Laurel Wiegand

Obstructive sleep apnea

The high prevalence of obstructive sleep apnea (OSA) has only recently been appreciated, in part because the symptoms and signs of chronic sleep disruption are often overlooked in spite of their debilitating consequences. They typically develop insidiously during a period of years. We now know that the lives of millions of people each year are significantly impaired by the sequelae of OSA. Many of these patients go unrecognized, with tremendous medical and economic consequences for individual patients and for society. Evidence indicates that chronic, heavy snoring may be associated with increased long-term cardiovascular and neurophysiologic morbidity. Therefore considerable interest lies in the study of the epidemiology and the natural history of these related disorders. The fundamental problem in OSA is the periodic collapse of the pharyngeal airway during sleep. The pathophysiology of this phenomenon is reviewed in some detail. During apneas caused by obstruction, airflow is impeded by the collapsed pharynx in spite of continued effort to breathe. This causes progressive asphyxia, which increasingly stimulates breathing efforts against the collapsed airway, typically until the person is awakened. Hypopneas predominate in some patients and are caused by partial pharyngeal collapse. The clinical sequelae of OSA relate to the cumulative effects of exposure to periodic asphyxia and to sleep fragmentation caused by apneas and hypopneas. Some patients with frequent, brief apneas and hypopneas and normal underlying cardiopulmonary function may have considerable sleep disruption without much exposure to nocturnal hypoxia. Patients with sleep apnea often have excessive daytime sleepiness. As the disorder progresses, sleepiness becomes increasingly irresistible and dangerous, and patients develop cognitive dysfunction, inability to concentrate, memory and judgment impairment, irritability, and depression. These problems may lead to family and social problems and job loss. Cardiac and vascular morbidity in OSA may include systemic hypertension, cardiac arrhythmias, pulmonary hypertension, cor pulmonale, left ventricular dysfunction, stroke, and sudden death. The challenge for the clinician is to routinely consider the diagnosis and to incorporate several basic questions in the historical review of systems regarding daytime or inappropriate sleepiness. The diagnosis of OSA is made with polysomnography, and the decision to treat is based on an overall assessment of the severity of sleep-disordered breathing, sleep fragmentation, and associated clinical sequelae. The therapeutic options for the management of OSA are reviewed. Recognition and appropriate treatment of OSA and related disorders will often significantly enhance the patients quality of life, overall health, productivity, and safety on the highways.

The post-cardiac injury syndrome following blunt chest trauma: case report.

The case of a 53-year-old man is reported in which the patient developed post-cardiac injury syndrome 2 weeks after blunt trauma to the thorax. The patient failed to respond adequately to ibuprofen but improved on corticosteroids. He suffered relapses 8 and 15 months after the original injury following reductions in the corticosteroid dosage. The patient at last follow-up had been asymptomatic for over 4 years.

DEVELOPMENT OF THE BI-DIRECTIONAL ULTRASOUND SYSTEM FOR BASE OF TONGUE IMAGING

The use of conventional ultrasound systems to image the upper airway has been limited because ultrasound energy is attenuated by the air column. In an attempt to study upper airway geometry, we developed a computer controlled bi-directional ultrasound system which combines two conventional ultrasound devices with computer image processing to yield images of upper airway structures. Human studies and cadaver studies were performed to evaluate the system. Images acquired by the bi-directional ultrasound system were comparable to images from 3D volume rendered CT scans. This system may provide valuable data in the study of upper airway physiology and pathology.

Human Sleep-Disordered Breathing

obstructive sleep apnea is a common clinical disorder primarily affecting men who have a long history of heavy snoring. The incidence of the illness increases with both aging and obesity; its major clinical manifestation is the complaint of daytime hypersomnolence. This illness has received a great deal of clinical and investigative attention in the last ten years because its occurrence appears almost epidemic in nature. In addition, apnea-associated cardiac rhythm abnormalities raise the question of the possible influence of obstructive sleep apnea on unexplained nocturnal death. Recently other associated cardiovascular abnormalities, such as sustained pulmonary and systemic hypertension, have resulted in further interest in this recently discovered illness.