University of Southern California Department of Biomedical Engineering The USC Andrew and Erna Viterbi School of Engineering USC
Sitemap

Cardiorespiratory Sleep Lab



Research


Closed-loop minimal model to quantify the long-term effect of sleep apnea on autonomic cardiovascular control

To better quantify the long-term effects of sleep apnea on autonomic cardiovascular control, a closed-loop minimal model has been used to identify abnormalities in the mechanisms that mediate heart-rate variability and blood pressure variability. The gains of the baroreflex and respiratory-cardiac coupling mechanisms were found to be substantially lower in sleep apnea patients compared to normals in both wakefulness and sleep. However, long-term (~6 months) therapy with continuous positive airway pressure (CPAP) was found to restore baroreflex and respiratory-cardiac coupling gains toward normality. Application of the minimal model to pediatric subjects has demonstrated that the detrimental effects of sleep apnea on autonomic function in childhood are different from those found in adults.



Examples of recent publications in this area:

(a) Belozeroff V, Berry RB, Sassoon CSH, Khoo MCK. Effects of CPAP therapy on cardiovascular variability in obstructive sleep apnea: a closed-loop analysis. Am. J. Physiol. (Heart Circ. Physiol.) 282:H110-H121, 2002.

(b) Jo JA, Blasi A, Valladares E, Juarez R, Baydur A, Khoo MCK. Model-based assessment of autonomic control in obstructive sleep apnea syndrome during sleep. Am J Respir Crit Care Med 2003; 167:128-136.

(c) Jo JA, Blasi A, Valladares E, Juarez R, Baydur A, Khoo MCK. Determinants of heart rate variability in obstructive sleep apnea during wakefulness and sleep. Am J Physiol Heart Circ Physiol 2005; 288:H1103-1112.