It is generally accepted that progressive cooling of global climate since the Late Cretaceous results from decreasing partial pressure of atmospheric CO2 (pCO2). However, details on how and why the carbon cycle evolved and how it would affect pCO2 have not been fully resolved. While the long-term decline of pCO2 might be caused by the decrease of volcanic degassing through the negative feedback...

INTRODUCTION This prospective non-interventional study intended to assess the prognostic value of gastric intramucosal acidosis in patients with severe trauma admitted to a medical/surgical ICU. METHODS Gastric tonometer catheters were introduced to measure air PCO2 level (Tonocap device) in forty consecutive critically ill trauma patients. Gastric intramucosal pH, air PCO2 gradient, lactate ...

INTRODUCTION We conducted the present study to investigate whether early large-volume crystalloid infusion can restore gut mucosal blood flow and mesenteric oxygen metabolism in severe sepsis. METHODS Anesthetized and mechanically ventilated male mongrel dogs were challenged with intravenous injection of live Escherichia coli (6 x 10(9) colony-forming units/ml per kg over 15 min). After 90 mi...

Rising CO2 concentrations may have large effects on aquatic microorganisms. In this study, we investigated how elevated pCO2 affects the harmful freshwater cyanobacterium Microcystis aeruginosa. This species is capable of producing dense blooms and hepatotoxins called microcystins. Strain PCC 7806 was cultured in chemostats that were shifted from low to high pCO2 conditions. This resulted in a ...

BACKGROUND Arterial blood gas (ABG) analysis is useful in evaluation of the clinical condition of critically ill patients; however, arterial puncture or insertion of an arterial catheter may cause many complications. The aim of this study was to determine whether venous blood gas (VBG) values can be used as an alternative to arterial blood gas measurements in patients under mechanical ventilati...

The role of the carotid bifurcation chemoreceptors in mediating the cerebrovascular response to altered arterial PCO2 has been suggested to be large. In the present study the cerebrovascular response to raised PCO2 was measured in a group of baboons before and after bilateral inactivation of the carotid bodies. The results suggest that these chemoreceptors do play a part in the cerebral vasodil...

Intramucosal-to-arterial carbon dioxide difference (the so-called PCO2 [partial carbon dioxide tension] gap) remains largely unaltered during decreased oxygen delivery, if the latter is reduced as flow is maintained. In this condition (hypoxic hypoxia or anaemic hypoxia), the PCO2 gap fails to mirror intestinal tissue dysoxia. Results from several experiments have demonstrated that blood flow i...

Mean inspiratory flow, occlusion pressure and end-tidal PCO2 were measured in six healthy, sitting subjects, during breathing air and rebreathing carbon dioxide, before and after pentazocine 0.5 mg kg-1 i.v. and again after naloxone 20 micrograms kg-1. Pentazocine reduced the occlusion pressure and inspiratory flow responses at a given PCO2 during carbon dioxide rebreathing and these effects we...

Measuring PCO2 (partial pressure of carbon dioxide) in an organ can enable early detection of ischemia. However, there are few clinical applicable solutions for measuring PCO2. Based upon the requirement for clinical applications, a conductivity based PCO2 sensor is proposed. A conductivity based PCO2 sensor measures conductance in an aqueous solution separated from the measured object by a gas...

The effects of changes in peritubular pH, carbon dioxide tension (PCO2), and HCO3- concentration on net HCO3- transport was examined in in vitro perfused cortical collecting tubules (CCTs) from unpretreated New Zealand white rabbits. Lowering peritubular HCO3- concentration and pH by reciprocal replacement of HCO3- with Cl-, significantly stimulated net HCO3- absorption. Lowering peritubular HC...