Previous studies demonstrated that cerebral blood flow (CBF) changes during dynamic exercise and a physiological basis for this observation may be explained by the tight control of CBF by arterial carbon dioxide tension (PaCO2). This study examined whether the steady state of the middle cerebral artery blood flow velocity (MCAVmean) and PaCO2 could be observed during constant work rate cycling ...

1. To study the validity of a CO2-rebreathing method at rest and during graded exercise, cardiac output was measured simultaneously on 59 occasions in 16 subjects with normal pulmonary function with the CO2-rebreathing method and the direct Fick method for oxygen. The correlation coefficient between the results of both methods was significantly higher during exercise than at rest. 2. No systema...

BACKGROUND Various pediatric conditions often necessitate a morphologic examination of the hip joint in infancy or childhood, and multiple imaging options have been employed to achieve this goal. Arthrography is one such modality. Different types of contrast media have been utilized and include pharmacologic contrast agents, air, and carbon dioxide. There are scattered reports of complications ...

To examine the relationship of expired capnograms and respiratory system resistance (Rrs) in intubated critically ill patients, we consecutively studied 41 mechanically ventilated patients to (1) analyze the association between expired CO2 slope and auto-positive end-expiratory pressure (auto-PEEP), between Rrs and auto-PEEP, between Rrs and expired CO2 slope, and between Rrs and arterial minus...

Introduction Magnetic resonance imaging may be used to measure fractional changes in cerebral oxygen metabolism via a metabolic model. One step commonly used in this measurement is calibration with image data acquired during hypercapnia, which is a state of increased CO2 content of the blood. In this study the most commonly used hypercapnia-inducing stimuli were compared in order to assess thei...

Use of waveform capnography during cardiac arrest was recomended in the 2010 International Consensus on Cardiopulmonary esuscitation (CPR) Science with Treatment Recommendations.1 primary benefit includes confirmation that a tracheal tube (or ther airway device) has been placed correctly and is providing entilation of the lungs.2 Capnography is considerably more relible than either clinical ass...

The resting mouth occlusion pressure 0.1 s after onset of inspiration (P0.1) and minute ventilation (V'E) and their response to CO2 in patients with chronic obstructive pulmonary disease (COPD) remain controversial. The ventilatory drive and the factors that predict resting arterial CO2 tension (Pa,CO2) were studied in 19 eucapnic and 14 hypercapnic severe COPD patients, and 20 controls. The CO...

This study investigated the hypothesis that hypercapnia in some chronic obstructive pulmonary disease (COPD) patients may be related to a high cerebrovascular response to carbon dioxide (CO2). The relationship between responses of ventilation and of cerebral blood volume (CBV) to acute changes in carbon dioxide tension in arterial blood (Pa,CO2) was measured in 17 chronic hypercapnic (Pa,CO2 >6...

set ventilators. Objective: To define and characterize the transient re¬ sponse of VCO2 to a well-defined change in ventilation. Methods: Forty-four patients in stable condition re¬ ceiving volume-controlled mechanical ventilation had trend recordings of ventilator pressures, flow, volumes, Vco2, and end-tidal CO2 (ETCO2) for 20 min. At time t0, the minute ventilation was either increased (n=22...

Mathematical models are able to estimate the outcome of a patient to a certain ventilator setting. Employed in a medical decision support system (MDSS) this supports finding the optimum ventilation strategy for patients mechanically ventilated in ICU. Here, knowledge about current blood gas values like end-tidal CO2 (etCO2) is important to asses patient’s status. A model to predict etCO2 respon...