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Circulating Methemoblogin Fraction in Dogs With Sepsis

“…Similarly, trends in the occurrence of MODS, renal, respiratory and hemostatic dysfunction appeared higher in cases with methemoglobin above or equal to the identified RI (Table 2), but did not reach statistical significance. Redox mechanisms of sepsis have been implicated in mithocondrial and cellular dysfunction (11), and high circulating methemoglobin fraction has been occasionally associated with organ failure in septic humans (9). It is hard, however, to draw conclusions from these preliminary data in dogs, as methemoglobin fraction was mildly elevated in our population, and the number of cases compared in each group was low.…”

“…Selected subsets of critical care patients (e.g., neonates), however, might be exposed to the detrimental consequences of increased methemoglobinemia, which should not be unnoticed (2). Despite the controversial results of the different studies available in the literature, methemoglobin has been suggested to promote sepsisrelated complications including inappropriate vasodilation and organ dysfunction (9,21). Nowadays, methemoglobin concentrations can be easily measured with multiple wavelength co-oximeters or modern co-oximeter blood gas analyzers, that typically measure the optical absorbance of blood at 4 up to 128 different wavelengths and automatically compute the fractional concentrations of the four major hemoglobin species (oxy-, deoxy-, carboxy-, and methemoglobin), as well as the total hemoglobin concentration (22).…”

“…Higher methemoglobin levels were reported in septic compared to non-septic adult patients (8,9). However, methemoglobin levels above 2% were rare during sepsis, and no association with outcome was identified (9). Similarly, comparable values of blood methemoglobin were reported between humans with sepsis and septic shock (8).…”

“…In humans, sepsis is considered a differential diagnosis among the endogenous causes of methemoglobinemia both in adult and pediatric patients (2,8,9). Inflammatory cytokines and bacterial lipopolysaccharides in sepsis activate endothelial cells and stimulate the production of an inducible form of nitric oxide synthase (iNOS) (2,8,10).…”