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Role of the Baroreflex in Long-Term Blood Pressure Regulation in Children Born With Very Low Birth Weight

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INTRODUCTION: Children born preterm and with very low birth weight are at increased risk of developing elevated blood pressure (BP) later in life. One mechanism of short-term BP regulation is the baroreflex, which can be assessed by calculating baroreflex sensitivity (BRS). There is evidence in animals that the baroreflex may play a role in regulating BP on a long-term basis, but evidence is lacking in humans, particularly children. PURPOSE: To examine relationships between short-term measures of baroreflex function (i.e. BRS) and long-term ambulatory BP and variability in a cohort of children born with very low birth weight. METHODS: Spontaneous BRS was measured during 10 minutes of supine rest using a Continuous Non-Invasive Arterial Pressure (CNAP) Monitor 500. Nevrokard software calculated BRS using the sequence method (BRSseq) and spectral method (LFα). Ambulatory BP monitoring took place over a 24-hour period. Data were analyzed separately for awake and asleep periods. Variability was calculated as standard deviations (SD) for awake and asleep and a weighted SD for the 24-hour period. Relationships between measures of BRS and ambulatory BP were examined using correlational analysis. RESULTS: A total of 33 participants (22 female, 11 male) had both BRS and ambulatory BP data. Mean BRS values were 24.2 ± 20.4 ms*mmHg-1 for BRSseq and 23.3 ± 12.7 ms*mmHg-1 for LFα. Mean absolute ambulatory SBP/DBP for the 24-hour period was 115.4/66.9. Mean ambulatory BP variability was 9.1 ± 17 mmHg for the 24-hour period. Negative correlations were found between BRSseq and both 24-hour SBP (r=-.336, p=.087) and asleep SBP (r=-.370, p=.053). There were no significant relationships between BRS and ambulatory BP variability. CONCLUSION: The results revealed that BRS accounted for 11-14% of the shared variance in ambulatory SBP suggesting that the baroreflex likely plays at least a partial role in regulating BP on a long-term basis in preterm, VLBW adolescents who are at risk for developing hypertension.
blood pressure regulation
low birth weight
Mazanka, Paul James (author)
Nixon, Patricia A (committee chair)
Brubaker, Peter H (committee member)
Washburn, Lisa K (committee member)
2012-06-12T08:36:04Z (accessioned)
2012 (issued)
Health and Exercise Science (discipline)
10000-01-01 (liftdate)
forever (terms)
http://hdl.handle.net/10339/37301 (uri)
en (iso)
Wake Forest University
Role of the Baroreflex in Long-Term Blood Pressure Regulation in Children Born With Very Low Birth Weight

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