Beat‐to‐beat blood pressure and heart rate responses to active standing in Japanese children

Abstract

Some pubertal children are susceptible to orthostatic stress but little is known about mechanisms of circulatory adjustment to the posture change in children. We investigated beat-to-beat blood pressure (BP) and heart rate (HR) responses to active standing in 173 schoolchildren, 92 boys and 81 girls, aged 6-18 years (mean age: 13.4 years) using a non-invasive continuous monitoring system (Finapres 2300, Ohmeda). The subjects were divided into four age groups: prepubertal I (7-9 years), prepubertal II (10-12 years), pubertal (13-15 years) and young adult (16-18 years). Supine BP increased and HR decreased with age. At the onset of active standing two older groups showed a significantly larger initial drop than the prepubertal groups (-36 +/- 15 versus -15 +/- 16% reduction for systolic BP and -36 +/- 14 versus -20 +/- 19% for diastolic BP, respectively, p < 0.01). Moreover, the pubertal group had a significantly smaller vasoconstrictor index than prepubertals and two older groups had a significantly more prolonged BP recovery time. In keeping with this the pubertal group most frequently had hypotensive symptoms during active standing. The rise in HR at the peak was higher in two older groups than in prepubertals (34 +/- 9 versus 29 +/- 8 beats/min-1, respectively, p < 0.001), whereas the baroreflex index was almost identical for the four groups. The effect of body proportion on BP responses was not found. There was no significant difference in BP and HR changes in the later stage during 7 min of standing. These results indicated that pubertal children were more susceptible to orthostatic stress, probably due to abnormal BP responses in the initial phase of active standing, which seemed to reflect enhanced cardiopulmonary reflexes and diminished sympathetic activation associated with the age. Moreover, BP reduction at an initial drop of more than 60% or a recovery time of more than 25 s might be postulated to be an abnormal circulatory response.

Initial circulatory response to active standing in Parkinson's disease without typical orthostatic hypotension

“…VCI was proposed as an indicator of PVR function 16,26 , and in our study, it was found decreased in PD-TOH compared to YHC (although not significantly). The lack of significant difference may be due to the way in which it is calculated (i.e., from the ratio between MBP recovery and its corresponding time) 26 , inasmuch as this calculus takes into account both the magnitude (mmHg) and the duration (sec) of the recovery and, as in the case of SBP, the former did not significantly differ between groups (data not shown).…”

“…t 0 was defined as the start of AS. The selection of sample points was prompted by the results of previous studies 2,3,15,16 . Unless otherwise stated, hemodynamic data are reported as absolute values and as changes between two different sample points (D).…”

“…Unless otherwise stated, hemodynamic data are reported as absolute values and as changes between two different sample points (D). When possible, vasoconstrictor (VCI) and baroreflex sensitivity (BRI) indices, as advanced by Yamaguchi et al, were additionally calculated 16 . Baroreflex sensitivity (BRS) was also obtained using a slightly modified version of the method already employed by Imholz et al 15 Statistical analysis was performed with STATISTICA for Windows 1 (v.5.1).…”

Lower limb-localized vascular phenomena explain initial orthostatic hypotension upon standing from squat

“…Our data demonstrate that SV elevation occurs during the squat and is not associated with the act of standing up from squat. A number of investigators have previously proposed that IOH is due to cardiopulmonary baroreflex-mediated sympathetic withdrawal brought about by a sudden increase in RAP upon standing (3,41,42,56). Some of these studies used a supine to standing transition (3,21,41,56).…”

Recent Advances in Autonomic Function Tests of the Cardiovascular System in Children

“…Wieling et al [53] reported that beat-to-beat blood pressure and heart rate changes in the first 30 s after the onset of standing provided the necessary information for the evaluation of orthostatic disorders. In our previous study [54], we selected a new criterion of the active standing test using continuous beat-to-beat blood pressure monitoring (Finapres) for the evaluation of orthostatic intolerance in Japanese children. As mentioned above, active standing causes a large and prolonged initial drop of blood pressure in children with orthostatic intolerance including vasovagal syncope and hyperadrenergic orthostatic hypotension ( fig.…”