INSERTION OF A FIBEROPTIC CATHETER INTO A HEPATIC VEIN WITHOUT USING AN IMAGE CONVERTER IN PATIENTS WITH MULTIPLE ORGAN DYSFUNCTION SYNDROME

As it is the driving force in the development of a multiorgan dysfunct ion syndrome (MODS), the gastro-intestinal region is at the centre of current discussion. Recently, hepatovenous oximetry has been used incr easingly to monitor the relationship between oxygen supply and consump tion in the splanchnic system. In the present paper we report an exclu sively oximetrically controlled catheterisation procedure that can be carried out at the bedside without the use of imaging procedures. In t he inferior vena cava a typical venous oxygen saturation profile can b e 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. Correspon dingly there is a significant drop in saturation in the area around th e opening of the hepatic veins. At the right atrium the oxygen saturat ion increases again due to admiring of more highly saturated blood fro m the superior vena cava. Taking these physiological facts into consid eration 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 w ith postoperative MODS (Apache II score greater than or equal to 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 wedg e position in the usual way. Subsequently it was pulled back up to the region of high renal venous saturation. At this point the catheter, n ow unblocked, was pushed forward again with gentle twisting motions un til a distinct decrease in saturation was reached well below the value of the mixed-venous saturation which can be taken as an indication fo r having entered the hepatic vein. Using a CO oximeter a slowly aspira ted blood specimen was taken from the distal line of the catheter and analysed. The placement of the hepatovenous catheter was verified by r adiograph of the abdomen. In most cases the catheter had to be readjus ted several times before it reached its final position. Results. Of th e 14 patients, 13 showed the saturation course in the inferior vena ca va that could theoretically be expected. In 12 patients (85.7%) we suc ceeded 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 saturatio n (ShvO2) amounted to an average of 35.1 +/- 9.4%. The minimum value w as 19%; the maximum ShvO2 came to 59%. Discussion. With the procedure presented it was possible in 12 of 14 patients to position a hepatoven ous catheter oximetrically controlled without further means. A precond ition for this is a typical saturation profile of the inferior vena ca va, which, however, was not found in one of the patients. A possible e xplanation for this could be an increased shunt volume in the hepatosp lanchnicus 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 eff icient therapy specific for this part of the cardiovascular system in patients with sepsis and MODS.