Daily monitoring of nucleated red blood cells in the blood of surgical intensive care patients

BackgroundIn intensive care patients the appearance of nucleated red blood cells (NRBC) in blood is associated with a variety of severe diseases. Generally, when NRBCs are detected in the patients' blood the prognosis is poor.Material and methodsIn the present study the detection of NRBCs was used for a day-to-day monitoring of 284 surgical intensive care patients.ResultsNRBCs were found at least once in 32.0% of all patients. The mortality of NRBC-positive patients was 44.0% (40/91); this was significantly higher (P < 0.001) than the mortality of NRBC-negative patients (4.2%, 8/193). With regard to intensive care mortality, NRBCs in blood showed sensitivity and specificity of 83.3% and 78.9%, respectively. The area under curve (C-statistic) was 0.86. Mortality increased with increasing NRBC concentration. All patients with more than 2000 NRBCs/μl died. Moreover, mortality increased with increasing frequency of occurrence. When after first detection of NRBCs in blood, during the further course of intensive care treatment the NRBCs have disappeared from the circulation, the mortality again decreased to values of NRBC-negative patients.The detection of NRBCs is associated with an increased mortality rate, the odds ratio after adjustment for other laboratory prognostic indicators being 1.8 (P < 0.001) for each increase in the NRBC category (1–40/μl; 41–80/μl; 81–240/μl, > 240/μl). NRBCs were detected for the first time, on average, 9 days (median 5 days) before death.ConclusionsThe routine analysis of NRBC in blood is of potential prognostic power with regard to mortality of critically ill patients. Therefore, this parameter could possibly serve as a daily indicator of patients at high mortality risk.