UNLABELLED Therapeutic decisions in patients with sleep apnea (eg, adjustment of continuous positive airway pressure [CPAP]) depend on differentiating central from obstructive apnea. Obstructive apnea is defined by cessation of airflow in the presence of continued respiratory effort, which is conventionally inferred from chest wall movement or intrathoracic pressure swings. Cardiogenic oscillat...

We investigated the spleen volume changes as related to the cardiovascular responses during short-duration apneas at rest. We used dynamic ultrasound splenic imaging and noninvasive photoplethysmographic cardiovascular measurements before, during, and after 15-20 s apneas in seven trained divers. The role of baroreflex was studied by intravenous bolus of vasodilating drug trinitrosan during tid...

Autonomic dysfunction is recognized to contribute to cardiovascular consequences in obstructive sleep apnea/hypopnea syndrome (OSAHS) patients who present predominant cardiovascular sympathetic activity that persists during wakefulness. Here, we examined 1) the factors that influence sympathetic cardiac modulation in response to apneas/hypopneas; and 2) the influence of autonomic activity durin...

The purpose of this study was 1) to answer whether the reduction in spleen size in breath-hold apnea is an active contraction or a passive collapse secondary to reduced splenic arterial blood flow and 2) to monitor the spleen response to repeated breath-hold apneas. Ten trained apnea divers and 10 intact and 7 splenectomized untrained persons repeated five maximal apneas (A1-A5) with face immer...

Seven patients with OSAS were studied during nocturnal sleep in order to assess the trend of PAP throughout apneas and to identify factors possibly associated with such a trend. All patients underwent a polysomnography including the monitoring of PAP and esophageal pressure. While intravascular PAP decreased during apneas and increased at the resumption of breathing, transmural PAP values (ie, ...

This report describes an unusual case of severe obstructive sleep apnea and alveolar hypoventilation leading to hypersomnolence and cor pulmonale, which were corrected by tracheostomy. Four years later, after a 22.5-kg weight gain, nocturnal apneas of similar frequency, duration, and depth of desaturation reappeared but were totally central in origin. The central apneas were eliminated with hom...

In order to investigate the role of hypoxia on the cyclic oscillation of transmural pulmonary artery pressure (PAP) in obstructive sleep apnea, oxygen was administered during one half of the night to six patients affected by obstructive sleep apnea syndrome during a nocturnal polysomnographic study. In each patient, transmural PAP measurements were performed on 15 randomly selected apneas recor...

Reduced upper airway muscle activity may contribute to the occurrence of obstructive apneas during sleep. There is no uniformly successful treatment of these apneas, and it is possible that agents which increase upper airway muscle activity could reduce the occurrence of obstruction during sleep. Nicotine, a known stimulant of breathing, also increases the activity of muscles which dilate the u...