Preoperative Type and Screen Before General Thoracic Surgery: A Nomogram to Reduce Unnecessary Tests

Abstract

BackgroundA preoperative type and screen (T&S) is traditionally routinely obtained before noncardiac thoracic surgery; however an intraoperative blood transfusion is rare. This practice is overly cautious and expensive. MethodsWe included adult patients undergoing major thoracic surgery at the Mayo Clinic from 2007 to 2016. Patients receiving a T&S blood test ≤72 hours of surgery was the main exposure. We randomly split the cohort into derivation and validation datasets. We used multiple logistic regression to create a parsimonious nomogram predicting the need for a T&S in relation to the likelihood of intraoperative blood transfusion. We validated the nomogram in terms of discrimination, calibration, and negative predictive value. ResultsOf 6280 patients 46.1% had a preoperative T&S, but only 7.1% received intraoperative transfusions. The derivation dataset had 4196 patients. Patients who had a T&S were more likely to have baseline hemoglobin level <10 g/dL (7.9% vs 3.6%, P < .001) and less likely to have minimally invasive operations (36.1% vs 43.5%, P < .001) but were otherwise similar in baseline age and comorbidities. A transfusion threshold of 5% was selected a priori. The nomogram included age, planned operation, approach, body mass index, and preoperative hemoglobin. The nomogram was validated with a c-statistic of 86% and a negative predictive value of 97.9%. Patients who needed a blood transfusion but who did not have a preoperative T&S did not have a higher rate of mortality (P = .121). ConclusionsAn intraoperative blood transfusion during major thoracic surgery is a rare event. Patient who required transfusion but did not have a T&S did not have worse outcomes. A simple nomogram can aid in the selective use of T&S orders preoperatively.