Blood Warming in Preterm Infants to Decrease Hypothermia

This randomized controlled trial aims to improve treatment protocols during packed red blood cell (PRBC) transfusions in very preterm infants by using a blood warming device, Ranger blood warmer (3M Healthcare, Oakdale, Minnesota) with the main goal of preventing hypothermic body temperatures (<36.5°C) in very preterm infants during packed red blood cell (PRBC) transfusions. Very preterm infants, born less than 32 weeks gestational age, experience hypothermia after birth and throughout their hospitalization in the neonatal intensive care unit due to inefficient heat production and environmental heat loss. Hypothermia in preterm infants causes increased morbidity and mortality and prevention of hypothermic body temperature is the focus of many interventions used in neonatal care. Most research has focused on prevention of hypothermia after birth through stabilization. Importantly, critical high-tech incubators are used to care for preterm infants throughout their hospitalization, to prevent heat loss and maintain a thermoneutral environment.

One area that has been overlooked is the warming of PRBC transfusions that are given to preterm infants to replace blood volume depleted due to frequent testing to guide clinicians in their medical management. Because these small blood transfusions are sent from the blood bank freezer, infusion of this life-saving blood into a very preterm infant often results in hypothermic body temperatures. We completed a national survey of blood transfusion practices in neonatal intensive care units which revealed that standard care across the nation does not dictate the use of a warming device for these small PRBC transfusions; although, few are beginning to use warming devices. Because hypothermia in preterm infants leads to increased morbidity and mortality, it is crucial to protect very preterm infants from heat loss from infusing cold blood. A study completed in 2020 performed simulated PRBC transfusions, using a commercial blood warmer and revealed that blood products can be delivered at near-physiologic temperatures with no detected damage to the cells however, the study was not designed to examine the impact of a blood warmer on hypothermia in very preterm infants. Therefore, the primary aim of this study is to test the effect of the Ranger blood warmer on the incidence of post PRBC transfusion hypothermia in very preterm infants.

Inclusion criteria

• Any infant born at PRISMA Health Richland hospital
• less than 32 weeks gestational age by obstetrical dating as indicated in the electronic medical chart
• admitted to the neonatal intensive care unit receiving one PRBC transfusion within the first month of life.

Exclusion criteria

• Infants having neurological anatomical abnormalities or major brain hemorrhage (Grade III or IV), because neurological damage can interfere with thermal control.