Iatrogenic blood loss is blood loss caused by medical interventions. It remains a persistent challenge in the NICU, driven largely by the need for frequent laboratory testing. Although these blood draws provide essential clinical information, their cumulative impact can be substantial, particularly for vulnerable neonatal patients.
In this article, we’ll explore the impact of blood loss in the NICU and how noninvasive monitoring technologies, particularly for CO2, can help reduce the reliance on frequent blood draws to support more conservative blood management for infants.
The Impact of Blood Draws in the NICU
Cumulative blood loss from laboratory testing is a recognized concern across healthcare settings, but it is especially problematic in neonates. Infants have small circulating blood volumes, meaning even small blood samples can account for a meaningful percentage of their total blood volume.
Research has shown that, in the first six weeks of life, up to 30% of the circulating blood volume of neonates is drawn for lab work each week.1
To put the significance of this loss into perspective, removing just 6-7 mL of blood from a 1kg infant is roughly equivalent to a 450 mL blood loss in an adult.2
Over time, cumulative blood loss can contribute to complications for already fragile infants. Phlebotomy-related blood loss is considered “the primary cause of neonatal anemia,”2, which occurs in up to 30% of NICU patients.3 This can eventually result in the need for red-blood-cell (RBC) transfusions, which itself carries additional risks, including:
- Infection4
- Vascular overload4
- Sensitization4
- Transfusion reaction4
- Increased risk of necrotizing enterocolitis (NEC)
The Role of CO2 Monitoring
Among the many parameters monitored through blood draws, CO2 is of particular significance due to its central role in ventilatory management. In neonates, especially those born preterm, CO2 levels can change quickly, and both hypercarbia (high CO2) and hypocarbia (low CO2), as well as fluctuations or sharp changes, have all been linked to adverse outcomes, including intraventricular hemorrhage (IVH).6 Close monitoring is therefore essential to guide ventilation strategies and maintain stability.
The standard method for measuring CO2 is through blood draws; Arterial Blood Gases (ABG) and capillary heel sticks are common in the NICU. Given CO2’s importance in clinical decision-making, these blood tests occur frequently and represents one of the primary drivers of blood draws in the NICU.7 This can translate to a substantial number of samples; one analysis found that an average of nearly 57 blood gas measurements are taken from very low birth weight infants within the first week of life.7
While CO2 is a major driver of blood sampling in the NICU, it presents an opportunity to reduce blood draws through noninvasive monitoring approaches.
Leveraging Transcutaneous CO2 Monitoring
Although blood draws provide crucial information and will likely never be eliminated from the NICU, incorporating noninvasive monitoring technologies into care can help reduce reliance on such frequent sampling.
One technology that can lead to an impactful reduction in blood draws is transcutaneous CO2 monitoring, which enables noninvasive measurement of patients’ CO2 levels. Providing continuous insight into CO2, this technology can lessen the need for frequent blood draws without sacrificing visibility to this critical parameter.
The impact of transcutaneous CO2 monitoring has been seen in several NICUs. Explore the following stories of successful blood draw reductions:
Other Strategies to Reduce Blood Loss in the NICU
As Counsilman et al. stated in their study, “decreasing the frequency and amount of phlebotomy loss is probably the area in the field of neonatology that can be changed the quickest. This will automatically decrease the risk of neonatal anemia and save substantial transfusions and complications.”
Along with adopting noninvasive monitoring technologies, there are other options and strategies for reducing blood loss in the NICU – and small changes can have a big impact for these fragile patients. Strategies for reducing phlebotomy blood loss include:
- Using placental and umbilical cord blood for initial testing at birth8
- Following strict protocols regarding the amount of blood needed for each test8
- Increasing education on the importance of blood loss reduction8
- Performing bedside point-of-care testing8
In Summary…
While blood loss remains a persistent challenge in the NICU, care teams can reduce its impact through targeted blood management strategies. Approaches such as point-of-care testing and optimized sampling techniques can help reduce loss during necessary phlebotomy testing, while noninvasive monitoring technologies like transcutaneous CO2 monitoring can help reduce their frequency. Together, these strategies can form an impactful blood management plan to reduce overall blood loss in the NICU and support the best outcomes for patients.
References
- Carroll, P.D., Widness, J.A. Nonpharmacological, blood conservation techniques for preventing neonatal anemia–effective and promising strategies for reducing transfusion. Semin Perinatol. 2012.
- Widness, J.A. Pathophysiology of Anemia During the Neonatal Period, Including Anemia of Prematurity. Neoreviews. 2008.
- Tilahun, D., et al. High Magnitude of Neonatal Anemia Among Sick Newborns Admitted to University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia. J Blood Med. 2008.
- Whitehead, N.S., et al. Interventions to prevent iatrogenic anemia: a Laboravtory Medicine Best Practices systematic review. Crit Care. 2019.
- Gephart, S.M. Transfusion-associated necrotizing enterocolitis: evidence and uncertainty. Adv Neonatal Care. 2012.
- Hochwald, O., et al. Continuous Noninvasive Carbon Dioxide Monitoring in Neonates: From Theory to Standard of Care. Pediatrics. 2019.
- Alves-Dunkerson, J.A., et al. Cost analysis of a neonatal point-of-care monitor. Am J Clin Pathol. 2002.
- Counsilman, C.E., et al. Iatrogenic blood loss in extreme preterm infants due to frequent laboratory tests and procedures. J Matern Fetal Neonatal Med. 2021.
