Obstructive sleep apnea

Obstructive sleep apnea

    * Introduction
    * Clinical forms of sleep apnea
    * Risk factors of obstructive sleep apnea SDR
    * Symptoms and signs
    * Laboratory examinations
    * Treatment of obstructive sleep apneii
    * Selective Bibliography
Sleep is a behavioral act cyclically reversible urge rest determined and characterized by partial suppression of the sensitivity functions and conscious relationship, resolution muscle, reducing vegetative functions and dream activity, but maintaining a certain degree of sensory integration, which it apart from narcosis and coma.

 
Suppressing function of relationship with the environment and leaving intact the vegetative maintenance of life processes, energy and sleep to recover functional potential of the body, in order to resume its normal activity once the transition to wakefulness.

To be restful sleep must have an optimal duration of which varies according to age and to follow a certain structure represented an average of five cycles of 90 minutes.

 
Each cycle is divided into several stages, electroencephalographic classified according to criteria of Rechtschaffen and Kales. These stages were defined according to the criteria printed by Dement and Kleitman in: - Sleep or slow which in turn includes four stages of increasing depth, is characterized by slow brain electrical activity and maintaining skeletal muscle tone; - Paradoxical or REM sleep, rapid brain electrical activity, rapid eye movements and skeletal muscle atony.

 Sleep stages Fig.1-sleep stages
Slow sleep is dependent on the serotonin system Rafei plane, while the paradoxical sleep is based on the participation of adrenergic neurons in the nucleus Pontin, located on the fourth ventricle floor, called the place coeruleus.

 
In terms of ventilation, sleep in general is accompanied by hypoventilation, regardless of its phases. During normal sleep may occur up to five respiratory events (apnea called short interruptions complete or incomplete known hipopnei) harmless. Increasing the number and duration of breathing pauses cause repeated awakenings, sleep fragmentation and the appearance of symptoms and complications. Prolonged wakefulness is accompanied by a disturbance of the processes of attention and behavioral manifestations of matter.

 
Sleep apnea term was first used by Broadbent in 1877 and 1965, Burwell et al. Pickwick syndrome proposed term, alluding to the character of Charles Dickens. Apnea was defined as a phenomenon of stopping the nasal-oral airflow lasting more than 10 seconds, while hypopnea is minimum 50% reduction of ventilation, accompanied by a decrease in oxygen saturation at least 4%.

 
Definition of sleep apnea syndrome (SAOS) to quantify these events involve the airway by the notion of apnea and hypopnea index (IAH), defined by recurrent episodes of this complete or incomplete obstruction of the upper airway, with the formula for calculating the ratio between the number of and duration of sleep apnea and hipopnei in minutes. A IAH over 5 per hour of sleep is conclusive for diagnosis of SAOS.