[Insertion of a fiber optic catheter into the hepatic veins of patients with multiple organ dsfunction syndrome (MODS)].

As it is the driving force in the development of a multiorgan dysfunction syndrome (MODS), the gastro-intestinal region is at the centre of current discussion. Recently, hepatovenous oximetry has been used increasingly to monitor the relationship between oxygen supply and consumption in the splanchnic system. In the present paper we report an exclusively oximetrically controlled catheterisation procedure that can be carried out at the bedside without the use of imaging procedures. In the inferior vena cava a typical venous oxygen saturation profile can be expected. Near the opening of renal veins there is a peak in venous saturation due to the large extent to which the kidneys partake in the cardiac output and their relatively low oxygen consumption. Correspondingly there is a significant drop in saturation in the area around the opening of the hepatic veins. At the right atrium the oxygen saturation increase again due to admixing of more highly saturated blood from the superior vena cava. Taking these physiological facts into consideration it was attempted to find the opening of the hepatic veins into the inferior vena cava using only continuous in vivo oximetry and to insert a hepatovenous catheter. MATERIAL AND METHODS. In 14 patients with postoperative MODS (Apache II score > or = 20) a fibreoptic pulmonary catheter for the continuous evaluation of oxygen saturation was inserted via the inferior vena cava (entrance through the femoral vein). First the catheter was pushed forward into the wedge position in the usual way. Subsequently it was pulled back up to the region of high renal venous saturation. At this point the catheter, now unblocked, was pushed forward again with gentle twisting motions until a distinct decrease in saturation was reached well below the value of the mixed-venous saturation which can be taken as an indication for having entered the hepatic vein. Using a CO oximeter a slowly aspirated blood specimen was taken from the distal line of the catheter and analysed. The placement of the hepatovenous catheter was verified by radiograph of the abdomen. In most cases the catheter had to be readjusted several times before it reached its final position. RESULTS. Of the 14 patients, 13 showed the saturation course in the inferior vena cava that could theoretically be expected. In 12 patients (85.7%) we succeeded in placing the hepatovenous catheter correctly by applying this procedure. The average depth of insertion of the catheter after final positioning was 57 +/- 4 cm. Initial values of hepatovenous saturation (ShvO2) amounted to an average of 35.1 +/- 9.4%. The minimum value was 19%; the maximum ShvO2 came to 59%. DISCUSSION. With the procedure presented it was possible in 12 of 14 patients to position a hepatovenous catheter oximetrically controlled without further means. A precondition for this is a typical saturation profile of the inferior vena cava, which, however, was not found in one of the patients. A possible explanation for this could be an increased shunt volume in the hepatosplanchnicus area, which can lead to high ShvO2 values. For this reason the opening of the hepatic veins could not be recognized by a decrease in saturation using the oximetric procedure. Placement of a catheter was not possible. Future studies on larger groups of patients will be required to show to what extent monitoring of ShvO2 can lead to an efficient therapy specific for this part of the cardiovascular system in patients with sepsis and MODS.