The separate effects of hypoxia and hypercapnia on the force-velocity relation of rabbit myocardium were compared in 10 papillary or trabecular muscles superfused using control (95% O2-5% CO2), hypoxic (18% O2), and hypercapnic (20% CO2) physiological salt solutions. This level of hypoxia did not irreversibly damage the muscles and reduced peak isometric force by 53 +/- 11%. The level of hyperc...

The alterations in cerebral perfusion with graded hypercapnia were measured in the baboon using the intra-carotid xenon clearance technique. In addition, the tidal percent of COj and the blood flow in the common carotid artery were measured using a capnograph and an electromagnetic flowmeter respectively. The delay times between the induced increments in tidal respiratory percent of CO] and the...

Specimens of the euryhaline elasmobranch, Dasyatis sabina were acclimated to seawater and fresh water, and exposed to normocapnic (air) and hypercapnic (1% CO2 in air) environmental water. Blood pH, PCO2, and [HCO3-], as well as whole-animal net-acid excretion, were measured for up to 24 h of hypercapnia. In a separate experimental series, urine was collected from freshwater acclimated stingray...

INTRODUCTION Severe hypercapnia is a rare but harmful complication of general anesthesia. We report the case of a newborn who developed severe hypercapnia with unknown reasons during general anesthesia but recovered well. This report will advance our understanding about the causes of severe hypercapnia during anesthesia, the possible compensatory mechanisms and the characteristics of neonatal r...

Hypoventilation, associated with hypercapnic acidosis (HCA), may improve outcome in acute lung injury (ALI). We have recently reported that HCA per se protects against ALI. The current study explored whether the mechanisms of protection with HCA were related to acidosis versus hypercapnia. Because CO(2) equilibrates rapidly across cell membranes, we hypothesized that (1) HCA would afford greate...

BACKGROUND In patients with Duchenne muscular dystrophy (DMD), implementation of mechanical ventilation depends on sleep investigation and measurement of CO2 tension. The objective of this cross-sectional study was to determine which noninvasive lung function parameter best predicts nocturnal hypercapnia and diurnal hypercapnia in these patients. METHODS According to transcutaneous CO2 (TcCO2...

The defense of the extracellular pH was evaluated in 17 patients with chronic obstructive lung disease and chronic hypercapnia during superimposed acute respiratory acidosis. In group I the chronic stable state PaC02pH-H01was not defined; in groups IA and II the stable state was defined. Duration of acute acidosis in groups I and IA was 16 and 23i hr, respectively ; in group 11, 30 rain . The d...

We have examined the effects of exposure to chronic maternal anemia, throughout the final one-third of gestation, on postnatal ventilatory and arousal responses to hypoxia, hypercapnia, and combined hypoxia-hypercapnia in sleeping lambs. While resting quietly awake, lambs from anemic ewes had higher arterial PCO(2) levels than control animals during the first 2-3 postnatal wk, but pH, arterial ...

In ten eucapnic patients with chronic obstructive lung disease (COLD) we evaluated the breathing pattern during induced progressive hypercapnia (CO2 rebreathing) and progressive exercise on an ergometric bicycle (30 W/3 min). The time and volume components of the respiratory cycle were measured breath by breath. When compared to hypercapnia, the increase in ventilation (VE) during exercise was ...