Jay Doucet

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

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

Independent Predictors of Enteric Fistula and Abdominal Sepsis After Damage Control Laparotomy: Results From the Prospective AAST Open Abdomen Registry

IMPORTANCE Enterocutaneous fistula (ECF), enteroatmospheric fistula (EAF), and intra-abdominal sepsis/abscess (IAS) are major challenges for surgeons caring for patients undergoing damage control laparotomy after trauma. OBJECTIVE To determine independent predictors of ECF, EAF, or IAS in patients undergoing damage control laparotomy after trauma, using the AAST Open Abdomen Registry. DESIGN The AAST Open Abdomen registry of patients with an open abdomen following damage control laparotomy was used to identify patients who developed ECF, EAF, or IAS and to compare these patients with those without these complications. Univariate analyses were performed to compare these groups of patients. Variables from univariate analyses differing at P < .20 were entered into a stepwise logistic regression model to identify independent risk factors for ECF, EAF, or IAS. SETTING Fourteen level I trauma centers. PARTICIPANTS A total of 517 patients with an open abdomen following damage control laparotomy. MAIN OUTCOMES AND MEASURES Complication of ECF, EAF, or IAS. RESULTS More patients in the ECF/EAF/IAS group than in the group without these complications underwent bowel resection (63 of 111 patients [57%] vs 133 of 406 patients [33%]; P < .001). Within the first 48 hours after surgery, the ECF/EAF/IAS group received more colloids (P < .03) and total fluids (P < .03) than did the group without these complications. The ECF/EAF/IAS group underwent almost twice as many abdominal reexplorations as did the group without these complications (mean [SD] number, 4.1 [4.1] vs 2.2 [3.4]; P < .001). After multivariate analysis, the independent predictors of ECF/EAF/IAS were a large bowel resection (adjusted odds ratio [AOR], 3.56 [95% CI, 1.88-6.76]; P < .001), a total fluid intake at 48 hours of between 5 and 10 L (AOR, 2.11 [95% CI, 1.15-3.88]; P = .02) or more than 10 L (AOR, 1.93 [95% CI, 1.04-3.57]; P = .04), and an increasing number of reexplorations (AOR, 1.14 [95% CI, 1.06-1.21]; P < .001). CONCLUSIONS AND RELEVANCE Large bowel resection, large-volume fluid resuscitation, and an increasing number of abdominal reexplorations were statistically significant predictors of ECF, EAF, or IAS in patients with an open abdomen after damage control laparotomy.

Tetanus and trauma: a review and recommendations.

BACKGROUND This review covers the pathogenesis and treatment of the disease along with the reexamination of the current recommendations for prophylaxis against tetanus in the United States. Although tetanus is still a major problem worldwide, the incidence in North America has become almost negligible because of the highly effective primary immunization program. Recently, there have been no deaths reported attributable to tetanus in the United States in trauma patients who had received the primary childhood immunization. However, tetanus immunization and prophylaxis in the acute injury setting is frequently misused and misunderstood. METHODS A review of the literature regarding tetanus. RESULTS After review, the authors recommend tetanus toxoid in adults only if it has been more than 10 years since their last immunization. There is no urgency for the administration of tetanus toxoid in the acute setting, as it provides protection against the next injury and not the current injury. Tetanus-diphtheria toxoid is not required unless there are plans for the injured patient to travel to diphtheria-prone countries in the future, as the incidence of diphtheria is negligible in the United States. CONCLUSION The review of reported cases of tetanus demonstrates that it is not possible to clinically determine which wounds are tetanus prone, as tetanus can occur after minor, seemingly innocuous injuries, yet is rare after severely contaminated wounds. Tetanus immunoglobulin should be reserved for patients with wounds who had never received primary immunization against tetanus.

Combat versus civilian open tibia fractures: The effect of blast mechanism on limb salvage

BACKGROUND This study compares open tibia fractures in US Navy and US Marine Corps casualties from the current conflicts with those from a civilian Level I trauma center to analyze the effect of blast mechanism on limb-salvage rates. METHODS Data from the 28,646 records in the University of California San Diego Trauma Registry from 1985 to 2006 was compared with 2,282 records from the US Navy and US Marine Corps Combat Trauma Registry Expeditionary Medical Encounter Database for the period of March 2004 to August 2007. Injuries were categorized by Gustilo-Anderson (G-A) open fracture classification. Independent variables included age, gender, mechanism of injury including blast mechanisms, shock, blood loss, prehospital time, procedures, Injury Severity Score, length of stay, and Mangled Extremity Severity Score (MESS). Dependent variables included early or late amputation and mortality. RESULTS The civilian group had 850 open tibia fractures with 45 amputations; the military group had 21 amputation patients (3 bilateral) in 115 open tibia fractures. Military group patients were more severely injured, more likely have hypotension, and had a higher amputation rate for G-A IIIB and IIIC fractures then civilian group patients. Blast mechanism was seen in the majority of military group patients and was rare in the civilian group. MESS scores had poor sensitivity (0.46, 95% confidence interval: 0.29-0.64) in predicting the need for amputation in the civilian group; in the military group sensitivity was better (0.67, 95% confidence interval: 0.43-0.85), but successful limb salvage was still possible in most cases with an MESS score of ≥7 when attempted. CONCLUSION Despite current therapy, limb salvage for G-A IIIB and IIIC grades are significantly worse for open tibia fractures as a result of blast injury when compared with typical civilian mechanisms. MESS scores do not adequately predict likelihood of limb salvage in combat or civilian open tibia fractures.

Dose adjusting enoxaparin is necessary to achieve adequate venous thromboembolism prophylaxis in trauma patients.

BACKGROUND Standard venous thromboembolism (VTE) prophylaxis with enoxaparin results in inadequate protection in certain patients, with subtherapeutic plasma anti-Xa levels associated with elevated VTE rates. We hypothesized that many trauma patients would be subtherapeutic on the standard prophylactic dose of enoxaparin. Our goal was to adjust the enoxaparin dose to achieve target anti-Xa levels to take advantage of the drug based on its pharmacologic properties. METHODS Patients admitted to the trauma service were included if they received at least three doses of prophylactic enoxaparin and underwent at least two screening venous duplex. Peak plasma anti-Xa levels of 0.2 IU/mL or less were considered low, and the dose was increased by 10 mg twice daily until adequate anti-Xa levels were obtained. A strict screening venous duplex protocol was followed. Patients were excluded if they were diagnosed with a deep venous thrombosis before beginning enoxaparin or did not have correctly timed anti-Xa levels. RESULTS Sixty-one trauma patients met inclusion criteria. There were three patients diagnosed with VTE (4.9%). Patients had a mean age of 45.9 years and were predominantly male (70.5%). Of the 61 patients, 18 (29.5%) had therapeutic anti-Xa levels on standard enoxaparin 30 mg twice daily. Compared with patients who had therapeutic anti-Xa levels on enoxaparin 30 mg twice daily, the 43 patients (70.5%) who were subtherapeutic were more likely to be male, have greater body weight, and larger body surface area. There were no significant bleeding events in the group that received an enoxaparin dose adjustment. CONCLUSION Most patients had subtherapeutic anti-Xa levels while on enoxaparin 30 mg twice daily, suggesting inadequate VTE prophylaxis. The need for routine use of a higher dose of prophylactic enoxaparin in trauma patients and the effects of routinely dose adjusting enoxaparin on VTE rates should be the study of future prospective, randomized trials. LEVEL OF EVIDENCE Therapeutic study, level IV.

A New Clopidogrel (Plavix) Point-of-Care Assay: Rapid Determination of Antiplatelet Activity in Trauma Patients

INTRODUCTION An increasing proportion of trauma patients are on anticoagulation or antiplatelet therapy. Unlike warfarin, where measuring international normalized ratio can help direct management, measuring platelet inhibition from clopidogrel (Plavix) is not standardized. We report the use of a new P2Y12 point-of-care assay (VerifyNow; Accumetrics, San Diego, CA) to determine the magnitude of platelet inhibition in trauma patients using clopidogrel. METHODS Trauma patients in 2009 were queried for clopidogrel use by prehospital personnel and the trauma team. Blood was obtained on admission for patients reportedly taking clopidogrel and was assayed for platelet inhibition using the VerfiyNow-P2Y12 device that measures P2Y12 reaction units and photometrically determines platelet inhibition percentage within 30 minutes. Patient demographics including age, Injury Severity Score, mechanism of injury, and complications from hemorrhage were also analyzed. RESULTS In the time studied, 46 patients taking clopidogrel were assayed for platelet inhibition. The mean age was 75.9 years±11.8 years, and the most common mechanism of injury was fall (86.9%). Platelet inhibition ranged from 0% to 89%. There were no deaths, and only two patients, from the 0% and>30% inhibition group, had hemorrhagic complications (increased intracranial hemorrhage). CONCLUSIONS The P2Y12 point-of-care assay determined that a large percentage of patients had undetectable or low platelet inhibition despite reportedly being on clopidogrel therapy. These patients may be clopidogrel nonresponders or noncompliant. It is unlikely that clopidogrel reversal therapies, such as platelet transfusions or Desmopressin, would be beneficial in this group. Further studies stratifying the percent platelet inhibition needed to increase bleeding complications is warranted to optimize management strategies.

Is contrast exposure safe among the highest risk trauma patients

Background: Despite improvements in the diagnosis and management of acute kidney injury (AKI), posttraumatic renal dysfunction continues to be associated with increased morbidity and mortality. Intravenous (IV) contrast is known to induce AKI in high-risk groups including the elderly and critically ill. We sought to determine whether IV contrast exposure among high-risk trauma patients resulted in renal dysfunction as defined by the Acute Kidney Injury Network criteria. Methods: We performed a 3-year retrospective analysis of all patients admitted to our Level I trauma center surgical intensive care unit for >48 hours. Patients with preexisting chronic renal dysfunction were excluded. We performed univariate and bivariate analyses to identify risk factors for AKI. Multivariable logistic regression analysis identified independent predictors for AKI. Subgroup analysis was undertaken among high-risk groups to include elderly patients (aged ≥65 years) with admission hypotension (systolic blood pressure <90 mm Hg) and an Injury Severity Score (ISS) ≥25. Results: Of the 6,317 patients, 571 (9.0%) patients met the inclusion criteria; 170 (29.8%) patients developed AKI. Age ≥65 years (odds ratio [OR] 2.26, 95% confidence interval [CI] = 1.06–4.80, p <0.034) and ISS ≥25 (OR 1.86, 95% CI = 1.12–3.07, p <0.015) were determined to be independent predictors of AKI. IV contrast was not identified to be a predictor of AKI. Upon subgroup analysis, IV contrast exposure was not a predictor of AKI among the elderly, hypotensive, or severely injured patients (ISS ≥25). Conclusion: A complete trauma workup including studies requiring IV contrast exposure should be considered safe even among high-risk trauma patients. Level of Evidence: II, prognostic study.

In vitro studies regarding the feasibility of bovine erythrocyte xenotransfusion.

Abstract:  Pigs are considered the most likely source of organs and tissues should the barriers to xenotransplantation be overcome. The use of animal blood for transfusion, xenotransfusion, would have advantages over blood from random human donors with respect to supply and infection control. Large animals such as cows would be more suitable than pigs for blood donation because of easier venous access and large volume phlebotomy. Blood from 12 Holstein cows was typed and then tested for hemagglutination assay (HA), complement mediated lysis (CML), human IgM and IgG antibody binding, anti‐human globulin augmented clinical cross‐match and osmotic fragility with normal human serum. Results were compared with porcine erythrocytes (pRBC) and with human type O controls (hRBC). The frequency of ultra‐low xenoantigen expressors was tested in a larger herd of various breeds using HA and CML. Median HA and CML titers were one of six (no HA – one of 64) and one of 26 (no CML – one of 64), respectively for bovine erythrocytes (bRBC). Hemagglutination titer was significantly higher for pRBC at one of 170 (one of four – one of 1024). HA and CML were lowest with bovine blood group J. Repeated HA and CML were negative with bRBC from one cow that also tested negative by anti‐human globulin augmented cross‐match with seven of nine random human sera representing the different blood groups. However, flow cytometry showed that bRBC from all cows bound human IgM and IgG. IgM mean channel fluorescence (MCF) was positively correlated with HA titer. The mean corpuscular fragility of pRBC, bRBC, and hRBC was 0.56, 0.48 and 0.41%, respectively. The frequency of HA‐negative and CML‐negative cows were 20 and 35%, respectively in herds of 49 animals. Bovine RBC elicit variable in vitro responses from human serum but these are uniformly much less than those seen with pRBC. Bovine RBC is more robust than pRBC. These characteristics including the potential ease and volume of blood collection make the cow a more suitable blood donor than the pig.

Evaluating porcine RBC and platelet α‐galactosyl expression

BACKGROUND : Naturally occurring human xenoreactive antibodies bind and agglutinate porcine RBCs.

Complete ultrasonography of trauma in screening blunt abdominal trauma patients is equivalent to computed tomographic scanning while reducing radiation exposure and cost

BACKGROUND Liberal use of computed tomography of the abdomen and pelvis (CTAP) in the screening of blunt abdominal trauma (BAT) has heightened concerns for increased radiation exposure and costs. We sought to demonstrate that in a select group of BAT patients, complete ultrasonography of trauma (CUST) is equivalent to routine CTAP but with significantly decreased radiation and costs. METHODS A retrospective analysis of patients screened for BAT from 2000 to 2011 in a Level 1 trauma center was performed. CUST was available from 8:00 AM to 11:00 PM daily, while CTAP was performed thereafter. Decision to perform CTAP or CUST overnight was made by the attending surgeon based on clinical examination. False negatives (FNs) were described as either a negative CUST or CTAP finding, which later required exploratory laparotomy. Medicare rates and previous data were used for the estimation of cost and radiation exposure. RESULTS There were 19,128 patients screened for BAT. A total of 12,577 patients (65.8%) initially underwent CUST, and 6,548 (34.2%) underwent CTAP; 11,059 patients (58% of the total BAT patients) avoided a CTAP, yielding an estimated savings of