This chapter focuses on the effects of hypo- and hypercapnia at the organ and tissue level. Carbon dioxide's role in determining acid-base status and tissue oxygenation is described, followed by its effects on major organ systems. The higher lipid solubility of CO2 compared to hydrogen ions allows acid-base changes caused by respiratory acidosis and alkalosis to equilibrate between extra- and intracellular fluids much faster than changes caused by metabolic acidosis or alkalosis. The primary determinants of tissue oxygen availability are arterial O2 tension, cardiac output, and local perfusion. Hypocapnia induced by hyperventilation is clinically used for treatment of increased intracranial pressure (ICP), but the compromise in tissue perfusion, and thus the resulting secondary ischemia, should be factored into the risk-benefit equation. The active management of CO2 is a promising strategy to consider for improving tissue perfusion, providing anti-inflammatory effects, and preventing apoptotic injury.

This chapter discusses the case of a 42-year-old patient who was admitted for the evaluation of opioid-induced central sleep apnea. It presents the clinical history, examination, follow-up, treatment, and the results of the procedures performed on the patient. The patient was presented for evaluation of frequent breathing pauses during sleep, which had been witnessed by his wife for 5 years along with intermittent mild snoring. His social history was negative for alcohol or other substance abuse, but he was an ex-smoker and he drank 12 cups of coffee per day. The patient had been maintained on narcotics for treatment of his chronic pain following the laminectomy, for a period of 8 years. In view of his sleep respiratory symptoms, polysomnography (PSG) was performed. Opioid-induced central sleep apnea (CSA) has attracted attention in recent years because of the surge in opioid administration to patients with pain.

This chapter presents the clinical history, examination, and the results of the procedures performed on a patient who was a 14-year-old young woman who, according to her parents, has had problems sleeping for several years. The results of the studies showed that the patient had a total of 144 sleep-related respiratory events, with an apnea-hypopnea index (AHI) of 22.47 per hour. There were 140 central apneas and four hypopneas, with 126 events occurring in NREM sleep. The diagnosis was Chiari 1 malformation with associated central sleep apnea. The patient also had a syrinx from C3 through the thoracic cord. Treatment of Chiari 1 malformation involves suboccipital decompression (posterior fossa craniectomy), with or without upper cervical laminectomy. In this case too, the patient underwent suboccipital decompression, and remained in the hospital for 4 days, with some immediate post-operative sleep-related apneas but subsequent significant improvement of sleep.

Obstructive sleep apnea (OSA), a frequent form of sleep disordered breathing (SDB), is associated with commonly occurring cardiovascular disorders, including hypertension, coronary artery disease, congestive heart failure. Central sleep apnea (CSA) is frequently associated with congestive heart failure (CHF). Cheyne Stokes respiration (CSR), a form of periodic breathing, commonly accompanies CSA patients with heart failure and portends increased mortality. This chapter explores these and other associations between sleep disorders and cardiovascular disease. SDB is highly prevalent in the elderly and the odds of having significant SDB are estimated at 1.79 per 10-year increase in age. The relation between insomnia and cardiovascular disorders has been less well examined than that between SDB and cardiovascular disorders, especially in the elderly. Large prospective studies will be needed to understand the association between insomnia complaints and coronary artery disease (CAD), and determine the direction of causality, if any.

This chapter provides some guidance on how to manage sleep apnea in the elderly. It focuses on obstructive and central sleep apnea. Sleep disordered breathing includes obstructive sleep apnea (OSA), central sleep apnea including Cheyne-Stokes respiration (CSR), and sleep hypoventilation. The underlying mechanisms that promote the development of sleep apnea in the elderly can be classified into three broad categories, namely: (1) replication of the pathophysiology of sleep apnea in middle-aged adults; (2) physiological changes that are uniquely associated with aging; and (3) consequences of chronic medical disorders and/or medications. Elderly patients with sleep apnea can present with typical clinical features such as snoring, choking or gasping respirations, witnessed apneas, morning headaches, hypertension, and daytime sleepiness. After the identification and treatment of any underlying medical disorders that contribute to sleep apnea, such as hypothyroidism and acromegaly, weight reduction, and postural therapy can be considered.

This chapter focuses on the pathophysiology, clinical features, and management of obstructive and central sleep apnea (CSA). CSA accounts for less than 15% of individuals with sleep apnea evaluated at sleep disorder centers. Though central apneas can occur in people with obstructive sleep apnea (OSA), diagnosis of CSA is usually made when more than 50% of the apneic events are central in nature. Nonhypercapnic central sleep apnea is the most common form of CSA. CSA due to Cheyne-Stokes breathing is seen in people with congestive heart failure (CHF), neurological disorders such as stroke, and probably renal failure. OSA commonly affects middle-aged men and women. There are many risk factors for OSA, with obesity and craniofacial features being by far the most common. The treatment for OSA is influenced by the severity of OSA, relative efficacy of various treatment options, associated comorbid conditions, and personal preference.