Effects of transfusion in anemia of prematurity

Physiological and Clinical Impact of Repeated Inhaled Oxygen Variation on Erythropoietin Levels in Patients After Surgery

The “Normobaric Oxygen Paradox” (NOP) is a physiologic mechanism that induces an increase of endogenous erythropoietin (EPO) production by creating a state of relative hypoxia in subjects previously exposed to hyperoxia, followed by a rapid return to normoxia. Oxygen exposure duration and inspired oxygen fraction required to observe a significant increase in EPO or hemoglobin are not clearly defined. Consequently, we here study the effect of one model of relative hypoxia on EPO, reticulocytes and hemoglobin stimulation in patients after surgery. Patients were prospectively randomized in two groups. The O₂ group (n = 10) received 100% oxygen for 1 h per day for eight consecutive days, via a non-rebreathing mask. The control group (n = 12) received no oxygen variation. Serum EPO, hemoglobin and reticulocyte count were measured on admission and postoperatively on days seven and nine. Percentage EPO at day nine with respect to the baseline value was significantly elevated within the groups [O₂ group: 323.7 (SD ± 139.0); control group: 365.6 (SD± 162.0)] but not between them. No significant difference was found between the groups in terms of reticulocytes count and hemoglobin. Our NOP model showed no difference on EPO increase between the two groups. However, both groups expressed separately significant EPO elevation.

[Assessment of erythropoietin treatment in preterm newborns older than 30 weeks of gestation]

BACKGROUND

Human recombinant erythropoietin (rhEPO) has shown a benefit in reducing the number of transfusions in very-low-birth-weight infants. However, no study has reported benefits in older preterms (i.e., 30-32 weeks of gestation [WG]). This study aimed to evaluate the benefit of rhEPO between 30 and 32 WG.

METHODS

Two groups of preterms between 30 and 32 WG were compared in a retrospective study: period 1 with rhEPO (January 2005 to October 2006) and period 2 without rhEPO (November 2006 to May 2007). Newborns with intra-uterine growth retardation, rhesus isoimmunization or surgical procedures were excluded. The main criterion was the number of blood transfusions; the second criterion was hemoglobin at 2, 4 and 6 weeks of life. Morbidity was evaluated on necrotizing enterocolitis, intraventricular hemorrhage (IVH) and periventricular leukomalacia.

RESULTS

Fifty-nine newborns receiving rhEPO and 19 not receiving rhEPO (controls) were included. The two groups were similar for birth weight (p=0.06) and hemoglobin at birth (p=0.41). Only one child (rhEPO group) needed a transfusion. Hemoglobin at 2 weeks (p=0.74), 4 weeks (p=0.13) and 6 weeks (p=0.35) were not statistically different. There was no difference between the 2 groups for necrotizing enterocolitis, IVH or periventricular leukomalacia.

CONCLUSION

This study did not find any benefit using rhEPO in 30 to 32 WG preterm infants in terms of the number of transfusions or hemoglobin levels.

Impact of delayed initiation of erythropoietin in critically ill patients

Background

The purpose of this study was to evaluate the impact of recombinant human erythropoietin (rHuEPO) use for anemia of critical illness at a practice site where delayed initiation is common.

Methods

Retrospective medical record review involving patients treated with rHuEPO for anemia of critical illness. Those patients given rHuEPO or diagnosed with end-stage renal disease (ESRD) prior to ICU admission were excluded. The primary endpoints were rHuEPO use and RBC transfusion patterns.

Results

Complete data were collected for consecutive admissions of 126 patients. Average age (SD) and APACHE II score were 56.5 (18.6) years and 25 (7.8), respectively. The median ICU (IQR) and hospital length of stay (LOS) were 24 (11.25, 39) and 29 (17, 44.75) days, respectively. Treatment with rHuEPO was started an average of 12.5 +/- 10.5 days after ICU admission and given for 3.8 +/- 3.8 doses. Eighty percent of patients were transfused with an average total of 5.42 +/- 5.08 units received. RBC exposure inversely correlated with a lower mean hemoglobin response to rHuEPO. ICU LOS (p < 0.0001), hemoglobin at 24 hours (p = 0.055), transfusion within 48 hours of admit (p < 0.0001), and postoperative status (p = 0.019) were the best predictors of transfusion requirements (r² = 0.37).

Conclusion

Delayed initiation of rHuEPO for anemia of critical illness resulted in comparable hemoglobin and transfusion benefits. Future studies are needed to establish clinical benefit and role in therapy. RBC exposure may blunt the erythropoietic effects of rHuEPO, potentially frustrating benefits to those of greatest apparent need.