Central Venous Pressure and Right Atrial Pressure Measurements in Supine, Semi-recumbent and Trendelenburg Position

Intensive care is directed towards patients with severe illness or risk of serious outcomes following, for example, surgery. Central venous pressure (CVP) is an important part of the hemodynamic assessment of patients in surgery and the intensive care unit (ICU). CVP is normally measured via a central venous catheter (CVC) inserted through the subclavian or internal jugular vein, with the tip placed at the junction to the right atrium. A pressure tubing is connected to one of the branches of the CVC and then connected to a pressure sensor that sends a digital signal to the monitoring screen where CVP can be read in mmHg. To accurately read CVP, the pressure sensor must be positioned at the level of the right atrium. Different external reference points are used nationally and internationally to locate the correct height for the pressure sensor. This study aims to investigate the most commonly used external reference points for CVP measurement in various body positions compared to CVP measured via a solid state pressure catheter in the right atrium (RAP).

A Millar Mikro-Cath solid state pressure catheter is inserted through one of the medial lines of the CVC and guided in position by the pressure curve and verified in position by ultrasound. CVP is compared to RAP in supine, semi-recumbent, Trendelenburg and lateral position. CVP, RAP and arterial pressure is recorded in each session with Biopac Acqnowledge. In each body position PEEP is raised 5 cmH20 and then lowered 5 cmH20. Ventilator settings, capillary refill time, perfusion index are collected in each setting and before and after PEEP adjustments.