In order to study possible differences among temporary shunts for carotid artery surgery, 4 types of shunts were studied in an experimental canine model of extracranial cerebrovascular insufficiency. Twenty five dogs were operated on and divided in five equal groups: one control group without shunt, two groups of animals with a short internal shunt and two groups with a long external shunt, catheters of two different gauges being used for each type of shunt. These shunts were evaluated by systemic arterial pressure (SAP), stump pressure (SP) and carotid blood flow, which were measured before and after carotid clamping, and 5 and 10 minutes after the release of blood flow through the carotid artery or through the shunts. Multivariate analysis of variance showed that all but the shorter and wider shunt acted as a stenosis in the carotid artery, with a decrease of 50% in blood flow. The analysis of other parameters did not show differences among the shunts, suggesting that even acting as a stenosis, no functional pressure alteration occurred with the different shunts in this model.