Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020440 (hypercapnia)
 7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Arterial blood gases were measured during 7 hours of sleep in 15 patients with severe stable chronic obstructive pulmonary discrease (COPD); 6 awake patients with COPD studies in recumbency for an average of 5 hours served as controls. Mean maximal decrease in arterial oxygen partial pressure (PaO2) (plus or minus SD) was 13.5 plus or minus 3.9 mm Hg for sleeping patients (p less than 0.005) and 5.5 plus or minus 1.7 mm Hg for controls (p less than 0.1), respectively. Changes in pH during sleep were of the magnitude expected with acute changes in arterial carbon dioxide partial pressure (PaCO2) in patients with chronic hypercapnia. Consistent changes in heart rate, respiratory frequency or cardiac rhythm were not observed during sleep. Nocturnal worsening of hypoxemia could be explained by alveolar hypoventilation in six sleeping patients and in five controls; in nine sleeping patients, further impariment of ventilation-perfusion mismatch also contributed to worsening of hypoxemia. There was no relationship between the decrease in PaO2 during sleep and the degree of airways obstruction or the PaO2 level when awake. Because of low PaO2, when awake, a fall in PaO2 during sleep brings values into the steep part of the oxyhemoglobin dissociation curve where slight changes in PaO2 result in marked changes in oxygen content. All patients with COPD whose waking PaO2 was below 60 mm Hg had PaO2 below 50 mm Hg during sleep; nocturnal oxygen therapy should be considered in such patients, particularly in the presence of polycythemia or troublesome right-sided heart failure.
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PMID:Arterial blood gases and pH during sleep in chronic obstructive pulmonary disease. 23 52

A case of primary alveolar hypoventilation is described. Despite characteristic clinical findings, the diagnosis was delayed for 4 years. Alleviation of nocturnal hypoxemia and hypercapnia initially by a rocking bed and subsequently by phrenic nerve stimulation was accompanied by reversal of cor pulmonale and polycythemia. Electrophrenic respiration is an effective form of long-term management in primary alveolar hypoventilation.
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PMID:Primary alveolar hypoventilation treated with nocturnal electrophrenic respiration. 30 26

Persons residing at high altitude who develop excessive polycythemia are more hypoxemic than normal high-altitude residents. We investigated the causes of hypoxemia in 20 patients with excessive polycythemia residing at an altitude of 3,100 m. Lung disease evidenced by abnormal spirometric features and results of a respiratory questionnaire was present in 10 of 20 patients and resulted in increased alveolar-arterial difference for PO2 [(A-a)PO2]. The excessive hypoxemia in the patients with normal lungs was not due to increased (A-a)PO2. We measured ventilatory responses to hypoxia and to hypercapnia to determine whether blunting of these responses was a cause of this excessive hypoxemia. We found, however, that chemical drives to breathe, although blunted, were the same in patients with polycythemia as in high-altitude control subjects. However, an abnormal breathing pattern was observed; the polycythemic patients had a smaller tidal volume and a greater ratio of dead space to tidal volume than did the normal subjects. In addition, the polycythemic patients had increased minute ventilation on breathing 100 percent O2, whereas the normal subjects did not. Thus, hypoxic depression of ventilation may have been present. Our findings suggested that blunted chemical drives are not causative in this disease, and that some other cause of hypoxemia must be present.
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PMID:Excessive polycythemia of high altitude: role of ventilatory drive and lung disease. 70 89

Ten patients with the Pickwickian syndrome, characterized by obesity, hypoxemia, hypercapnia, polycythemia, and cor pulmonale, underwent long-term treatment as outpatients with medroxyprogesterone acetate. Although there was no significant weight change in the group, PaO2 rose 12.6 +/- 2.7 mm Hg (SEM) from 49 +/- 2.6 mm Hg to 62 +/- 2.3 mm Hg (P less than 0.001), while PaCO2 fell 13 +/- 2.6 mm Hg from 51 +/- 1.9 mm Hg to 38 +/- 1.2 mm Hg (P less than 0.001). Hematocrit fell from 56 +/- 2.5% to 50 +/- 1.2%, a mean fall of 6% (P less than 0.01), during medroxyprogesterone acetate therapy. In the 2 patients who had cardiac catheterization before and during medroxyprogesterone acetate therapy, mean pulmonary arterial pressure fell 13 and 19 mm Hg. There were no recurrences of cor pulmonale during treatment. These effects on arterial blood gas values and clinical state were sustained during therapy. On withdrawal of medroxyprogesterone acetate during 1-month period, arterial oxygen and carbon dioxide tensions deteriorated to their previous pretreatment values. Reinstitution of medroxyprogesterone acetate caused improvement in both the oxygen and carbon dioxide tensions. We conclude that sublingual medroxyprogesterone acetate therapy is useful in the management of the Pickwickian syndrome.
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PMID:Progesterone for outpatient treatment of Pickwickian syndrome. 110 59

Most patients with extreme obesity do not exhibit alveolar hypoventilation, but an intriguing minority do. The mechanism(s) of this phenomenon remain unknown. A disorder in ventilatory control has been suggested as a major factor in the pathogenesis of the obesity-hypoventilation syndrome. Accordingly, hypoxic and hypercapnic ventilatory drives were measured in 10 patients with the typical symptoms of the syndrome: obesity, hypersomnolence, hypercapnia, hypoxemia, polycythemia and cor pulmonale. Hypoxic ventilatory drive, measured as the shape parameter A, averaged 21.9 +/- 5.35, approximately one-sixth that in normal controls, A = 126 +/- 8.6 (P less than 0.01). The ventilatory response to hypercapnia also was markedly reduced, the slope of the response averaging 0.51 +/- 0.005, or about one-third the normal value of 1.83 +/- 0.13 (P less than 0.01). This decreased responsiveness in hypoxic and hypercapnic ventilatory drive was consistent throughout the group. The depression in ventilatory drive found in the obesity-hypoventilation syndrome may be causally related to the alveolar hypoventilation manifested by these patients.
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PMID:Decreased hypoxic ventilatory drive in the obesity-hypoventilation syndrome. 116 44

Hilltop (H) and Madison (M) strains of Sprague-Dawley rats exhibit strikingly different susceptibilities to the effects of chronic altitude exposure. The H rats develop greater polycythemia, hypoxemia, and pulmonary hypertension. We studied ventilation, pulmonary gas exchange, tissue oxygenation, and hematologic adaptations in the two rat strains during a 50-day exposure to a simulated altitude (HA) of 5,500 m (18,000 ft). There were no strain differences among the variables we studied under sea level (SL) conditions. Within the first 14 days of hypoxic exposure, the only significant strain differences were that erythropoietin (EPO) rose much higher and erythroid activity was greater in the H rats, even though arterial Po2 and PCo2 (Pao2 and PaCo2, respectively), renal venous PO2 (Prvo2), and ventilation (VE) were equivalent in the two strains during this time. By day 14 at HA, the H rats had significantly higher erythroid activity, hematocrit (Hct), and EPO levels, significantly lower PaO2 and PrvO2, but equivalent VE and PaCO2. These changes persisted for the remainder of the exposure, except that the Hct continued to rise and the increase was greater in H rats. Despite the greater O2-carrying capacity of H rats in the later stages of hypoxic exposure, PaO2 and PrvO2 were significantly lower in H rats. There were no strain differences at either SL or HA in ventilatory responses to hypercapnia or hypoxia, in blood O2 affinity or 2,3-diphosphoglycerate, in extrarenal production of EPO, or in EPO clearance. We conclude that early in the hypoxic exposure the H rats produce more EPO at apparently equivalent levels of hypoxia, and this is the first step in the pathogenesis of the maladaptation to HA manifest by H rats. We find no consistent evidence that differences in VE contribute to the variable susceptibility to hypoxia in the two rat strains.
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PMID:Ventilatory and hematopoietic responses to chronic hypoxia in two rat strains. 162 91

Cor pulmonale is right ventricular enlargement secondary to pulmonary hypertension. Although most often caused by parenchymal lung disease, derangements of the ventilatory drive, the respiratory pumping mechanism, or the pulmonary vascular bed may also result in right ventricular hypertrophy and dilatation. Arterial hypoxemia (and resultant polycythemia), hypercapnia, and respiratory acidosis all contribute to the increased afterload on the right ventricle. Diagnosis is often difficult, since pulmonary vascular disease, pulmonary hypertension, and cor pulmonale have few specific manifestations, especially early in their evolution. Treatment is primarily directed at the underlying pulmonary or ventilatory disorder, rather than at the right ventricular failure per se. Supplemental oxygen is essential to avoid hypoxia; corticosteroids, anticoagulants, vasodilators, and other specific therapies are used as indicated to treat the underlying pulmonary disorders. When medical therapies fail, lung or heart-lung transplantation has become a possibility for selected patients.
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PMID:Chronic cor pulmonale. Etiology and management. 239 36

A 62 year-old woman with a bilateral carotid body paraganglioma presented, 2 years after the removal of the right one, with signs of right-heart failure. Hypoxemia, hypercapnia, polycythemia and pulmonary hypertension with normal ventilatory capacity were found. Central alveolar hypoventilation was diagnosed on the basis of absence of ventilatory response and sensation of provoked hypercapnia, prolonged breath-holding time and correction of hypercapnia by voluntary ventilation. Progesterone (200 mg/d during 3 weeks) or naloxone did not improve either arterial blood gases (ABG) or the P 0.1/PCO2 curve. Hypoxemia and hypercapnia were not corrected during metabolic acidosis provoked by acetazolamide (250 mg/d). Nasal CPAP did not control hypoventilation periods. Mechanical ventilation was initiated with negative pressure (NPV) through a poncho. The patient presented severe discomfort with NPV and obstructive apneas were verified during it. She refused to continue NPV. Mechanical ventilation was initiated with positive intermittent pressure (IPPV) through a nasal mask. The patient had excellent tolerance to the procedure. SpO2 during IPPV was always higher than 95%. During sleep induction (under IPPV), respiration in phase with the ventilator 1: 1 was observed; instead, during consolidated sleep there was a complete dependence of the ventilator with apnea for over 2 min when IPPV was interrupted (Fig. 1). After 2 months of treatment, a relief of right ventricular failure occurred and hematocrit fell to 39%. There was an improvement of day-time ABG (Table I). The P. 0.1/PaCO2 curve 3 months after IPPV was the same as the previous one (Fig. 2). The patient has been for 18 months on home ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Central alveolar hypoventilation with cor pulmonale: successful treatment by non-invasive intermittent positive pressure ventilation]. 771 33

A 62-year-old woman with a bilateral carotid body paraganglioma presented, 2 years after the removal of the right one, with signs of right-heart failure. Hypoxemia, hypercapnia, polycythemia and pulmonary hypertension with normal ventilatory capacity were found. Central alveolar hypoventilation was diagnosed on the basis of absence of ventilatory response and sensation to provoked hypercapnia, prolonged breath-holding time and correction of hypercapnia by voluntary hyperventilation.
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PMID:Bilateral carotid body paraganglioma and central alveolar hypoventilation. 826 82

We report on a 45-year old woman with daytime sleepiness, polycythemia, hypoxemia and hypercapnia, admitted to hospital on three occasions in a 10 month period for acute respiratory failure. Polysomnography demonstrated apneas of central type, testing of the respiratory drive suggested central alveolar hypoventilation and magnetic resonance imaging showed an Arnold-Chiari malformation with syringomyelia. The originality of this case is the absence of any neurologic sign, respiratory failure being the sole manifestation of the Arnold-Chiari malformation.
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PMID:[Isolated respiratory insufficiency in Arnold-Chiari malformation]. 892


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