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Biomedical subjects

A J Block

Publications and source records attributed to A J Block.

At least 73 records · Page 4Linked to original sources
PubMed1987

Snoring, nocturnal hypoxemia, and the effect of oxygen inhalation.

Men who snore heavily have an increased incidence of hypertension, angina, stroke, and neuropsychologic dysfunction, which may be due to nocturnal oxygen desaturation. Nocturnal oxygen therapy might be beneficial to such individuals by improving oxygenation and relieving tissue hypoxia. Twenty-eight asymptomatic heavy snoring men were recruited for polysomnographic monitoring during sleep. During the first half-night, air was breathed through a nasal cannula, and during the latter half-night, 2 L/min oxygen was administered. Breathing air, 20 subjects demonstrated sleep apneas, hypopneas and nocturnal oxygen desaturation. Eighteen subjects had more than ten apneas plus hypopneas per hour. Thirteen subjects reached low oxygen saturation below 80 percent and eight below 70 percent. Only 13 of the 20 subjects showed improvement with oxygen therapy. Apneas alone were not decreased in frequency and were lengthened with oxygen therapy. Episodes of oxygen desaturation were improved by oxygen therapy and consequently, rates of hypopnea were decreased. Severe sleep apnea, hypopnea and oxygen desaturation are common in asymptomatic male snorers, and oxygen therapy is not always beneficial.

Electroencephalography↗
PubMed1987

Ingestion of either scotch or vodka induces equal effects on sleep and breathing of asymptomatic subjects.

Polysomnography was performed on 13 asymptomatic men and four women on three consecutive nights in our sleep laboratory. In random order, the subjects ingested either orange juice alone or the equivalent of 1 mL of 100-proof alcoholic beverage (scotch or vodka) per pound of body weight in 1.5 hours or less. All subjects ingested a different beverage on each of the three nights. Blood alcohol level in the subjects before sleep was, for vodka, 73 mg/100 mL, and, for scotch, 74 mg/100 mL. On control nights the subjects showed significantly more time in bed, sleep period time, and total sleep time, and more rapid eye movement sleep. On the scotch and vodka nights, oxygen saturation was significantly lower; there were more episodes of oxygen desaturation in which there was greater than 4% decrease in saturation, more desaturation to levels of less than 90%, and more hypopnea. Comparison of data of scotch with vodka nights showed no significant differences in any variable. Both scotch and vodka ingestion in equal dosage induced sleep-disordered breathing and nocturnal oxygen desaturation in asymptomatic volunteers, and the beverages had equal effects.

Adult↗
PubMed1986

Effect of alcohol ingestion on breathing and oxygenation during sleep. Analysis of the influence of age and sex.

Breathing and oxygenation were monitored in 78 asymptomatic volunteers on two successive nights of sleep. Four groups of subjects were recruited: 20 young men, 20 young women, 20 men older than 40 years, and 18 postmenopausal women. In random order, subjects ingested either 2 ml/kg (body weight) of 100-proof vodka in orange juice or a similar amount of water in orange juice before bedtime. Alcohol ingestion shortened sleep in the older men and in the postmenopausal women. No effect of alcohol ingestion on breathing or oxygenation during sleep was seen in any group of women. In men, alcohol ingestion increased the numbers of desaturation episodes and caused more severe oxygen desaturation during sleep. The effect of alcohol ingestion on breathing and oxygenation during the sleep of asymptomatic volunteers appears to be limited to men.

Adult↗
PubMed1986

Nocturnal hypoxia and neuropsychological variables.

Hypoxia is a well known cause of brain dysfunction. Neuropsychological impairments have been observed in normal subjects experiencing hypoxia iatrogenically as well as in patients with chronic lung disease. Recent investigations have demonstrated significant nocturnal hypoxia in subjects with sleep-disordered breathing. In the present study, heavy-snoring males, a group known to experience frequent episodes of sleep-disordered breathing received neuropsychological testing and a night of continuous monitoring of respiratory parameters. Partial correlations, controlling for age, weight, and education, indicated reliable relationships between nocturnal hypoxia and measures of general intelligence, verbal and nonverbal memory, and expressive verbal fluency. It is proposed that heavy-snoring males may potentially serve as a population in which to model the neurobehavioral effects of hypoxia. Further research in subjects with sleep-disordered breathing may help clarify the extent of the possible cognitive deficits as well as point out possible ameliorative treatments.

Brain Damage, Chronic↗
PubMed1986

Sleep-disordered breathing and its concomitants in a subclinical population.

In order to evaluate possible deficits accompanying sleep-disordered breathing (SDB) in a subclinical population, the nocturnal respiration, health status, and sleep/wake cycle of 46 healthy, heavy-snoring men were measured. Sixty-two percent of these subjects had at least one episode of apnea/hypopnea, while 13% had high levels of apnea/hypopnea [apnea/hypopnea index (AHI) greater than or equal to 5]. Most events occurred in stages 1 or 2 or in REM sleep. Strong relationships between weight and SDB were observed, as were more modest relationships between age and SDB. Correlational procedures indicated relationships between SDB and higher blood pressure, subjective sleepiness, and napping. Because similar, but stronger, relationships involving these variables are observed in patients with a sleep apnea syndrome (SAS), it appears that a continuum exists between heavy-snoring men and patients with SAS. When these subjects were grouped by level of SDB, subjects with high levels of SDB (AHI greater than or equal to 5) had significantly lower nocturnal oxygenation parameters than the remaining subjects. However, there were no between-group differences in health or sleep/wake variables. It is concluded that while apnea/hypopnea events in subclinical populations may not be completely benign events, the level at which they may be considered frankly pathological is presently unclear.

Adult↗
PubMed1986

Obstructive sleep apnea following treatment of velopharyngeal incompetence by Teflon injection.

From 1967 to 1974 a clinical trial of Teflon injection into the posterior pharyngeal wall for correction of velopharyngeal incompetence (VPI) was conducted in thirty-six patients. Six years after Teflon injection, one of the patients reported the onset of severe snoring punctuated by silences when he seemed not to be breathing, daytime hypersomnolence, and tiredness severe enough to interfere with work and studies. The diagnosis of obstructive sleep apnea (OSA) was confirmed by polysomnographic sleep monitoring, and the dynamics of the obstruction elucidated by cinefluoroscopy performed with the patient asleep. Resection of the lower 3/4 of the Teflon pad, leaving the upper rim to avoid recurrence of his VPI, has eliminated the symptoms of OSA and produced an improvement in his polysomnographic findings.

Adult↗
PubMed1985

Sleep apnea and related disorders.

This article has ranged far and wide, from the pickwickian patient weighing 500 pounds to the tiny 4-lb premature baby, but the common thread is cessation or diminution of breathing during sleep and consequent oxygen desaturation. Associations have been made between abnormalities of sleep and breathing and multiple diseases--some causative and some fortuitous. Despite relating this information, we are only beginning to understand sleep and breathing. Although we spend a third of our lives asleep, very little attention was paid to the study of sleep until the mid 1970s. Even to this day, there is little interest in snoring and its adverse effects. The situation may be a sexist one in which men have done the research and the snoring, but the snoring has bothered only women. I predict that the next 15 years will see a vast increase both in studies of sleep and in our understanding of the importance of breathing during sleep--to the well-being of all of us.

Adult↗
PubMed1985

Minimal effect of alcohol ingestion on breathing during the sleep of postmenopausal women.

Eighteen asymptomatic postmenopausal women volunteered to ingest 2 ml of 100-proof vodka per kg of body weight in orange juice on one night and a placebo on another. Overnight sleep monitoring was performed immediately thereafter. Alcohol ingestion caused reduction in total sleep time from 329 to 281 minutes and a decrease in rapid eye movement sleep. There was no difference from placebo in the number of episodes of apnea or hypopnea, or in the frequency, length, or severity of oxygen desaturation. In contrast to the effects of alcohol ingestion in men, the effects on breathing and oxygenation are minimal during the sleep of women if this amount of alcohol is ingested.

Aged↗
PubMed1984

Positive nasal airway pressure eliminates snoring as well as obstructive sleep apnea.

Nine men who were habitual snorers were studied during a control and a treatment night (in random order) to assess the effect of nasal continuous positive airway pressure (CPAP) on snoring, sleep-disordered breathing, and nocturnal oxygen desaturation. Four subjects had symptoms suggestive of the sleep apnea syndrome, but the other five were asymptomatic. Polysomnography and recordings of snores were obtained on both nights. On the treatment night, the subjects wore a customized infant anesthesia mask over their noses, and CPAP was applied and adjusted upward from 4 cm H2O to a level that obliterated snoring. Nasal CPAP (range 4 to 13 cm H2O) reduced the mean number of snores per night from 1,015 per subject to 23 per subject (p less than 0.01). Mean numbers of episodes of apnea, hypopnea, and desaturation were also significantly reduced. Analysis of sleep structure showed no significant differences in sleep period time, total sleep time, or the percentages of stages 3 and 4 sleep. The percentage of stages 1 and 2 was significantly greater on control nights, and the percentage of REM sleep was greater on treatment nights. On the control nights, snoring was common in stages 3 and 4 and least common during REM sleep.

Adult↗
PubMed1984

Clinical conference in pulmonary disease. Factors influencing upper airway closure.

The factors which produce closure of the upper airway (UAW) in patients with the sleep apnea syndrome are still poorly understood. A distinction should be made between the factors which induce closure and those which reopen the UAW. Neurologic factors include arousal phenomena, the magnitude and timing of various motor outputs, and postsynaptic inhibition. Mechanical factors include the anatomy of the UAW, especially that above the tongue, the position of the neck and jaw, and mucosal adherence once occlusion has occurred. Muscle factors include the type of myosin isozyme, the forces generated by the large number of UAW muscles and the diaphragm, and the possibility of high-frequency fatigue occurring during occlusion. Hypoxia and acidosis probably play a critical role in making the UAW less stable. Currently, the best method to prevent UAW closure is by nasal CPAP. Patients with life-threatening arrhythmias due to sleep apnea should have a tracheostomy. The role of drugs is controversial. Respiratory or muscle stimulants should probably be avoided; oxygen, medroxyprogesterone, and protriptyline may be useful adjuncts.

Humans↗
PubMed1984

Sleep apnea syndrome. A critical review of the apnea index as a diagnostic criterion.

The utility of the apnea index (number of apneic events per hour of sleep) in diagnosing sleep apnea syndrome is reviewed. Data from currently extant reports indicate that many otherwise normal, aging subjects may be classified as having sleep apnea syndrome based on the current diagnostic threshold of five apneic episodes per hour: A chi 2 analysis suggests a relationship between age and level of sleep apnea. Several other reports indicate that use of a threshold of five apneic episodes per hour does not reliably predict increased health risk or somnolence in aging subjects. Adjustment of the apnea index, based on studies of aging normal subjects and of aging patients with sleep apnea syndrome is necessary to ensure reliable results in clinical and research applications.

Adult↗