Estimated versus actual; The accuracy of accounting for blood loss during endoscopic sinus surgery

Abstract Purpose Endoscopic sinus surgery (ESS) is the mainstay for chronic inflammatory and neoplastic sinonasal process and as a result many modalities have been studied to minimize blood loss and patient morbidity and to maximize intraoperative visualization. However, often conclusions of actual blood loss are based on surgeons' estimations without ever actually assessing the accuracy of these estimations. The objective of this study was to determine the accuracy of intraoperative blood loss estimates by attending otolaryngology surgeons among patients undergoing ESS. Materials and methods After obtaining institutional review board approval, data were collected on six surgeons performing ESS at a military academic medical center for 21 surgical cases. Specifically, both hourly and end-of-case total “estimated” (EBL) and “calculated actual” (ABL) blood loss values were recorded and compared statistically. Surgeons were blinded to the results until after all data were collected. Results The difference between mean EBL and ABL was 62.5 ml and was statistically significant (p = .007, Power 86.2%). EBL lagged ABL for both hourly intervals during a surgical case and the total end-of-surgery values. Conclusion The surgeons studied had EBL that were statistically significantly less than ABL both at hourly intervals during the surgery and at the conclusion of the case. As a result there exists potential for adverse consequences in clinical care and in efforts in medical research/advancement.