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  • Relationship Between Percent Change in Hemoglobin and Perioperative Adverse Events Among Spine Surgery Patients

    Final Number:

    Taylor Elise Purvis BA; C. Rory Goodwin MD PhD; Camilo A. Molina MD; Ali Karim Ahmed BS MD candidate; Steven M. Frank MD; Daniel M. Sciubba MD

    Study Design:

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2017 Annual Meeting

    Introduction: To the authors’ knowledge, no study has examined the association between percent delta Hb and perioperative morbidity in spine surgery patients. We thus aimed to determine the perioperative clinical outcomes associated with percent delta Hb as an independent factor among spine surgery patients.

    Methods: Patients who underwent spine surgery at our institution between December 4, 2008 and June 26, 2015 were eligible for this retrospective study. Patients undergoing the following procedures were included: atlantoaxial fusion, subaxial anterior cervical fusion, subaxial posterior cervical fusion, anterior lumbar fusion, posterior lumbar fusion, lateral lumbar fusion, excision of intervertebral disc, and excision of spinal cord lesion. Data on intraoperative transfusion were obtained from an automated prospectively collected anesthesia data management system. Data on postoperative hospital transfusions were obtained through a Web-based intelligence portal. Percent delta Hb was defined as: ((first Hb - nadir Hb)/first Hb) x 100. Clinical outcomes included in-hospital morbidity and length of stay associated with percent delta Hb.

    Results: A total of 3,949 patients who underwent spine surgery were identified. A total of 1204 patients (30.5%) received at least one unit of packed red blood cells (PRBC). The median nadir Hb level was 10.6 g/dL (IQR, 8.7-12.4 g/dL), yielding a mean percent delta Hb of 23.6% (SD=15.4%). Perioperative complications occurred in 234 patients (5.9%) and were more common in patients with a larger percent delta Hb (P = 0.017). Hospital-related infection, which occurred in 60 patients (1.5%), was also more common in patients with a greater percent delta Hb (P = 0.001).

    Conclusions: Percent delta Hb is independently associated with a higher risk of developing any one perioperative complication and hospital-related infections. Our results suggest that percent delta Hb may be a useful measure to identify patients at risk for adverse perioperative events.

    Patient Care: Our results suggest that additional consideration of relative anemia, rather than an absolute nadir Hb trigger alone, may be useful in informing transfusion practices during spine surgery. Because patient baseline Hb concentrations are variable, an absolute nadir Hb trigger of 7 g/dL may not be an ideal indicator of clinically important acute anemia for all patients.

    Learning Objectives: By the conclusion of this session, participants should be able to: 1) Appreciate the importance of considering delta Hb in the formula for appropriate transfusions, and 2) Explain the association between percent delta Hb and perioperative morbidity in spine surgery patients.


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