Validation in awake rats of a tail-cuff method for measuring systolic pressure.

Bu~~AG, RUBEN D. Validation in awake rats of a tail-cuf method for measuring systolic pressure. J. Appl. Physiol. 34(2) : 279-282. 1973. -To determine why results of recent studies on applicability of the tail-cuff method to awake rats have been conflicting, arterial pressures were measured under various conditions. A Doppler ultrasonic flowmeter was used to detect blood flow changes occurring in rats’ tails during cuff inflation and deflation. Simultaneous recording of arterial pressures from different sites showed that systolic pressure in the carotid artery approximates tail-cuff values more closely than that in the lower abdominal aorta or iliac artery. Tail cuffs 15 mm long gave the most accurate readings; determinations with shorter cuffs were falsely high while those with longer ones were falsely low. Pressures measured in unanesthetized normotensive and hypertensive rats by using a Doppler flowmeter together with a 15-mm tail cuff were the same as those recorded concurrently from a carotid artery. Correlation between direct and indirect methods under these conditions was highly significant ( r = 0.974). Contrary to the previous conclusions of Bufiag, McCubbin, and Page, the present data indicate that systolic pressure can be measured reliably with the tail-cuff method even in awake rats.