Arterial oxygen pressure

PaOa Arterial oxygen pressure PGP Protein gene-related peptide Ph Philadelphia (chromosome)... 

Patients may present with PEF rates greater than 80% and oxygen saturation greater than 95% in mild exacerbations to PEF rates less than 50%, oxygen saturations less than 91%, partial arterial oxygen pressures (Pao2) less than... 

Hypoxia A pathologic condition in which the body (generalized hypoxia) or region of the body (tissue hypoxia) is deprived of adequate oxygen supply (partial arterial oxygen pressure less than 80 mm Hg). Hypoxia in which there is complete deprivation of the oxygen supply is referred to as anoxia. 

Arterial oxygen pressure (Pa02) and saturation (Sa02) may be measured invasively by obtaining an arterial blood sample. Arterial blood gases measured by conventional arterial sampling are considered... 

FIGURE 9 The effects of 80-ppm nitric oxide (NO) inhalation in six patients with transient graft dysfunction after lung transplantation. Pulmonary artery pressure (PAp), pulmonary vascular resistance index (PVRI), and intrapulmonary shunt fraction (Qs/Qt) decreased significantly, while arterial oxygen pressure (PaOi increased. [Adapted and reproduced with permission from Adatia et al. (77).]... 

DHPs are potent arterial vasodilators. They act on resistance vessels and therefore reduce peripheral vascular resistance, lower arterial blood pressure, and antagonize vasospasms in coronary or peripheral arteries. By reducing afterload, DHPs also reduce cardiac oxygen demand. Together with their vascular spasmolytic effect, this explains most of the beneficial actions of DHPs in angina pectoris. Most DHPs are only licensed for the therapy of hypertension, some of them also for the treatment of angina pectoris and vasospastic (Prinzmetal) angina. 

Snider, G. L. Interpretation of the Arterial Oxygen and Carbon Dioxide Partial Pressures A Simplified Approach for Bedside Use. Chest (1973), 6, 801 - 806. 

The partial oxygen pressure, p02, is particularly significant in metabolic processes of cells, and its variation from normal values often indicates pathologies (ischemic diseases, strokes, tumors). Accurate and localized measurements of the oxygen concentration are also desirable for differentiation between venous and arterial blood, or for cerebral mapping of task activation. In the past, invasive methods were used involving oxygen-sensitive electrodes which had to be placed directly in the blood or tissue and could only offer p02 from a few body points. 

Respiratory alkalosis is associated with low partial pressure of02 (25 to 35 mm Hg) and alkaline pH, but normal bicarbonate. The first two values are measured by arterial blood gas, which also yields partial pressure of carbon dioxide and arterial oxygen saturation. Circulating arterial oxygen saturation can also be measured by an oximeter, which is a noninvasive method that is fairly accurate and useful at the patient s bedside. 

HCO3, bicarbonate Pco2, partial pressure of carbon dioxide Po2, partial pressure of oxygen Sa02, saturation of arterial oxygen. 

Vincamine (91) is the major alkaloid of V. minor, a plant used against headache and vertigo. It exerts a sedative CNS action and produces a fall in blood pressure. The principal activity is a moderate cerebral vasodilation. Clinical studies have demonstrated that i.v. administration of 91 to humans reduces the arterial blood pressure and increases cerebral blood flow and oxygen consumption. The improved cerebral hemodynamic conditions significantly and positively affect the state of patients with advanced arteriosclerosis with beneficial effects on memory, concentration, and behavior. It has thereafter been introduced under several trade names as a pharmaceutical in many European countries (232). Vobasine (32) has been widely studied it exhibits a weak CNS depressive, analgesic, and antipyretic action (21). 

The integrated function of the vasculature and heart, as a closed circulatory system, supplies nutrients and oxygen to critical organs and removes metabolic wastes and carbon dioxide. This integrated system results from the careful control of cardiac output, arterial blood pressure (systolic and diastolic pressures integrated to derive mean arterial pressure), and systemic vascular resistance, thereby maintaining blood perfusion through... 

Nifedipin causes relaxation of smooth musculature, dilation of coronary and peripheral arteries, and reduction of peripheral resistance and arterial blood pressure, and enhances oxygen supply to the heart. 

Arterial blood pressure (afterload) is also reduced by propranolol. Although the mechanisms responsible for this antihypertensive effect are not completely understood, they are thought to involve (1) a reduction in cardiac output, (2) a decrease in plasma renin activity, (3) an action in the central nervous system, and (4) a resetting of the baroreceptors. Thus, propranolol may exert a part of its benehcial effects in secondary angina by decreasing three of the major determinants of myocardial oxygen demand, that is, heart rate, contractihty, and systolic wall tension. 

In the lungs, NO affects not only blood vessels but also the bronchi and bronchioles as well. In newborns with defective gas exchange, NO inhalation decreases pulmonary arterial blood pressure, enabling more blood to be oxygenated. In adults with obstructive lung diseases, NO inhalation seems to relax airway smooth muscle, thus acting as a bronchodilator. 

The most prominent effect of halothane on the circulation is a dose-related decrease in arterial blood pressure. This is due mainly to reduced myocardial contractility and ventricular slowing. Cardiac output falls due to a decrease in stroke volume and bradycardia. Systemic vascular resistance also falls but this is less pronounced than with some other agents. Although halothane reduces myocardial oxygen consumption it also reduces oxygen demand and it is suitable for patients with myocardial ischaemia. 

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