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Biomedical subjects

A R Gold

Publications and source records attributed to A R Gold.

13 recordsLinked to original sources
PubMed1991

Effect of weight loss on upper airway collapsibility in obstructive sleep apnea.

Previous investigators have demonstrated in patients with obstructive sleep apnea that weight reduction results in a decrease in apnea severity. Although the mechanism for this decrease is not clear, we hypothesize that decreases in upper airway collapsibility account for decreases in apnea severity with weight loss. To determine whether weight loss causes decreases in collapsibility, we measured the upper airway critical pressure (Pcrit) before and after a 17.4 +/- 3.4% (mean +/- SD) reduction in body mass index in 13 patients with obstructive sleep apnea. Thirteen weight-stable control subjects matched for age, body mass index, gender (all men), and non-REM disordered breathing rate (DBR) also were studied before and after usual care intervention. During non-REM sleep, maximal inspiratory airflow was measured by varying the level of nasal pressure and Pcrit was determined by the level of nasal pressure below which maximal inspiratory airflow ceased. In the weight loss group, a significant decrease in DBR from 83.3 +/- 31.0 to 32.5 +/- 35.9 episodes/h and in Pcrit from 3.1 +/- 4.2 to -2.4 +/- 4.4 cm H2O (p less than 0.00001) was demonstrated. Moreover, decreases in Pcrit were associated with nearly complete elimination of apnea in each patient whose Pcrit fell below -4 cm H2O. In contrast, no significant change in DBR and a minimal reduction in Pcrit from 5.2 +/- 2.3 to 4.2 +/- 1.8 cm H2O (p = 0.031) was observed in the "usual care" group. We conclude that (1) weight loss is associated with decreases in upper airway collapsibility in obstructive sleep apnea, and that (2) the resolution of sleep apnea depends on the absolute level to which Pcrit falls.

Adult↗
PubMed1991

Premises liability.

Like other health care providers, optometrists have a duty to maintain offices and equipment in a safe condition. Failure to meet this duty results in premises liability. This article discusses premises liability with particular emphasis on pupillary dilation as a causative factor for patient injuries.

Humans↗
PubMed1988

Induction of upper airway occlusion in sleeping individuals with subatmospheric nasal pressure.

In collapsible biologic conduits, occlusion and cessation of flow occur when upstream pressure falls below a critical pressure (Pcrit). To examine the relationship between Pcrit and the development of upper airway occlusion, we examined the relationship between maximal inspiratory airflow and nasal pressure in seven normal subjects during sleep. At varying levels of subatmospheric pressure applied to a nasal mask during non-rapid-eye-movement (NREM) sleep, maximal inspiratory airflow decreased in proportion to the level of nasal pressure. When nasal pressure fell below a Pcrit, subjects demonstrated upper airway occlusions terminated by arousals. In these normal subjects, the upper airway Pcrit was found to be -13.3 +/- 3.2 (SD) cmH2O. In four subjects who sustained sleep while nasal pressure remained below the Pcrit, recurrent occlusive apneas were demonstrated. The relationship between maximal inspiratory airflow and nasal pressure in each subject was fit by linear regression and demonstrated upper airway Pcrit at the zero-flow intercept that were not significantly different from those observed experimentally. These data demonstrate that the normal human upper airway during sleep is characterized by a negative Pcrit and that occlusion may be induced when nasal pressure is decreased below this Pcrit.

Adult↗
PubMed1988

Upper airway pressure-flow relationships in obstructive sleep apnea.

We examined the pressure-flow relationships in patients with obstructive sleep apnea utilizing the concepts of a Starling resistor. In six patients with obstructive sleep apnea, we applied incremental levels of positive pressure through a nasal mask during non-rapid-eye-movement sleep. A positive critical opening pressure (Pcrit) of 3.3 +/- 3.3 (SD) cmH2O was demonstrated. As nasal pressure was raised above Pcrit, inspiratory airflow increased in proportion to the level of positive pressure applied until apneas were abolished (P less than 0.01). However, at pressures greater than Pcrit, esophageal pressures either did not correlate or correlated inversely with inspiratory airflow provided that esophageal pressure was less than Pcrit. When pressure was applied to a full face mask, inspiratory airflow did not occur and Pcrit could not be obtained at pressures well above Pcrit demonstrated with the nasal mask. These results are consistent with the view that the upper airway functions as a Starling resistor with a collapsible segment in the oropharynx. These findings offer a unifying construct for the association of sleep apnea, periodic hypopnea, and snoring.

Adult↗
PubMed1988

A review of five recent cases of significance for optometrists.

The standard of care expected of optometrists continues to be defined by the courts. Misdiagnosis of ocular disease and liability for injuries caused by ophthalmic products remain the leading causes of litigation. Documentation of findings, warnings, and key management decisions is an essential aspect of clinical practice and must not be neglected by clinicians.

Accidents, Occupational↗
PubMed1987

Malpractice reform.

The continuing debate over malpractice claims against physicians has led to widespread efforts to reform state laws affecting these claims. The most common changes have been: limitations on size of awards; shortening the statute of limitations; abolition of the collateral source rule; proscription of ad damnum clauses for damages; limitation of contingency fees; the establishment of screening panels; and the use of arbitration. Inevitably, optometrists and other health care practitioners have also benefitted from these changes, which serve to lessen the likelihood of malpractice claims or to limit their effects. Optometrists continue to be among the least-sued practitioners in health care.

Humans↗
PubMed1986

The effect of chronic nocturnal oxygen administration upon sleep apnea.

Administration of nocturnal oxygen for 1 night to patients with obstructive sleep apnea (OSA) causes a moderate reduction in apnea frequency without improving hypersomnolence. Therefore, we administered oxygen chronically to patients with OSA to determine: whether apnea frequency would be further reduced, whether the effect of oxygen upon apnea frequency is correlated with an increased ventilatory response to hypoxia and hypercapnia, and whether hypersomnolence improves with more prolonged oxygen administration. In a single-blinded, nonrandomized trial, we compared the effects of 1 month of oxygen (4 L/min by nasal cannula) with room air (4 L/min by nasal cannula) placebo during sleep in 7 men and 1 woman with obstructive sleep apnea. During non-REM sleep, acute oxygen administration elevated the average low oxy-hemoglobin saturation during apneic events and decreased apnea frequency. These acute effects persisted during chronic oxygen administration but reverted to the preoxygen effects immediately upon discontinuing oxygen. One month of oxygen did not affect the waking ventilatory response to hypoxia or hypercapnia; however, waking PaCO2 increased from 40 +/- 1 mm Hg (mean +/- SE) after placebo to 43 +/- 1 mm Hg after oxygen (p less than 0.01). Neither subjective nor objective hypersomnolence consistently improved after 1 month of oxygen administration. We conclude that: first, oxygen has no effect upon apnea frequency beyond the period of administration, and the reduction of apnea frequency is not correlated with an increased sensitivity to chemical ventilatory stimuli. The reduced apnea frequency may be related to an increased PaCO2 stimulating ventilation during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1978

Rise in female-initiated sexual activity at ovulation and its suppression by oral contraceptives.

This study was designed to test the hypothesis that women exhibit peaks of sexual activity at ovulation, as would be predicted from estrous effects in animals. Married women who used contraceptive devices other than oral contraceptives experienced a significant increase in their sexual behavior at the time of ovulation. This peak was statistically significant for all female-initiated behavior, including both autosexual and female-initiated heterosexual behavior, but was not present for male-initiated behavior except under certain conditions of contraceptive use. Previous failures to find an ovulatory peak may be due to use of measures of sexual behavior that are primarily determined by initiation of the male partner. Women using oral contraceptives did not show a rise in female-initiated sexual activity at the corresponding time in their menstrual cycles, probably owing to the suppression of ovulatory increases in hormone secretion by the oral contraceptives.

Adult↗
PubMed1978

Reexamining barriers to women's career development.

This paper reviews recent literature concerned with beliefs and values relevant to women's careers. Changes in sex-role stereotyping, potential problems relating to affirmative action programs, and the conflict between "counter-culture" values and values of the women's liberation movement are discussed.

Achievement↗
PubMed1975

Cognitive and hormonal factors accecting coital frequency.

Sexual behavior of female undergraduates was assessed by daily questionnaries. Of the 24 subjects, 13 were taking oral contraceptives ("pill" subjects) and 11 were using other methods of birth control ("nonpill" subjects), primarily diaphragm or male prophylactic methods. Three main results were obtained: (1) Intercourse rates were lowest during menstruation and highest immediately following menstruation. (2) Self-rated sexual arousal on a given day correlated with the type of heterosexual encouters on that day rather than with period of the menstrual cycle. (3) Pill subjects reported intercourse on more days than nonpill subjects but reported a lower number of intercourse sessions on day with intercourse than nonpill subjects. These results are interpreted within a general framework of sexual behavior which recognizes the sexual behavior of humans as primarily influenced by cultural and cognitive factors. The possibility is discussed that female sexual behavior might also be found to be affected by hormones if more sensitive measures were used.

Adolescent↗