Dishemoglobinemias

Question 1

Hyperbaric Oxygen

Answer 1

Prevents lipid peroxidation (?) and delayed neurologic sequelae in CO poisoning

Question 2

Nitrites

Answer 2

Turns RBC hemoglobin to methemoglobin; CN moves from Fe(3+) on cytochromes to those in RBCs creating cyanomethemoglobin. Dangerous in concurrent CO poisoning

Question 3

Sodium Thiosulfate

Answer 3

Enhances normal metabolism of cyanide via rhodanase

Question 4

Hydroxycobalamin

Answer 4

Binds with cyanide –> cyanocobalamin (B12). Smoke inhalation victims not improving with supportive care, cyanide exposure, nitroprusside at risk patients . Give concurrently with sodium thiosulfate

Question 5

Methylene Blue

Answer 5

Cofactor of NADPH reductase; gains electron, donates directly to reduce methemoglobin. Methemoglobinemia >20-30%, or with symptoms . Hemolytic anemia (weak oxidizing capability). Painful at injection site, dyspnea, restlessness, tremor, precordial pain, and apprehension.