Matthew J. Pommerening

Time to first take-back operation predicts successful primary fascial closure in patients undergoing damage control laparotomy.

BACKGROUND Failure to achieve primary fascial closure (PFC) after damage control laparotomy is costly and carries great morbidity. We hypothesized that time from the initial laparotomy to the first take-back operation would be predictive of successful PFC. METHODS Trauma patients managed with open abdominal techniques after damage control laparotomy were prospectively followed at 14 Level 1 trauma centers during a 2-year period. Time to the first take-back was evaluated as a predictor of PFC using hierarchical multivariate logistic regression analysis. RESULTS A total of 499 patients underwent damage control laparotomy and were included in this analysis. PFC was achieved in 327 (65.5%) patients. Median time to the first take-back operation was 36 hours (interquartile range 24-48). After we adjusted for patient demographics, resuscitation volumes, and operative characteristics, increasing time to the first take-back was associated with a decreased likelihood of PFC. Specifically, each hour delay in return to the operating room (24 hours after initial laparotomy) was associated with a 1.1% decrease in the odds of PFC (odds ratio 0.989; 95% confidence interval 0.978-0.999; P = .045). In addition, there was a trend towards increased intra-abdominal complications in patients returning after 48 hours (odds ratio 1.80; 95% confidence interval 1.00-3.25; P = .05). CONCLUSION Data from this prospective, multicenter study demonstrate that delays in returning to the operating room after damage control laparotomy are associated with reductions in PFC. These findings suggest that emphasis should be placed on returning to the operating room within 24 hours after the initial laparotomy if possible (and no later than 48 hours).

Measuring thrombin generation as a tool for predicting hemostatic potential and transfusion requirements following trauma.

BACKGROUND Thrombin is the central coagulation protease that activates clotting proteins, triggers platelet aggregation, and converts fibrinogen to fibrin. Relationships between thrombin generation (TG) and clinical outcomes have not been defined following trauma. We hypothesize that TG is predictive of transfusion requirements and patient outcomes. METHODS Plasma was collected from 406 highest-level activation trauma patients upon admission and 29 healthy donors. Standard coagulation tests were performed, and TG was measured by calibrated automated thrombogram. Mann-Whitney U-tests were used to compare healthy versus trauma patients, and subgroup analyses were used to compare hypocoagulable versus nonhypocoagulable patients. Hypocoagulability was determined by area under the receiver operating characteristic curve analysis and was defined as peak TG of less than 250 nM. Multiple logistic regressions were used to assess the ability of TG to predict massive transfusion and mortality. RESULTS The median (interquartile range) age was 39 years (28–52 years), with an Injury Severity Score (ISS) of 17 (9–26). The trauma patients had greater TG (peak, 316.2 nM [270.1–355.5 nM]) compared with the healthy controls (124.6 nM [91.1–156.2 nM]), p < 0.001. The overall rate of hypocoagulability was 17%. The patients with peak TG of less than 250 nM were more severely injured (ISS, 25 [13–30] vs. 16 [9–25], p = 0.003); required more transfusions of red blood cells (p = 0.02), plasma (p = 0.003), and platelets (p = 0.006); had fewer hospital-free days (p = 0.001); and had increased mortality (10% vs. 3% at 24 hours, p = 0.006, and 29% vs. 11% at 30 days, p = 0.0004). Peak TG of less than 250 nM was predictive of massive transfusion (odds ratio, 4.18; p = 0.01) and 30-day mortality (odds ratio, 2.78; p = 0.02). Finally, peak TG was inversely correlated with standard coagulation tests. CONCLUSION While the physiologic response to injury is to upregulate plasma procoagulant activity, the patients with reduced TG required more transfusions and had poorer outcomes. Measuring TG may provide an exquisitely sensitive tool for detecting disturbances in the enzymatic phases of coagulation in critically injured patients. LEVEL OF EVIDENCE Prognostic/epidemiologic study, level III.

Early surgical intervention for blunt bowel injury: The Bowel Injury Prediction Score (BIPS)

BACKGROUND Computed tomography (CT) scan of the abdomen has been used for 30 years to evaluate the stable blunt trauma patient. However, the early diagnosis of blunt hollow viscus injury (BHVI) remains a challenge. Delayed diagnosis and intervention of BHVI lead to significant morbidity and mortality. This study aimed to identify a combination of radiographic and clinical variables present at admission that could lead to earlier surgical intervention for BHVI. METHODS Significant predictors were identified through a retrospective review of all blunt trauma patients admitted to a Level 1 trauma center from 2005 to 2010 with an admission CT of the abdomen/pelvis and diagnosed with any mesenteric injury. The Bowel Injury Prediction Score (BIPS) was calculated based on the following three elements with a point given for each outcome: white blood cell count of 17.0 or greater, abdominal tenderness, and CT scan grade for mesenteric injury of 4 or higher. RESULTS A total of 18,927 blunt trauma patients were admitted during the study period. Of these, 380 had a mesenteric injury, 110 met inclusion criteria, 60 had a surgical intervention, and 43 had BHVI. Of the 110 study patients, 43 (39%) had an immediate operation, 17 (16%) had a delayed operation (>4 hours), and 50 (46%) had no surgical intervention. The median BIPS for the immediate and delayed group was 2, while for the no-surgery group, the score was 0. Patients with a BIPS of 2 or greater were 19 times more likely to have a BHVI than patients with a BIPS of less than 2 (odds ratio, 19.2; 95% confidence interval, 6.78–54.36; p < 0.001). CONCLUSION Three predictors (admission CT scan grade of mesenteric injury, white blood cell count, and abdominal tenderness) were used to create a new bowel injury score, with a score of 2 or greater being strongly associated with BHVI. Prospective validation of these retrospective findings is warranted to fully assess the accuracy of the BIPS. LEVEL OF EVIDENCE Prognostic study, level III.

Hypercoagulability after energy drink consumption

BACKGROUND Energy drink consumption in the United States has more than doubled over the last decade and has been implicated in cardiac arrhythmias, myocardial infarction, and even sudden cardiac death. We hypothesized that energy drink consumption may increase the risk of adverse cardiovascular events by increasing platelet aggregation, thereby resulting in a relatively hypercoagulable state and increased risk of thrombosis. METHODS Thirty-two healthy volunteers aged 18-40 y were given 16 oz of bottled water or a standardized, sugar-free energy drink on two separate occasions, 1-wk apart. Beverages were consumed after an overnight fast over a 30-min period. Coagulation parameters and platelet function were measured before and 60 min after consumption using thrombelastography and impedance aggregometry. RESULTS No statistically significant differences in coagulation were detected using kaolin or rapid thrombelastography. In addition, no differences in platelet aggregation were detected using ristocetin, collagen, thrombin receptor-activating peptide, or adenosine diphosphate-induced multiple impedance aggregometry. However, compared to water controls, energy drink consumption resulted in a significant increase in platelet aggregation via arachidonic acid-induced activation (area under the aggregation curve, 72.4 U versus 66.3 U; P = 0.018). CONCLUSIONS Energy drinks are associated with increased platelet activity via arachidonic acid-induced platelet aggregation within 1 h of consumption. Although larger clinical studies are needed to further address the safety and health concerns of these drinks, the increased platelet response may provide a mechanism by which energy drinks increase the risk of adverse cardiovascular events.

Early Diagnosis of Clinically Significant Hyperfibrinolysis Using Thrombelastography Velocity Curves

BACKGROUND Clot lysis values (LY30) determined by rapid thrombelastography (rTEG) predict postinjury transfusion needs and mortality risk. However, the first derivative velocity curve values generated by rTEG measuring lysis—maximum rate of lysis (MRL) and total lysis (TL)—have not been evaluated. Although recent data support use of antifibrinolytics in trauma, the population that would benefit remains poorly defined. The purpose of this study was to determine if velocity curves more accurately predict large volume transfusions and early mortality than conventional rTEG values. STUDY DESIGN Conventional and velocity curve admission rTEG values of adult trauma patients were retrospectively evaluated for their ability to predict early transfusion of RBC and plasma, substantial bleeding, massive transfusion, and mortality. Patient outcomes were compared according to hyperfibrinolysis diagnosed by velocity curve values and the conventional LY30 cutoff. RESULTS There were 1,625 patients included. Clot lysis values predicted early transfusion of RBC (p = 0.003), but not plasma (p = 0.298), within 3 hours of arrival. With respect to velocity curves, MRL and TL predicted both early RBC and plasma transfusion (p < 0.05). All 3 parameters predicted massive transfusion, but only MRL and TL predicted substantial bleeding (odds ratio [OR] 3.1 and 2.9, respectively). In addition, MRL was a stronger predictor of 24-hour and 30-day mortality (p < 0.001) and was also available earlier after arrival than LY30 (p < 0.001). CONCLUSIONS Velocity curve measures of fibrinolysis are stronger predictors of early transfusion of blood components, bleeding, and mortality after trauma compared with conventional rTEG values. In addition, the MRL is more rapidly available after arrival, which may facilitate earlier diagnosis and treatment of clinically significant hyperfibrinolysis.

Hypercoagulability after injury in premenopausal females: A prospective, multicenter study

BACKGROUND Recent studies suggest there are gender-specific differences in injury response that may be related to coagulation. The objective of this study was to test the hypothesis that rapid thrombelastography (rTEG) coagulation profiles differ by gender. METHODS Adult trauma patients were prospectively followed at 3 level 1 trauma centers over a 14-month period. rTEG was obtained upon arrival and serially at several time points during the hospital stay. Female patients were stratified into premenopausal (≤50 years) and postmenopausal (>50 years) age groups with age-matched male cohorts. Values were analyzed using a repeated-measures multilevel linear model to evaluate the effect of gender on coagulation. RESULTS A total of 795 patients had serial rTEG data (24% female and 76% male). Compared with age-matched males, premenopausal females were more hypercoagulable by rTEG on admission (P < .001) and for the first 12 hours after arrival. Gender was an effect modifier for alpha angle (P = .02) and maximum amplitude (P = .04). Controlling for Injury Severity Score and mechanism of injury, age-matched males had a >4-fold increased risk of hypercoagulable complications than premenopausal females (odds ratio, 4.7; P = .038). CONCLUSION This prospective, multicenter study demonstrates that premenopausal females are relatively hypercoagulable compared with age-matched males early after injury. However, this did not translate into higher thromboembolic complications.