Response of volume and osmoregulatory kidney function to infusion loading in patients with dopamine-dependent compensation of sepsis-induced hypotension

Abstract

Objective. To study the response of volume and osmoregulatory kidney function to increased volume of extracellular space (IVECS) with dopamine-dependent compensation of sepsis-induced hypotension. Materials and methods. The inclusion criteria involved patients with purulent-septic complications (predominantly surgical abdominal sepsis) with dopamine-dependent compensation (5–10 μg/kg-min) according to the initial values: SBP >70 mmHg, BPs >95 mmHg, CVP >4 mmHg, diuresis >30 ml/h. The control group consisted of patients with systemic inflammatory response syndrome (SIRS) who met the requirements of ICD-10 classifier: SIRS, ICD-10: R-65.2. All patients were divided into 4 groups: groups I and II for control studies (SIRS, n = 21); groups III and IV included patients with severe sepsis (n = 30). The patients of groups II and IV received an infusion load in the form of Ringer's solution in the amount of 7–8 ml/kg at a rate of 18–20 ml/min. Results. The depression of glomerular filtration rate (GFR) in the patients from group ІІІ was 41 % (Р < 0.05), the excreted water fraction was 45 % higher than the control value (Р < 0.05), and urine output reached 88 % (Р < 0.05) of that in the comparison group. This result is due to different reabsorption rates. In doing so the sodium clearance was 81 % (P < 0.05) of the SIRS rate. The main cause is a decrease in the sodium filtration fraction, as the reabsorption of the cation according to the values of the excreted fraction was less than the control value. Depression of the osmoregulatory function of the kidneys had the same direction. The comparative analysis of the values between groups ІІ and IV (response of volume and osmoregulatory kidney function in patients with SIRS and severe sepsis (SS) to IVECS) shows that after IVECS the GFR remains reduced and represents 59 % of that in group II. Despite the more intensive compensatory suppression of water reabsorption, sodium and osmotically active substances (OAS) according to the indicators of the excreted fraction of water, sodium and OAS (an increase, Δ, P < 0.05) and a decrease in clearance of sodium-free water, in the reabsorption of osmotically free water (Δ, P < 0.05), in sodium clearance and OAS after IVECS in the patients from group IV were reduced by 16 % and 35 %, in urine output by 26 % (P < 0.05) respectively. Conclusions. In compensated sepsis-induced hypotension despite the compensatory suppression of water, sodium and OAS reabsorption according to the clearance characteristics there is an inhibition of volume and osmoregulatory kidney function both spontaneously (by 19 and 24 %, Δ, P < 0.05) and, accordingly, after IVECS (by 16 and 35 %, Δ, P < 0.05).

Keywords

• kidney function tests
• extracellular space
• severe sepsis