Insertion of a catheter into a hepatic vein for ShvO2 - control without using an image converter

Abstract

A catheter in a hepatic vein for ShvO2-control can indicate the relation between oxygen-delivery and -consumption in the splanchnic area. Is the insertion of such a catheter possible without using an image converter? In six patients with septic multiple organ dysfunction syndrome (MODS) a fibre-optic pulmonary artery catheter (Opticath®, Fa. Abbott) was inserted into the femoral vein and pushed forward slowly up to the right ventricle. At the level of the renal veins a peak of more than 90% in the Sv¯O2 was recorded. Continuing the insertion of the catheter in most cases there is a corresponding significant drop in saturation in the area around the opening of the hepatic veins shortly under the diaphragm. After only a few more centimetres the right atrium is reached, where the Sv¯O2 increases. Having reached the right atrium the catheter is unblocked and pulled back into the area of the high renal-venous saturation and is then pushed forward again with gentle twisting motions until there is a distinct decrease in saturation well below the value of the mixed-venous saturation which can be taken as an indication of having entered a hepatic vein. Now a blood specimen from the distal lumen of the catheter is analysed using a Co-Oxymeter and its correct placement is verified through an abdominal X-ray. In 10 out of 12 trials we succeeded in placing the catheter correctly with this procedure. The minimum ShvO2 was 19%, the average was 33±12%. Patients suffering from severe sepsis and MODS can benefit from ShvO2-monitoring, because it gives evidence of the perfusion and eventually of the relation between oxygen-delivery and -consumption in the gastrointestinal region. In future the evaluation of the ShvO2 may lead to an individually controllable drug therapy in order to increase perfusion in this area. So far an image converter has always been necessary for positioning the catheter. This often requires the transport of sick patients into the X-ray department. Using the procedure presented this can be avoided. A precondition for the insertion of the catheter is the typical saturation profile in the inferior vena cava with a reduced ShvO2, compared with mixed-venous saturation. The results of the measurements should be examined regularly using a Co-Oxymeter, because the intensity of the light signal often does not suffice to ensure valid measurements. There have been no important complications, using this procedure. (Table 13)Table 13: (abstract 46). Typical saturation changes during the insertion of the catheter