Hemodynamic response to lower body negative pressure in children: a pilot study.

Area of Science:

• Physiology
• Cardiovascular Research
• Pediatric Health

Background:

• Orthostatic stress is commonly induced by head-up tilt or standing.
• Lower body negative pressure (LBNP) is a gravity-independent method for inducing orthostatic stress.
• The application of LBNP in pediatric populations has not been previously studied.

Purpose of the Study:

• To investigate the efficacy of LBNP in inducing hemodynamic adaptations in pre-pubertal boys.
• To assess the safety and feasibility of using LBNP for orthostatic stress testing in children.

Main Methods:

• Ten healthy pre-pubertal boys (mean age 9 years) were enrolled.
• Participants were exposed to three levels of LBNP (15, 20, and 25 mm Hg).
• Continuous monitoring of heart rate, blood pressure, and beat-by-beat hemodynamics was performed, alongside aortic diameter and blood velocity measurements.

Main Results:

• Increasing LBNP levels led to a significant increase in total peripheral resistance (TPR) and a decrease in systolic blood pressure (SBP).
• A trend towards decreased stroke volume (SV) and cardiac output (Q) was observed with increasing LBNP.
• Baroreceptor sensitivity (BRS) and the low frequency/high frequency (LF/HF) ratio of R-R intervals did not change significantly.

Conclusions:

• Low levels of LBNP effectively induce expected hemodynamic adaptations in pre-pubertal children during orthostatic stress.
• LBNP is demonstrated as a safe and effective method for inducing orthostatic stress in pediatric subjects.
• Findings support the potential use of LBNP in pediatric research and clinical settings for assessing cardiovascular responses.