Biomedical subjects
M Kryger
Publications and source records attributed to M Kryger.
Clinical semi-starvation: depression of hypoxic ventilatory response.
A decreased metabolic rate has been associated with decreased ventilatory response to hypoxia and hypercapnia, and also with starvation. We fed a 500-calorie carbohydrate diet with supplemental electrolytes, designed to simulate alimentation by usual intravenous fluids, to seven normal subjects for 10 days to determine the effect of semi-starvation on metabolic rate and ventilatory responses. By the 10th day metabolic rate was significantly decreased, and hypoxic ventilatory response decreased to 42% of control (P less than 0.05). In two subjects, hypoxic ventilatory response was virtually abolished at day 10. These changes reversed toward normal with refeeding. The decrease in hypoxic ventilatory response response was significantly (P less than 0.01) related to the decrease in metabolic rate. Hypercapnic ventilatory response, measured as the slope of the ventilatory response to hypercapnia, decreased slightly but not significantly. The decrease in hypoxic ventilatory response seen during semi-starvation may contribute to the hypoxemia and respiratory failure subsequent to caloric restriction.
Diagnosis of obstruction of the upper and central airways.
Patients with obstruction of the upper airways are often treated for long periods of time for other disorders. Correct diagnosis is important since treatment is quite specific. Such patients may present with a characteristic history and findings on physical examination. Certain physiologic tests such as flow-volume loops with and without helium help to prove the diagnosis. Patients with upper airway obstruction may also have sleep apneas and the sleep deprivation syndrome. Methods of diagnosis of upper airway obstruction are presented and three instructive cases are reviewed.
The sleep deprivation syndrome of the obese patient. A problem of periodic nocturnal upper airway obstruction.
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Effect of gas density and expiratory flow on "closing volume".
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Gas diffusion across collateral channels.
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Successful treatment of comorbid panic disorder and sleep apnea with continuous positive airway pressure.
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