The use of ultrasound in the non-invasive detection of changes in the renal circulation in response to blood loss using an animal model.

Using a continuous haemorrhage model, 8 anaesthetised swine were bled 1 ml/kg per min for 30 min. The resistance index (RI) of the main renal artery, interlobar and arcuate vessels all significantly increased. Cortical Doppler signals were lost in 4 animals at a mean arterial pressure of 26 mmHg. After reinfusion of blood and normal saline only the RI of the interlobar vessels was significantly different from baseline readings. Ultrasound demonstrated non-invasively changes in regional blood flow within the kidney in response to hypovolaemic shock.