Anemia, transfusion, and phlebotomy practices in critically ill patients with prolonged ICU length of stay: a cohort study

Introduction Anemia among the critically ill has been described in patients with short to medium length of stay (LOS) in the intensive care unit (ICU), but it has not been described in long-stay ICU patients. This study was performed to characterize anemia, transfusion, and phlebotomy practices in patients with prolonged ICU LOS. Methods We conducted a retrospective chart review of consecutive patients admitted to a medical-surgical ICU in a tertiary care university hospital over three years; patients included had a continuous LOS in the ICU of 30 days or longer. Information on transfusion, phlebotomy, and outcomes were collected daily from days 22 to 112 of the ICU stay. Results A total of 155 patients were enrolled. The mean age, admission Acute Physiology and Chronic Health Evaluation II score, and median ICU LOS were 62.3 +/- 16.3 years, 23 +/- 8, and 49 days ( interquartile range 36 - 70 days), respectively. Mean hemoglobin remained stable at 9.4 +/- 1.4 g/dl from day 7 onward. Mean daily phlebotomy volume was 13.3 +/- 7.3 ml, and 62% of patients received a mean of 3.4 +/- 5.3 units of packed red blood cells at a mean hemoglobin trigger of 7.7 +/- 0.9 g/dl after day 21. Transfused patients had significantly greater acuity of illness, phlebotomy volumes, ICU LOS and mortality, and had a lower hemoglobin than did those who were not transfused. Multivariate logistic regression analysis identified the following as independently associated with the likelihood of requiring transfusion in nonbleeding patients: baseline hemoglobin, daily phlebotomy volume, ICU LOS, and erythropoietin therapy ( used almost exclusively in dialysis dependent renal failure in this cohort of patients). Small increases in average phlebotomy (3.5 ml/day, 95% confidence interval 2.4 - 6.8 ml/day) were associated with a doubling in the odds of being transfused after day 21. Conclusion Anemia, phlebotomy, and transfusions, despite low hemoglobin triggers, are common in ICU patients long after admission. Small decreases in phlebotomy volume are associated with significantly reduced transfusion requirements in patients with prolonged ICU LOS.