ABSTRACT
Adequate estimation of the dry weight of hemodialysis [HD] patients represents a central issue for renal replacement therapy. This work aimed to evaluate inferior vena cava [IVC] echography as well as cGMP plasma levels as reliable, non invasive markers of the hydration state of HD patients. Twenty five uremic patients [group A] as well as fifteen healthy volunteers [group B] were included in the study. Blood pressure, body weight, plasma cGMP level and IVC echography were recorded before and after HD both expiratory and inspiratory IVC diameters decreased significantly as compared to predialysis values [p < 0.05 and p < 0.05 respectively]. A significant positive correlation was observed between the expiratory IVC diameter and the body weight in patients of group A before [r = 0.57, p < 0.05] and after [r = 0.62, p < 0.05] HD. There was a positive correlation between the decrease in body weight and decrease in mean BP [MBP] [p < 0.05]. There was no significant, increase in WC collapse index [CI] after HD [p>0.05]. Also, there was no correlation between the CI and body weight of RD patients before and after HI] [p>0.05 and p> 0.05 respectively]. Predialysis cGMP levels were highly significantly greater [p <0.001] in group A patients compared to group B patients. HD resulted in a decrease in plasma cGMP levels, and this decrease is of a high statistical significance [p < 0.001]. However, postdialysis plasma cGMP level was highly significantly greater in Group A than in group B [p < 0.001]. There was a significant positive correlation between HD induced percent decrease in plasma cGMP level and reductions recorded in body weight [p < 0.05]. There was no significant correlation between plasma cGMP and MBP changes both pre and post dialysis [p > 0.05 and p > 0.05 respectively]. A significant correlation was found between IVC diameter and cGMP before HD [r = 0.69, p < 0.001]. No such correlation was found between CI and cGMp values [p > 0.05]. Furthermore, a significant correlation was observed between IVC diameter before and after HD and the change in cGMP during HD [r = 0.66, p < 0.01]. We conclude that cGMP is a sensitive marker for overhydration and fluid overload in HD patients, however, it cannot be considered as a marker for the dry weight of such patients since it does not return to normal found in healthy subjects after fluid removal. Furthermore, IVC diameter as estimated by echography appears to be a valuable accurate non invasive tool to assess the hydration state of HD patients