Paul T. Engels

Quantitative cerebral water content mapping in hepatic encephalopathy

There is increasing evidence that the pathophysiology of hepatic encephalopathy is tightly associated with low-grade cerebral oedema; however, no method has yet specifically and unambiguously confirmed this hypothesis in vivo. The current study describes the quantitative measurement of localised water content using MRI in a cohort of 38 patients suffering from hepatic encephalopathy. A significant global increase in cerebral water content was observed in white matter whereas water content in grey matter was globally unaffected. However, significant spatial variations in the water content distribution, especially in grey matter, were observed and were correlated with disease grade and critical flicker frequency. In addition, regions-of-interest were defined and a significant change in water content with disease grade was found in the frontal and occipital white matter, the globus pallidus, the anterior limb of the internal capsule and the putamen. No association of water content and HE grade was established for the occipital visual and frontal cortices, the thalamus, the posterior limb of the internal capsule, the caudate nucleus and the coronal white matter. In conclusion, the measurements presented here are the first direct and quantitative demonstration of the presence of low-grade cerebral oedema in patients with hepatic encephalopathy. Further, absolute changes in tissue water content were quantified for various brain regions.

Intravenous fat emulsion to reverse haemodynamic instability from intentional amitriptyline overdose

We report the first case of amitriptyline toxicity treated with intravenous fat emulsion (IFE). Toxicity was manifested as vasopressor-refractory haemodynamic instability despite standard therapy. Our patient recovered with no adverse effects noted.

Tourniquet use for peripheral vascular injuries in the civilian setting

BACKGROUND Haemorrhage in peripheral vascular injuries may cause life-threatening exsanguination. Tourniquets are used extensively by the military, with increased interest in the civilian setting to prevent deaths. This is a retrospective study of trauma patients at two large Canadian trauma centres with arterial injury after isolated extremity trauma. We hypothesized that tourniquet use may decrease mortality rate and transfusion requirements if applied early. METHODS The study group was all adult patients at two Level 1 Trauma Centres in two Canadian cities in Canada, who had arterial injuries from extremity trauma. The study period was from January 2001 to December 2010. We excluded patients with significant associated injuries. The intervention in this study was prehospital tourniquet use. The main outcome was in-hospital mortality. Secondary outcomes were length of stay, compartment syndrome, amputation, and blood product transfusion. RESULTS 190 patients were included in the study, and only 4 patients had a prehospital tourniquet applied. They arrived directly from the scene of injury, had improvised tourniquets by police or bystanders, and showed a trend to be more hypotensive and acidotic. Four other patients had tourniquets applied in the trauma bay within 1h of injury. There were no differences in age, sex, injury severity or physiologic presentation between patients who had an early tourniquet applied and those who died without a tourniquet. However, six patients died without a tourniquet, and all bled to death. Of the eight patients who had early tourniquets applied, none died. CONCLUSIONS Tourniquets may prevent exsanguination in the civilian setting for patients suffering either blunt or penetrating trauma to the extremity. Future studies will help determine the utility of deploying tourniquets in the civilian setting, given the rarity of exsanguinating haemorrhage from isolated extremity trauma in this setting.

The Natural History of Trauma-related Coagulopathy: Implications for Treatment

BACKGROUND Hemorrhage is a leading cause of death in trauma patients and coagulopathy is a significant contributor. Although the exact mechanisms of trauma-associated coagulopathy (TAC) are incompletely understood, hemostatic resuscitation strategies have been developed to treat TAC. Our study sought to identify which trauma patients develop TAC and the factors associated with its development, to describe the natural history of TAC, and to identify patients with TAC who may not require hemostatic resuscitation. METHODS Patients with early coagulopathy (International Normalized Ratio >1.3) who were admitted directly from the scene within 1 hour of injury were identified in our institutional trauma registry. We analyzed these data for the presence of TAC, predictors of early and delayed TAC, and evolution of TAC during the first 24 hours of admission. RESULTS Of 2,473 patients, 290 (12%) had early TAC (International Normalized Ratio >1.3) and 271 (11%) developed delayed TAC. Multivariate analysis identified female gender (odds ratio [OR] 1.25 [1.11-1.41]), lower pH (OR 0.08 [0.015-0.47]), lower hemoglobin (OR 0.96 [0.95-0.97]), lower temperature (OR 0.82 [0.70-0.95]), and blunt mechanism (OR 0.49 [0.33-0.71]) as factors significantly associated with development of early TAC. Progression of early TAC occurred in 64%, and these patients had more severe abdominal injury and received more emergency room crystalloid. Of patients with early TAC who did not receive fresh frozen plasma, only 49% developed worsening coagulopathy. Patients with isolated intracranial hemorrhage had higher rates of bleeding progression (75% vs. 20%, p < 0.005) in the presence of early TAC. CONCLUSIONS TAC may appear in an early or delayed form and its presence and progression are associated with a number of identifiable factors. Although TAC commonly progresses, it also resolves spontaneously in many patients. Further research is required to identify which patients with TAC require hemostatic treatment, although those with intracranial hemorrhages seem to warrant aggressive therapy.

Spatial segregation in copepod species from a brackish water habitat

Abstract The segregation along the horizontal space dimension of the niche has been investigated in six copepod species occurring together in a brackish water habitat. All but one species show an aggregated pattern which may be described by a negative binomial distribution. The aggregations are small with a radius of 5–15 cm and are distributed randomly in the habitat. Aggregations of different species do not overlap; niche-breadth and niche-overlap in this dimension show a somewhat wider utilization of space by the dominant species and insignificant overlap between species; there was no competition for space at the time of the investigation.

Physical rehabilitation of the critically ill trauma patient in the ICU.

Objectives:To 1) review the existing evidence for early mobilization of the critically ill patients in the ICU with polytrauma; 2) provide intensivists with an introduction to the biomechanics, physiology, and nomenclature of injuries; 3) summarize the evidence for early mobilization in each anatomic area; and 4) provide recommendations for the mobilization of these patients. Data Sources:A literature search of the MEDLINE and EMBASE databases for articles published in English between 1980 and 2011. Study Selection:Studies pertaining to physical therapy and rehabilitation in trauma patients were selected. Articles were excluded if they dealt with pediatrics, geriatrics, burn injuries, isolated hand injuries, chronic (i.e., not acute) injuries, nontraumatic conditions, and pressure/decubitus ulcers, were in a language other than English, were published only in abstract form, were letters to the editor, were case reports, or were published prior to 1980. Data Extraction:Reviewers extracted data and summarized results according to anatomical areas. Data Synthesis:Of 1,411 titles and abstracts, 103 met inclusion criteria. We found no articles specifically addressing the rehabilitation of polytrauma patients in the ICU setting or patients with polytrauma in general. We summarized the articles addressing the role of mobilization for specific injuries and treatments. We used this evidence, in combination with biologic rationale and physician and surgeon experience and expertise, to summarize the important considerations when providing physical therapy to these patients in the ICU setting. Conclusions:There is a paucity of evidence addressing the role of early mobilization of ICU patients with polytrauma and patients with polytrauma in general. Evidence for the beneficial role of early mobilization of specific injuries exists. Important considerations when applying a strategy of early physical therapy and mobilization to this distinctive patient group are summarized.

Gelseal versus Gelweave dacron prosthetic grafts in the descending thoracic aorta: a two-year computed tomography scan follow-up study.

BACKGROUND In the abdominal aorta, the use of knitted rather than woven dacron prostheses has shown an early and slow late dilation. The dilation of woven versus knitted dacron prostheses in the thoracic aortic position has not yet been investigated. METHOD From 1992, 25 patients entered a prospective study: 13 Gelweave and 12 Gelseal prostheses (diameter 18-26 mm) were implanted in the descending thoracic aorta. Computed tomography (CT) scans without contrast-enhancement were performed 2 weeks, and 1 and 2 years postoperatively. The full length of the grafts was scanned and the diameter was measured in mm measured at a level outside the areas of intercostal artery reimplantation. Patient determinants analysed were age, hypertension and implantation diameter of the grafts. The Gelseal group had a mean age of 63.7 years and seven were males. The Gelweave group had a mean age of 67.8 years and seven were males. RESULTS the mean implantation diameters were 19.6 +/- 1.7 mm and 22.0 +/- 2.7 mm (P = 0.02) for the Gelseal and Gelweave grafts, respectively. On the CT-scans at 2 weeks postoperatively, the diameter had increased by 18.8 +/- 4.8% (P = 0.0001) in the Gelseal and by 5.7 +/- 6.4% (P = 0.007) in the Gelweave grafts. This difference in diameter at 2 weeks between the two prostheses was significant (P < 0.0000 1). At 1 year the diameter had increased by 28.4 +/- 5.2% (P = 0.0001) and by 8.4 +/- 4.6% (P = 0.0003) for the Gelseal and Gelweave grafts, respectively, compared with the implantation diameter. The increase in diameter between the postoperative values at 2 weeks and those at 1 year was statistically significant in the Gelseal grafts (P = 0.0002) but not in the Gelweave grafts (P = 0.56). At 2 years an increase in diameter by 31.4 +/- 5.2% (P = 0.0001) and by 7.4 +/- 7.1% (P = 0.014) for the knitted and woven prosthetic grafts, respectively, was noted compared with the initial implantation diameter. The increase in diameter between the CT measurements at 2 weeks and those at 2 years was statistically significant in the Gelseal group (P = 0.001) but not in the Gelweave group (P = 0.86). The difference in this late increase in diameter between the two implanted grafts was also significant (P < 0.005). Age, hypertension and initial diameter did not appear to be significant determinants. CONCLUSION In contrast to the Gelseal prosthesis in the descending aorta, the Gelweave prosthesis does not show any late dilation.

S.T.A.R.T.T.: development of a national, multidisciplinary trauma crisis resource management curriculum-results from the pilot course.

BACKGROUND Most medical errors are nontechnical and include failures in team communication, situational awareness, resource use, and leadership. Other high-risk industries have adopted team-based crisis resource management (CRM) training strategies to address “nontechnical” skills and to improve human error and safety. Here, we describe the development and evaluation of a national multidisciplinary trauma CRM curriculum. METHODS A needs analysis survey was distributed to general surgery program directors across Canada. With the use of this feedback, a course called STARTT [Standardized Trauma and Resuscitation Team Training] was developed and held in conjunction with the Canadian Surgery Forum. Participants completed a precourse and postcourse evaluation exploring changes in attitudes toward simulation and CRM principles using previously validated instruments. RESULTS Twenty surgical residents, 6 nurses, 4 respiratory therapists, and 11 instructors (trauma surgeons, emergency physicians, nurses, and intensivists) participated. Of the participants, 100% completed the survey. Satisfaction was very high, with 97.5% of the participants rating the course as “good” or “excellent” and 97.5% recommending it to others. The presurvey and postsurvey showed statistically significant improvement in attitudes toward simulation and overall CRM principles (136.3 vs. 140.3 of 170, p = 0.004) following the course, primarily in the domain of teamwork (69.1 vs. 72.0 of 85, p = 0.002). CONCLUSION Creation of a national multidisciplinary trauma CRM curriculum is feasible, has high satisfaction among participants, and can improve attitudes toward the importance of simulation and CRM principles with the ultimate goal of improving patient safety and care.

Detection of significant bowel and mesenteric injuries in blunt abdominal trauma with 64-slice computed tomography.

BACKGROUND Approximately 5% of blunt abdominal trauma patients experience blunt bowel and mesenteric injuries (BBMIs). The diagnosis may be elusive as computed tomography (CT) can occasionally miss these injuries. Recent advancements in CT technology, however, may improve detection rates. This study will assess the false-negative rate of BBMI using a 64-slice computed tomographic scanner in adults with blunt abdominal trauma. METHODS All blunt abdominal trauma patients with laparotomy confirmed BBMI were retrospectively identified within a 5-year period at a Level I trauma center. Only patients who underwent preoperative abdominal CT were included. CT reports were examined specifically for findings suggestive of BBMI and compared with operative findings. A completely normal computed tomographic scan result as interpreted by a staff radiologist but operative findings of BBMI was considered a false negative. RESULTS One hundred ninety five cases of laparotomy-proven BBMI were identified from the trauma registry, of which 68 patients met study inclusion criteria. All study patients had free fluid present on CT. As a result, there were no false-negative computed tomographic scan results for BBMI. Four patients had isolated small amounts of free fluid without any additional suggestive CT findings of BBMI or solid-organ injury. Mesenteric or bowel hematomas and bowel wall thickening were present in 57% and 50% of cases, respectively. CONCLUSION The false-negative rates of BBMI may be reduced with a 64-slice computed tomographic scan. In this study, all patients had free fluid identified on CT. Consequently, even minimal free fluid remains relevant in patients with blunt abdominal injury. LEVEL OF EVIDENCE Diagnostic test, level III.

Compliance to advanced trauma life support protocols in adult trauma patients in the acute setting

IntroductionAdvanced Trauma Life Support (ATLS) protocols provide a common approach for trauma resuscitations. This was a quality review assessing compliance with ATLS protocols at a Level I trauma center; specifically whether the presence or absence of a trauma team leader (TTL) influenced adherence.MethodsThis retrospective study was conducted on adult major trauma patients with acute injuries over a one-year period in a Level I Canadian trauma center. Data were collected from the Alberta Trauma Registry, and adherence to ATLS protocols was determined by chart review.ResultsThe study identified 508 patients with a mean Injury Severity Score of 24.5 (SD 10.7), mean age 39.7 (SD 17.6), 73.8% were male and 91.9% were involved in blunt trauma. The overall compliance rate was 81.8% for primary survey and 75% for secondary survey. The TTL group compared to non-TTL group was more likely to complete the primary survey (90.9% vs. 81.8%, p = 0.003), and the secondary survey (100% vs. 75%, p = 0.004). The TTL group was more likely than the non-TTL group to complete the following tasks: insertion of two large bore IVs (68.2% vs. 57.7%, p = 0.014), digital rectal exam (64.6% vs. 54.7%, p = 0.023), and head to toe exam (77% vs. 67.1%, p = 0.013). Mean times from emergency department arrival to diagnostic imaging were also significantly shorter in the TTL group compared to the non-TTL group, including times to pelvis xray (mean 68min vs. 107min, p = 0.007), CT chest (mean 133min vs. 172min, p = 0.005), and CT abdomen and pelvis (mean 136min vs. 173min, p = 0.013). Readmission rates were not significantly different between the TTL and non-TTL groups (3.5% vs. 4.5%, p = 0.642).ConclusionsWhile many studies have demonstrated the effectiveness of trauma systems on outcomes, few have explored the direct influence of the TTL on ATLS compliance. This study demonstrated that TTL involvement during resuscitations was associated with improved adherence to ATLS protocols, and increased efficiency (compared to non TTL involvement) to diagnostic imaging. Findings from this study will guide future quality improvement and education for early trauma management.