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XXXVIII.f

XXXVIII - Miscellaneous - Varia

Cyanosis, a low SpO2 and normal measured PaO2

Last update 08/01/2021

See also under XIVa, b, e. Cyanosis is slate-greay rather that purple. SpO2 is low or spurious/erratic. Cyanosis is resistant to oxygen therapy. SpO2 low or spurious. PaO2 measured by the Clarke electrode is normal. The hallmarks of methemoglobinemia. Diagnosis is confirmed by chocolate-brown color of blood; which does not turn bright red when bubbled with O2 and/or by spectrophotometric measurement of blood methemoglobin (normally <2%). Four-wavelength pulse CO-oxymetry can also measure methemoglobin and COHb. Methemoglobinemia can be life-threatening or fatal if >40%. Treatment is with oxygen and methylene blue. Severe cases may require HBO or exchange transfusion. Oxidant-induced hemolytic anemia can be found in association.

Causative drugs

Frequency - Incidence

Incidence of cardiac adverse event(s) due to the specific drug as assessed by number of reported/published cases in the literature. Red digits in stars indicate: 0 = Very rare, questionable signal · 1 = < 10 cases · 2 = 10-50 cases · 3 = 50–100 cases · 4 = 100-200 cases · 5 = >200 cases

Evidence level/grade

Evidence level for cardiac adverse event(s) due to the specific drug as estimated using Hill’s (1965), Naranjo’s (1981), and Bégaud’s (1985) criteria applied to published cases. Blue digits in stars indicate: 0 = Questionable · 1 = Low · 2 = Moderate · 3 = Robust · 4 = Definite · 5 = Unquestionable, pathognomonic