altitude asthma blood vessel blue fugates blue baby syndrome bronchospasm cyan deep vein thrombosis desquamation diaphoresis diffuse sky radiation finger heart failure heart valve hemoglobin hyperesthesia hypoesthesia hypothermia hypoventilation icd induration lip medical sign methemoglobinemia mucous membrane myocardial infarction oxygen saturation oxygenation pallor paresthesia petechia pulmonary embolism rash skin symptom tetralogy of fallot vasoconstriction