Abstract
Accurate blood pressure measurement is essential for advancing research in cardiovascular and exercise physiology. The most commonly used indirect method to measure blood pressure in animals is the tail-cuff system. In addition to requiring less expensive equipment and offering a non-invasive alternative to surgical blood pressure measurements, this technique allows for repeated assessments in conscious animals during both short- and long-term studies. Despite prior validation against the gold-standard methods (i.e., radiotelemetry and arterial catheterization), the reliability, variability and reproducibility of this technique have not been fully established. PURPOSE: The aim of the study was to evaluate the intra- and inter-day variability of non-invasive blood pressure measurement in rats. METHODS: Experiments were conducted in adult, healthy male Sprague-Dawley rats (n=8; age: 12 weeks old; body weight: 373 ± 45 g). Non-invasive blood pressure measurements were performed on two consecutive days at the same time of day using a tail-cuff system (CODA® High Throughput System; Kent Scientific). Before the experiments, all rats underwent a familiarization period to allow acclimation to the restrainer. Tail temperature was monitored and maintained between 35oC and 38oC throughout the experiment using a warming pad. Each day consisted of several measurements cycles, and blood pressure parameters included systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP) and heart rate (HR). Standard deviation (SD) and coefficient of variation (CV) were used to determine intra-day variability, while technical error of measurement (TEM) and intraclass correlation coefficient (ICC) were used to determine inter-day variability. In addition, comparisons between days were analyzed using paired-t test. Results are presented as mean ± SD. RESULTS: Only valid cycles were included in the analysis for each rat (6 ± 2 cycles per rat per day). The mean SDs for SPB, DBP, MBP and HR were 7 mmHg, 9 mmHg, 8 mmHg, 48 bpm, respectively. Intra-day analysis showed CVs of 5% for SBP, 10% for DBP, 7% for MBP and 16% for HR. There were no significant differences between days in SBP (138 ± 11 mmHg and 140 ± 14 mmHg; p=0.622), DBP (93 ± 10 mmHg and 95 ± 17 mmHg; p=0.749), MBP (108 ± 10 mmHg and 110 ± 16 mmHg; p=0.697) and HR (335 ± 47 bpm and 338 ± 64 bpm; p=0.848). Inter-day analysis revealed TEM values of 9% for SBP, 7% for DBP, 7% for MBP and 28% for HR, with ICCs of 0.7 for SBP and 0.8 for DBP, MBP, and HR. CONCLUSION: Non-invasive blood pressure measurement using the tail-cuff system demonstrated good intra- and inter-day reliability in rats. These findings suggest that this method is consistent and represents a viable alternative to cardiovascular and exercise physiology research using animal models.
Recommended Citation
Engelke, Paulo and Samora, Milena
(2026)
"Reliability, Variability and Reproducibility of Non-Invasive Blood Pressure Measurements in Rats,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
18, Article 110.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss18/110