Background: Reliable measurement of intraoperative blood loss remains a serious challenge during correction of craniosynostosis. This study analyzed the relationship between estimated blood loss (EBL) and calculated blood loss (CBL) in fronto-orbital advancement and its implications on blood transfusion practice and hospital length of stay (LOS).
Methods: The authors reviewed infants who underwent primary fronto-orbital advancement for craniosynostosis (1997–2009). Estimated blood loss was based on anesthesia records and CBL by preoperative/postoperative hemoglobin. Perioperative red blood cell transfusion (RCT) and hospital LOS were recorded.
Results: Ninety infants were included. Mean EBL was 42.2% of estimated blood volume (% EBV), and CBL was 39.3% EBV, without significant difference (P = 0.23). Bland-Altman analysis revealed that EBL was greater than CBL at lower levels of blood loss (≤47.0% EBV) and less than CBL at higher levels (>47.0% EBV). Mean intraoperative RCT was 45.8% EBV; overtransfusion was more frequent at lower levels of bleeding, and undertransfusion at higher levels. Postoperative RCT occurred more frequently with greater blood loss. Mean LOS was 3.7 days, increasing with CBL (hazard ratio of discharge, HRdischarge = 0.988, P < 0.01), postoperative RCT (HRdischarge = 0.96, P < 0.05), total RCT (HRdischarge = 0.991, P < 0.05), and total intraoperative fluid (HRdischarge = 0.999, P < 0.05).
Conclusions: Estimated blood loss is a less accurate marker for CBL at the extremes of blood loss during fronto-orbital advancement. The tendency to overestimate blood loss with less intravascular volume loss can result in unnecessary transfusion, whereas underestimation with greater actual blood loss can lead to delay in resuscitation and longer hospitalization.