Sleep apnea and body position during sleep.

In patients with obstructive sleep apnea, it is believed that body position influences apnea frequency. Sleeping in the lateral decubitus position often results in significantly fewer apneas, and some have recommended sleeping on the side as the major treatment intervention. Previous studies, although calculating apnea-hypopnea index (AHI) for supine and lateral decubitus positions, have not taken sleep stage into account.

Sleep in restrictive lung disease.

Restrictive lung disease patients exhibit a wide range of breathing and oxygenation abnormalities during sleep. The combination of degree of restriction, whether it is intrapulmonary or extrapulmonary, and confounding factors, such as obesity, age, and sex, will ultimately determine the degree of disturbed nocturnal physiology. The sleep literature is still sparse in most restrictive diseases.

Dynamic in vivo response characteristics of three oximeters: Hewlett-Packard 47201A, Biox III, and Nellcor N-100.

Pulse oximeters (Biox III, Nellcor N-100) and a transmittance oximeter [Hewlett-Packard 47201A (HP)] were compared for SaO2 measurement and responsiveness during dynamic changes in arterial oxygen saturation and heart rate. Five sleep apnea syndrome patients were studied because they had large oscillations in SaO2 and heart rate in sleep. During sleep, each patient exhibited a series of rapid (18.

Snoring in normal young adults: prevalence in sleep stages and associated changes in oxygen saturation, heart rate, and breathing pattern.

Six men and three women, asymptomatic light snorers ranging in age from 25-34 years, were studied during sleep to determine the prevalence of snoring in the different sleep stages, the associated changes in oxygen saturation (SaO2), heart rate (HR), and breathing frequency (f), and the associated breathing arrhythmias. Snoring was defined as a 1-minute epoch with more than 80% of the breaths associated with snores. Most of the snoring epochs as well as the apneas and hypopneas occurred during stage 2, mainly because it is the most prolonged sleep stage.

Oxygenation and breathing pattern during phasic and tonic REM in patients with chronic obstructive pulmonary disease.

Oxygen desaturation in chronic obstructive pulmonary disease (COPD) occurs during sleep and is most marked in REM sleep. REM is not a homogeneous state, consisting of phasic REM (PREM) (REMs, myoclonic twitches) and tonic REM (TREM) (muscle atonia, desynchronized electroencephalogram). In normals, onset of PREM produces transient changes in breathing pattern with a decrease in respiratory amplitude and an increase in frequency, which produce reductions in oxygen saturation (SaO2).

The effect of excessive ethanol ingestion on sleep in severe chronic obstructive pulmonary disease.

The effect of a moderately intoxicating dose of ethanol on sleep was evaluated in five patients with severe emphysematous chronic obstructive pulmonary disease (COPD) (mean FEV1 0.83 L, PaO2 75 mm Hg). Mean serum ethanol before sleep was 129 mg/dl.

Hypercapnia and sleep O2 desaturation in chronic obstructive pulmonary disease.

There is a wide clinical spectrum in chronic obstructive pulmonary disease (COPD). The extremes of this spectrum, the "pink puffer" (PP) and "blue bloater" (BB) stereotypes differ in their degree of sleep hypoxemia and pulmonary hypertension. Most patients cannot be characterized as either PP or BB.

Perfluorochemical artificial blood as a volume expander in hypoxemic respiratory failure in dogs.

The perfluorochemical O2-transport fluid, Fluosol-DA 20 percent (PFC), is being clinically evaluated as a volume expander in patients who are unable to receive blood products. Since patients treated with Fluosol-DA may be at risk of developing adult respiratory distress syndrome (ARDS) as a complication of the original disorder for which they were transfused, we examined central hemodynamics and gas exchange in anesthetized O2-ventilated dogs with oleic-acid induced pulmonary edema before and after transfusion with 400 ml of either PFC (n = 5) or whole blood (n = 5). Transfusion produced similar increases in cardiac output, pulmonary and systemic vascular pressures and intrapulmonary shunt in the two groups.

Effect of aminophylline and relief from hypoxia on central sleep apnoea due to medullary damage.

A 17-year old boy presented with severe, predominantly central sleep apnoeas secondary to structural damage in the medulla. At low O2 saturation, the electroencephalogram showed the sudden onset of slow waves. Hypercapnic ventilatory response was low and hypoxic ventilatory response was absent.

Alteration in breathing pattern with progression of chronic obstructive pulmonary disease.

We examined the relationship between breathing pattern and severity of disease in patients with chronic obstructive pulmonary disease (COPD). Resting breathing pattern was recorded for 45 min using the respiratory inductance plethysmograph (RIP) in 22 patients with stable COPD. Six subjects (moderate group) had FEV1 25 to 50% predicted, 8 subjects (severe group) had FEV1 less than 25% predicted, and 8 subjects (respiratory failure group) had FEV1 less than 25% predicted and were hypoxemic.

Atypical manifestations of pulmonary adenoid cystic carcinoma.

Pulmonary adenoid cystic carcinoma (PACC) typically arises in large airways. A patient who presented with a peripheral lung mass due to PACC is reported. She was found to have multiple pulmonary nodules due to PACC 11 years after resection of the original tumour.

Breathing during sleep in normal pregnant women.

Physiologic changes during the last trimester of pregnancy include reduced functional residual capacity and residual volume, increased alveolar-arterial difference for oxygen, and in the supine position reduced cardiac output. In conjunction with sleep-related apnea or hypoventilation, these could lead to maternal oxygen desaturation during sleep. Because we could not find detailed respiratory sleep studies in late pregnancy, we performed complete polysomnography on 6 pregnant women at 36 wk gestation and again postpartum.

Sleep and respiration: terminology and methodology.

Sleep and respiratory recording techniques and the methods of interpretation employed in a clinical setting are reviewed. Sleep organization and the rules by which sleep state is classified are discussed, as well as the theory of operation pertaining to respiratory instrumentation.

Fat, sleep, and Charles Dickens: literary and medical contributions to the understanding of sleep apnea.

Although the relationship between breathing and sleep has only recently been "discovered" by the medical community, excellent literary descriptions of what we know to be the sleep apnea syndrome were made long ago. Although ancient Greek writings described probable sleep apnea, the most important literary contributions in this area are by Charles Dickens. His description of Joe the fat boy in the Pickwick Papers is an example of his brilliant skills of observation and description.

Sleep and respiration: a postscript.

The recent advances in our understanding of breathing in sleep include an evolution in the selection and surgical therapy of patients with the sleep apnea syndrome. Recent work suggests that shorter polysomnographic studies may be adequate for diagnostic purposes in many sleep apnea patients. It is now clear that central apnea may occur, paradoxically, in patients with either very blunted chemical drives to breathe or increased drives to breathe.

Sleep in restrictive lung disorders.

Abnormalities in sleep occur in patients with both extrapulmonary restriction and intrapulmonary restriction. Patients with extrapulmonary restriction such as kyphoscoliosis may develop severe apneas during sleep, particularly during the REM stage. Patients with interstitial lung disease continue to have a rapid shallow breathing pattern during sleep, but may also develop abnormalities in the breathing pattern.

Sleep and control of heart rate.

The heart rate in normal humans is determined by many factors. Assuming a normal hemoglobin concentration, left ventricular function, and metabolic rate, respiration, and its effects, along with autonomic nervous activity, appear to influence heart rate the most. Hypoxia and hypercapnia both increase heart rate during wakefulness and probably do the same during sleep.

Breathing during sleep in patients with interstitial lung disease.

Patients with interstitial lung disease (ILD) have a rapid shallow breathing pattern while awake that is thought to be due to activation of lung reflexes. We wondered whether sleep would result in changes in respiratory control and thus cause hypoxemia and poor sleep quality. Eleven patients with ILD (5 men and 6 women) and 11 age- and sex-matched control subjects were studied during sleep.

Breathing patterns in patients with chronic obstructive pulmonary disease.

The respiratory inductance plethysmograph (RIP) was used to record resting breathing for 45 min in 12 patients with stable chronic obstructive pulmonary disease (COPD) and 8 age- and sex-matched control subjects. The COPD group had mean FEV1.0 of 31% predicted (range: 15 to 49%), mean PaO2 of 70 mmHg (56 to 83 mmHg), and mean PaCO2 of 37 mmHg (31 to 47 mmHg).

Sleep apnea. From the needles of Dionysius to continuous positive airway pressure.

It is generally believed that the first description of the sleep apnea syndrome was made by Charles Dickens in the Pickwick Papers and that the first medical description was published in 1956. In fact, some of the features of the sleep apnea syndrome were described in antiquity and brief medical reports were published prior to the Pickwick Papers. This article traces the literary and medical contributions to our understanding of sleep apnea.