German investigators have demonstrated that continuous positive airway pressure (CPAP) treatment rapidly improves insulin sensitivity in patients with obstructive sleep apnea syndrome (OSAS). Less obese patients improved after 2 days of treatment. The researchers studied insulin sensitivity in 40 OSAS patients who had a mean apnea-hypopnea index of 43 breathing pauses per hour. Insulin sensitivity readings were taken before, 2 days after CPAP treatment started, and after 3 months of treatment. The authors said that insulin resistance seems to play a key role among the mechanisms responsible for the metabolic effects of OSAS. In fact, the presence of increased insulin resistance has repeatedly been reported in patients with OSAS. (Obstructive sleep apnea is characterized by airway collapse and cessation of breathing (airflow) for 10 seconds or more during sleep. These pauses, which can occur many times over during the night, are followed by a brief arousal and resumption of breathing.) Since the problem leads to inadequate amounts of oxygen in the blood, it can bring on deficits to the individual, including daytime sleepiness, inattention, and impaired quality of life. The standard treatment for the disorder is CPAP. This device delivers air through a mask that usually covers the mouth and nose. CPAP increases air pressure in the throat and prevents tissues in the airway from collapsing when the individual inhales. In the 31 patients the investigators followed for 3 months, they found no further significant improvement in their individual insulin sensitivity indexes; however, the positive differences from baseline measurements remained statistically significant. The study appears in the second issue for January 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.
MEASURING AIRWAY RESISTANCE IN KIDS SHOWS LATER ASTHMA RISK
Measurement of airway resistance in 4-year-old children with different types of wheezing, using a new approach, could help identify those at high risk of asthma at a later date. The study's investigators pointed out that measurement of airway resistance in 838 4-year-olds with what is called the interrupter resistance technique (Rint) could help identify young children at high risk of asthma. The technique does not require the active cooperation of the child as do other airway tests. Just over half of the children (482) never wheezed, 236 (28 percent) had early transient wheezing, 22 (3 percent) had late onset wheezing; and 98 (12 percent) had persistent wheezing. Children with persistent wheezing had significantly higher Rint values than children in the never-wheeze and early transient wheeze groups. The authors said that, in children with asthma, chronic airway inflammation is already present at a young age, and can lead to irreversible airway remodeling and decreased lung function. They noted that early intervention and treatment could prevent irreversible damage to the airways. The children will be rechecked at 8 years of age. The study appears in the second issue for January 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.
A SIMPLE, NONINVASIVE UPPER AIRWAY TEST CAN HELP IDENTIFY, WHILE AWAKE,CHILDREN WITH SLEEP-DISORDERED BREATHING
A simple, noninvasive upper airway test, performed while a youngster is awake, could provide more accurate identification of children with sleep-disordered breathing, according to a study in the second issue for January 2004 of American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine. In their study, the investigators measured the upper airway cross-sectional area of 247 children who snored. All children tested were between the ages of 4 and 16, and were otherwise healthy. Snoring is the cardinal symptom that raises a physician's suspicion of sleep-disordered breathing. That problem affects 11 percent of children from ages 2 to 8. But sleep disordered breathing is hard to diagnose, except through an overnight sleep test. This experience imposes a substantial burden on the child and his or her parents, according to the researchers. The non-invasive procedure studied permits the evaluation of a cross-sectional area of the upper airway as a function of the distance from the mouth during both wakefulness and sleep. This approach permits identification of the collapsible segment of the airway in awake children during obstructive events which cut off air in those with disordered breathing. Administration of a topical anesthetic in the upper airway removed local reflexes that promote airway patency (openness) during wakefulness. From their tests, the researchers discovered that the children's airways were smaller in sleep-disordered breathing patients, and that upper airway collapsibility and sleep-disordered breathing severity were "markedly" and "significantly greater" in such children.
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