Hematologic and bacteriologic assessment of autologous cord blood for neonatal transfusions

Recent advances toward defining the benefits and risks of erythrocyte transfusions in neonates

Like many treatments available to small or ill neonates, erythrocyte transfusions carry both benefits and risks. This review examines recent publications aimed at better defining those benefits and those risks, as means of advancing evidence-based neonatal intensive care unit transfusion practices. Since decisions regarding whether to not to order an erythrocyte transfusion are based, in part, on the neonate's blood haemoglobin concentration, the authors also review recent studies aimed at preventing the haemoglobin from falling to a point where a transfusion is considered.

Reduction in red blood cell transfusions using a bedside analyzer in extremely low birth weight infants

BACKGROUND

Preterm infants typically experience heavy phlebotomy losses from frequent laboratory testing in the first few weeks of life. This results in anemia, requiring red blood cell (RBC) transfusions. We recently introduced a bedside point-of-care (POC) blood gas analyzer (iSTAT, Princeton, NJ) that requires a smaller volume of blood to replace conventional Radiometer blood gas and electrolyte analysis used by our neonatal intensive care unit (NICU). The smaller volume of blood required for sampling (100 vs 300-500 microl), provided an opportunity to assess if a decrease in phlebotomy loss occurred and, if so, to determine if this resulted in decreased transfusions administered to extremely low birth weight (ELBW) infants.

OBJECTIVE

We hypothesized that the use of the POC iSTAT analyzer that measures pH, PCO(2), PO(2), hemoglobin, hematocrit, serum sodium, serum potassium and ionized calcium would result in a significant decrease in the number and volume of RBC transfusions in the first 2 weeks of life.

DESIGN/METHODS

A retrospective chart review was conducted of all inborn premature infants with birth weights less than 1000 g admitted to the NICU that survived for 2 weeks of age during two separate 1-year periods. Blood gas analysis was performed by conventional laboratory methods during the first period (designated Pre-POC testing) and by the iSTAT POC device during the second period (designated post-POC testing). Data collected for individual infants included the number of RBC transfusions, volume of RBCs transfused, and the number and kind of blood testing done. There was no effort to change either the RBC transfusion criteria applied or blood testing practices.

RESULTS

The mean (+/-SD) number of RBC transfusions administered in the first 2 weeks after birth was 5.7+/-3.74 (n=46) in the pre-POC testing period to 3.1+/-2.07 (n=34) in the post-POC testing period (p<0.001), a 46% reduction. The mean volume of RBC transfusions decreased by 43% with use of the POC analyzer, that is, from 78.4+/-51.6 ml/kg in the pre-POC testing group to 44.4+/-32.9 ml/kg in the Post-POC testing group (p<0.002). There was no difference between the two periods in the total number of laboratory blood tests done.

CONCLUSIONS

Use of a bedside blood gas analyzer is associated with clinically important reductions in RBC transfusions in the ELBW infant during the first two weeks of life.

Usefulness of cord-blood harvesting for autologous transfusion in surgical newborns with antenatal diagnosis of congenital anomalies

BACKGROUND/PURPOSE

The risks of homologous transfusion and the effectiveness of predeposit autologous transfusion have been described. The authors examined the clinical usefulness of cord-blood harvesting for autologous transfusion in newborns who had congenital anomalies antenatally diagnosed that would require surgical intervention at or near the time of delivery.

METHODS

Of 112 cases of antenatal diagnosis of congenital anomalies, 50 mothers gave informed consent and enrolled in this study. Cord-blood was withdrawn immediately after clamping of the umbilical cord and was used for autologous transfusion in newborns within the first 3 days postpartum.

RESULTS

A mean of 72 +/- 54 mL of cord-blood was harvested (27 +/- 18 mL/kg). While preserving cord-blood for 3 days at 4 degrees C, no signs of clot formation or hemolysis were observed. The harvested cord-blood included plasma-free Hb ranging from 1 to 68 (13 +/- 18) mg/dL and thrombin-antithrombin III complex ranging from 2 to 273 (18 +/- 50) ng/mL. Bacteriologic examination of the stored cord-blood showed negative cultures, except for samples from 3 newborns after vaginal delivery. A mean of 46 +/- 34 mL of cord-blood was used in 26 patients for autologous transfusion. No significant complications related to cord-blood transfusion were recognized clinically.

CONCLUSIONS

Autologous cord-blood transfusion has the potential to be a useful alternative to homologous transfusion in newborns requiring surgery. Adequate collection and storage techniques for cord-blood must be developed. J Pediatr Surg 36:851-854.

Cord blood stem cells: how to get them and what to do with them

This article reviews the means of obtaining cells from the available reservoirs of cord blood, intended as sources of immature hematopoietic stem cells that ultimately could be useful for transplantation, gene therapy, and research. Various issues must be considered when collecting umbilical cord blood regardless of the method employed. One must regard the basic fetal-placental physiology and hemodynamic characteristics prior to and at the time of procurement. Additional concerns exist with the mother, not only at the time of collection but also prenatally, including informed consent, health history, and psychosocial issues. Collection methods may be characterized as either ex utero or in utero, employing either open or closed collections methods. Each of these variables presents limitations and offers specific advantages over the others. Once collected, the cells must be appropriately tested, processed, and prepared for cryopreservation if not used immediately, using good manufacturing practices and acceptable standards of operation. An ideal collection method has yet to be defined that fulfills the need for reliability, reproducibility, and ease of use.

Autologous cord blood transfusion

Newborn piglets were exsanguinated (60% of blood volume) and retransfused 1 h later. One test group received adult pig red blood cells, the other piglet cord blood cells; controls were infused with plasma. While all controls died, satisfactory results were achieved in piglets transfused with either adult or foetal blood. The feasibility of collecting human cord blood for transfusion was assessed in 100 samples of human cord blood. Blood was collected aseptically and aerobic and anaerobic cultures set up. All samples of cord blood were sterile, and all were Mycoplasma negative. Coagulation parameters were analysed in eight cord plasma samples stored at -20 degrees C for 45 days. No significant abnormalities were found immediately after birth or after storage.