Vasodilator responses to chemical stimuli in the cerebral circulation and the forearm are impaired in many patients with obstructive sleep apnea. Some of these impairments can be improved with continuous positive airway pressure.

An unprecedented demographic transformation is occurring as our population ages. Those older than age 65 represent the fastest growing segment of the population. Within this older group, approximately 10% to 30% of adults are estimated to have dysphagia, but true incidence and prevalence are unknown. They make up a heterogeneous mix of both healthy and disabled individuals that reside across a spectrum of living settings. As clinicians approach older adults with dysphagia, general geriatric principles should be followed to optimize care for this diverse group. Likewise, practitioners need to appreciate the physiology that distinguishes a healthy old swallow from dysphagia and acknowledge the wide array of causes that contribute to dysphagia in older people. Clinicians need to recognize the heterogeneity in health, functional abilities, social supports, and resources among the elderly and understand how these factors may influence approaches to dysphagia in different care settings. Standard outcome measures of pneumonia, malnutrition, and mortality must be blended with other quality of life indices. Advanced directives are essential in caring for elderly patients with dysphagia irrespective of their health acuity or care setting. Ultimately, patient and family preferences should dictate the swallowing and feeding interventions offered.

Our previous work showed a diminished cerebral blood flow (CBF) response to changes in Pa(CO(2)) in congestive heart failure patients with central sleep apnea compared with those without apnea. Since the regulation of CBF serves to minimize oscillations in H(+) and Pco(2) at the site of the central chemoreceptors, it may play an important role in maintaining breathing stability. We hypothesized that an attenuated cerebrovascular reactivity to changes in Pa(CO(2)) would narrow the difference between the eupneic Pa(CO(2)) and the apneic threshold Pa(CO(2)) (DeltaPa(CO(2))), known as the CO(2) reserve, thereby making the subjects more susceptible to apnea. Accordingly, in seven normal subjects, we used indomethacin (Indo; 100 mg by mouth) sufficient to reduce the CBF response to CO(2) by approximately 25% below control. The CO(2) reserve was estimated during non-rapid eye movement (NREM) sleep. The apnea threshold was determined, both with and without Indo, in NREM sleep, in a random order using a ventilator in pressure support mode to gradually reduce Pa(CO(2)) until apnea occurred. results: Indo significantly reduced the CO(2) reserve required to produce apnea from 6.3 +/- 0.5 to 4.4 +/- 0.7 mmHg (P = 0.01) and increased the slope of the ventilation decrease in response to hypocapnic inhibition below eupnea (control vs. Indo: 1.06 +/- 0.10 vs. 1.61 +/- 0.27 l x min(-1) x mmHg(-1), P < 0.05). We conclude that reductions in the normal cerebral vascular response to hypocapnia will increase the susceptibility to apneas and breathing instability during sleep.