Arterial carbon dioxide

Paco2 partial pressure of arterial carbon dioxide... 

Respiratory acidosis and alkalosis result from primary disturbances in the arterial carbon dioxide (C02) levels. Metabolic compensation of respiratory disturbances is a slow process, often requiring days for the serum HC03 to reach the steady state. 

MRSA Methicillin-resistant Staphylococcus aureus Paco2 Arterial carbon dioxide tension... 

Chemoreceptors. The peripheral chemoreceptors include the carotid bodies, located at the bifurcation of the common carotid arteries, and the aortic bodies, located in the aortic arch. These receptors are stimulated by a decrease in arterial oxygen (hypoxia), an increase in arterial carbon dioxide (hypercapnia),... 

A summary of the responses of the peripheral and the central chemoreceptors to reduced arterial oxygen, increased arterial carbon dioxide, and increased arterial hydrogen ion concentration is found in Table 17.2. 

Respiratory acid-base disorders are caused by altered alveolar ventilation producing changes in arterial carbon dioxide tension (PaC02). Respiratory acidosis is characterized by increased PaC02, whereas respiratory alkalosis is characterized by decreased PaC02. 

Nitrous oxide decreases tidal volume and increases the rate of breathing and minute ventilation. Although arterial carbon dioxide partial pressures tend not to be affected the normal ventilatory responses to carbon dioxide and to hypoxia are depressed. Alveolar collapse in structured lung segments may be more rapid in the presence of nitrous oxide than with oxygen due to its greater solubility. Similarly, it depresses mucous flow and chemotaxis. In theory these factors predispose to postoperative respiratoiy complications. 

Patients with severe COPD can have a low arterial oxygen tension (Pa02 45 to 60 mm Hg) and an elevated arterial carbon dioxide tension (PaC02 50 to 60 mm Hg). Hypoxemia results from hypoventilation (V) of lung tissue relative to perfusion (Q) of the area. The low V Q ratio progresses over several years, resulting in a consistent decline in the Pa02. 

FEVi forced expiratory volume at 1 second FVC forced vital capacity Pa02 partial pressure of arterial oxygen PaC02 partial pressure of arterial carbon dioxide SLPI secretory leukocyte protease inhibitor UTP uridine triphosphate... 

Measurements of rCBV in man by PET not only reveal the expected regional difiFerences due to difiFerences in vascular density between grey and white matter, but also provide a clear delineation of the major vascular structures, primarily venous, surrounding the brain. Furthermore, the responsiveness of the cerebral blood volmne to changes in arterial carbon dioxide tension observed with emission tomography compare favorably with such measurements obtained by a variety of other such techniques (10). 

Abbreviations Pac02, arterial carbon dioxide pressure COPD, chronic obstractive pulmonary disease. 

In healthy volunteers, acute increases of arterial carbon dioxide to 54 mmHg (corresponding to a pH of about 7.29) reduces the capacity of the unfatigued diaphragm to generate pressure by 10-30% (Fig. 12) (98). This direct inhibitory effect of respiratory acidosis on respiratory muscle function could provide a potential mechanism for the rapid clinical deterioration that can occur with severe asthma and during COPD exacerbations (98). Yet, the human data suggesting a direct deleterious effect of respiratory acidosis on respiratory muscle function... 

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