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Query: UMLS:C0085383 (hypocapnia)
 1,697 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of respiratory gas mass-transfer by high-efficiency hemodialyzers with regard to respiratory status and acid-base balance were studied in three groups of patients. Patients dialyzed with acetate dialysate and a single pass delivery system (group I) and those dialyzed with the same dialysate and a recirculating single pass system (group II) had significant intradialytic decreases in PCO2 (p is less than 0.05), while patients hemodialyzed aginst a carbon dioxide/bicarbonate dialysate (group III) had no significant alterations in arterial PCO2. The massfransfer rate of carbon dioxide was 0.3 mM/min in group I and 0.2 mM/min in group II. The hypocapnia caused by dialyzer mass-transfer of carbon dioxide was associated with a significant drop in minute ventilation volume and a decrease in PO2 which was significant in group I (p is less than 0.05). Although bicarbonate mass-transfer reduced serum bicarbonate levels, the loss of carbon dioxide to the dialysate resulted in an increased arterial pH during dialysis.
Nephron 1978
PMID:Respiratory gas exchange by high-efficiency hemodialyzers. 67 97

In Wistar rats exposed during one hour to mixtures of oxygen and carbon dioxide producing hypoxia, hypercapnia, hyperoxia and hypocapnia, and so on, adrenaline contents of the suprarenals is reduced by high concentration of carbon dioxide (30%), with or without hypoxia. Noradrenaline contents is increased by carbon dioxide (15 to 30%). Hypercapnia is more potent than hypoxia as a suprarenal stimulus.
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PMID:[CO2 and the catecholamine content of the adrenal medulla of the rat]. 644 72

A high frequency of metabolic acidosis in a group of 30 patients on regular dialysis treatment initiated a study of the effect (and possible side effects) of a higher concentration of acetate in the dialysate. The concentration of acetate in the dialysate was increased from 32.6 ('low ac') to 38.2 mmol/l ('high ac'). The 'low ac' dialysis treatment changes the metabolic acidoses (mean pH = 7.34; base excess, BEb = - 8.3 mmol/l) to chronic hypocapnia (pH = 7.40; BEb = - 5.4 mmol/l). 'High ac' normalized the acid base status (pH = 7.44; BEb = -0.6 mmol/l). No side effects occurred. Since PaCO2 does not change much during hemodialysis it is convenient to look at the linearly related changes of the pH and the logarithmic standard bicarbonate concentration along iso-PCO2 lines in a log standard bicarbonate-pH-nomogram.
Nephron 1981
PMID:Improved effect of hemodialysis on acidemic patients from an acetate concentration of 38 mmol/l. 678 71

Chronic episodic hypoxia produces a wide array of cardiovascular dysfunctions in rats, including increases in blood pressure, heart rate, and sympathetic nerve activity. The action of episodic hypoxia might be related to low oxygen itself (hypoxemia) and/or combined with low CO2 (hypocapnia) resulting from hyperventilation. It is unknown whether or not the cardiovascular abnormalities are related to alterations in the central nervous system (CNS) that may be manifested as neurotransmitter and/or behavioral changes. In this study, we investigated effects of episodic eucapnic and hypocapnic hypoxia on monoamine metabolism in both CNS and adrenal glands, and on motor behavioral activity. Thirty-five male rats were divided into 3 groups. Experimental rats were exposed 8 h daily to varying fractional concentrations of inspired oxygen (FiO2) and carbon dioxide (FiCO2) for 35 days. These consisted of brief exposures (3-6s) of episodic (twice every min) eucapnic (3.5% FiO2 and 10% FiCO2, n = 6) or hypocapnic (3.5% FiO2 and 0% FiCO2, n = 14) hypoxia, or room air (21% FiO2 and 0.03% FiCO2, n = 15). Norepinephrine, dopamine, serotonin, and their metabolites in the hypothalamus, hippocampus, and adrenal glands were measured by high-performance liquid chromatography (HPLC). Spontaneous behavioral activity was assessed for 30 min by automated activity monitors. Episodic hypocapnic hypoxia produced a decrease in dopamine turnover and eucapnic hypoxia increased norepinephrine levels in the hypothalamus. Animals exposed to hypocapnic hypoxia also exhibited a consistent increase in horizontal (walking) and vertical (rearing) activity, as well as in total activity time. From these results, it is concluded that episodic eucapnic and hypocapnic hypoxia may affect metabolism of different neurotransmitters in the CNS.
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PMID:Effects of chronic episodic hypoxia on monoamine metabolism and motor activity. 888 35

Hypoventilation increases PaCO(2) (hypercapnia) and initiates the acid-base disorder known as respiratory acidosis. Hyperventilation decreases PaCO(2) (hypocapnia) and initiates the acid-base disorder known as respiratory alkalosis. The impact on acidity of these primary changes in PaCO(2) is ameliorated by secondary, directional changes in plasma bicarbonate concentration that occur in two stages. Acutely, modest changes in plasma bicarbonate originate from titration of the body's nonbicarbonate buffers. In chronic hypercapnia and hypocapnia, larger changes in plasma bicarbonate occur that reflect adjustments in renal acidification mechanisms. As a result, the amelioration of systemic acidity is more pronounced in the chronic forms of the respiratory acid-base disorders.
Nephron Physiol 2003
PMID:Cross-talk between two organs: how the kidney responds to disruption of acid-base balance by the lung. 1266 Apr 92