, Netherlands), were enrolled. Patients were sedated with midazolam infusion at 0,15 to 0,6 mg kg-1 h-1 . Before the trial in each patient, heart rate (HR) invasive (IBP) and non - invasive blood pressure, (NIBP) infusion rate of catecholamines and non adrenergic vasopressors was recorded and PiCCO device was callibrated by transpulmonary thermodilution with 20 ml of cold saline. Global end diastolic volume (GEDV), intrathoracic blood volume (ITBV) and stroke volume variation (SVV) were calculated and recorded. For effective ventilation with increased tidal volume of 8 ml kg-1 of Predicted Body Weight, each patient recieved propofol bolus of 0,25 mg kg-1, 0,5 mg kg-1 and 1,0 mg kg-1 consecutively. Higher doses were used at good tolerance of the lower ones. After each bolus systolic and diastolic invasive blood pressure, heart rate (HR), continuous cardiac output (CCO), continuous cardiac index (CCI), stroke volume index (SI), stroke volume variantion (SVV), and left ventricular contractility index (dPmax) were recorded every fifteen seconds for ten minutes. The absolute and realtive change in blood pressure, compared to the values of blood pressure before the drug administration, were correlated with SVV. Time interval between each examination ranged from 4 to 48 hours.

Inclusion Criteria:

ICU patient Haemodynamically instable Mechanically ventilated

Exclusion Criteria:

Simultaneous propofol infusion Contraindications for propofol Atrial fibrillation Valvular malfunction Aortic stenosis Aortic aneurysm

Mechanically ventilated ICU patients with heamodynamic instability aged above 18.