[Hypertonic solutions in the intensive care unit]

Abstract

The use of small volumes of hypertonic saline (HTS) 7.2-7.5% (small volume resuscitation) in combination with colloidal solutions has been proved to be of value in stabilizing oxygen transport in hemorrhagic shock. The specific effects of HTS lead to an improvement in tissue oxygenation by increasing the cardiac preload, decreasing the afterload and endothelial and interstitial edema within the microcirculation. This study investigates whether the use of HTS combined with hydroxyethylstarch (HAES) leads to a significant increase in the O2 delivery (DO2) and O2 consumption (VO2) in hyperdynamic critically ill patients. A total of 41 patients, 20 septic patients and 21 patients without sepsis were investigated. When a hyperdynamic circulation (DO2 > 700 ml/min/m2) was attained, 2-4 ml/kg 7.5% HTS in 6% HAES were infused over 15 minutes. In the septic patients this leads to a significant increase in the DO2 of 14% (p < 0.001). The VO2 (calculated from the cardiovascular Fick) increased by 7% (p < 0.05). The VO2 calculated from the respiratory gases increased by 4% (n.s.). This < 10% increase in VO2 does not seem to be due to a relevant tissue oxygen debt. This is supported by the fact that in the non septic group the DO2 and VO2 increased by the same extent, there was no significant difference between the two groups. Further there was an equal increase in the O2 extraction ratio of 10% (septic patients) and 9.5% (non septic patients). In both groups the mean plasma lactate levels before and 90 min after the HTS/HAES infusion were within normal range so that a wash-out phenomenon was not discernible.(ABSTRACT TRUNCATED AT 250 WORDS)