Perioperative Blood Transfusion, Postoperative Hemoglobin, and Clinical Outcomes in Neonates: A Retrospective...

Neonates are the most frequently transfused population perioperatively. Current guidelines based on evidence from neonatal trials and expert consensus recommend restrictive transfusion strategies, with hemoglobin (Hb) transfusion threshold levels between 7.5 and 12.0 g/dL based on gestational age, postnatal age, oxygen dependency, respiratory support, hemodynamic status, and comorbidities. This retrospective observational single center study aimed to assess red blood cell (RBC) transfusion practices in neonates undergoing noncardiac surgery. The rate of RBC transfusion and incidence of over transfusion (Hb ≥12 g/dL) is reported. The relationship between postoperative Hb levels, perioperative RBC transfusion volume, and patient-centered outcomes is explored for transfused neonates.

Following approval from the Boston Children's Hospital Institutional Review Board (IRB-P00029159), neonates undergoing noncardiac surgery who received a RBC transfusion in the perioperative period were included. Over transfusion was defined as an immediate postoperative Hb level ≥12.0 g/dL in transfused neonates. Patient demographics, laboratory variables, transfusion exposure, and clinical outcomes pertaining to the perioperative course were analyzed using univariate and multivariable logistic regression models. The primary aim was to define the rate of RBC transfusion in our total neonatal surgical cohort and to define the incidence of perioperative neonatal over transfusion for the transfused neonates. The secondary aims were to identify if patient or surgical factors correlate with the likelihood of perioperative over transfusion and determine if over transfusion and/or a transfusion volume threshold is associated with adverse postoperative outcomes, such as length of hospital or neonatal intensive care unit (NICU) stay, major morbidity, or mortality.

The database spanned over a 6-year period from January 2017 to December 2023 and consisted of 1305 neonates who underwent noncardiac surgery at Boston Children's Hospital. In the total neonatal surgical population, the perioperative RBC transfusion rate was 22.8% (297/1305) and the 30-day mortality was 10.9% (30/274). Of those neonates transfused perioperatively, the incidence of over transfusion was 51.1% with 140/274 meeting the criteria for over transfusion (defined as Hb level ≥12.0 g/dL; median Hb 13.9, range: 12.0-21.3). Risk factors for over transfusion were preoperative Hb between 10 and 13 g/dL (odds ratio [OR] = 0.28 [95% confidence interval {CI}, 0.14-0.53]; P < .001) and preoperative Hb <10 g/dL (OR = 0.18 [95% CI, 0.07-0.44]; P < .001). No significant association (negative or positive) was found between over transfusion and postoperative outcomes, such as length of hospital ( P = .151) or NICU stay ( P = .549), composite morbidity ( P = .868), 24-hour mortality ( P = .051), 30-day mortality ( P = .094), or 1-year mortality ( P = .672). Neonates with 30-day postoperative mortality received significantly higher total transfusion volumes (median = 41.0 mL/kg [interquartile range {IQR}, 20.2-115.2]) than patients without 30-day mortality (median = 20.8 mL/kg [IQR, 14.8-34.0]; P < .001). Thirty-day mortality was increased (OR = 1.05 [95% CI, 1.01-1.09]; P = .027) per extra 5 mL/kg of RBCs transfused (after adjusting for age, weight, prematurity, preoperative anemia, emergency procedure, and American Society of Anesthesiologists physical status [ASA-PS]). Perioperative RBC transfusion volumes over a threshold of 25 mL/kg were significantly associated with increased 30-day mortality (median, 41.0 [IQR, 20.2-115.2] vs median, 20.7 [IQR, 14.8-34.0]; P < .001) and 1-year mortality (median, 26.3 [IQR, 19.6-62.5] vs 20 [IQR, 14.7-33.3]; P < .004).

We report >22% of neonates were exposed to a RBC transfusion perioperatively in our entire surgical cohort with an incidence of >50% of those transfused being over transfused to Hb levels ≥12.0 g/dL. Our results suggest that transfusion volumes >25 mL/kg may be associated with worse outcomes. Our findings underscore the need for comprehensive evidence-based patient blood management strategies to clearly define acceptable perioperative conservative RBC transfusion thresholds and minimize unnecessary transfusions in neonates.