Dynamic coagulability after injury: Is delaying venous thromboembolism chemoprophylaxis worth the wait? Sumislawski JJ, Kornblith LZ, Conroy AS, Callcut RA, Cohen MJ. J Trauma Acute Care Surg. 2018 Nov; 85 (5):907-914.
This article is an important contribution to the trauma literature as it debunks several myths about trauma-induced coagulopathy and the timing of DVT chemoprophylaxis in severely injured trauma patients. Broadly, the authors evaluate the coagulation status on admission in severely injured trauma patients and how that changes over time. Furthermore, they evaluate how timing of DVT chemoprophylaxis affects VTE incidence.
The study is a secondary analysis of a larger prospective cohort study. Serial blood samples were collected from patients who met criteria for the highest (level 1) trauma activation (n= 898). Samples were collected at 6, 12, 24, 48, 72, 96 and 120 hrs. 31% of patients had a TBI. Extrinsic thromboelastometry (EXTEM) was performed on each sample using the ROTEM device. Based on Maximum Clot Firmness (MCF), three categories were defined: HYPO (<49mm), NORM (49-71mm), or HYPER (>71mm). They found that only 3% of the cohort were hypocoagulable on admission. 90% had normal coagulation and 7% were hypercoagulable on admission. The coagulapathic patients were predictably the most severely injured with the lowest median GCS, greatest base deficit and highest mortality between the groups. However, the coagulopathy largely resolved by 24 hours with only 1% remaining coagulopathic. Notably, an inflection point between 24 – 48 hours showed a trend to a hypercoagulable state with roughly 50% of patients who were initially HYPO or NORM becoming hypercoagulable at 120 hours. 71 (8%) patients developed a symptomatic VTE. While initial coagulation status did not predict VTE at any time point, initiation of chemoprophylaxis >72hours was associated with increased VTE development. When they looked at the cohort of patients that did not receive chemoprophylaxis within 72 hours, they were noted to be the most severely injured (median ISS = 29 vs. 21, head AIS = 4 vs. 0, GCS 11 vs. 14) with a prevalence of intracranial and orthopedic injuries. Importantly, the cohort whose chemoprophylaxis was withheld was not more coagulopathic at arrival (HYPO; 0% vs. 1%, p > 0.05) or at 72 hours (2% vs. 0%, p > 0.05).
After certain injuries like intracranial hemorrhage and blunt solid abdominal organ injury, it is common to withhold anticoagulation empirically out of a concern for bleeding risk. This paper largely debunks this myth and shows that these decisions are at least not evidence based. Additionally, though many believe that TBI promotes a prolonged coagulopathy that necessitates deferring prophylaxis, NO differences in coagulability were shown between patients with no TBI, isolated TBI and polytrauma at any time point. Further studies are needed to look at earlier administration (<24 hours) of VTE chemoprophylaxis based on correction of coagulopathy; nonetheless, this manuscript should put to bed the notion of delaying chemoprophylaxis beyond 72 hours in any trauma patient.
Early Seizure Prophylaxis in Traumatic Brain Injuries Revisited: A Prospective Observational Study. Khor D, Wu J, Hong Q, Benjamin E, Xiao S, Inaba K, Demetriades D. World J Surg. 2018 Jun; 42 (6): 1727-1732.
The current Brain Trauma Foundation guidelines recommend early pharmacological seizure prophylaxis. This recommendation is largely based on a study from 1990 by Temkin et. al. that showed significantly lower incidence of early seizures after TBI when phenytoin was given for 1 year when compared to placebo (3.6% vs. 14.2%). There was no effect on late seizures. These results could not be replicated with subsequent analyses. Additionally, several studies have challenged the efficacy and safety of this practice, which has resulted in varied use of seizure prophylaxis around the world and little agreement on its use or duration of treatment.
This article attempts to compare the incidence of early clinical seizures (within 7 days from injury) following TBI between two large hospitals: one that routinely uses seizure prophylaxis and one that does not use seizure prophylaxis. This is a prospective observational study comparing a U.S. level 1 trauma center and large hospital in Shenzhen, China. At the U.S. Center, all patients received seizure prophylaxis with levetiracetam for 7 days. All patients with blunt TBI and a CT scan showing intracranial hemorrhage or diffuse axonal injury were included in the study. The subjects were monitored for clinical seizures daily for the first 7 post-injury days. 522 patients were included. 272 patients at the U.S. center received seizure prophylaxis, 250 at the Chinese center did not receive any prophylaxis. Overall 3.7% of patients who received prophylaxis developed early seizures compared with 2.8% who did not receive prophylaxis (p=0.593). There was no significant difference. Analyses of isolated TBI, those that received decompressive craniectomy and by head AIS (3-5) sub-groups also showed no significant difference between the 2 cohorts. Interestingly, patients with an admission GCS < 9 had an overall seizure incidence of 7%; however, the prophylaxis group showed a trend toward reduced seizure incidence (4.3% vs. 14.3%, p = 0.062) but did not reach significance. Though there are significant differences in the way TBI patients were managed between these two centers, the data seem to indicate that most TBI patients do not need seizure prophylaxis at all. The sub-group with a GCS < 9 may be an exception to this conclusion that requires further study. Given that the p-value approached significance, this subgroup finding may represent a type II statistical error.
Factors Contributing to Morbidity after Combined Arterial and Venous Lower Extremity Trauma. Manley NR, Magnotti LJ, Fabian TC, Cutshall MB, Croce MA, Sharpe JP. Am Surg. 2018 Jul 1; 84 (7):1217-1222.
The purpose of this study was to evaluate how management of lower extremity major venous injuries affects outcomes for combined arterial and venous injury. This was a single center retrospective review. Patients who had combined injuries to the common iliac, external iliac, SFA or popliteal arteries and veins were included. The study compared those who had the associated vein ligated vs. those that any vein repair. Primary outcomes included development of muscle ischemia requiring debridement and necessity for secondary intervention of the arterial repair (i.e. thrombosis/embolism). There were 40 injuries where the vein was ligated and 30 where the vein was repaired. They found that there was no difference in ischemia time between the two groups. Also, vein ligation did not increase the need for muscle debridement, secondary interventions or amputation.
Degree of shock during the first operation appeared to be the biggest risk factor for secondary intervention. Patients who received the most blood product transfusions (13units vs. 6 units, p= 0.02) had significantly increased incidence of muscle debridement, secondary arterial interventions and amputations. Based on these data the paper makes two conclusions. First, vein ligation in concomitant injuries is a safe option that does not increase morbidity. Second, patient morbidity after extremity vascular trauma is mostly related to the degree of shock present during the initial operation.