Evaluation of the Effect of an Acclimatization Period in Doppler Ultrasonic Indirect Blood Pressure Measurements in Conscious Dogs
*Jesús Talavera, Mª Josefa Fernández del Palacio, Alejandro Bayón, Angel Albert
*Hospital Clínico Veterinario. Universidad de Murcia, Campus Universitario Espinardo
Objective Doppler ultrasonic sphygmomanometry (DUS) is an inexpensive and practical tool for indirect systolic blood pressure measurement (SBPM) in veterinary practice. Several investigations in dogs using DUS have been performed to evaluate the effect of stress and another variables in the SBPM. Differences between SBPM obtained in different environment situations, animal positioning, or depending of the individual character of the dog have been found. However, in the author's knowledge, little information has been published about the effect of an acclimatization period in SBPM by DUS in dogs. The aim of this study was to evaluate the effect of an acclimatization period in Doppler ultrasonic SBPM in conscious dogs.
This study was performed using eight dogs (2 males and 6 females) between 10 months and 6 years of age (mean 2.61 ± 2 years) and weighing between 6 and 23 kg (mean 15.37 ± 5.83 kg). The SBPM were performed by mean a Ultrasonic Doppler flow detector with a 9.5-MHz probe (Parks model 811-BTS, Parks Medical Electronics, INC. Aloha, Oregon, USA) using the following protocol: hair of the metacarpal limb segment was clipped just proximal to the palmar metacarpal pad at the level of the superficial palmar arterial arch on a forelimb. An inflatable cuff (CutikonTM Cuff Johnson & Johnson, Medical INC, CE) was placed around the midantebrachial region. Cuffs were selected to achieve a ratio between cuff width and limb circumference of approximately 0.4. Ultrasonic coupling gel (Aquasonic 100 Ultrasonic Transmission Gel, Parks Medical, Perimed, Bury St, Edmons, UK) was placed over the clipped area of skin and the probe was placed over superficial palmar arterial arch and fixed manually when a suitable pulse signal was obtained. The cuff was inflated to not less of 40 mmHg above the cutoff point of the audible signal. A manometer (Pressostabil, Speidel + Keller, Germany) was used to measure the pressure. The cuff was slowly deflated, and systolic pressure was recorded as the pressure at which the pulse signal was again audible.
Each definitive measurement was taken as the mean of 5 readings. In each dog, all measurements were performed by 2 different groups of operators (A and B, two people in every group) in different days. Each operator's group performed the SBPM from each dog in two different times of the day: in the morning (9-10 h AM) and in the evening (4-5 h PM). In each time two different measurements were performed: immediately to introduce the dog in the room and after of an acclimatization period of 20 minutes. Each operator's group did not know the results of the each other until the study was finished.
Statistical analysis of the data was performed by way of ANOVA to determine whether there were statistical differences over after and before the acclimatization period, over the operator or over the different measurements of the day. The coefficient of variation (CV = [standard deviation/mean] x 100) was used as an estimate of variability of SBPM. For all analyses, a P-value of < 0.05 was considered significant.
The mean of all SBPM was 144 mmHg with a standard deviation of 21 mmHg and range of 92-190 mmHg. Group A obtained a mean SBPM higher than group B (146 ±19 mmHg for the group A and 142 ± 24 mmHg for the group B), but these differences were not statistically significant. The SBPM showed a low variability, with lows CV for both groups (1.28% for the group A and 1.68% for the group B, mean 1.48%). No statistical differences between SBPM before and after the acclimatization period were found. The time of the day or the operator did not influence significantly in the SBPM.
By mean of the protocol above described, the measurements of systolic blood pressure in dogs before and after an acclimatization period of twenty minutes do not change significantly even whether the operator or the time of the day were different.