Evaluation of Thromboelastometry (ROTEM) During Spinal Surgery

Study methods This is a prospective, randomized parallel-group single center study in patients undergoing elective major spine surgery. Patients will be randomized to ROTEM-guided hemostatic therapy algorithm or standard of care hemostatic therapy: arterial blood gas analysis (ABG), normalized index ratio (INR), prothrombin time (PT), thromboplastin time (aPTT), hemoglobin (Hb), platelets, and fibrinogen.

Study Procedures Patients will be randomized in a 1:1 ratio to either standard of care coagulation tests (SOC) or ROTEM. No changes in surgery or anesthesia technique will be made for the purposes of the study.

Standard of Care Coagulation Tests If patients are randomized to standard of care coagulation tests, these will be performed according to Ohio State University Wexner Medical Center standard practices and attending's criteria.

Standard of care tests include but are not limited to: hemoglobin, platelet count, fibrinogen concentration, INR, aPTT, and PT. These will be performed at fixed time points (preoperatively, every 2 hours intraoperatively, procedure completion, and 24 hours after procedure completion). Arterial blood gases will be performed repetitively intraoperative at a fixed range every 1-hour or at attending's criteria, as well as any postoperative laboratory tests.

ROTEM If patients are randomized to ROTEM, the anesthesiologist will be blinded to any intraoperative conventional coagulation test that might be performed.

ROTEM will be used according to the manufacturer's instructions, using equipment and test reagents provided by Tem International GmbH. All tests will be performed at the bedside by a clinical perfusionist trained to perform ROTEM. A specific algorithm has been created and should be followed according to clinical criteria

ROTEM monitoring will be performed in patients with signs of clinically relevant diffuse bleeding and in whom blood transfusion is considered (Temp >35 Celsius degrees; pH lower than 7.2; Cai above 4.6 mg/dL; Hb below 9g/dL, or below 10g/dL with anticipated greater blood loss) or at a fixed range every 2 hours or at Anesthesiologist criteria based on patient's clinical situation.

Patient´s clinical situation should be consider as the most important component on the transfusion decision-making process. Packed erythrocytes will be transfused to maintain hemoglobin concentrations higher 9g/dl and higher 10g/dl in individuals with underlying cardiovascular disease or anticipated greater blood loss. Individual based dynamics strongly indicating the need for erythrocyte transfusion at anesthesiologist criteria will be also part of the transfusion making decision-making process (tachycardia, hypotension, sings of ischemia on electrocardiogram, lactic acidosis, and dynamics of bleeding).

Assessment and reporting of Adverse Events The occurrence of adverse events (AE) and serious adverse events (SAE) will be recorded from the time of consent until discharge. For each AE, the relationship to the study procedures and monitoring, severity, expectedness, outcome will be determined by the PI and recorded in the study source accordingly If the case a subject withdraws from the study due to a serious adverse event the local Institutional Review Board (IRB) will be notified within 10 days.

Inclusion criteria

• Male or female age 18 years or older.
• Able to provide inform consent or have a legal authorized representative able to sign consent on the patients behalf.
• Female subject with a negative urine or serum pregnancy test, or not of childbearing potential, defined as surgically sterile due to bilateral tubal ligation, bilateral oophorectomy or hysterectomy; or are postmenopausal for at least 1 year.
• Patients schedule to undergo elective neurosurgery, orthopedic, or combined procedures that are expected to receive blood products intraoperatively.

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Exclusion criteria

• Subjects younger than 18 years old.
• Subjects who are prisoners.
• Subjects who refuse transfusion of blood products.
• Females who are pregnant or breastfeeding.
• Subjects unable to participate in the study for any reason in the opinion of the Principal Investigator.