Parents of a first child who has died from sudden infant death syndrome (SIDS) and who are considering another pregnancy can be reassured that their next child has at least a 99.65 percent chance of surviving infancy, according to a State-of-the-Art article. This statement holds true depending on the magnitude of assorted environmental factors that could be encountered by the newborn such as sleeping in a face-down position, soft bed and blankets, cigarette smoke exposure, and thermal stress. (SIDS is defined as the sudden death of an infant younger than 1 year of age that remains unexplained after a thorough case investigation that includes a complete autopsy, examination of the death scene, and review of the baby’s clinical history.) In 1998, the fatal disorder accounted for 2,529 deaths in American babies. A SIDS diagnosis is made in 80 to 82 percent of sudden, unexpected infant deaths in the U.S. Groups at increased risk include premature infants as well as babies who have had unexplained apparent life-threatening events. Abnormalities observed in the infants include frequent and prolonged apnea (cessation of respiration for some seconds), diminished response to low oxygen levels in the blood, impaired control of heart and respiratory rates, abnormal heart rates, deficient or absent arousal from sleep, metabolic abnormalities, infections, and impaired inflammatory response to infectious agents. Intentional suffocation, usually by the mother, is another risk facing SIDS siblings. According to the author, the population-based incidence of intentional suffocation has been estimated as high as 10 percent of sudden, unexpected infant deaths, but it is more likely to be less than 5 percent, and may be as low as 2 percent. The article appears in the first of two August issues of the American Thoracic Society’s peer reviewed American Journal of Respiratory and Critical Care Medicine.
SPACE FLIGHT DRAMATICALLY REDUCES SLEEP-RELATED DISTURBANCES AND SNORING
In the microgravity of space flight, 5 astronauts showed dramatic reductions in the number of sleep-related disturbances, time spent snoring, and the number of arousals associated with respiratory-related events, according to a research study. The investigators believe their project is the first direct demonstration that gravity plays a dominant role in the generation of apnea, hypopneas, and snoring in healthy persons. (Apneas constitute a state of not breathing for some seconds during sleep and hypopnea is very shallow, slow breathing.) The microgravity of space was associated with a 55 percent reduction in the apnea-hypopnea index (AHI), which decreased from 8.3 events per hour preflight among the 5 astronauts to 3.4 events per hour during sleep in space. This reduction in AHI was accompanied by a virtual elimination of snoring which fell from 16.5 percent of sleep time preflight to 0.7 percent in space. According to the investigators, the respiratory system is greatly influenced by the force of gravity, especially when an individual goes from standing to lying on their back (supine). It causes the tongue, soft palate, uvula, and epiglottis to move backward toward the pharyngeal wall, increasing upper airway resistance. The study appears in the first of two August issues of the American Thoracic Society’s peer- reviewed American Journal of Respiratory and Critical Care Medicine.
UNDIAGNOSED AIRFLOW OBSTRUCTION IN OLDER U.S. ADULTS
Researchers examining data from a national survey involving 5,743 white participants who were approximately age 65-1/2, on average, discovered undiagnosed airflow obstruction in 12 percent, chronic obstructive pulmonary disease in 3.1 percent, and asthma in 2.7 percent. Although the undiagnosed airflow obstruction was usually very mild, approximately 5 percent of the entire sample had lung function test results of less than 75 percent of their predicted value. At that level, over 50 percent of those individuals had pronounced shortness of breath (dyspnea). The data for analysis by the investigators came from a selected segment of individuals from households involved in the Third National Health and Nutrition Survey (NHANES III) conducted in 81 U.S. counties between 1988 and 1994. Results were from white participants (52 percent female) 45 years of age or older who performed a lung function test, received a health examination, and answered a questionnaire. The authors noted that ever-smoking was strongly associated with all types of airflow obstruction, whether diagnosed or not. They also felt that the high occurrence of mild airflow obstruction shown suggests potential for a large burden of illness which could manifest itself in the future. The study appears in the first of two issues for August of the American Thoracic Society’s peer-reviewed American Journal of Respiratory and Critical Care Medicine.
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Journal
American Journal of Respiratory and Critical Care Medicine