NONPULMONARY FACTORS
Abnormalities other than alterations in lung function may influence the Pao2 through their effect on the mixed venous Po2(Py02). The Pv02 is decreased when cardiac output is inappropriately low, when 02 consumption (Vo2) is increased (as with exercise or fever), or when the hemoglobin concentration or 02 saturation is low. For any lung unit, the resultant end-capillary Po2 is influenced by the Pvo2, although the magnitude of this effect on the arterial 02 content will be greatest in lungs with Va/Q inequality or shunt (Fig. 17-9). The importance of this phenomenon is the recognition that a fall in Pao2 in a patient with lung disease may be due to one of these nonpulmonary factors rather than a deterioration in lung function, thus requiring a very different intervention.
- HEART DISEASE AND PREGNANCY
- ARTERIOSCLEROSIS OBLITERANS
- NONRESPIRATORY FUNCTIONS OF THE LUNG
- RAYNAUD'S PHENOMENON
- GAS TRANSFER
- THROMBOANGIITIS OBLITERANS
- PERIPHERAL ANEURYSMS AMD FISTULAE
- PERFUSION
- VENTILATION
- PERIPHERAL VENOUS DISEASE
- MISCELLANEOUS AORTIC DISEASE
- ARTERIAL TRAUMA
- GENERAL PRINCIPLES OF CARDIAC SURGERY
- THE AIRWAY STRUCTURE
- GENERAL SURGERY IN THE PATIENT WITH HEART DISEASE
- THE BLOOD VESSELS STRUCTURE
- PULMONARY GAS EXCHANGE
- ENVIRONMENTAL DAMAGE OF THE EXTREMITIES
- NONPULMONARY FACTORS