Perioperative assessment of coagulability in neurosurgical patients using thromboelastography

Thrombelastography is a useful technique for evaluating coagulability. We hypothesized that it could be used to determine postoperative hematologic complications during and after neurologic surgery.

Forty-six neurosurgical patients were stratified by diagnosis: subarachnoid hemorrhage from ruptured intracranially aneurysms, intracranial-axial lesions, intracranial-extra-axial lesions, and degenerative spine disease. Thromboelastograms were performed before, during, and after surgery. Hematologic data were collected preoperatively and postoperatively; computed tomography scans and lower extremity Doppler sonography were performed postoperatively. A thrombosis index (TI) was used to assess coagulability.

Coagulability increased over the course of surgery for all patients (p < 0.0001). In craniotomy patients, coagulability increased over the course of surgery (p < 0.05) with the most dramatic increase from intubation to skin incision (p < 0.05), and then after tumor removal or aneurysm clipping (p < 0.10). Univariate analysis among craniotomy patients showed that female gender (p < 0.0004) and smoking (p < 0.06) were associated with hypercoagulability. Among craniotomy patients, younger age was associated with hypercoagulability in the preoperative period (p < 0.01). There was no significant association between coagulability and aspirin or NSAID use, or intraoperative fluid volume. No patient developed a postoperative hematoma and one patient (2.2%) developed a lower extremity deep vein thrombosis.

Increased coagulability begins between induction of anesthesia and skin incision, and continues to increase throughout surgery. These changes are more pronounced in patients undergoing craniotomy compared to patients undergoing spine procedures.