Assessment of Fluid Responsiveness by Elevation of PEEP in Patients With Septic Shock

The aim of the study is to evaluate whether fluid responsiveness of the critically ill patient can be assessed by analysing the PEEP-induced hemodynamic effects to systolic blood pressure, pulse pressure, aortic blood flow, aortic time-velocity integral and left ventricular end diastolic area measured with transesophageal echocardiography (PEEP-test). The chances are compared to increase of CI after volume expansion (gold standard). In clinical practise, it would be especially relevant if PEEP-induced changes in arterial pressure variations could be used in evaluation of volume status and fluid responsiveness. However, as ECHO-derived variables are used in greater extent to guide the treatment with inappropriate evidence, the simultaneous registration of ECHO-derived hemodynamic measurements is essential in the study design.

Hemodynamic changes indicating fluid responsiveness assessed during elevation of PEEP. Change in mean arterial pressure or aortic velocity time integral.

Measurement of hemodynamic variables using a pulmonary catheter and transesophageal echocardiography at baseline PEEP 10, during elevation of PEEP and after volume challenge at PEEP 10 cmH2O

Inclusion Criteria:• Written informed consent by patient or relative Time in ICU < 48 hours Septic shock Pulmonary artery catheter and radial arterial catheter Age 18 - 75 years Sinus rhythm Need for norepinephrine over 0.1 ug/kg/min but otherwise hemodynamically stable i.e no need to change the dose over the last 15min period before the study Mechanical ventilation with sedation Pwcp <18 mmHg Exclusion Criteria: Contraindication to elevation of PEEP ( elevated intracranial pressure, pulmonary hypertension or other contraindication ) Contraindication to fluid challenge Contraindication to TEE Previous heart failure, heart valve stenosis of insufficiency