Background: Several studies suggest that the detection of nucleated red blood cells (NRBCs) in hospitalized patients indicates an increased risk of mortality. This study evaluates the impact of low arterial oxygen partial tension (pO₂) on NRBC appearance and prognosis in NRBC positive patients.
Methods: NRBCs in blood, arterial blood gases, and other laboratory parameters were monitored daily in 234 surgical intensive care patients. pO₂ was assessed in relation to mortality and the detection of NRBCs.
Results: NRBCs were found in 67 patients (28.6%). Mortality was significantly higher in NRBC positive patients (41.8%, 28/67) than in those that were NRBC negative (3.0%, 5/167). Multivariate logistic regression showed an increased mortality in NRBC positive patients (odds ratio 5.79; 95% confidence interval (CI) 1.07-31.33, p < 0.05). NRBC positive patients showed significantly lower pO₂ levels during intensive care treatment than NRBC negative patients. Prior to the initial detection of NRBCs in the peripheral blood, pO₂ levels were significantly lower in patients who died than in surviving patients. After the first appearance of NRBCs, no significant difference in pO₂ between these groups was found.
Conclusions: The detection of NRBCs is of prognostic significance concerning patient mortality. In NRBC positive patients, hypoxemia occurs more frequently. Low-levels of pO₂ seem to precede the appearance of NRBCs, especially in those patients with high risk of mortality.