Diurnal Variations of Blood Pressure in Dogs

Abstract

ABSTRACT. Using the telemetry system, we measured the blood pressure (BP) invasively in seven adult mongrels while unanesthetized and unbound. Post-operative BP after implanting the telemetry BP transmitter showed temporarily high values due to the invasive nature of the surgery. It was, however, observed that BP gradually decreased thereafter, and showed settled trends from the eighth day postoperatively. When we took the average of the systolic, mean and diastolic BP at hourly intervals for each of the dogs once their BP had settled, a twin peak diurnal variation (at 8:00 and 19:00) was observed. Moreover, significantly high values (p<0.05) were identified in active state compared with when sleeping or at rest. The 24 hr BP measured by the telemetry system in seven normal dogs resulted in the following values: systolic 123.4 ± 7.9 mmHg, mean 91.1 ± 5.6 mmHg, and diastolic 74.5 ± 4.9 mmHg.-KEY WORDS: blood pressure, canine, diurnal variation.J. Vet. Med. Sci. 61(6): 643-647, 1999 were exposed under anesthesia, and BP measuring transmitter (model TL10M2-D70) catheter was indwelled. The transmitter body was implanted into a subcutaneous pocket that had created first. After examining the BP by use of transmitter, the digital signal was received by a receiver (RLA2000), and was sent in turn to a consolidation matrix (BCM-100), and a universal adapter (UA10). Finally, the digital signal was converted to an analogue signal by the universal adapter, and output to an analytical computer system (Softron ECG Processor SBP4.8:Softron Co., Tokyo, Japan) (Fig. 1). Further, the systolic, mean and diastolic BP were calculated from the continuous BP readings input for approximately 10 sec at a time at 5 min intervals, and the average were taken to be the systolic, mean and diastolic values for each hour. These measurements were taken continuously for 24 hr, and the following examinations were conducted. Examination of the BP changes after implanting transmitter:We examined the effect of the invasive surgery on BP after the transmitter had been implanted for 14 days post-operatively. For the BP examination, we used the total and average values (24 hr BP) taken every 24 hr using the systolic, mean and diastolic pressure measured at 5 min intervals.Examination into the diurnal BP variations: We examined the diurnal BP variations in normal dogs for a period of seven days after at least one month had passed since the transmitter were implanted. First of all, the systolic, mean and diastolic BP were measured at 5 min intervals and totaled in hourly blocks and examined using their average values. In order to observe the relationship between BP and activity, a comparison was made among the sleeping period (1:00-6:00), the resting period (12:00-17:00), awaking but comparatively settled period, and the periods of intense activity (7:00-9:00 and 18:00-20:00). In addition, comparisons were also made with both the 24 hr BP and For measuring blood pressure (BP) in awake dogs, there are either invasive method by arterial puncture or nonin...

Chronobiologic blood pressure assessment: Maturation of the daily rhythm in newborn foals

“…Some studies, carried out on dogs, reported low mean BP throughout the night to early morning and high BP from early morning and throughout the day (Broten et al, 1988). Other authors (Mishina et al, 1999) have monitored the 24-h BP in dogs using telemetry and observed changes almost identical to those reported in humans (Baumgart, 1991;Mancia et al, 1993;Sundberg et al, 1988) with the highest values during periods of activity and the lowest during sleep.…”

“…A circadian rhythm in blood pressure has been demonstrated in various species of mammals, including rat (Van Den Buuse, 1994;Sato et al, 1995), rabbit (Sato et al, 1995), cat (Brown et al, 1997), dog (Mishina et al, 1999;Piccione et al, 2005a), cattle (Fazio et al, 2002), marmoset (Schnell and Wood, 1993) and mouse (Gross et al, 2000). Many reseachers have reported that cardiovascular indices, like sympathetic activity increase significantly during the day and decrease during the night; parasympathetic activity does the opposite (Veerman et al, 1995).…”

Development of Hypertension and Effects of Benazepril Hydrochloride in a Canine Remnant Kidney Model of Chronic Renal Failure

“…Furthermore, we employed telemetry, which allows accurate determination of blood pressure in the absence of anesthesia or constraint. We have previously demonstrated that telemetrically acquired 24-hr blood pressure is suitable for evaluating or comparing individual blood pressure in dogs [31].…”

“…Telemetric blood pressure measurements: Blood pressure was determined by telemetric system as described previously [31]. The catheter of the transmitter for blood pressure measurement (TA11PA-C40; DATA SCIENCE INTERNATIONAL Inc., Tokyo, Japan) was indwelled within the femoral artery, and blood pressure was determined without anesthesia or constraint.…”

“…In order to avoid the influence of time-dependent changes in the RAA system, blood was sampled between 16:00 and 18:00 as previously described [31]. Following anticoagulation with ethylenediaminetetraacetic acid, blood samples were quickly cooled and centrifuged at 3,000 rpm for 5 min at 4°C.…”