Point of care coagulation testing in neurosurgery

Dynamic Changes of Hemostasis in Patients with Traumatic Brain Injury Undergoing Craniotomy: Association with in-Hospital Mortality

BACKGROUND

Traumatic brain injury (TBI) induces complex systemic hemostatic alterations associated with secondary brain damage and death. We specifically investigated perioperative changes of hemostasis in patients with isolated TBI undergoing major neurosurgery and searched for their influence on outcome.

METHODS

Serial analysis (four time points, T0-T3) of conventional coagulation assay and rotational thromboelastometry data acquired during 72 h from admission of 68 patients who underwent craniotomy to remove hematoma and/or to decompress the brain was performed. The primary outcome was in-hospital mortality. Secondary outcomes were the prevalence of hypocoagulation and increased clotting activity, coagulation parameters between survivors and nonsurvivors, and cutoff values of coagulation parameters predictive of mortality.

RESULTS

Overall mortality was 22%. The prevalence of hypocoagulation according to rotational thromboelastometry decreased from 35.8% (T0) to 15.9% (T3). Lower fibrinogen levels, hyperfibrinolysis and fibrinolysis shutdown in the early period (T0-T1) following TBI were associated with higher mortality. Optimal cutoff values were identified: fibrin polymerization thromboelastometry (FIBTEM) clot amplitude at 10 min after clotting time ≤ 13 mm at T0 and FIBTEM clot amplitude at 10 min after clotting time ≤ 16.5 mm at T1 increased the odds of death by 6.0 (95% confidence interval [CI] 1.54-23.13, p = 0.010) and 9.7 (95% CI 2.06-45.36, p = 0.004), respectively. FIBTEM maximum clot firmness ≤ 14.5 mm at T0 and FIBTEM maximum clot firmness ≤ 18.5 mm at T1 increased the odds of death by 6.3 (95% CI 1.56-25.69, p = 0.010) and 9.1 (95% CI 1.88-44.39, p = 0.006). Fibrinogen < 3 g/L on postoperative day 1 (T1) was associated with a 9.5-fold increase of in-hospital mortality (95% CI 1.72-52.98, p = 0.01). Increased clotting activity was not associated with mortality.

CONCLUSIONS

Rotational thromboelastometry adds important information for identifying patients with TBI at increased risk of death. Early fibrinogen-related coagulation disorders are associated with mortality of patients with TBI undergoing major neurosurgical procedures. Maintenance of higher fibrinogen levels might be necessary for neurosurgical patients with acute TBI.

[Hemostatic disorders in neurosurgical patients: diagnostics and correction]

The authors analyzed the main causes of perioperative hemostatic disorders in neurosurgical patients. The problem of preoperative hemostatic screening, intraoperative and postoperative factors contributing to hemostatic disorders are considered. The authors also discuss the methods for correction of hemostatic disorders.

Implementation of Thromboelastometry for Coagulation Management in Isolated Traumatic Brain Injury Patients Undergoing Craniotomy

BACKGROUND Coagulopathy (CP) is a modifiable factor linked with secondary brain damage and poor outcome of traumatic brain injury (TBI). A shift towards goal-directed coagulation management has been observed recently. We investigated whether rotational thromboelastometry (ROTEM) based management could be successfully implemented in TBI patients and improve outcomes. MATERIAL AND METHODS A prospective, case-control study was performed. Adult patients with isolated TBI requiring craniotomy were included in this study. All patients underwent standard coagulation tests (SCT). Patients were identified as either in control group or in case group. Patients in the case group were additionally tested with ROTEM to specify their coagulation status. Management of the patients in the control group was based on SCT, whereas management of patients in the case group was guided by ROTEM. Outcome measures were as follows: CP rate, protocol adhesion, blood loss, transfusions, progressive hemorrhagic injury (PHI), re-intervention, Glasgow coma score (GCS) and Glasgow outcome score (GOS) at discharge, and in-hospital mortality. RESULTS There were 134 patients enrolled (65 patients in the control group and 69 patients in the case group). Twenty-six patients in the control group (40%) were found to be coagulopathic (control-CP subgroup) and 34 patients in the case group (49.3%) were found to be coagulopathic (case-CP subgroup). Twenty-five case-CP patients had ROTEM abnormalities triggering protocolized intervention, and 24 of them were treated. Overall ROTEM-based protocol adhesion rate was 85.3%. Postoperative ROTEM parameters of case-CP patients significantly improved, and the number of coagulopathic patients decreased. The incidence of PHI (control versus case group) and neurosurgical re-intervention (control-CP versus case-CP subgroup) was in favor of ROTEM guidance (P<0.05). Mortality and GCS and GOS at discharge did not differ significantly between groups. CONCLUSIONS ROTEM led to consistent coagulation management, improved clot quality, and decreased incidence of PHI and neurosurgical re-intervention. Further studies are needed to confirm benefits of ROTEM in cases of TBI.

Assessment of Platelet Function in Traumatic Brain Injury-A Retrospective Observational Study in the Neuro-Critical Care Setting

BACKGROUND

Despite seemingly functional coagulation, hemorrhagic lesion progression is a common and devastating condition following traumatic brain injury (TBI), stressing the need for new diagnostic techniques. Multiple electrode aggregometry (MEA) measures platelet function and could aid in coagulopathy assessment following TBI. The aims of this study were to evaluate MEA temporal dynamics, influence of concomitant therapy, and its capabilities to predict lesion progression and clinical outcome in a TBI cohort.

MATERIAL AND METHODS

Adult TBI patients in a neurointensive care unit that underwent MEA sampling were retrospectively included. MEA was sampled if the patient was treated with antiplatelet therapy, bled heavily during surgery, or had abnormal baseline coagulation values. We assessed platelet activation pathways involving the arachidonic acid receptor (ASPI), P2Y12 receptor, and thrombin receptor (TRAP). ASPI was the primary focus of analysis. If several samples were obtained, they were included. Retrospective data were extracted from hospital charts. Outcome variables were radiologic hemorrhagic progression and Glasgow Outcome Scale assessed prospectively at 12 months posttrauma. MEA levels were compared between patients on antiplatelet therapy. Linear mixed effect models and uni-/multivariable regression models were used to study longitudinal dynamics, hemorrhagic progression and outcome, respectively.

RESULTS

In total, 178 patients were included (48% unfavorable outcome). ASPI levels increased from initially low values in a time-dependent fashion (p < 0.001). Patients on cyclooxygenase inhibitors demonstrated low ASPI levels (p < 0.001), while platelet transfusion increased them (p < 0.001). The first ASPI (p = 0.039) and TRAP (p = 0.009) were significant predictors of outcome, but not lesion progression, in univariate analyses. In multivariable analysis, MEA values were not independently correlated with outcome.

CONCLUSION

A general longitudinal trend of MEA is identified in this TBI cohort, even in patients without known antiplatelet therapies. Values appear also affected by platelet inhibitory treatment and by platelet transfusions. While significant in univariate models to predict outcome, MEA values did not independently correlate to outcome or lesion progression in multivariable analyses. Further prospective studies to monitor coagulation in TBI patients are warranted, in particular the interpretation of pathological MEA values in patients without antiplatelet therapies.

Assessment of Haemostasis in patients undergoing emergent neurosurgery by rotational Elastometry and standard coagulation tests: a prospective observational study

BACKGROUND

Rotational elastometry (ROTEM) has been shown useful to monitor coagulation in trauma patients and in major elective surgery. In this study, we aimed to evaluate the utility of ROTEM to identify hemostatic disturbances and to predict the need for transfusion, compared with standard coagulation tests (SCTs) in patients undergoing emergent neurosurgery.

METHODS

Over a four-year period, adult patients who met criteria for emergent neurosurgery lasting more than 90 min were included in the study. Blood was collected preoperatively and analyzed with SCTs (international normalized ratio [INR], fibrinogen concentration, prothrombin time [PT or Quick], partial thromboplastine time [PTT], fibrinogen concentration and platelet count), and ROTEM assays. Correlations between SCTs and ROTEM parameters as well as receiver operating characteristic curves were performed to detect a coagulopathic pattern based on standard criteria and the need for transfusing at least 3 units of packed red blood cells (PRBCs).

RESULTS

In a cohort of 92 patients, 39 (42%) required ≥3 PRBCs and a coagulopathic pattern was identified in 32 patients based on SCTs and in 19 based on ROTEM. There was a strong correlation between PTT and INTEM coagulation time (R = 0.76) as well as between fibrinogen concentrations and FIBTEM maximal clot firmess (R = 0.70). The need for transfusion (≥ 3 PRBCs) was best predicted by the maximal clot firmess of EXTEM and FIBTEM (AUC of 0.72 and 0.71, respectively) and by fibrinogen concentration (AUC of 0.70).

CONCLUSIONS

In patients undergoing emergent neurosurgery, ROTEM analysis provides valid markers of early coagulopathy and predictors of blood transfusion requirements.

Point-of-care testing in the acute management of traumatic brain injury: Identifying the coagulopathic patient

Background:

The use of anticoagulants or antiplatelet medications has become increasingly common and is a well-established risk factor for worsening of hemorrhages in trauma patients. The current study addresses the need to investigate the efficacy of point-of-care tests (POC) as an adjunct to conventional coagulation testing in traumatic brain injury (TBI) patients.

Methods:

A retrospective review of 190 TBI patients >18 years of age who underwent both conventional and POC testing as part of their admission coagulopathy workup was conducted. Coagulation deficiency was defined as an international normalized ratio (INR) >1.4, a reaction time (r-value) on rapid thromboelastography >50 seconds, or a VerifyNow Aspirin (VN-ASA) level of < 550 Aspirin Reaction Units.

Results:

Among 190 patients, 91 (48%) disclosed a history of either warfarin or antiplatelet use or had documented INR >1.4. Of the 18 (9%) patients who reported warfarin use, 83% had elevated INR and 61% had elevated r-value. However, 41% of the patients without reported anticoagulant usage revealed significantly elevated r-value consistent with a post-traumatic hypocoagulable state. Of 64 (34%) patients who reported taking ASA, 51 (80%) demonstrated therapeutic VN-ASA. Interestingly, 31 of 126 (25%) patients not reporting ASA use were also noted to have therapeutic VN-ASA suggestive of platelet dysfunction.

Conclusions:

The coagulopathy POC panel consisting of r-TEG and VN-ASA successfully identified a subset of TBI patients with an occult coagulopathy that would have otherwise been missed. Standardization of these POC assays on admission in TBI may help guide patient resuscitation in the acute setting.

High prevalence of pharmacologically induced platelet dysfunction in the acute setting of brain injury

BACKGROUND

The management of patients with traumatic brain injury (TBI), primary intracerebral hemorrhage (pICH) and primary subarachnoid hemorrhage (pSAH) remains a highly demanding challenge in critical care medicine. Antithrombotic agents are one of the most relevant risk factors for poor outcome. However, in the acute setting of brain injury, information on preexisting medication might not be available. This group of patients is insufficiently characterized regarding pharmacologically induced platelet impairment.

METHODS

We retrospectively analyzed consecutive patients with TBI, pICH and pSAH admitted to our department with unknown preexisting medication. The impact of acetylsalicylic acid and ADP-receptor antagonists on platelet function was tested via the Multiplate analyzer. Patients' characteristics, management and the influence of platelet impairment on outcome were evaluated.

RESULTS

Within 25 months 103 patients with TBI (61), pICH (32) or pSAH (10) and unknown antithrombotic medication were admitted to our department. In 54 (52.4 %) of the patients reduced platelet function was detected, mainly caused by acetylsalicylic acid. In the TBI group, 30 patients (49.2 %) were identified, while Multiplate analysis detected platelet dysfunction in 19 (59.4 %) subjects in the pICH group and 5 in the pSAH group (50 %). In multivariable analysis the pathological Multiplate result was not associated with worse outcome; however, in our cohort 47 (87 %) patients received hemostatic therapy following detection of impaired platelet function.

CONCLUSION

Our results demonstrate the high frequency of pharmacologically impaired platelet function in patients with unknown preexisting medication. Early assessment of platelet function is an important tool to allow optimized treatment in these patients.