Hemostatic Agent Use and Intraoperative Blood Loss in Lumbar Spine Surgery

Blood loss is a major concern in spine surgery. Within lumbar fusion surgery, one study estimated an average blood loss of 800 mL (range 100-3,100 mL) for non-instrumented fusion and 1,517 mL (range 360-7,000 mL) for instrumented fusions. Blood transfusions are required in an estimated 8% to 36% of patients undergoing spine surgery.Transfusion promotes tissue perfusion and oxygen delivery during extensive surgeries, yet carries with it rare but significant risks. These include acute lung injury, febrile reactions, allergic episodes, infection, and impaired immune response. Given these potential risks, strategies to minimize extensive blood loss and resultant transfusion are warranted.

Previously described approaches in the literature that can minimize blood loss during spine surgery include: hypotensive anesthesia, hemostatic agents (e.g. FloSeal®), antifibrinolytic medications, advanced bipolar cautery (e.g. Aquamantys®), autologous blood salvage (e.g. Cell Saver®), perioperative and intraoperative temperature, operative time, nutritional state, coagulopathy, restrictive transfusion triggers, and rotational thromboelastometry (ROTEM).

Researchers in several medical fields have attempted to delineate comprehensive anemia prevention strategies described as "blood-saving bundles". A bundle encapsulates multiple evidence-based interventions that result in improved patient outcomes-here with a focus on reduced blood loss-when combined versus when each intervention is used in isolation. Care bundles applied to intensive care unit treatment and pneumonia, sepsis, and acute kidney injury care have demonstrated improved clinical outcomes. However, no bundled protocol currently exists that aim to decrease blood loss and transfusion incidence during spine surgery. Moreover, no data exist that identify whether use of FloSeal® over other hemostatic agents as part of a bundled protocol results in decreased blood loss and transfusion rates, improved surgical outcomes, and improved cost effectiveness.

Perioperative variables that can be used to create a bundled approach quality improvement protocol to minimize blood loss in spine surgery will be evaluated using retrospective data collection and multivariate analysis of previously performed spinal surgeries at Johns Hopkins Hospital. In particular the investigators are interested in determining whether FloSeal® contributes towards increased control over perioperative bleeding compared to other hemostatic agents for potential inclusion in a future bundled approach.

This retrospective multivariate analysis will identify potential factors associated with increased blood loss and transfusion incidence. The investigators anticipate using these findings to develop a future bundled protocol for implementation in all patients undergoing spine surgery at Johns Hopkins Hospital after approval by the Institutional Review Board. Such a bundled protocol has the potential to improve surgical outcomes and decrease institutional costs.

Inclusion criteria

• Age 18 or older
• Undergoing lumbar spine surgery
• Surgery performed between July 1, 2016 and November 30, 2018
• Surgery performed at the Johns Hopkins East Baltimore Campus
• Available data on hemostatic agents used

Exclusion criteria

• Age under 18
• Surgery at location other than lumbar spine
• Surgical details unavailable
• Data unavailable for specified endpoints, including:

• Hemostatic agent use
• Blood loss
• Operative time