Association of Postoperative Drift in Hemoglobin With Mortality After Brain Tumor Craniotomy

BACKGROUND: Postoperative downward drift in hemoglobin (Hb) concentration may be associated with complications and death, even if nadir Hb remains more than the red blood cell transfusion threshold of 7 g/dL.OBJECTIVE: To assess whether postoperative Hb drift in patients undergoing brain tumor craniotomy influences mortality in the immediate perioperative period.METHODS: This retrospective cohort study included patients undergoing craniotomy for brain tumors. We defined no postoperative Hb decrease, mild decrease, moderate decrease, and severe decrease as postoperative Hb drift of =25%, 26% to 50%, 51% to 75%, and >75%, respectively. The primary outcome was 30-day mortality after craniotomy.RESULTS: This study included 8159 patients who underwent a craniotomy for brain tumors. Compared with patients with no postoperative Hb drift, the odds of postoperative mortality at 30 days increased in patients with mild postoperative Hb drift (adjusted odds ratio [OR] 2.47, 95% CI 1.72-3.56), moderate drift (adjusted OR 6.56, 95% CI 3.42-12.59), and severe drift (adjusted OR 12.33, 95% CI 3.48-43.62). When postoperative Hb drift was analyzed as a continuous variable, for each 10% increase in Hb drift, the adjusted OR of postoperative mortality at 30 days was 1.46 (95% CI 1.31-1.63).CONCLUSION: In patients undergoing brain tumor craniotomy, a small postoperative Hb drift was associated with increased odds of postoperative mortality at 30 days, even if the nadir Hb level remained greater than the red blood cell transfusion threshold of 7 g/dL. Future randomized clinical trials of perioperative transfusion practices may examine the effect of both nadir Hb and Hb drift.