Inter- and intraindividual variation in Doppler ultrasonic indirect blood pressure measurements in healthy cats.

This study was undertaken to evaluate reference ranges for systolic blood pressure (SBP) in cats under conditions mimicking a clinical setting. SBP was measured in 50 healthy adult cats of various ages (range, 1.5-16 years) and body weights (range, 2.2-6.1 kg) by Doppler ultrasonic sphygmomanometry. A cuff width of 2.5 cm was used, placed on the left antebrachium, and this represented a mean cuff width of 35% limb circumference (range, 31-42%). The mean (+/-SD) SBP in the 50 cats was 162 +/- 19 mm Hg (range 124-210), with only 1 cat having a SBP > or = 200 mm Hg. No significant difference (P > .05) in SBP was found between male and female cats, and no significant correlation was found between SBP and age (r(s) = 0.075) or body weight (r(s) = 0.007). Further studies in some of these cats indicated that allowing a period of 10 minutes for acclimatization to the environment where SBP was recorded resulted in a significant decrease in SBP from 176 +/- 17 to 157 +/- 21 mm Hg (n = 7) and that use of a 3.3-cm-width cuff resulted in a significant decrease in measured SBP from 168 +/- 13 to 164 +/- 13 mm Hg (n = 10). Reproducibility of SBP measurements was evaluated in 7 cats by assessing SBP 7 times at intervals of > or = 24 hours over a 10-day period. These 7 cats had a low intraindividual coefficient of variation of SBP measurements (CV < or = 7.9%) although 2 of the 7 cats had SBP values > 200 mm Hg on at least 1 occasion.