Evaluation of the effectiveness of packed red blood cell irradiation by a linear accelerator

Effects of Freshly Irradiated vs Irradiated and Stored Red Blood Cell Transfusion on Cerebral Oxygenation in Preterm Infants: A Randomized Clinical Trial

IMPORTANCE

Gamma irradiation of leukoreduced red blood cells (RBCs) prevents transfusion-associated graft-vs-host disease but also exacerbates storage lesion formation in RBCs. It is unknown whether freshly irradiated RBCs are more efficacious than irradiated and stored RBCs in preterm infants with high transfusion requirements.

OBJECTIVE

To examine whether transfusion of freshly irradiated vs irradiated and stored RBC components improves cerebral oxygen delivery in preterm infants with anemia.

DESIGN, SETTING, AND PARTICIPANTS

This single-center, double-blinded, proof-of-concept randomized clinical trial was conducted at the neonatal intensive care unit of Wellington Regional Hospital in Wellington, New Zealand, between December 1, 2017, and November 30, 2018. Participants were preterm infants (<34 weeks' gestation at birth) who were at least 14 days of age and had anemia. Participants underwent nonurgent transfusions, and these episodes were randomized to the intervention group (in which the infants received a transfusion of RBCs that were freshly irradiated on the day of transfusion) or control group (in which the infants received a transfusion of RBCs that were irradiated and stored for up to 14 days). Data were analyzed using the evaluable population approach.

INTERVENTION

Transfusion of freshly irradiated RBCs.

MAIN OUTCOMES AND MEASURES

The prespecified primary outcome was the change in cerebral regional oxygen saturation (crSO2) from baseline (immediately before) to immediately after the transfusion. The prespecified secondary outcomes were the change in cerebral fractional tissue oxygen extraction (cFTOE) at different time points (immediately after, 24 hours after, and 120 hours or 5 days after transfusion). Outcomes were measured by blinded clinicians using near-infrared spectroscopy. A covariate-adjusted linear mixed model was used to quantify mean treatment effects and account for multiple transfusions in some infants.

RESULTS

A total of 42 infants (mean [SD] gestational age, 26 [10] weeks and 3 days; 29 [69%] boys) were enrolled in the trial and underwent 64 transfusion episodes, which were randomized to the intervention (n = 31) or control (n = 33) group. Compared with infants in the control group, those in the intervention group showed a covariate-adjusted mean increase in crSO2 (2.0 percentage points; 95% CI, 1.2-2.8 percentage points) and a mean decrease in cFTOE (0.02; 95% CI, 0.01-0.04) immediately after transfusion. These differences were sustained up to 120 hours or 5 days after transfusion. There were negligible mean changes in crSO2 or cFTOE in infants in the control group at any of the follow-up time points.

CONCLUSIONS AND RELEVANCE

Results of this trial showed that transfusion of freshly irradiated RBCs conferred a small advantage in cerebral oxygenation for at least 5 days after transfusion compared with transfusion of irradiated and stored RBC components. On-demand irradiation of RBC components may be considered to optimize oxygen delivery in the recipient, but this physiological finding requires further research.

TRIAL REGISTRATION

ANZCTR Identifier: ACTRN12617001581358.

Effects of hypoxic storage on the efficacy of gamma irradiation in abrogating lymphocyte proliferation and on the quality of gamma-irradiated red blood cells in additive solution 3

BACKGROUND

Gamma irradiation of blood products is used to prevent transfusion-associated graft-versus-host disease by inhibiting the proliferation of lymphocytes that are implicated in the disease. Gamma irradiation also damages the red blood cells (RBCs). It is unknown whether hypoxia reduces the efficacy of gamma irradiation in inhibiting lymphocyte proliferation (LP). The objectives of the study were to investigate the effects of hypoxia on gamma irradiation-induced inhibition of LP and on the in vitro properties of RBCs.

MATERIALS AND METHODS

Forty-four units (300-340 ml each) of less than 8-h-old ABO-matched leukocyte reduced red cell concentrates (LR-RCC) in additive solution 3 were pooled in pairs. Peripheral blood mononuclear cells were isolated from non-leukocyte reduced RCCs and added back to the pool at a final concentration of 2 × 10⁵ /ml. The pool was divided equally into a conventional storage bag A and a hypoxic processing and storage bag B. The units were gamma-irradiated at 25Gy on day 7 for the LP experiment and on either day 7 or 14 for the RBC quality experiments. LP was measured using a limiting dilution assay, and several in vitro metrics of RBCs were measured.

RESULTS

Gamma irradiation inhibited T-lymphocyte proliferation by 4.7 × 10⁴ -fold reduction in both hypoxic and conventional storage. The in vitro metrics of RBC quality were better preserved in hypoxic storage.

DISCUSSION

T lymphocytes present in hypoxic RBC are equally susceptible to gamma irradiation as conventional storage. Hypoxic storage also reduces the deleterious effects of gamma irradiation on RBCs.

Anesthetic Considerations for Pediatric Craniofacial Surgery

Anesthetic management of craniosynostosis remains a challenging experience. It requires input and collaboration from multiple specialties to improve patient outcomes. Understanding the surgical corrective techniques and the underlying risks of each is essential to providing the best care to this patient population. The propensity for significant blood loss necessitates fundamental knowledge of pediatric resuscitation and the development of perioperative transfusion protocols that have been shown to reduce transfusion requirements in the peri-operative period.

Nanostructural Changes in the Cell Membrane of Gamma-Irradiated Red Blood Cells

The effect of gamma radiation on the ultrastructure of the cell membranes of red blood cells has been probed using a powerful tool, namely, atomic force microscopy. We used mice erythrocytes as a model. Blood samples withdrawn from mice were gamma-irradiated using a ⁶⁰Co source unit with doses of 10,15,20,25 and 30 Gy. Structural changes appeared in the form of nanoscale potholes, depressions and alterations of the cell membrane roughness. The roughness of the cell membrane increased dramatically with increasing doses, although at 10 Gy , the cell membrane roughness was less than that of normal red blood cells (controls). Therefore, such modifications at the nano-scale level may affect the biophysical properties of membranes, resulting in impairment of their function.