呼吸科呼吸系统课件3.pptVIP

Summaries on Gas Exchange and Gas Transport-Continued As a product of non-complete combustion, CO is dangerous to life. It binds to Hb in a competitive manner. The binding affinity for Hb is 250 times higher than that of oxygen’s. PaO2 is normal, so there is lack of feedback mechanism to indicate that oxygen content is low. The appropriate treatment is the administration of high concentration of oxygen; high CO2 may be helpful in the case of spontaneous breathing is still existed. * * Summary on Oxygen Transport Oxygen is transported by the blood in two forms: oxyhemoglobin and physically dissolved. The relationship between oxygen partial pressure and the saturation of hemoglobin is the oxygen dissociation curve. Changes in blood chemistry (pH, PaCO2, temperature and 2.3-DPG) alter oxyhemoglobin equilibrium curve. P50 is a measure of Hb affinity to bind oxygen. When Hb affinity increases, the P50 changes in the opposite direction. * * Summary on Carbon Monoxide As a product of non-complete burn, CO is odorless, colorless, and non-irritating gas; it is virtually undetectable. It binds to Hb at the same site as oxygen does. The binding affinity for Hb is 210 times as that of oxygen’s. PaO2 is normal, so there is lack of feedback mechanism to indicate that oxygen content is low. The appropriate treatment is the administration of high concentration of oxygen; high CO2 may be helpful in the case of spontaneous breathing is still existed. * * Summary on Gas Transport-Carbon Dioxide Carbon dioxide is transported in three distinct forms: Dissolved (10%) Bicarbonate in the plasma and in the red cells (60%) Hemoglobin (carbamino proteins, 30%) * * * 5.3. Gas transport Oxygen is transported by the blood in both physically dissolved and hemoglobin-bond forms. Carbon monoxide binds the same site on hemoglobin as oxygen does and is dangerous to life. Carbon dioxide (CO2) is transported in three forms: physically dissolved, bicarbonate, and carbaminohemoglobin * * Oxyge