COMPARISON OF SYSTEMIC AND RENAL HEMODYNAMICS MEASURED BY DOPPLER ULTRASONOGRAPHY IN CANINE EXPERIMENTAL HYPOVOLEMIA

The aim of this study was to examine renal hemodynamics at the hypovol emic and recovery phases in two different hypovolemic shock models usi ng Doppler ultrasonography, and to compare this with systemic hemodyna mics. In experiment 1, the hypovolemic phase was induced in 6 mongrel dogs by removing arterial blood at 30 ml/kg for 60 min. In the recover y phase, this blood was reinfused at 30 ml/kg over 60 min. In experime nt 2, hypovolemia was induced in 12 beagle dogs by rapid blood removal until blood pressure decreased to 40 mmHg and was maintained at this pressure for 30 min. Six of the dogs were then infused with 20 ml/kg h ydroxyethyl starch over 5 min, and the other 6 were infused with 60 ml /kg lactated Ringer's solution also over 5 min. Parameters for systemi c and renal hemodynamics were measured by using a polygraph and the Do ppler method, respectively. The decrease of diastolic blood flow, resu lted in an increase of vessel resistance, and was detected in the hypo volemic kidney by the Doppler method. The rapid and large volume infus ion of resuscitation fluids was effective for the recovery of both sys temic circulation and renal blood flow, however this induced an increa se of kidney vessel resistance, a result of the autoregulation mechani sm of the kidney. The changes in these parameters at the main renal ar tery and interlobar artery were similar.