Endogenous carboxyhemoglobin concentrations in the assessment of severity in patients with community-acquired...

Previous studies have shown that carbon monoxide, which is endogenously produced, is increased in community-acquired pneumonia (CAP). However, it has not been studied enough whether severity of pneumonia is correlated with increased carboxyhemoglobin (COHb) concentrations in CAP. The aim of this study was to determine whether endogenous carbon monoxide levels in patients with CAP were higher compared with the control group and, if so, to determine whether COHb concentrations could predict severity in CAP.

Eighty-two patients with CAP were evaluated in this cross-sectional study during a 10-month period. Demographic data, pneumonia severity index and confusion, uremia, rate respiratory, pressure blood, age>65 (CURB-65) scores, hospital admission or discharge decisions, and 30-day hospital mortality rate were recorded. In addition, 83 control subjects were included to study. The COHb concentration was measured in arterial blood sample.

The levels of COHb in patients with CAP were 1.70% (minimum-maximum, 0.8-3.2), whereas those in control subjects, 1.40% (minimum-maximum, 0.8-2.9). The higher COHb concentrations in patients with CAP were statistically significant (P < .05). Concentration of COHb correlated with pneumonia severity index (P = .04, r = 0.187); however, it did not correlate with CURB-65 (P = .218, r = 0.112).

Although COHb concentrations show an increase in patients with pneumonia, it was concluded that this increase did not act as an indicator in diagnosis process or prediction of clinical severity for the physicians.