Preoperative Blood Loss Prediction Formulas in Burn Surgeries: A Review.

Extensive burn surgeries lead to a considerable amount of blood loss. Predicting preoperative blood loss is essential for blood ordering and cross-matching. Accurate amount of ordered blood units ensures patients' safety and minimizes cost. However, blood loss estimation is complicated due to a variety of factors influencing blood loss, including patient and operative-related variables. Currently, no standard method to predict blood loss exists prior to surgery. Our goal is to review factors influencing blood loss and formulas that can predict blood loss. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) and MEDLINE databases for studies investigating blood loss in burn surgeries with a clear quantitative outcome. Fifteen studies were included, comprising 1613 subjects. All studies calculated blood loss and assessed possible related factors, and four studies proposed preoperative blood loss prediction formulas. Larger areas of tissue excised and grafted, younger age, and delayed surgery were correlated with increased blood loss. Varying decrease in blood loss was observed with tumescent usage and other bleeding control methods. Other variables produced inconsistent results. From four prediction formulas, only one formula, Dye's Formula, had been applied and proven effective in reducing unused blood units clinically by up to 40% of cross-matched blood. Various confounding factors and dissimilarities between studies make reliable prediction method construction challenging. With consideration of diverse patient characteristics, some study develops formulas to achieve optimal patient care and avoid unnecessary hospital expenditure. Further research with consistent variables should be done to construct a standardized blood loss estimation formula.