Effect of remote ischemic conditioning on the immune-inflammatory profile in patients with traumatic hemorrhagic shock in a randomized controlled trial

Resuscitation induced ischemia/reperfusion predisposes trauma patients to systemic inflammation and organ dysfunction. We investigated the effect of remote ischemic conditioning (RIC), a treatment shown to prevent ischemia/reperfusion injury in experimental models of hemorrhagic shock/resuscitation, on the systemic immune-inflammatory profile in trauma patients in a randomized trial. We conducted a prospective, single-centre, double-blind, randomized, controlled trial involving trauma patients sustaining blunt or penetrating trauma in hemorrhagic shock admitted to a Level 1 trauma centre. Patients were randomized to receive RIC (four cycles of 5-min pressure cuff inflation at 250 mmHg and deflation on the thigh) or a Sham intervention. The primary outcomes were neutrophil oxidative burst activity, cellular adhesion molecule expression, and plasma levels of myeloperoxidase, cytokines and chemokines in peripheral blood samples, drawn at admission (pre-intervention), 1 h, 3 h, and 24 h post-admission. Secondary outcomes included ventilator, ICU and hospital free days, incidence of nosocomial infections, 24 h and 28 day mortality. 50 eligible patients were randomized; of which 21 in the Sham group and 18 in the RIC group were included in the full analysis. No treatment effect was observed between Sham and RIC groups for neutrophil oxidative burst activity, adhesion molecule expression, and plasma levels of myeloperoxidase and cytokines. RIC prevented significant increases in Th2 chemokines TARC/CCL17 (P < 0.01) and MDC/CCL22 (P < 0.05) at 24 h post-intervention in comparison to the Sham group. Secondary clinical outcomes were not different between groups. No adverse events in relation to the RIC intervention were observed. Administration of RIC was safe and did not adversely affect clinical outcomes. While trauma itself modified several immunoregulatory markers, RIC failed to alter expression of the majority of markers. However, RIC may influence Th2 chemokine expression in the post resuscitation period. Further investigation into the immunomodulatory effects of RIC in traumatic injuries and their impact on clinical outcomes is warranted.ClinicalTrials.gov number: NCT02071290.

Harmful or Physiologic: Diagnosing Fibrinolysis Shutdown in a Trauma Cohort With Rotational Thromboelastometry

BACKGROUND

Despite its central role in early trauma coagulopathy, abnormal fibrinolysis continues to be poorly understood. Excessive fibrinolysis is a known contributor to mortality. Recent studies with thromboelastography (TEG) suggest decreased fibrinolysis (or shutdown) may be just as harmful. Considering the broad use of 2 different viscoelastic assays, which are not interchangeable, we proposed for the first time to define and characterize fibrinolysis shutdown using rotational thromboelastometry (ROTEM).

METHODS

Retrospective cohort study of severely injured patients with admission ROTEM. Shutdown was defined by the best Youden index value of the maximum lysis. Fibrinolysis phenotypes were physiologic, hyperfibrinolysis, and shutdown. Multivariable logistic regression evaluated association between Injury Severity Score and the fibrinolysis phenotypes, and the association among shutdown phenotype with mortality, blood transfusion, and thrombotic events.

RESULTS

Five hundred fifty patients were included. Maximum lysis <3.5% was selected to define shutdown. Predominant phenotype was physiologic (70.7%), followed by shutdown (25.6%) and hyperfibrinolysis (3.6%). Shutdown patients had higher Injury Severity Score, lower base excess, and required more transfusions than physiologic group. Shutdown was associated with acidosis (base excess: odds ratio [OR] for a 1 mEq/L increase, 0.93; 95% confidence interval [CI], 0.88-0.98; P = .0094) and the combination of clotting derangements, higher clot firmness (maximum clot formation: OR for a 2 mm increase, 1.8; 95% CI, 1.5-2.27; P < .0001), lower fibrinogen (OR for a 0.5 g/dL decrease, 1.47; 95% CI, 1.18-1.84; P = .0006), and poor clot formation dynamics (clot formation time: OR for a 5 seconds increase, 1.25; 95% CI, 1.15-1.36; P < .0001). Fibrinolysis shutdown was not independently associated with mortality (OR, 0.61; 95% CI, 0.28-1.33; P = .21), massive transfusion (OR, 2.14; 95% CI, 0.79-5.74; P = .1308), or thrombotic events (OR, 1.08; 95% CI, 0.37-3.15; P = .874). Shutdown was associated with increased 24-hour transfusion (OR, 2.24; 95% CI, 1.24-4.04; P = .007).

CONCLUSIONS

Despite higher injury burden, evidence of shock, and greater need for blood transfusions, early fibrinolysis shutdown was not associated with mortality, suggesting that it could represent an adaptive physiologic response to life-threatening trauma.

Catecholamines as outcome markers in isolated traumatic brain injury: the COMA-TBI study

Background

Elevated catecholamine levels might be associated with unfavorable outcome after traumatic brain injury (TBI). We investigated the association between catecholamine levels in the first 24 h post-trauma and functional outcome in patients with isolated moderate-to-severe TBI.

Methods

A cohort of 174 patients who sustained isolated blunt TBI was prospectively enrolled from three Level-1 Trauma Centers. Epinephrine (Epi) and norepinephrine (NE) concentrations were measured at admission (baseline), 6, 12 and 24 h post-injury. Outcome was assessed at 6 months by the extended Glasgow Outcome Scale (GOSE) score. Fractional polynomial plots and logistic regression models (fixed and random effects) were used to study the association between catecholamine levels and outcome. Effect size was reported as the odds ratio (OR) associated with one logarithmic change in catecholamine level.

Results

At 6 months, 109 patients (62.6%) had an unfavorable outcome (GOSE 5–8 vs. 1–4), including 51 deaths (29.3%). Higher admission levels of Epi were associated with a higher risk of unfavorable outcome (OR, 2.04, 95% CI: 1.31–3.18, p = 0.002) and mortality (OR, 2.86, 95% CI: 1.62–5.01, p = 0.001). Higher admission levels of NE were associated with higher risk of unfavorable outcome (OR, 1.59, 95% CI: 1.07–2.35, p = 0.022) but not mortality (OR, 1.45, 95% CI: 0.98–2.17, p = 0.07). There was no relationship between the changes in Epi levels over time and mortality or unfavorable outcome. Changes in NE levels with time were statistically associated with a higher risk of mortality, but the changes had no relation to unfavorable outcome.

Conclusions

Elevated circulating catecholamines, especially Epi levels on hospital admission, are independently associated with functional outcome and mortality after isolated moderate-to-severe TBI.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1620-6) contains supplementary material, which is available to authorized users.

A Geospatial Analysis of Severe Firearm Injuries Compared to Other Injury Mechanisms: Event Characteristics, Location, Timing, and Outcomes

OBJECTIVES

Relatively little is known about the context and location of firearm injury events. Using a prospective cohort of trauma patients, we describe and compare severe firearm injury events to other violent and nonviolent injury mechanisms regarding incident location, proximity to home, time of day, spatial clustering, and outcomes.

METHODS

This was a secondary analysis of a prospective cohort of injured children and adults with hypotension or Glasgow Coma Scale score ≤ 8, injured by one of four primary injury mechanisms (firearm, stabbing, assault, and motor vehicle collision [MVC]) who were transported by emergency medical services to a Level I or II trauma center in 10 regions of the United States and Canada from January 1, 2010, through June 30, 2011. We used descriptive statistics and geospatial analyses to compare the injury groups, distance from home, outcomes, and spatial clustering.

RESULTS

There were 2,079 persons available for analysis, including 506 (24.3%) firearm injuries, 297 (14.3%) stabbings, 339 (16.3%) assaults, and 950 (45.7%) MVCs. Firearm injuries resulted in the highest proportion of serious injuries (66.3%), early critical resources (75.3%), and in-hospital mortality (53.5%). Injury events occurring within 1 mile of a patient's home included 53.9% of stabbings, 49.2% of firearm events, 41.3% of assaults, and 20.0% of MVCs; the non-MVC events frequently occurred at home. While there was geospatial clustering, 94.4% of firearm events occurred outside of geographic clusters.

CONCLUSIONS

Severe firearm events tend to occur within a patient's own neighborhood, often at home, and generally outside of geospatial clusters. Public health efforts should focus on the home in all types of neighborhoods to reduce firearm violence.

Inflammatory cytokine and chemokine profiles are associated with patient outcome and the hyperadrenergic state following acute brain injury

Background

Traumatic brain injury (TBI) elicits intense sympathetic nervous system (SNS) activation with profuse catecholamine secretion. The resultant hyperadrenergic state is linked to immunomodulation both within the brain and systemically. Dysregulated inflammation post-TBI exacerbates secondary brain injury and contributes to unfavorable patient outcomes including death. The aim of this study was to characterize the early dynamic profile of circulating inflammatory cytokines/chemokines in patients admitted for moderate-to-severe TBI, to examine interrelationships between these mediators and catecholamines, as well as clinical indices of injury severity and neurological outcome.

Methods

Blood was sampled from 166 isolated TBI patients (aged 45 ± 20.3 years; 74.7 % male) on admission, 6-, 12-, and 24-h post-injury and from healthy controls (N = 21). Plasma cytokine [interleukin (IL)-1β, -2, -4, -5, -10, -12p70, -13, tumor necrosis factor (TNF)-α, interferon (IFN)-γ] and chemokine [IL-8, eotaxin, eotaxin-3, IFN-γ-induced protein (IP)-10, monocyte chemoattractant protein (MCP)-1, -4, macrophage-derived chemokine (MDC), macrophage inflammatory protein (MIP)-1β, thymus activation regulated chemokine (TARC)] concentrations were analyzed using high-sensitivity electrochemiluminescence multiplex immunoassays. Plasma catecholamines [epinephrine (Epi), norepinephrine (NE)] were measured by immunoassay. Neurological outcome at 6 months was assessed using the extended Glasgow outcome scale (GOSE) dichotomized as good (>4) or poor (≤4) outcomes.

Results

Patients showed altered levels of IL-10 and all chemokines assayed relative to controls. Significant differences in a number of markers were evident between moderate and severe TBI cohorts. Elevated IL-8, IL-10, and TNF-α, as well as alterations in 8 of 9 chemokines, were associated with poor outcome at 6 months. Notably, a positive association was found between Epi and IL-1β, IL-10, Eotaxin, IL-8, and MCP-1. NE was positively associated with IL-1β, IL-10, TNF-α, eotaxin, IL-8, IP-10, and MCP-1.

Conclusions

Our results provide further evidence that exaggerated SNS activation acutely after isolated TBI in humans may contribute to harmful peripheral inflammatory cytokine/chemokine dysregulation. These findings are consistent with a potentially beneficial role for therapies aimed at modulating the inflammatory response and hyperadrenergic state acutely post-injury.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0500-3) contains supplementary material, which is available to authorized users.

Fresh frozen plasma: red blood cells (1:2) coagulation effect is equivalent to 1:1 and whole blood

BACKGROUND

Preemptive treatment of trauma-associated coagulopathy involves transfusion of fresh frozen plasma (FFP) at 1:1 ratio with red blood cells (RBCs), but the optimal ratio remains controversial. In combat theaters, fresh whole blood (FWB) is also an option. The objective of this study was to determine the effect of FFP:RBC ratios 1:1, 1:2, 1:3 and FWB on coagulation during resuscitation.

MATERIALS AND METHODS

Thirty-six rats were randomized in the following six groups: Group 1: sham; Group 2: hemorrhage followed by sole lactated Ringer (LR) infusion; Group 3: FFP:RBC (1:1); Group 4: FFP:RBC (1:2); Group 5: FFP:RBC (1:3); Group 6: FWB transfusion. Another 25 animals were used for blood harvesting. Hemorrhage was induced by withdrawing 40% of total blood volume, mean arterial pressure (MAP) decreased to 45% of baseline, and laparotomy. Animals underwent LR infusion followed by blood product transfusion preset for each group. Blood samples were obtained at baseline and in the 105th minute for thromboelastometry and lactate.

RESULTS

Hemorrhage caused a significant decrease in MAP and increase in lactate (P < 0.05). MAP was persistently low in group 2 despite fluid infusion (P < 0.05), but not in the other groups after 20 min of resuscitation. Mean clot formation time, alpha angle, and maximum clot firmness decreased significantly (P < 0.05) in group 2 (LR) and group 5 (1:3) compared with other groups.

CONCLUSIONS

FFP:RBC in a 1:2 ratio optimally harnessed hemostatic resuscitation and prudent use of blood products compared with 1:1 and 1:3 ratios and to FWB transfusion.

Blood Biomarkers in Moderate-To-Severe Traumatic Brain Injury: Potential Utility of a Multi-Marker Approach in Characterizing Outcome

BACKGROUND

Blood biomarkers are valuable tools for elucidating complex cellular and molecular mechanisms underlying traumatic brain injury (TBI). Profiling distinct classes of biomarkers could aid in the identification and characterization of initial injury and secondary pathological processes. This study characterized the prognostic performance of a recently developed multi-marker panel of circulating biomarkers that reflect specific pathogenic mechanisms including neuroinflammation, oxidative damage, and neuroregeneration, in moderate-to-severe TBI patients.

MATERIALS AND METHODS

Peripheral blood was drawn from 85 isolated TBI patients (n = 60 severe, n = 25 moderate) at hospital admission, 6-, 12-, and 24-h post-injury. Mortality and neurological outcome were assessed using the extended Glasgow Outcome Scale. A multiplex platform was designed on MULTI-SPOT(®) plates to simultaneously analyze human plasma levels of s100 calcium binding protein beta (s100B), glial fibrillary acidic protein (GFAP), neuron specific enolase (NSE), brain-derived neurotrophic factor (BDNF), monocyte chemoattractant protein (MCP)-1, intercellular adhesion molecule (ICAM)-5, and peroxiredoxin (PRDX)-6. Multivariable logistic regression and area under the receiver-operating characteristic curve (AUC) were used to evaluate both individual and combined predictive abilities of these markers for 6-month neurological outcome and mortality after TBI.

RESULTS

Unfavorable neurological outcome was associated with elevations in s100B, GFAP, and MCP-1. Mortality was related to differences in six of the seven markers analyzed. Combined admission concentrations of s100B, GFAP, and MCP-1 were able to discriminate favorable versus unfavorable outcome (AUC = 0.83), and survival versus death (AUC = 0.87), although not significantly better than s100B alone (AUC = 0.82 and 0.86, respectively).

CONCLUSION

The multi-marker panel of TBI-related biomarkers performed well in discriminating unfavorable and favorable outcomes in the acute period after moderate-to-severe TBI. However, the combination of these biomarkers did not outperform s100B alone.

Multivariate analysis of traumatic brain injury: development of an assessment score

Important challenges for the diagnosis and monitoring of mild traumatic brain injury (mTBI) include the development of plasma biomarkers for assessing neurologic injury, monitoring pathogenesis, and predicting vulnerability for the development of untoward neurologic outcomes. While several biomarker proteins have shown promise in this regard, used individually, these candidates lack adequate sensitivity and/or specificity for making a definitive diagnosis or identifying those at risk of subsequent pathology. The objective for this study was to evaluate a panel of six recognized and novel biomarker candidates for the assessment of TBI in adult patients. The biomarkers studied were selected on the basis of their relative brain-specificities and potentials to reflect distinct features of TBI mechanisms including (1) neuronal damage assessed by neuron-specific enolase (NSE) and brain derived neurotrophic factor (BDNF); (2) oxidative stress assessed by peroxiredoxin 6 (PRDX6); (3) glial damage and gliosis assessed by glial fibrillary acidic protein and S100 calcium binding protein beta (S100b); (4) immune activation assessed by monocyte chemoattractant protein 1/chemokine (C–C motif) ligand 2 (MCP1/CCL2); and (5) disruption of the intercellular adhesion apparatus assessed by intercellular adhesion protein-5 (ICAM-5). The combined fold-changes in plasma levels of PRDX6, S100b, MCP1, NSE, and BDNF resulted in the formulation of a TBI assessment score that identified mTBI with a receiver operating characteristic (ROC) area under the curve of 0.97, when compared to healthy controls. This research demonstrates that a profile of biomarker responses can be used to formulate a diagnostic score that is sensitive for the detection of mTBI. Ideally, this multivariate assessment strategy will be refined with additional biomarkers that can effectively assess the spectrum of TBI and identify those at particular risk for developing neuropathologies as consequence of a mTBI event.

Vagus nerve stimulation improves coagulopathy in hemorrhagic shock: a thromboelastometric animal model study

Introduction

Inflammation plays a major role in the multifactorial process of trauma associated coagulopathy. The vagus nerve regulates the cholinergic anti-inflammatory pathway. We hypothesized that efferent vagus nerve stimulation (VNS) can improve coagulopathy by modulating the inflammatory response to hemorrhage.

Methods

Wistar rats (n = 24) were divided in 3 groups: Group (G1) Sham hemorrhagic shock (HS); (G2) HS w/o VNS; (G3) HS followed by division of the vagus nerves and VNS of the distal stumps. Hemorrhage (45% of baseline MAPx15 minutes) was followed by normotensive resuscitation with LR. Vagus nerves were stimulated (3.5 mA, 5 Hz) for 30 sec 7 times. Samples were obtained at baseline and at 60 minutes for thromboelastometry (Rotem®) and cytokine assays (IL-1 and IL-10). ANOVA was used for statistical analysis; significance was set at p < 0.05.

Results

Maximum clot firmness (MCF) significantly decreased in G2 after HS (71.5 ± 1.5 vs. 64 ± 1.6) (p < 0.05). MCF significantly increased in G3 compared to baseline (67.3 ± 2.7 vs. 71.5 ± 1.2) (p < 0.05). G3 also showed significant improvement in Alfa angle, and Clot Formation Time (CFT) compared to baseline. IL-1 increased significantly in group 2 and decrease in group 3, while IL-10 increased in group 3 (p < 0.05).

Conclusions

Electrical stimulation of efferent vagus nerves, during resuscitation (G3), decreases inflammatory response to hemorrhage and improves coagulation.

Selective non-operative management of abdominal gunshot wounds: survey of practise

BACKGROUND

There is a growing body of evidence attesting to the effectiveness and safety of selective non-operative management (SNOM) of abdominal gunshot wounds. However, much of the research which supports this conclusion has originated from a few centres, and the actual utilisation of SNOM by trauma surgeons is not known. We therefore conducted a survey to assess the acceptance of this strategy and evaluate variations in practise.

METHODS

Electronic questionnaire survey of trauma surgeons in the United States of America, Canada, Brazil, and South Africa. Responses were compared using Chi(2) and Fisher's exact tests.

RESULTS

183 replies were received. 105 (57%) respondents practise SNOM of abdominal gunshot wounds, but there are marked regional variations in the acceptance of this strategy (p<0.01). Respondents who had completed trauma (p<0.01) or critical care (p<0.01) fellowships, and those who practise in a higher volume centre (defined as >50 penetrating abdominal injuries seen per year) (p<0.01) are more likely to practise SNOM of gunshot wounds. Most surgeons who practise SNOM regard peritonitis, omental and bowel evisceration, and being unable to evaluate a patient as a contraindication to attempting non-operative management. Almost all regard CT as essential. Respondents' preparedness to consider SNOM is related to injury extent.

CONCLUSIONS

SNOM of abdominal gunshot wounds is practised by trauma surgeons in all four countries surveyed, but is not universally accepted, and there are variations in how it is practised.

Pulmonary emboli after blunt trauma: timing, clinical characteristics and natural history

BACKGROUND

Venous thromboembolism (VTE) frequently complicates the recovery of trauma patients, and contributes to morbidity and mortality. Recent studies showed an increase in diagnosis of pulmonary embolism (PE) mainly in the early or immediate period after trauma. The clinical significance of those incidental PEs is unclear.

METHODS

The study cohort included all blunt trauma patients who had a contrast-enhanced CT of the chest performed as part of their initial trauma assessment from January 1, 2005 to January 31, 2007 in a large academic Canadian trauma centre. Patients diagnosed with PE at any point during admission were identified using our institutional trauma registry. All chest CT scans and electronic charts were reviewed. Patients were classified according to time of PE detection (immediate, early or late) and symptoms (asymptomatic or symptomatic). The clinical characteristics and hospital course of the patients who were diagnosed with immediate PE were described.

RESULTS

1259 blunt trauma patients were reviewed. Six patients presented with immediate PE (0.5%); nine patients were found to have early PE (0.7%) and 13 had late PE (1.0%). All six of the patients with immediate PE were classified as asymptomatic. Five of the nine patients with early PE were symptomatic and all 13 patients who developed late PE were symptomatic. Amongst the six patients with immediate PE, five survived 24h hospitalisation. Four of them were managed with prophylactic low molecular weight heparin and no other thromboembolic events were observed during admission or after discharge.

CONCLUSIONS

The increased use of advanced CT technology in trauma patients has resulted in an increased diagnosis of incidental PEs that are asymptomatic. The clinical significance and management of these small, incidental PE are uncertain and further studies are needed to clarify the natural history of this controversial finding.

Permissive hypotension does not reduce regional organ perfusion compared to normotensive resuscitation: animal study with fluorescent microspheres

Introduction

The objective of this study was to investigate regional organ perfusion acutely following uncontrolled hemorrhage in an animal model that simulates a penetrating vascular injury and accounts for prehospital times in urban trauma. We set forth to determine if hypotensive resuscitation (permissive hypotension) would result in equivalent organ perfusion compared to normotensive resuscitation.

Methods

Twenty four (n=24) male rats randomized to 4 groups: Sham, No Fluid (NF), Permissive Hypotension (PH) (60% of baseline mean arterial pressure - MAP), Normotensive Resuscitation (NBP). Uncontrolled hemorrhage caused by a standardised injury to the abdominal aorta; MAP was monitored continuously and lactated Ringer’s was infused. Fluorimeter readings of regional blood flow of the brain, heart, lung, kidney, liver, and bowel were obtained at baseline and 85 minutes after hemorrhage, as well as, cardiac output, lactic acid, and laboratory tests; intra-abdominal blood loss was assessed. Analysis of variance was used for comparison.

Results

Intra-abdominal blood loss was higher in NBP group, as well as, lower hematocrit and hemoglobin levels. No statistical differences in perfusion of any organ between PH and NBP groups. No statistical difference in cardiac output between PH and NBP groups, as well as, in lactic acid levels between PH and NBP. NF group had significantly higher lactic acidosis and had significantly lower organ perfusion.

Conclusions

Hypotensive resuscitation causes less intra-abdominal bleeding than normotensive resuscitation and concurrently maintains equivalent organ perfusion. No fluid resuscitation reduces intra-abdominal bleeding but also significantly reduces organ perfusion.

A technical modification for percutaneous tracheostomy: prospective case series study on one hundred patients

The purpose of this study is to describe a technical modification of percutaneous tracheostomy that combines principles of the Percu Twist™ and the Griggs-Portex® methods in a reusable kit. One hundred patients underwent the procedure. There were no false passage, tube misplacement, or deaths related to the procedure. There were two minor bleedings managed conservatively. The technical modification described in this study is safe and simple to execute.

The Toronto prehospital hypertonic resuscitation--head injury and multiorgan dysfunction trial: feasibility study of a randomized controlled trial

OBJECTIVE

The aim of the study was to evaluate the feasibility of a prehospital trial comparing hypertonic saline and dextran (HSD) with normal saline (NS) in blunt head injury patients.

DESIGN

The study used a double blind randomized trial.

SETTING

The study was conducted in air and land emergency medical services and 2 trauma centers serving a population of 4 million people.

PATIENTS

The study population consisted of head injured, blunt trauma adult patients with a Glasgow Coma Scale of lower than 9.

INTERVENTIONS

We used 250 mL of HSD vs NS given within 4 hours of the accident.

MEASUREMENTS

The specific objectives were to assess protocol-related logistical issues, randomization, HSD safety, and follow up rates and to obtain survival and neurocognitive end point estimates.

MAIN RESULTS

Of 132 eligible patients, 113 were randomized. Nineteen eligible patients were missed because of lack of time (9 [22%]), paramedic discretion (3 [7%]), the paramedic forgot (6 [15%]), and the paramedic refused (1 [2%]). Randomization compliance was 96% (109/113). Four randomized cases met exclusion criteria: penetrating trauma (1), cardiac arrest (2), and fall from standing (1). Three randomized patients were excluded from the final analysis: 2 patients received less than 50 mL of study solution due to an interstitial intravenous line and 1 lost randomization identification. Fifty patients (47%) were randomized to HSD and 56 (53%) to NS. Mean injury severity score was 32.7 for HSD and 32.6 for NS. There was no difference in length of stay, Sequential Organ Failure Assessment maximum, Multiple Organ Dysfunction Score maximum, delta Multiple Organ Dysfunction Score, or Apache scores. Initial head scans scored 3 or higher by Marshall classification for 12 HSD and 11 NS patients. Zero adverse events occurred, and follow-up for the primary outcome was 100%. Alive at 30 days for HSD and NS, respectively, was 70% (35/50) and 75% (42/56) and at discharge was 68% (34/50) and 73% (41/56). Only 49.3% (37/77) of surviving patients consented to follow-up at 4 months and 89% (33/37) completed the assessment. Disability rating scale (median, interquartile range) was 3 (0, 6) for HSD and was 0 (0, 6) for NS. Glasgow Outcome Scale Evaluation was higher than 4 for HSD (12/12 [100%]) and NS (15/21 [72%]). Functional Independence Measure (mean, SD) was 62 (37) for HSD and 80 (32) for NS.

CONCLUSIONS

It is feasible to conduct a prehospital randomized controlled trial with HSD for treatment of blunt trauma patients with head injuries; however, consent for neurofunctional outcomes in this cohort is problematic and threatens the feasibility of definitive trials using these potentially meaningful end points.

Rabbit model of uncontrolled hemorrhagic shock and hypotensive resuscitation

Clinically relevant animal models capable of simulating traumatic hemorrhagic shock are needed. We developed a hemorrhagic shock model with male New Zealand rabbits (2200-2800 g, 60-70 days old) that simulates the pre-hospital and acute care of a penetrating trauma victim in an urban scenario using current resuscitation strategies. A laparotomy was performed to reproduce tissue trauma and an aortic injury was created using a standardized single puncture to the left side of the infrarenal aorta to induce hemorrhagic shock similar to a penetrating mechanism. A 15-min interval was used to simulate the arrival of pre-hospital care. Fluid resuscitation was then applied using two regimens: normotensive resuscitation to achieve baseline mean arterial blood pressure (MAP, 10 animals) and hypotensive resuscitation at 60% of baseline MAP (10 animals). Another 10 animals were sham operated. The total time of the experiment was 85 min, reproducing scene, transport and emergency room times. Intra-abdominal blood loss was significantly greater in animals that underwent normotensive resuscitation compared to hypotensive resuscitation (17.1 ± 2.0 vs 8.0 ± 1.5 mL/kg). Antithrombin levels decreased significantly in normotensive resuscitated animals compared to baseline (102 ± 2.0 vs 59 ± 4.1%), sham (95 ± 2.8 vs 59 ± 4.1%), and hypotensive resuscitated animals (98 ± 7.8 vs 59 ± 4.1%). Evidence of re-bleeding was also noted in the normotensive resuscitation group. A hypotensive resuscitation regimen resulted in decreased blood loss in a clinically relevant small animal model capable of reproducing hemorrhagic shock caused by a penetrating mechanism.

Resuscitation with hypertonic saline-dextran reduces serum biomarker levels and correlates with outcome in severe traumatic brain injury patients

In the treatment of severe traumatic brain injury (TBI), the choice of fluid and osmotherapy is important. There are practical and theoretical advantages to the use of hypertonic saline. S100B, neuron-specific enolase (NSE), and myelin-basic protein (MBP) are commonly assessed biomarkers of brain injury with potential utility as diagnostic and prognostic indicators of outcome after TBI, but they have not previously been studied in the context of fluid resuscitation. This randomized controlled trial compared serum concentrations of S100B, NSE, and MBP in adult severe TBI patients resuscitated with 250 mL of 7.5% hypertonic saline plus 6% dextran70 (HSD; n = 31) versus 0.9% normal saline (NS; n = 33), and examined their relationship with neurological outcome at discharge. Blood samples drawn on admission (<or=3 h post-injury), and at 12, 24, and 48 h post-resuscitation were assayed by ELISA for the selected biomarkers. Serial comparisons of biomarker concentrations were made by ANOVA, and relationships between biomarkers and outcome were assessed by multiple regression. On admission, mean (+/-SEM) S100B and NSE concentrations were increased 60-fold (0.73 +/- 0.08 microg/L) and sevenfold (37.0 +/- 4.8 microg/L), respectively, in patients resuscitated with NS, compared to controls (0.01 +/- 0.01 and 6.2 +/- 0.6, respectively). Compared with NS resuscitation, S100B and NSE were twofold and threefold lower in HSD-treated patients and normalized within 12 h. MBP levels were not significantly different from controls in either treatment arm until 48 h post-resuscitation, when a delayed increase (0.58 +/- 0.29 microg/L) was observed in NS-treated patients. Biomarkers were elevated in the patient group showing an unfavorable outcome. HSD-resuscitated patients with favorable outcomes exhibited the lowest serum S100B and NSE concentrations, while maximal levels were found in NS-treated patients with unfavorable outcomes. The lowest biomarker levels were seen in survivors resuscitated with HSD, while maximal levels were in NS-resuscitated patients with fatal outcome. Pre-hospital resuscitation with HSD is associated with a reduction in serum S100B, NSE, and MBP concentrations, which are correlated with better outcome after severe TBI.

Prehospital resuscitation with hypertonic saline-dextran modulates inflammatory, coagulation and endothelial activation marker profiles in severe traumatic brain injured patients

Background

Traumatic brain injury (TBI) initiates interrelated inflammatory and coagulation cascades characterized by wide-spread cellular activation, induction of leukocyte and endothelial cell adhesion molecules and release of soluble pro/antiinflammatory cytokines and thrombotic mediators. Resuscitative care is focused on optimizing cerebral perfusion and reducing secondary injury processes. Hypertonic saline is an effective osmotherapeutic agent for the treatment of intracranial hypertension and has immunomodulatory properties that may confer neuroprotection. This study examined the impact of hypertonic fluids on inflammatory/coagulation cascades in isolated head injury.

Methods

Using a prospective, randomized controlled trial we investigated the impact of prehospital resuscitation of severe TBI (GCS < 8) patients using 7.5% hypertonic saline in combination with 6% dextran-70 (HSD) vs 0.9% normal saline (NS), on selected cellular and soluble inflammatory/coagulation markers. Serial blood samples were drawn from 65 patients (30 HSD, 35 NS) at the time of hospital admission and at 12, 24, and 48-h post-resuscitation. Flow cytometry was used to analyze leukocyte cell-surface adhesion (CD62L, CD11b) and degranulation (CD63, CD66b) molecules. Circulating concentrations of soluble (s)L- and sE-selectins (sL-, sE-selectins), vascular and intercellular adhesion molecules (sVCAM-1, sICAM-1), pro/antiinflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin (IL-10)], tissue factor (sTF), thrombomodulin (sTM) and D-dimers (D-D) were assessed by enzyme immunoassay. Twenty-five healthy subjects were studied as a control group.

Results

TBI provoked marked alterations in a majority of the inflammatory/coagulation markers assessed in all patients. Relative to control, NS patients showed up to a 2-fold higher surface expression of CD62L, CD11b and CD66b on polymorphonuclear neutrophils (PMNs) and monocytes that persisted for 48-h. HSD blunted the expression of these cell-surface activation/adhesion molecules at all time-points to levels approaching control values. Admission concentrations of endothelial-derived sVCAM-1 and sE-selectin were generally reduced in HSD patients. Circulating sL-selectin levels were significantly elevated at 12 and 48, but not 24 h post-resuscitation with HSD. TNF-α and IL-10 levels were elevated above control throughout the study period in all patients, but were reduced in HSD patients. Plasma sTF and D-D levels were also significantly lower in HSD patients, whereas sTM levels remained at control levels.

Conclusions

These findings support an important modulatory role of HSD resuscitation in attenuating the upregulation of leukocyte/endothelial cell proinflammatory/prothrombotic mediators, which may help ameliorate secondary brain injury after TBI.

Trial registration

NCT00878631.

Occult pneumomediastinum in blunt chest trauma: clinical significance

INTRODUCTION

Thoracic injuries are potentially responsible for 25% of all trauma deaths. Chest X-ray is commonly used to screen patients with chest injury. However, the use of computed tomography (CT) scan for primary screening is increasing, particularly for blunt trauma. CT scans are more sensitive than chest X-ray in detecting intra-thoracic abnormalities such as pneumothoraces and pneumomediastinums. Pneumomediastinum detected by chest X-ray or "overt pneumomediastinum", raises the concern of possible aerodigestive tract injuries. In contrast, there is scarce information on the clinical significance of pneumomediastinum diagnosed by CT scan only or "occult pneumomediastinum". Therefore we investigated the clinical consequences of occult pneumomediastinum in our blunt trauma population.

METHODS

A 2-year retrospective chart review of all blunt chest trauma patients with initial chest CT scan admitted to a level I trauma centre. Data extracted from the medical records include; demographics, occult, overt, or no pneumomediastinum, the presence of intra-thoracic aerodigestive tract injuries (trachea, bronchus, and/or esophagus), mechanism and severity of injury, endotracheal intubation, chest thoracostomy, operations and radiological reports by an attending radiologist. All patients with intra-thoracic aerodigestive tract injuries from 1994 to 2004 were also investigated.

RESULTS

Of 897 patients who met the inclusion criteria 839 (93.5%) had no pneumomediastinum. Five patients (0.6%) had overt pneumomediastinum and 53 patients (5.9%) had occult pneumomediastinum. Patients with occult pneumomediastinum had significantly higher ISS and AIS chest (p<0.0001) than patients with no pneumomediastinum. A chest thoracostomy tube was more common (p<0.0001) in patients with occult pneumomediastinum (47.2%) than patients with no pneumomediastinum (10.4%), as well as occult pneumothorax. None of the patients with occult pneumomediastinum had aerodigestive tract injuries (95%CI 0-0.06). Follow up CT scan of patients with occult pneumomediastinum showed complete resolution in all cases, in average 3 h after the initial exam.

CONCLUSION

Occult pneumomediastinum occurred in approximately 6% of all trauma patients with blunt chest injuries in our institution. Patients who had occult pneumomediastinum were more severely injured than those who without. However, none of the patients with occult pneumomediastinum had aerodigestive tract injuries and follow up chest CT scans demonstrated their complete and spontaneous resolution.

The Toronto prehospital hypertonic resuscitation-head injury and multi organ dysfunction trial (TOPHR HIT)--methods and data collection tools

Background

Clinical trials evaluating the use of hypertonic saline in the treatment of hypovolemia and head trauma suggest no survival superiority over normal saline; however subgroup analyses suggest there may be a reduction in the inflammatory response and multiorgan failure which may lead to better survival and enhanced neurocognitive function. We describe a feasibility study of randomizing head injured patients to hypertonic saline and dextran vs. normal saline administration in the out of hospital setting.

Methods/Design

This feasibility study employs a randomized, placebo-controlled design evaluating normal saline compared with a single dose of 250 ml of 7.5% hypertonic saline in 6% dextran 70 in the management of traumatic brain injuries. The primary feasibility endpoints of the trial were: 1) baseline survival rates for the treatment and control group to aid in the design of a definitive multicentre trial, 2) randomization compliance rate, 3) ease of protocol implementation in the out-of-hospital setting, and 4) adverse event rate of HSD infusion.

The secondary objectives include measuring the effect of HSD in modulating the immuno-inflammatory response to severe head injury and its effect on modulating the release of neuro-biomarkers into serum; evaluating the role of serum neuro-biomarkers in predicting patient outcome and clinical response to HSD intervention; evaluating effects of HSD on brain atrophy post-injury and neurocognitive and neuropsychological outcomes.

Discussion

We anticipate three aspects of the trial will present challenges to trial success; ethical demands associated with a waiver of consent trial, challenging follow up and comprehensive accurate timely data collection of patient identifiers and clinical or laboratory values. In addition all the data collection tools had to be derived de novo as none existed in the literature.

Trial registration number

NCT00878631

Normal range values for thromboelastography in healthy adult volunteers

Thromboelastography (TEG) provides a functional evaluation of coagulation. It has characteristics of an ideal coagulation test for trauma, but is not frequently used, partially due to lack of both standardized techniques and normal values. We determined normal values for our population, compared them to those of the manufacturer and evaluated the effect of gender, age, blood type, and ethnicity. The technique was standardized using citrated blood, kaolin and was performed on a Haemoscope 5000 device. Volunteers were interviewed and excluded if pregnant, on anticoagulants or having a bleeding disorder. The TEG parameters analyzed were R, K, alpha, MA, LY30, and coagulation index. All volunteers outside the manufacturer's normal range underwent extensive coagulation investigations. Reference ranges for 95% for 118 healthy volunteers were R: 3.8-9.8 min, K: 0.7-3.4 min, alpha: 47.8-77.7 degrees, MA: 49.7-72.7 mm, LY30: -2.3-5.77%, coagulation index: -5.1-3.6. Most values were significantly different from those of the manufacturer, which would have diagnosed coagulopathy in 10 volunteers, for whom additional investigation revealed no disease (81% specificity). Healthy women were significantly more hypercoagulable than men. Aging was not associated with hypercoagulability and East Asian ethnicity was not with hypocoagulability. In our population, the manufacturer's normal values for citrated blood-kaolin had a specificity of 81% and would incorrectly identify 8.5% of the healthy volunteers as coagulopathic. This study supports the manufacturer's recommendation that each institution should determine its own normal values before adopting TEG, a procedure which may be impractical. Consideration should be given to a multi-institutional study to establish wide standard values for TEG.

Penetrating injury to the chest by an attenuated energy projectile: a case report and literature review of thoracic injuries caused by "less-lethal" munitions

We present the case of a patient who sustained a penetrating injury to the chest caused by an attenuated energy rubber bullet and review the literature on thoracic injuries caused by plastic and rubber "less-lethal" munitions. The patient of this report underwent a right thoracotomy to extract the projectile as well as a wedge resection of the injured lung parenchyma. This case demonstrates that even supposedly safe riot control munition fired at close range, at the torso, can provoke serious injury. Therefore a thorough investigation and close clinical supervision are justified.

Non-operative management of right side thoracoabdominal penetrating injuries--the value of testing chest tube effluent for bile

INTRODUCTION

While mandatory surgery for all thoracoabdominal penetrating injuries is advocated by some, the high rate of unnecessary operations challenges this approach. However, the consequences of intrathoracic bile remains poorly investigated. We sought to evaluate the outcome of patients who underwent non-operative management of right side thoracoabdominal (RST) penetrating trauma, and the levels of bilirubin obtained from those patients' chest tube effluent.

PATIENTS AND METHODS

We managed non-operatively all stable patients with a single RST penetrating injury. Chest tube effluent samples were obtained six times within (4-8 h; 12-16 h; 20-24 h; 28-32 h; 36-40 h; 48 h and 72 h) of admission for bilirubin measurement and blood for complete blood count, bilirubin, alanine (ALT) and aspartate aminotransferases (AST) assays. For comparison we studied patients with single left thoracic penetrating injury.

RESULTS

Forty-two patients with RST injuries were included. All had liver and lung injuries confirmed by CT scans. Only one patient failed non-operative management. Chest tube bilirubin peaked at 48 h post-trauma (mean 3.3+/-4.1 mg/dL) and was always higher than both serum bilirubin (p<0.05) and chest tube effluent from control group (27 patients with left side thoracic trauma). Serum ALT and AST were higher in RST injury patients (p<0.05). One RST injury patient died of line sepsis.

CONCLUSION

Non-operative management of RST penetrating trauma appears to be safe. Bile originating from the liver injury reaches the right thoracic cavity but does not reflect the severity of that injury. The highest concentration was found in the patient failing non-operative management. The presence of intrathoracic bile in selected patients who sustain RST penetrating trauma, with liver injury, does not preclude non-operative management. Our study suggests that monitoring chest tube effluent bilirubin may provide helpful information when managing a patient non-operatively.

An evaluation of tactical combat casualty care interventions in a combat environment

BACKGROUND

Tactical combat casualty care (TCCC) is a system of prehospital trauma care designed for the combat environment. Although widely adopted, very few studies have reported on how TCCC interventions are actually delivered on the battlefield, from a quality of care perspective.

STUDY DESIGN

This was a prospective study of all trauma patients treated at the Role 3 multinational medical unit (MMU) at Kandahar Airfield Base from February 7, 2006 to May 30, 2006. Primary outcomes were whether or not two TCCC interventions were underused, overused, or misused. Interventions studied were needle decompression of tension pneumothoraces and tourniquet application for exsanguinating extremity injuries.

RESULTS

One hundred thirty-four trauma patients were treated at the Role 3 MMU during the study period. Six patients had eight tourniquets applied. Five tourniquets were applied to four patients appropriately and saved their lives. There was one case of misuse where a venous tourniquet was applied. There was one case of overuse where one patient had two tourniquets placed for 4 hours on extremities with no vascular injury. There were seven cases where needle decompression was underused: Seven patients presented with vital signs absent with no needle decompression. There was one case of overuse of needle decompression. There were seven cases of misuse where the patients were decompressed too medially.

CONCLUSIONS

Tourniquets save lives. Needle decompression can save lives, but is usually performed in patients with multiple critical injuries. TCCC instructors must reinforce proper techniques and indications for each procedure to ensure that the quality of care provided to injured soldiers on the battlefield remains high.

Safety of rFVIIa in hemodynamically unstable polytrauma patients with traumatic brain injury: post hoc analysis of 30 patients from a prospective, randomized, placebo-controlled, double-blind clinical trial

BACKGROUND

Trauma is a leading cause of mortality and morbidity, with traumatic brain injury (TBI) and uncontrolled hemorrhage responsible for the majority of these deaths. Recombinant activated factor VIIa (rFVIIa) is being investigated as an adjunctive hemostatic treatment for bleeding refractory to conventional replacement therapy in trauma patients. TBI is a common component of polytrauma injuries. However, the combination of TBI with polytrauma injuries is associated with specific risk factors and treatment modalities somewhat different from those of polytrauma without TBI. Although rFVIIa treatment may offer added potential benefit for patients with combined TBI and polytrauma, its safety in this population has not yet been assessed. We conducted a post hoc sub analysis of patients with TBI and severe blunt polytrauma enrolled into a prospective, international, double-blind, randomized, placebo-controlled study.

METHODS

A post hoc analysis of study data was performed for 143 patients with severe blunt trauma enrolled in a prospective, randomized, placebo-controlled study, evaluating the safety and efficacy of intravenous rFVIIa (200 + 100 + 100 microg/kg) or placebo, to identify patients with a computed tomography (CT) diagnosis of TBI. The incidences of ventilator-free days, intensive care unit-free days, and thromboembolic, serious, and adverse events within the 30-day study period were assessed in this cohort.

RESULTS

Thirty polytrauma patients (placebo, n = 13; rFVIIa, n = 17) were identified as having TBI on CT. No significant differences in rates of mortality (placebo, n = 6, 46%, 90% confidence interval (CI): 22% to 71%; rFVIIa, n = 5, 29%, 90% CI: 12% to 56%; P = 0.19), in median numbers of intensive care unit-free days (placebo = 0, rFVIIa = 3; P = 0.26) or ventilator-free days (placebo = 0, rFVIIa = 10; P = 0.19), or in rates of thromboembolic adverse events (placebo, 15%, 90% CI: 3% to 51%; rFVIIa, 0%, 90% CI: 0% to 53%; P = 0.18) or serious adverse events (placebo, 92%, 90% CI: 68% to 98%; rFVIIa, 82%, 90% CI: 60% to 92%; P = 0.61) were observed between treatment groups.

CONCLUSION

The use of a total dose of 400 (200 + 100 + 100) microg/kg rFVIIa in this group of hemodynamically unstable polytrauma patients with TBI was not associated with an increased risk of mortality or with thromboembolic or adverse events.

Multi-drug resistant Acinetobacter infections in critically injured Canadian forces soldiers

Background

Military members, injured in Afghanistan or Iraq, have returned home with multi-drug resistant Acinetobacter baumannii infections. The source of these infections is unknown.

Methods

Retrospective study of all Canadian soldiers who were injured in Afghanistan and who required mechanical ventilation from January 1 2006 to September 1 2006. Patients who developed A. baumannii ventilator associated pneumonia (VAP) were identified. All A. baumannii isolates were retrieved for study patients and compared with A. baumannii isolates from environmental sources from the Kandahar military hospital using pulsed-field gel electrophoresis (PFGE).

Results

During the study period, six Canadian Forces (CF) soldiers were injured in Afghanistan, required mechanical ventilation and were repatriated to Canadian hospitals. Four of these patients developed A. baumannii VAP. A. baumannii was also isolated from one environmental source in Kandahar – a ventilator air intake filter. Patient isolates were genetically indistinguishable from each other and from the isolates cultured from the ventilator filter. These isolates were resistant to numerous classes of antimicrobials including the carbapenems.

Conclusion

These results suggest that the source of A. baumannii infection for these four patients was an environmental source in the military field hospital in Kandahar. A causal linkage, however, was not established with the ventilator. This study suggests that infection control efforts and further research should be focused on the military field hospital environment to prevent further multi-drug resistant A. baumannii infections in injured soldiers.

Perioperative Vasopressors Are Associated with an Increased Risk of Gastrointestinal Anastomotic Leakage

BACKGROUND

The purpose of this study was to investigate the effect of vasopressors on gastrointestinal (GI) anastomotic leaks. Vasopressors are commonly used in surgical patients admitted to the intensive care unit (ICU) and their effects on GI anastomotic integrity are unknown.

PATIENTS AND METHODS

Surgical patients admitted to the ICU in our tertiary university hospital following the creation of a GI anastomosis were studied by a retrospective chart analysis for anastomotic leaks and complications

RESULTS

A total of 223 patients with 259 GI anastomoses, mostly for cancer, were admitted to the ICU immediately after surgery. Twenty-two patients developed anastomotic leaks (9.9%). The two groups (leak versus no-leak) had similar demographics, surgery type and indication, type of anastomosis, co-morbidities, cancer, steroid use, blood transfusion, drains, and epidural catheters. Vasopressor use was associated with increased anastomotic leakage (p = 0.02, OR 3.25). Multiple vasopressors and prolonged exposure caused even higher leaking rates. This effect was independent of the medical status and operative morbidity (APACHE II, POSSUM). Blood pressure preceding vasopressor use was similar in both groups. Vasopressors might have been occasionally used to treat hypovolemia. Patients with leaks had higher reoperation rates (41% versus 1%, p < 0.0001) and mortality (21% versus 4%, p = 0.002).

CONCLUSIONS

Vasopressors appear to increase anastomotic leaks threefold, independent of clinical/surgical status or hypotension. Evidence-based guidelines are warranted for the optimal use of vasopressors in postoperative patients admitted to the ICU.

Recombinant activated factor VII as an adjunctive therapy for bleeding control in severe trauma patients with coagulopathy: subgroup analysis from two randomized trials

Introduction

We conducted a post-hoc analysis on the effect of recombinant factor VIIa (rFVIIa) on coagulopathic patients from two randomized, placebo-controlled, double-blind trials of rFVIIa as an adjunctive therapy for bleeding in patients with severe trauma.

Methods

Blunt and penetrating trauma patients were randomly assigned to rFVIIa (200 + 100 + 100 μg/kg) at 0, 1, and 3 hours after transfusion of 8 units of red blood cells (RBCs) or to placebo. Subjects were monitored for 48 hours post-dosing and followed for 30 days. Coagulopathy was retrospectively defined as transfusion of fresh frozen plasma (FFP) (>1 unit of FFP per 4 units of RBCs), FFP in addition to whole blood, and transfusion of platelets and/or cryoprecipitate.

Results

Sixty rFVIIa-treated and 76 placebo subjects were retrospectively identified as being coagulopathic. No significant differences were noted in baseline characteristics. The rFVIIa-treated coagulopathic subgroup consumed significantly less blood product: RBC transfusion decreased by 2.6 units for the whole study population (P = 0.02) and by 3.5 units among patients surviving more than 48 hours (P < 0.001). Transfusion of FFP (1,400 versus 660 ml, P < 0.01), platelet (300 versus 100 ml, P = 0.01), and massive transfusions (29% versus 6%, P < 0.01) also dropped significantly. rFVIIa reduced multi-organ failure and/or acute respiratory distress syndrome in the coagulopathic patients (3% versus 20%, P = 0.004), whereas thromboembolic events were equally present in both groups (3% versus 4%, P = 1.00).

Conclusion

Coagulopathic trauma patients appear to derive particular benefit from early adjunctive rFVIIa therapy.

Preventable deaths from hemorrhage at a level I Canadian trauma center

BACKGROUND

Studies of trauma deaths have had a tremendous impact on the quality of contemporary trauma care. We studied causes of trauma death at a Level I Canadian trauma center, and tabulated preventable deaths from hemorrhage using explicit criteria.

METHODS

Trauma registry data were used to identify all trauma deaths at our institution from January 1, 1999 to December 31, 2003. Demographics, mechanism, and time or location of death were recorded. Registry data analysis and selective chart or autopsy review were then performed to assign causes of death.

RESULTS

A total of 558 consecutive trauma deaths were reviewed. Mean age was 48.7 (46.7-50.6), and mean Injury Severity Score was 38.8 (37.6-40.0); 29% were females. Blunt trauma represented 87% of all cases; penetrating injuries were only 13%. Central nervous system (CNS) injuries were the most frequent cause of death (60%), followed by hemorrhage (15%), and then combination CNS and hemorrhagic injuries (11%). Multiple organ failure caused 5% of deaths and 9% of deaths were from other causes. Of hemorrhagic deaths, 48% (n = 41) were from blunt injury, and 52% (n = 45) were from a penetrating mechanism. Of these hemorrhagic deaths, 16% were judged to be preventable because of significant delays in identifying the major source of hemorrhage. Hemorrhage from blunt pelvic injury was the major cause of exsanguination in 12 of 14 of these preventable deaths.

CONCLUSIONS

Blunt injury is the major mechanism leading to trauma deaths. Massive bleeding from blunt pelvic injury is the major cause of preventable hemorrhagic deaths in our study.

Recombinant activated coagulation factor VII and bleeding trauma patients

BACKGROUND

Recombinant activated coagulation factor VII (rFVIIa) is increasingly being administered to massively bleeding trauma patients. rFVIIa has been shown to correct coagulopathy and to decrease transfusion requirements. However, there is no conclusive evidence to suggest that rFVIIa improves the survival of these patients. The purpose of this study was to determine whether or not rFVIIa has an effect on the in-hospital survival of massively bleeding trauma patients.

METHODS

A retrospective cohort study was conducted from January 1, 2000 to January 31, 2005, at a Level I trauma center in Toronto, Canada. Inclusion criteria included trauma patients requiring transfusion of 8 or more units of packed red cells within the first 12 hours of admission. The primary exposure of interest was the administration of rFVIIa. Primary outcome was a 24-hour survival and secondary outcome was overall in-hospital survival.

RESULTS

There were 242 trauma patients identified who met inclusion criteria; 38 received rFVIIa. rFVIIa patients were younger, had more penetrating injuries, and fewer head injuries. However, rFVIIa patients required more red cell transfusions initially, and were more acidotic. Administering rFVIIa was associated with improved 24-hour survival, after adjusting for baseline demographics and injury factors. The odds ratio (OR) for survival was 3.4 (1.2-9.8). Furthermore, there was a strong trend toward increased overall in-hospital survival. The OR of in-hospital survival was 2.5 (0.8-7.6). Also, subgroup analysis of rFVIIa patients showed that 24-hour survivors required a slower initial rate of red cell transfusion (4.5 vs. 2.9 units/hr, p = 0.002), had higher platelet counts (175 vs. 121 [x10(-9)/L], p = 0.05) and smaller base deficits (7.1 vs. 14.3, p = 0.001) compared with rFVIIa patients who died during the first 24 hours.

CONCLUSION

rFVIIa may be able to improve the early survival of massively bleeding trauma patients. However, surgical control of massive hemorrhage still has primacy, as rFVIIa did not appear efficacious if extremely high red cell transfusion rates were required. Also, correction of acidosis and thrombocytopenia may be important for rFVIIa efficacy. Prospective studies are required.

Radiation Exposure From Diagnostic Imaging in Severely Injured Trauma Patients

BACKGROUND

Trauma patients often require multiple imaging tests, including computed tomography (CT) scans. CT scanning, however, is associated with high-radiation doses. The purpose of this study was to measure the radiation doses trauma patients receive from diagnostic imaging.

METHODS

A prospective cohort study was conducted from June 1, 2004 to March 31, 2005 at a Level I trauma center in Toronto, Canada. All trauma patients who arrived directly from the scene of injury and who survived to discharge were included. Three dosimeters were placed on each patient (neck, chest, and groin) before radiologic examination. Dosimeters were removed before discharge. Surface doses in millisieverts (mSv) at the neck, chest, and groin were measured. Total effective dose, thyroid, breast, and red bone marrow organ doses were then calculated.

RESULTS

Trauma patients received a mean effective dose of 22.7 mSv. The standard "linear no threshold" (LNT) model used to extrapolate from effects observed at higher dose levels suggests that this would result in approximately 190 additional cancer deaths in a population of 100,000 individuals so exposed. In addition, the thyroid received a mean dose of 58.5 mSv. Therefore, 4.4 additional fatal thyroid cancers would be expected per 100,000 persons. In all, 22% of all patients had a thyroid dose of over 100 mSv (mean, 156.3 mSv), meaning 11.7 additional fatal thyroid cancers per 100,000 persons would result in this subgroup.

CONCLUSION

Trauma patients are exposed to significant radiation doses from diagnostic imaging, resulting in a small but measurable excess cancer risk. This small individual risk may become a greater public health issue as more CT examinations are performed. Unnecessary CT scans should be avoided.

Association Between Alcohol and Mortality in Patients With Severe Traumatic Head Injury

HYPOTHESIS

Admission blood alcohol concentration (BAC) is associated with in-hospital death in patients with severe brain injury from blunt head trauma.

DESIGN

Retrospective cohort study.

SETTING

Academic level I trauma center in Toronto, Ontario.

PATIENTS

Using trauma registry data, between January 1, 1988, and December 31, 2003, we identified 1158 consecutive patients with severe brain injury from blunt head trauma.

INTERVENTION

There was no active intervention. The primary exposure of interest was the BAC at admission, stratified into the following 3 levels: 0, no BAC; 0 to less than 230 mg/dL, low to moderate BAC; and 230 mg/dL or greater, high BAC.

MAIN OUTCOME MEASURE

In-hospital death.

RESULTS

In patients with severe brain injury, low to moderate BAC was associated with lower mortality than was no BAC (27.9% vs 36.3%; P = .008). High BAC was associated with higher mortality than was no BAC (44.7% vs 36.3%), although this was not statistically significant (P = .10). These associations were all statistically significant after adjusting for demographic data and injury factors using logistic regression analysis. The odds ratio for death was 0.76 (95% confidence interval, 0.52-0.98) for low to moderate BAC compared with no BAC. The odds ratio for death was 1.73 (95% confidence interval, 1.05-2.84) for high BAC compared with no BAC.

CONCLUSIONS

Low to moderate BAC may be beneficial in patients with severe brain injury from blunt head trauma. In contrast, high BAC seems to have a deleterious effect on in-hospital death in these patients, which may be related to its detrimental hemodynamic and physiologic effects. Alcohol-based fluids may have a role in the management of patients with severe brain injury after they have been well resuscitated.

Traumatic Abdominal Wall Hernia: Epidemiology and Clinical Implications

BACKGROUND

Traumatic abdominal wall hernias (TAWHs) are uncommon, and it remains controversial whether such patients require urgent laparotomy. As such, this study was undertaken to assess the clinical sequelae of operative versus nonoperative management of TAWH, and whether certain patient or injury characteristics are predictive of the need for early surgery.

METHODS

Retrospective review of all patients presenting acutely with a TAWH at a Regional Trauma Center from January 2000 to December 2004.

RESULTS

Thirty-four patients were identified (age 39 +/- 12 years; Injury Severity Score 31 +/- 13). The most frequent mechanism of injury was motor vehicle collision (MVC; 24 cases), followed by motorcycle collision (6) and falls (4). The diagnosis of a TAWH was made primarily by computed tomography scan. Overall, 19 patients underwent urgent laparotomy or laparoscopy (56%) and 15 patients required bowel resection (44%). TAWH secondary to a MVC more frequently required urgent laparotomy and bowel resection than other mechanisms (p < 0.05). All three patients with clinically apparent anterior TAWH had intra-abdominal injuries and required urgent laparotomy. Only eight patients (24%) had their TAWH repaired acutely. At follow-up, two patients managed nonoperatively had symptomatic hernias, and three patients that had had an early repair had developed recurrent hernias.

CONCLUSIONS

First, the mechanism of injury should be considered when deciding if a patient with a TAWH needs an urgent laparotomy. Clinically apparent anterior TAWHs appear to have a high rate of associated injuries requiring urgent laparotomy. Finally, occult TAWHs diagnosed only by computed tomography may not require urgent laparotomy or hernia repair.

Diagnosis and Outcome of Blunt Caval Injuries in the Modern Trauma Center

BACKGROUND

Blunt vena caval injury (BCI) is uncommon with only a few published reports in the literature. Recently, with high resolution computed tomography (CT) scan imaging signs of caval injury are sometimes found in hemodynamically stable patients. The purpose of this study was to assess the current course of patients with BCI.

METHODS

Retrospective review of all patients with BCI treated at a Regional Trauma Center from April 1999 to May 2005. Data collected included demographics, mechanism of injury, associated injuries, diagnostic investigations, surgical findings, and outcomes.

RESULTS

During the 6-year study period, 10 patients presented with BCI (age 42 +/- 19 years; 70% mortality; Injury Severity Score 39 +/- 15). The spectrum of vena cava injury ranged from an intimal flap to extensive destruction. Six of the seven deaths were secondary to exsanguination and one secondary to severe brain injury. Four patients presented with refractory shock and were taken emergently to surgery (all died). Six patients responded to fluid resuscitation and underwent CT imaging (three out of six survived). Although active venous contrast extravasation was not seen in any patient, all six had indirect signs on CT suggestive of BCI. Overall, the diagnosis of BCI was confirmed at surgery in nine patients. The remaining patient had an intimal flap and contained pericaval hematoma confirmed by ultrasound, and was successfully managed nonoperatively.

CONCLUSIONS

The spectrum of BCI ranges from intimal flaps to extensive destruction. CT imaging may not diagnose or may underestimate the severity of BCI. Stable patients with intimal flaps and contained hematoma may be successfully managed nonoperatively.

Do trauma patients with a Glasgow Coma Scale score of 3 and bilateral fixed and dilated pupils have any chance of survival?

BACKGROUND

Low Glasgow Coma Scale score (GCS) and pupillary status predict poor outcomes in head injury (HI) patients. We compared the mortality of GCS 3 patients having bilateral fixed and dilated pupils (BFDP) with GCS 3 patients having reactive pupils (RP). We then determined if trauma system or patient factors were responsible for the difference in mortality.

METHODS

We reviewed all adult, blunt HI patients with GCS=3, admitted to our institution from January 1, 2001 to December 31, 2003. Demographics, injury data, prehospital times, procedures, and outcomes were recorded.

RESULTS

During this period, 245 patients were admitted with GCS of 3, and met inclusion criteria. In all, 173 patients were analyzed, after excluding 23 patients who were dead-on-arrival, and 45 others, who were intoxicated with alcohol, or received paralytic agents in the trauma room. All BFDP patients died, whereas 42.0% of reactive pupil (RP) patients died (p < 0.0001). With regards to patient factors, BFDP patients were more likely to be unstable, have extra-axial bleeding, and evidence of midline shift and/or herniation. Trauma system factors, however, may also have had an impact on outcome. Despite having more extra-axial bleeding, BFDP patients were less likely to have a neurosurgical operation than RP patients.

CONCLUSION

Patients with GCS of 3 and BFDP have a dismal prognosis. These patients have suffered devastating brain injuries and tend to be hemodynamically unstable. Clinicians, however, are less likely to aggressively treat BFDP patients than RP patients. Further prospective studies are required to determine which patients with GCS of 3 and BFDP are likely to benefit from aggressive treatment.

Risk and benefit of intravenous contrast in trauma patients with an elevated serum creatinine

OBJECTIVE

Assess if the benefits outweigh the risks of intravenous (iv) contrast in trauma patients who present with an elevated serum creatinine (Cr).

BACKGROUND

Radiologic investigations with iv contrast are often used in trauma patients to rapidly assess for life threatening injuries. However, contrast nephropathy (CNP) is associated with increased morbidity and mortality. This poses a dilemma for the physician who must weigh the risks and benefits of proceeding with iv contrast versus the risks of missed injuries/delayed diagnosis.

METHODS

A 2 year (2002-2003) retrospective chart review of all trauma patients presenting with an elevated Cr(> or =1.3 mg/dL or > or =115 micromol/L). Results are mean +/- sd (p < 0.05 significant).

RESULTS

Ninety-five patients (age 51 +/- 23 years; ISS 31.7 +/- 15.6; hospital stay 29 +/- 32 days; mortality 9%) presented with a Cr > or = 1.3 mg/dL (31 with Cr > or =1.7; 3 dialysis dependent). Fifty-six (59%) were given iv contrast (C+), of which only 2 (3%) had a transient rise of 25% in Cr within 48 hours versus 6 (16%) patients not exposed to contrast (C-). No C+ patient developed CNP requiring longterm dialysis. Of the 56 undergoing C+ tests, 16 had injuries requiring urgent intervention identified; 16 had injuries that were managed nonoperatively, and 24 had serious injuries ruled out. Of the 39 C- patients, 9 had indeterminate CT's; 2 had missed injuries; and 2 had no intraabdominal injuries found at celiotomy.

CONCLUSION

This study suggests the benefits may outweight the risks for proceeding prn with iv contrast in trauma patients with an elevated creatinine. A larger study is needed to confirm these findings.

The immunomodulatory effects of hypertonic saline resuscitation in patients sustaining traumatic hemorrhagic shock: a randomized, controlled, double-blinded trial

OBJECTIVE

To investigate the potential immunologic and anti-inflammatory effects of hypertonic saline plus dextran (HSD) in hemorrhagic trauma patients.

BACKGROUND

Unbalanced inflammation triggered by shock has been linked to multiorgan dysfunction (MOD) and death. In animal and cellular models, HSD alters the inflammatory response to shock, attenuating MOD and improving outcome. It remains untested whether HSD has similar effects in humans.

METHODS

A single 250-mL dose of either HSD (7.5% NaCl, 6% dextran-70) or placebo (0.9% NaCl) was administered to adult blunt trauma patients in hemorrhagic shock. The primary outcome was to measure changes in immune/inflammatory markers, including neutrophil activation, monocyte subset redistribution, cytokine production, and neuroendocrine changes. Patient demographics, fluid requirements, organ dysfunction, infection, and death were recorded.

RESULTS

A total of 27 patients were enrolled (13 HSD) with no significant differences in clinical measurements. Hyperosmolarity was modest and transient, whereas the immunologic/anti-inflammatory effects persisted for 24 hours. HSD blunted neutrophil activation by abolishing shock-induced CD11b up-regulation and causing CD62L shedding. HSD altered the shock-induced monocyte redistribution pattern by reducing the drop in "classic" CD14 and the expansion of the "pro-inflammatory" CD14CD16 subsets. In parallel, HSD significantly reduced pro-inflammatory tumor necrosis factor (TNF)-alpha production while increasing anti-inflammatory IL-1ra and IL-10. HSD prevented shock-induced norepinephrine surge with no effect on adrenal steroids.

CONCLUSIONS

This first human trial evaluating the immunologic/anti-inflammatory effects of hypertonic resuscitation in trauma patients demonstrates that HSD promotes a more balanced inflammatory response to hemorrhagic shock, raising the possibility that similar to experimental models, HSD might also attenuate post-trauma MOD.

The emerging role of recombinant activated Factor VII (rFVIIa) in the treatment of blunt traumatic haemorrhage

Recombinant activated Factor VII (rFVIIa; eptacog alpha [activated], NovoSeven) is currently used for the management of a subgroup of haemophilia patients with inhibitors to Factors VIII or IX, and is under investigation as an adjuvant therapy for critical bleeding from other causes, including trauma. rFVIIa has a mode of action founded on physiological coagulation processes, and causes localised haemostasis at injury sites, both spontaneous and traumatic, with the capacity to correct the systemic coagulopathy associated with massive blood loss and its management. This review charts the development of rFVIIa as a new and potent adjuvant therapy for severe bleeding and coagulopathy caused by blunt trauma, where it is reported to produce rapid and significant haemostasis, reducing transfusion requirements and improving clinical outcome.

Blood conservation for critically ill patients

Anemia may be the most common illness of critically ill patients. The majority of critically ill patients are anemic at admission to the intensive care unit (ICU), and hemoglobin concentrations typically decline during the first 3 days of ICU stay. Hemoglobin continues to decline for patients with sepsis and higher severity of illness. This patient population may be at particular risk of adverse consequences of anemia given the cardiovascular, respiratory, and metabolic compromise frequently encountered during critical illness. The etiology of anemia of critical illness is multifactorial, resulting from phlebotomy, gastrointestinal bleeding, coagulation disorders, blood loss from vascular procedures, renal failure, nutritional deficiencies,bone marrow suppression, and impaired erythropoietin response.

Crystalloids and colloids in trauma resuscitation: a brief overview of the current debate

BACKGROUND

Controversy regarding crystalloids or colloids for resuscitation has existed for over five decades, and large numbers of clinical trials have failed to resolve the controversy. In fact, the limitations of these studies have intensified the debate. This overview aims to revisit the debate of fluid resuscitation in trauma patients by critically appraising the meta-analyses on the subject.

METHODS

This study was a critical analysis of six meta-analyses found by MEDLINE search.

RESULTS

Overall, the choice of fluid may have a small or no effect on mortality. In trauma, the use of colloids is associated with a trend toward increased mortality.

CONCLUSION

There is an urgent need for well-designed clinical trials. Because of many limitations, meta-analysis should be interpreted with caution, possibly as hypothesis generating. However, even considering all weaknesses and nuances of interpretation, the meta-analyses reviewed suggest that trauma patients should continue to be resuscitated with crystalloids.

Saturday night fever: finding and controlling the source of sepsis in critical illness

Fever is a daily concern in the intensive care unit. Although about half of all febrile cases are due to non-infectious causes, fear of sepsis frequently leads to diagnostic tests and escalation of therapy, including broadening antibiotic therapy. Using a case to illustrate this dilemma, we discuss the commonest non-infectious and infectious causes of fever, and suggests approaches to their management. Any unexplained fever in intensive care unit patients warrants investigation, which includes complete clinical assessment and blood cultures. When the source of fever is not immediately apparent, non-infectious and infectious causes should be considered. If stable, non-neutropenic patients should be monitored before further tests or empiric antibiotics are started. In an era of rapid emergence and spread of antimicrobial-resistant pathogens and intense scrutiny of resources, optimal diagnosis and management of patients with suspected infection entails much more than the escalation of antimicrobial therapy.

Advances in fluid resuscitation of hemorrhagic shock

The optimal fluid for resuscitation in hemorrhagic shock would combine the volume expansion and oxygen-carrying capacity of blood without the need for cross-matching or the risk of disease transmission. Although the ideal fluid has yet to be discovered, current options are discussed in this review, including crystalloids, colloids, blood and blood substitutes. The future role of blood substitutes is not yet defined, but the potential advantages in trauma or elective surgery may prove to be enormous.

In vivo and in vitro modulation of intercellular adhesion molecule (ICAM)-1 expression by hypertonicity

Hepatic ischemia-reperfusion (I/R) is an important cause of organ dysfunction in the critically ill. With reperfusion, Kupffer cells release pro-inflammatory cytokines that promote endothelial cell (EC) expression of adhesion molecules such as intercellular adhesion molecule (ICAM)-1, facilitating neutrophil (PMN) infiltration. Studies suggest hypertonic saline (HTS) might exert beneficial effects on development of organ injury following shock on the basis of reduced PMN-EC interactions. We hypothesized that HTS alters expression of EC ICAM-1 and thus minimizes PMN-mediated injury. To test our hypothesis, we used an in vivo model of hepatic I/R and an in vitro model of activated EC. Rats underwent 30 min of hepatic ischemia after pretreatment with HTS (7.5% NaCl, 4cc/kg ia) or normal saline (NS). At 4 h reperfusion, plasma was taken for aspartate aminotransferase (AST) and liver tissue was harvested for assessment of hepatic ICAM-1 mRNA by Northern blot analysis. Human umbilical vein endothelial cells (HUVECs) were activated by lipopolysaccharide (LPS) and exposed to hypertonic medium (350-500 mOsM). HUVEC ICAM-1 protein was measured by cell ELISA and ICAM-1 mRNA by Northern blot analysis. HTS prevented hepatic I/R injury as measured by AST. AST of shams was 282.6+/-38.1 IU/L. I/R following NS pretreatment caused significant injury (AST 973.8+/-110.9 IU/L) compared to sham (SM) (P < 0.001). Pretreatment with HTS exerted significant protection following I/R with an AST of 450.9+/-56.3 IU/L (P < 0.05). There was no significant difference in AST levels between SM and HTS groups. Reduced hepatic injury after HTS and I/R was accompanied by inhibition of I/R-induced hepatic ICAM-1 mRNA expression compared to NS treated animals (P < 0.01). Similarly, hypertonicity inhibited HUVEC LPS-induced ICAM-1 protein (LPS: 1.86+/-0.19 absorbance units; 400 mOsM +/- LPS: 1.45+/-0.14 absorbance units; 450 mOsM + LPS: 1.02+/-0.19 absorbance units, P < 0.001) and mRNA expression. Thus, hypertonicity modulates endothelial ICAM-1 expression as one possible protective mechanism against I/R injury.

Hypertonic inhibition of exocytosis in neutrophils: central role for osmotic actin skeleton remodeling

Hypertonicity suppresses neutrophil functions by unknown mechanisms. We investigated whether osmotically induced cytoskeletal changes might be related to the hypertonic inhibition of exocytosis. Hyperosmolarity abrogated the mobilization of all four granule types induced by diverse stimuli, suggesting that it blocks the process of exocytosis itself rather than individual signaling pathways. Concomitantly, osmotic stress provoked a twofold increase in F-actin, induced the formation of a submembranous F-actin ring, and abolished depolymerization that normally follows agonist-induced actin assembly. Several observations suggest a causal relationship between actin polymerization and inhibition of exocytosis: 1) prestimulus actin levels were inversely proportional to the stimulus-induced degranulation, 2) latrunculin B (LB) prevented the osmotic actin response and restored exocytosis, and 3) actin polymerization induced by jasplakinolide inhibited exocytosis under isotonic conditions. The shrinkage-induced tyrosine phosphorylation and the activation of the Na(+)/H(+) exchanger were not affected by LB. Inhibition of osmosensitive kinases failed to prevent the F-actin change, suggesting that the osmotic tyrosine phosphorylation and actin polymerization are independent phenomena. Thus cytoskeletal remodeling appears to be a key component in the neutrophil-suppressive, anti-inflammatory effects of hypertonicity.

Cell volume-dependent regulation of L-selectin shedding in neutrophils. A role for p38 mitogen-activated protein kinase

Neutrophil-mediated organ damage is a common feature of many disease states. We previously demonstrated that resuscitation with hypertonic salt solutions prevented the endotoxin-induced leukosequestration and consequent lung injury, and this effect was partially attributed to an altered surface expression of adhesion molecules, CD11b and L-selectin. In this study we investigated the mechanisms whereby osmotic stress evokes L-selectin shedding. The metalloprotease inhibitor RO 31-9790 prevented the osmotic down-regulation of L-selectin, indicating that this process was catalyzed by the same "sheddase" responsible for L-selectin cleavage induced by diverse inflammatory stimuli. The trigger for hypertonic shedding was cell shrinkage and not increased osmolarity, ionic strength, or intracellular pH. Volume reduction caused robust tyrosine phosphorylation and its inhibition by genistein and erbstatin abrogated shedding. Shrinkage stimulated tyrosine kinases Hck, Syk, and Pyk2, but prevention of their activation by the Src-family inhibitor PP1 failed to affect the L-selectin response. Hypertonicity elicited the Src family-independent activation of p38, and the inhibition of this kinase by SB203580 strongly reduced shedding. p38 was also essential for the N-formyl-methionyl-leucyl-phenylalanine- and lipopolysaccharide-induced shedding but not the phorbol ester-induced shedding. Thus, cell volume regulates L-selectin surface expression in a p38-mediated, metalloprotease-dependent manner. Moreover, p38 has a central role in shedding induced by many inflammatory mediators.