Noninvasive blood pressure measurement in mice using pulsed Doppler ultrasound

Existing tail-cuff pressure devices for mice use tail flow sensors that measure only systolic and mean pressure. We developed a method to obtain systolic and diastolic pressure in mice using a pulsed Doppler flow velocity sensor and a tail-cuff and validated the method against pressure signals obtained simultaneously from a fluid-filled catheter. The tail-cuff was pressurized to suprasystolic levels to completely occlude the tail artery and then released gradually. The pressure at which the tail flow reappeared was recorded as systolic and the pressure at which the tail flow became continuous was recorded as diastolic. Regression analysis of tail-cuff pressures over catheter pressures obtained from healthy mice (n = 16) showed a high degree of association (r_sys = 0.95, r_dia = 0.94, both at p < 0.001). Bland-Altman analysis showed good agreement between the two methods, with a mean difference of -13 ( ± 12 SD) mmHg and 3 ( ± 10 SD) mmHg in the systolic (58 to 250 mmHg) and diastolic (48 to 178 mmHg) pressure measurements, respectively. Bland-Altman plots of tail-cuff blood pressures of a second group of mice (n = 20) showed good agreement between repeated measurements obtained on the same day, but had higher variability between measurements made on different days.