ultrasonographic assessment of caudal vena cava to aorta ratio as a novel endpoint in hemorrhagic shock resuscitation in dogs

Objective- the aim of this study was to assess ultrasonography-derived caudal vena cava to aorta ratio (cvc/ao) as a novel endpoint in the resuscitation of experimental hemorrhagic shock in dogs. design- experimental study. animals- ten adult mongrel healthy dogs. procedures- after induction of anesthesia (control assessments), hemorrhagic shock was induced by blood withdrawal to a mean arterial pressure of 40 to 50 mmhg within 30 minutes and then maintained in a hypovolemic situation for an additional 30 minutes (second and third stages of assessments). afterward, the dogs were randomly assigned to two groups which received 20 ml/kg lactated ringer's solution or 5 ml/kg hydroxyethyl starch, in four consecutive 15 minutes intervals (fourth stage of assessments). one hour after the last resuscitation step, final ultrasonographic assessments were performed. results- hemorrhagic shock caused a significant decrease in the cvc and ao diameters as well as the cvc/ao (2.14 ± 0.28 cm, 0.85 ± 0.07 cm and 0.4 ± 0.06, respectively) (p<0.05). following the fluid resuscitation cvc/ao increased and returned to pre-shock values in both groups. conclusion and clinical relevance- findings indicated that serial ultrasonographic assessment of the cvc/ao can be a useful endpoint in the resuscitation of dogs with hemorrhagic shock.