Postural Orthostatic Tachycardia Syndrome (POTS) is a chronic disorder of orthostatic intolerance that primarily (90-95%) affects premenopausal females. Patients experience debilitating symptoms, and excessive heart rate (HR) increases ≥30bpm within 10min standing without blood pressure (BP) drop (>20/10mmHg). exhibit postural hyper-ventilation (VE), leading to hypocapnia (i.e., low CO2). Hypoc...

There is some evidence that breathing retraining may be beneficial for patients with asthma, but the mechanism behind this benefit is still unknown. One hypothesis is that individuals can be trained to raise carbon dioxide levels and thereby reverse the bronchoconstrictive effects of hypocapnia and utilize the bronchodilatory effects of hypercapnia. This theory presupposes that individuals with...

Hypocapnia induced by hyperventilation (HV) has powerful effects on neuronal excitability and synaptic transmission. We have studied the effect of hyperventilation on the phase-locked oscillatory components of the evoked responses in the human brain. We recorded visually evoked magnetoencephalographic responses before, during, and after voluntary hyperventilation to pattern-reversal checkerboar...

We determined regional cerebral blood flow (rCBF) using [I]HIPDm [ iV'-(2-hydroxy-3-methyl-5-iodobenzyl)-l,3-propanediamine] and [I]iodoantipyrine autoradiography under control and pathologic conditions (hypercapnia [acidosis], hypocapnia [alkalosis], and disrupted blood-brain barrier) conditions in 35 rats. In control rats, HIPDm rCBF (indicator fractionation method, n = 5) was lower than the ...

53 Airway Physiology Following Arousal—Jordan et al. INTRODUCTION The pathogenesis of obstructive sleep apnea (OSA) is only partially understood; in particular, the potential role of arousals from sleep in destabilizing upper airway function is controversial.1 Arousals from sleep commonly occur at the termination of respiratory events in OSA2,3 and have been suggested by some authors to predisp...

BACKGROUND Monitoring cerebral saturation is increasingly seen as an aid to management of patients in the operating room and in neurocritical care. How best to manipulate cerebral saturation is not fully known. We examined cerebral saturation with graded changes in carbon dioxide tension while isoxic and with graded changes in oxygen tension while isocapnic. METHODOLOGY/PRINCIPAL FINDINGS The...

We investigated the relative contribution of humoral (carbon dioxide) and neural (trigeminal stimulation) inputs in the cerebrovasodilatory response to simulated diving in the rat. The cerebral hemodynamic profile of rats was determined using the brain blood flow tracer N-[14C]isopropyl- p-iodoamphetamine. During a simulated dive response, cerebral vascular resistance (CVR) decreased 63.1%, res...