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6 Cards in this Set
- Front
- Back
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(Hayes)
In regards to Methaemoglobinaemia, which of the following is correct? A. The normal form of iron in haemoglobin is the ferric 3+ form B. The ferrous form cannot carry oxygen C. Methylene blue acts as a co-factor for the minor pathway involving NADPH-dependentMetHb reductase D. The normal metHb level is adults is 5% |
C.
A = ferrous 2+ B = Ferric form 3+ cannot carry oxygen D = 1% |
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(Hayes)
Which of the following is not a known acquired cause of methaemoglobinaemia? A. Bupivicaine B. Dapsone C. Phenytoin D. Quinine and chloroquine |
A: Prilocaine ( Amide) and procaine (Ester) are
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(Hayes)
Which of the following is incorrect regarding methaemoglobinaemia? A. Symptoms become apparent at 15% MetHb levels. B. Methaemoglobinaemia interferes with normal pulse oximetry - typically giving a SaO2 reading of 85% C. The dose of methylene blue is 1 mg/kg over 5 minutes D. Alternatives to methylene blue therapy are Hyperbaric oxygen and exchange transfusions. |
A
15% =cyanosis 30% = symptoms ( SOB and tachycardia ) > 60% = seizures / arrhythmias |
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List the drug causes of Methaemoglobinaemia.
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1. Local Anaesthetics [ prilocaine / procaine ]
2. Dapsone 3. Nitrates / Nitrites 4. Rifampicin 5. Sulfurs |
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Which of the following is incorrect regarding methaemoglobinaemia?
A. Methaemoglobin is unable to bind oxygen. B. There is a right shift of the Hb-O2 dissociation curve. C. Tissue hypoxia occurs from the reduced oxygen-carrying capacity of the blood. D. The patient's skin gets a grey-blue discolouration to it. |
B. Left shift
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Which of the following is correct regarding acquired methaemoglobinaemia ?
A. It involves reduction of the iron in the haemoglobin molecule. B. The ferric form (Fe3+) gets converted to the ferrous form (Fe2+) C. The pulse oximeter reports a falsely low value-even though the patient remains hypoxic. D. There is an "increased oxygen saturation gap" in severe methaemoglobinaemia. |
D.
A = oxidising B. The opposite. Ferrous to Ferric C = Falsely normal / elevated value. |
