Mechanisms of cyanosis Caused by absolute increase of amount of reduced Hb in blood, usually 5g/dl(capillary) The higher the hemoglobin concentration The greater tendency toward cyanosis gdI 20 18 16 15 口 Total Hb 12 □R-Hb 10 8 b orm Polycythemia Anemia
15 5 20 5 5 5 0 2 4 6 8 10 12 14 16 18 20 Total Hb R-Hb Normal Polycythemia Anemia g/dl Mechanisms of Cyanosis Caused by absolute increase of amount of reduced Hb in blood, usually > 5g/dl (capillary) The higher the hemoglobin concentration, The greater tendency toward cyanosis
Clinical Classification Etiology True Cyanosis(increased amount of reduced Hb Central Type Peripheral lype Mixed Type Cyanosis due to abnormal Hb derivatives Methemoglobinemia(高铁血红蛋白血症 Sulfhemoglobinemia(硫化血红蛋白血症
Clinical Classification & Etiology True Cyanosis (increased amount of reduced Hb) — Central Type — Peripheral Type — Mixed Type Cyanosis due to abnormal Hb derivatives — Methemoglobinemia(高铁血红蛋白血症) — Sulfhemoglobinemia(硫化血红蛋白血症)
Cyanosis may be subdivided into central and peripheral types. In the central e the sao is reduced or an abnormal hemoglobin derivative is resent and the mucous membranes p1 and skin are both affected
Cyanosis may be subdivided into central and peripheral types. In the central type, the SaO2 is reduced or an abnormal hemoglobin derivative is present, and the mucous membranes and skin are both affected
PEripheral cyanosis is due to a slowing of blood flow and abnormally great extraction of o2 from normally saturated arterial blood. It results from vasoconstriction and diminished peripheral blood flow, such as occurs in cold exposure, shock, congestive failure, and peripheral vascular disease
Peripheral cyanosis is due to a slowing of blood flow and abnormally great extraction of O2 from normally saturated arterial blood. It results from vasoconstriction and diminished peripheral blood flow, such as occurs in cold exposure, shock, congestive failure, and peripheral vascular disease
Often in these conditions the mucous membranes of the oral cavity or those beneath the tongue may be spared. Clinical differentiation between central and peripheral cyanosis may not always be simple, and in conditions such as cardiogenic shock(心源性休克)with pulmonary edema(肺水肿) )there may be a mixture of both types
Often in these conditions the mucous membranes of the oral cavity or those beneath the tongue may be spared. Clinical differentiation between central and peripheral cyanosis may not always be simple, and in conditions such as cardiogenic shock (心源性休克)with pulmonary edema(肺水肿)there may be a mixture of both types