Cerebral blood flow (CBF) and its response to hypercapnia were evaluated in cats with brainstem transected either at rostropontine (pretrigeminal preparation) or prepontine (cerveau isole preparation) level. Additionally, the effect of pentobarbital on CBF response to hypercapnia and to papaverine were examined. CBF was measured with 133 Xe intracarotid injection method. Cortical EEG activity w...

BACKGROUND AND PURPOSE The present study examined the relationship between circulatory and metabolic reserve in patients with hemodynamic impairment. METHODS Positron emission tomography was used to investigate 40 patients with major cerebral artery occlusive disease. The ratio of cerebral blood volume to cerebral blood flow (CBV/CBF) and vasoreactivity in response to hypercapnia (%CBF(hyperc...

The role of prostaglandins in maintenance of resting cerebral blood flow (CBF) and in cerebral vaso­ dilatation during hypercapnia remains controversial. The effect of indomethacin, a cyclo-oxygenase inhibitor, on CBF and cerebrovascular resistance (CVR) was exam­ ined in conscious animals. Regional and total CBF were measured with radioactive microspheres, and the efficacy of blockade of prost...

BACKGROUND The aim of this study is to investigate the effect of acute hypercapnia on surgery outcomes among patients receiving bronchoscopic interventions under general anesthesia. Furthermore, independent predictive factors for surgery complications were analyzed. METHOD A total of 323 patients with airway stenosis were enrolled in this retrospective study. Each patient underwent interventi...

In rats, chronic hypercapnia has been reported to ameliorate hypoxia-induced pulmonary hypertension in newborn and adult and to enhance endothelium-dependent vasorelaxation in adult pulmonary arteries. The underlying mechanisms accounting for chronic hypercapnia-induced improvements in pulmonary vascular function are not understood. Hypothesizing that downregulation of arginase activity may be ...

BACKGROUND In patients with cystic fibrosis (CF), it has been proposed that hypoxemia and hypercapnia occur during episodes of stress, such as exercise and sleep, and that respiratory muscle weakness because of malnutrition may be responsible. METHODS Pulmonary function, respiratory muscle strength, and nutrition were assessed and correlated with the degree of hypoxemia and hypercapnia during...

The effects of hypercapnia on enhancement of reduced cerebral perfusion were re-evaluated in areas of ischemia produced by occlusion of the canine middle cerebral artery. Perfusion was measured by 85Kr (beta-ray) and 133Xe (gamma-ray) clearances, fluorescein angiography and diameter measurement of arteries. Between 45 and 55 mm Hg of PaCO2 rCBF measured with both isotopes increased significantl...

The carotid bodies respond to changes in arterial O(2), CO(2), and pH, and Ca(2+) influx via voltage-gated Ca(2+) channels is an important step in the chemoreception process. The objectives of the present study were as follows: 1) to determine whether hypercapnia modulates Ca(2+) current in glomus cells, and if so, to determine if this modulation is secondary to changes in pH; 2) to examine the...

AIMS Non-invasive positive pressure ventilation rapidly improves the symptoms of acute heart failure (AHF). A portion of patients, however, are forced to be intubated even though intubation is associated with serious complications, and hypercapnia is often observed in AHF requiring intubation. The purpose of this study is to examine the clinical profile and management of hypercapnia in AHF pati...

Chronic hypoxia causes oxidative injury of pulmonary vessels and attenuates their reactivity to different stimuli. When combined with hypercapnia, biochemical markers of this injury are reduced but the effect of concomitant hypoxia and hypercapnia on vascular reactivity is not fully understood. This study was therefore designed to test whether hypercapnia can prevent also the hypoxia-induced lo...