Age-related injury patterns resulting from knife violence in an urban population.

Interpersonal violence involving knives is a major public health problem. The majority of patients are young people in urban areas, but little is known about age-specific patterns of injury and recent trends in injury characteristics. We performed a retrospective cohort study of all patients presenting to an urban major trauma centre with stab injuries resulting from assault between 2012 and 2018. A total of 3583 patients were included. Young people (age under 25) were more likely to have sustained multiple stab wounds compared to older people (43% vs 35%, p < 0.001) and had significantly higher rates of stab injuries involving the lower limbs, groin and buttocks. The annual number of injuries increased steadily during the study period in patients aged under 25 (r2 = 0.82, p = 0.005) and those over 25 (r2 = 0.95, p < 0.001). Over time, limb and junctional injuries accounted for an increasing proportion of stab wounds in young people, overtaking torso injuries as most common pattern of injury by the end of the study period. These findings illustrate the influence of age on injury patterns resulting from knife violence, and support the expansion of outreach initiatives promoting bystander-delivered haemorrhage control of extremity wounds.

Point-of-care Hepatitis C virus testing and linkage to treatment in an Australian inner-city emergency department.

BACKGROUND: In Australia, Hepatitis C Virus (HCV) treatment is declining, despite broad access to direct-acting antiviral medication. People who inject drugs are proportionally over-represented in emergency department presentations. Emergency department assessment of people who have injected drugs for HCV presents an opportunity to engage this marginalised population with treatment. We describe the outcomes of risk-based screening and point-of-care anti-HCV testing for emergency department patients, and linkage to outpatient antiviral treatment. METHODS: During the three-month study period, consecutive adult patients who presented to the emergency department during the study times were screened for risk factors and offered the OraQuick oral HCV antibody test. Those with reactive results were offered venepuncture in the emergency department for confirmatory testing and direct-acting antiviral treatment in clinic. The main outcome measures were the number and proportion of viremic participants that were linked to the hepatitis clinic, commenced treatment and achieved a sustained viral response. Secondary outcome measures were the proportion (%) of presentations screened that were oral antibody reactive, and the prevalence and type of HCV risk factors. RESULTS: During the study period, 2408 of the 3931 (61%) presentations to the emergency department were eligible for screening. Of these 2408 patients, 1122 (47%) participated, 307 (13%) declined participation and 977 (41%) could not be approached during their time in the emergency department. Among the 1122 participants, 378 (34%) reported at least one risk factor. Subsequently, 368 (97%) of the 378 participants underwent OraQuick anti-HCV test, and 50 (14%) had a reactive result. A risk factor of ever having injected drugs was present in 44 (88%) of participants who were sero-positive. Of the 45 that had blood tested, 30 (67%) were HCV ribonucleic acid (RNA) positive. Three participants died. Of the 27 remaining participants, 10 (37%) commenced treatment and 7 of these 10 (70%) obtained a cure. There was a high rate of homelessness (24%) among anti-HCV positive participants. CONCLUSION: Among emergency department participants with a risk factor for HCV, positive serology was common using a rapid point-of-care test. A history of injecting drug use was identified as the risk factor with highest yield for positive HCV serology, and is suitable as a single screening question. However, linkage to care post ED presentation was low in this marginalised population. There is a need for new pathways to improve the care cascade for marginalised individuals living with HCV infection.

Spleen preserving management of a non-parasitic splenic cyst in pregnancy.

Non-parasitic splenic cysts are rare entities. In pregnancy, they are rarer still, with as few as seven cases reported in the literature. There is little consensus regarding the optimal management of this condition in pregnancy. Although small, the theoretical risk of intrapartum splenic rupture is associated with a fetal mortality rate as high as 70%. The authors of at least three case reports advocate total splenectomy as first-line management of splenic cyst in pregnancy. Paradoxically, spleen conserving surgery is the recognised gold standard treatment for symptomatic splenic cysts in non-pregnant patients. We present a case of a large maternal splenic cyst that was treated successfully with a laparoscopic cystectomy.

Meta-analysis of prognostic factors for amputation following surgical repair of lower extremity vascular trauma.

BACKGROUND: Lower extremity vascular trauma (LEVT) is a major cause of amputation. A clear understanding of prognostic factors for amputation is important to inform surgical decision-making, patient counselling and risk stratification. The aim was to develop an understanding of prognostic factors for amputation following surgical repair of LEVT. METHODS: A systematic review was conducted to identify potential prognostic factors. Bayesian meta-analysis was used to calculate an absolute (pooled proportion) and relative (pooled odds ratio, OR) measure of the amputation risk for each factor. RESULTS: Forty-five studies, totalling 3187 discrete LEVT repairs, were included. The overall amputation rate was 10·0 (95 per cent credible interval 7·4 to 13·1) per cent. Significant prognostic factors for secondary amputation included: associated major soft tissue injury (26 versus 8 per cent for no soft tissue injury; OR 5·80), compartment syndrome (28 versus 6 per cent; OR 5·11), multiple arterial injuries (18 versus 9 per cent; OR 4·85), duration of ischaemia exceeding 6 h (24 versus 5 per cent; OR 4·40), associated fracture (14 versus 2 per cent; OR 4·30), mechanism of injury (blast 19 per cent, blunt 16 per cent, penetrating 5 per cent), anatomical site of injury (iliac 18 per cent, popliteal 14 per cent, tibial 10 per cent, femoral 4 per cent), age over 55 years (16 versus 9 per cent; OR 3·03) and sex (men 7 per cent versus women 8 per cent; OR 0·64). Shock and nerve or venous injuries were not significant prognostic factors for secondary amputation. CONCLUSION: A significant proportion of patients who undergo lower extremity vascular trauma repair will require secondary amputation. This meta-analysis describes significant prognostic factors needed to inform surgical judgement, risk assessment and patient counselling.

Going for gold: blood planning for the London 2012 Olympic Games.

The Olympics is one of the largest sporting events in the world. Major events may be complicated by disruption of normal activity and major incidents. Health care and transfusion planners should be prepared for both. Previously, transfusion contingency planning has focused on seasonal blood shortages and pandemic influenzas. This article is the first published account of transfusion contingency planning for a major event. We describe the issues encountered and the lessons identified during transfusion planning for the London 2012 Olympics. Planning was started 18 months in advance and was led by a project team reporting to the Executive. Planning was based on three periods of Gamestime. The requirements were planned with key stakeholders using normal processes enhanced by service developments. Demand planning was based on literature review together with computer modelling. The aim was blood-stock sufficiency complimented by a high readiness donor panel to minimise waste. Plans were widely communicated and table-top exercised. Full transfusion services were maintained during both Games with all demands met. The new service improvements and high readiness donors worked well. Emergency command and control have been upgraded. Red cell concentrate (RCC) stock aged but wastage was not significantly increased. The key to success was: early planning, stakeholder engagement, service developments, integration of transfusion service planning within the wider health care community and conduct within an assurance framework.

Optimal electromagnetic energy transmission and real-time dissipation in extended media.

Pulse reshaping effects that give rise to fast and slow light phenomena are inextricably linked to the dynamics of energy exchange between the pulse and the propagation medium. Energy that is dissipated from the pulse can no longer participate in this exchange process, but previous methods of calculating real-time dissipation are not valid for extended propagation media. We present a method for calculating real-time dissipation that is valid for electromagnetic pulse propagation in extended media. This method allows one to divide the energy stored in an extended medium into the portion that can be later transmitted out of the medium, and that portion which must be lost to either dissipation or reflection.

Blood and bombs: the demand and use of blood following the London Bombings of 7 July 2005--a retrospective review.

Mass casualty events (MCE) present health systems with a sudden demand on key services. The overall objective of this study was to describe the experience of the National Blood Service (NBS) following the largest UK MCE in recent times. Data was collated from the NBS database and directly from the hospitals involved. All data was collected immediately following the event and included: all blood components requested, issued and transfused in relation to the bombings, blood stock levels at the time and the injury profiles of the casualties transfused. The total NBS order from hospitals for the event was 1455 units of blood components. All requests were fulfilled, this included: 978 units of red cells (RC), 36 doses of platelets, 141 units of fresh frozen plasma (FFP) and 300 doses of cryoprecipitate. The amount of blood ordered was three times that initially used and the total number of RC transfused in treating all victims from admission to discharge was approximately 440 units. The greatest use of blood components was for those casualties who had sustained traumatic amputations amongst their injury profile. Published data with which to compare these results is lacking, although the RC use was similar to the initial mean individual usage described in previous military and civilian bombings. The overall implication for any blood service remains, there is now likely to be a far greater demand for plasma, platelets and cryoprecipitate in any future incidents involving victims suffering major haemorrhage.

Cholinergic suppression of excitatory synaptic transmission in layers II/III of the parasubiculum.

Layer II of the parasubiculum (PaS) receives excitatory synaptic input from the CA1 region of the hippocampus and sends a major output to layer II of the medial and lateral entorhinal cortex. The PaS also receives heavy cholinergic innervation from the medial septum, which contributes to the generation of theta-frequency (4-12 Hz) electroencephalographic (EEG) activity. Cholinergic receptor activation exerts a wide range of effects in other areas of the hippocampal formation, including membrane depolarization, changes in neuronal excitability, and suppression of excitatory synaptic responses. The present study was aimed at determining how cholinergic receptor activation modulates excitatory synaptic input to the layer II/III neurons of the PaS in acute brain slices. Field excitatory postsynaptic potentials (fEPSPs) in layer II/III of the PaS were evoked by stimulation of either layer I afferents, or ascending inputs from layer V. Bath-application of the cholinergic agonist carbachol (0.5-10 µM) suppressed the amplitude of fEPSPs evoked by both superficial- and deep layer stimulation, and also enhanced paired-pulse facilitation. Constant bath-application of the GABA(A) antagonist bicuculline (10 µM) failed to eliminate the suppression, indicating that the cholinergic suppression of fEPSPs is not due to increased inhibitory tone. The muscarinic receptor antagonist atropine (1 µM) blocked the suppression of fEPSPs, and the selective M(1)-preferring receptor antagonist pirenzepine (1 µM), but not the M(2)-preferring antagonist methoctramine (1-5 µM), also significantly attenuated the suppression. Therefore, cholinergic receptor activation suppresses excitatory synaptic input to layer II/III neurons of the PaS, and this suppression is mediated in part by M(1) receptor activation.

Real-time recoverable and irrecoverable energy in dispersive-dissipative dielectrics.

We discuss the recoverable and irrecoverable energy densities associated with a pulse at a point in the propagation medium and derive easily computed expressions to calculate these quantities. Specific types of fields are required to retrieve the recoverable portion of the energy density from the point in the medium, and we discuss the properties that these fields must have. Several examples are given to illustrate these concepts.

Unfavourable expression of pharmacologic markers in mucinous colorectal cancer.

Patients with mucinous colorectal cancer generally have worse prognoses than those with the nonmucinous variety. The reason for this disparity is unclear, but may result from a differential response to adjuvant chemotherapy. We examined known molecular markers for response to common chemotherapy in these two histological subtypes. In all, 21 patients with mucinous and 30 with nonmucinous Dukes C colorectal cancer were reviewed for demographic data and outcome. Total RNA from the tumours and adjacent normal mucosa was isolated and reverse transcribed. Quantitative expression levels of drug pathway genes were determined using TaqMan RT-PCR (5-fluorouracil (5-FU): TYMS, DPYD, ECGF1; oxaliplatin: GSTP1 (glutathione S-transferase pi), ERCC1 and 2; irinotecan: ABCB1, ABCG2, CYP3A4, UGT1A1, CES2, TOP1). Mucinous tumours significantly overexpressed both TYMS and GSTP1 relative to nonmucinous tumours and patient-matched normal mucosa. No significant differences in expression of the remaining markers were found. Mean follow-up was 20 months; 17 patients had recurrent disease. Among patients receiving 5-FU, those with mucinous tumours experienced shorter disease-free survival (DFS) than those with nonmucinous tumours (median DFS 13.8 vs 46.5 months, P=0.053). Mucinous colorectal cancer overexpresses markers of resistance to 5-FU and oxaliplatin. Likewise, DFS may be decreased in patients with mucinous tumours who receive 5-FU. The presence of mucin should be carefully evaluated in developmental trials of new agents for treating colorectal cancer.

Poynting's theorem and luminal total energy transport in passive dielectric media.

Without approximation the energy density in Poynting's theorem for the generally dispersive and passive dielectric medium is demonstrated to be a system total dynamical energy density. Thus the density in Poynting's theorem is a conserved form that by virtue of its positive definiteness prescribes important qualitative and quantitative features of the medium-field dynamics by rendering the system dynamically closed. This fully three-dimensional result, applicable to anisotropic and inhomogeneous media, is model independent, relying solely on the complex-analytic consequences of causality and passivity. As direct applications of this result, we show (1). that a causal medium responds to a virtual, "instantaneous" field spectrum, (2). that a causal, passive medium supports only a luminal front velocity, (3). that the spatial "center-of-mass" motion of the total dynamical energy is also always luminal and (4). that contrary to (3). the spatial center-of-mass speed of subsets of the total dynamical energy can be arbitrarily large. Thus we show that in passive media superluminal estimations of energy transport velocity for spatially extended pulses is inextricably associated with incomplete energy accounting.

Role of the instantaneous spectrum on pulse propagation in causal linear dielectrics.

A model-independent theorem demonstrates how a causal linear dielectric medium responds to the instantaneous spectrum, that is, the spectrum of the electric field pulse that is truncated at each new instant (as a given locale in the medium experiences the pulse). This process leads the medium to exchange energy with the front of a pulse differently than with the back as the instantaneous spectrum laps onto or off of nearby resonances. So-called superluminal pulse propagation in either absorbing or amplifying media as well as highly subluminal pulse propagation are understood qualitatively and quantitatively within this context.

Role of group velocity in tracking field energy in linear dielectrics.

A new context for the group delay function (valid for pulses of arbitrary bandwidth) is presented for electromagnetic pulses propagating in a uniform linear dielectric medium. The traditional formulation of group velocity is recovered by taking a narrowband limit of this generalized context. The arrival time of a light pulse at a point in space is defined using a time expectation integral over the Poynting vector. The delay between pulse arrival times at two distinct points consists of two parts: a spectral superposition of group delays and a delay due to spectral reshaping via absorption or amplification. The use of the new context is illustrated for pulses propagating both superluminally and subluminally. The inevitable transition to subluminal behavior for any initially superluminal pulse is also demonstrated.

Energy transport in linear dielectrics.

We examine the energy exchanged between an electromagnetic pulse and a linear dielectric medium in which it propagates. While group velocity indicates the presence of field energy (the locus of which can move with arbitrary speed), the velocity of energy transport maintains strict luminality. This indicates that the medium treats the leading and trailing portions of the pulse differently. The principle of causality requires the medium to respond to the instantaneous spectrum, the spectrum of the pulse truncated at each new instant as a given locale in the medium experiences the pulse.

Comparison of various hemoglobin polyoxyethylene conjugate solutions as resuscitative fluids after hemorrhagic shock.

BACKGROUND: Previous research suggested that splanchnic hypoperfusion occurs after resuscitation with certain acellular hemoglobin solutions. We examined the influence of maltose content and oxygen affinity on resuscitation with various hemoglobin polyoxyethylene conjugate solutions after hemorrhage. METHODS: Fifteen swine underwent hemorrhage and equal volume resuscitation with pyridoxalated hemoglobin polyoxyethylene conjugate containing 0% or 8% maltose, or low P50 conjugate, which also contained 8% maltose. Five control animals were monitored but not bled. Regional blood flow was determined by using radioactive microspheres, gastric mucosal perfusion was estimated with tonometry, and gut histopathology was evaluated. RESULTS: All hemoglobin solutions produced vasoconstriction, manifested by elevated mean systemic and pulmonary artery pressures without a significant decrease in cardiac index compared with the sham group. Resuscitation with maltose-containing solutions elevated arterial and regional PCO2 and depressed arterial pH and gastric pHi (p < 0.05 for all). Splanchnic and renal blood flows were reduced in the low P50 + 8% maltose group (p < 0.05 vs. sham and baseline for renal blood flow), possibly indicating greater regional vasoconstriction in this group. Ileal mucosal damage was more severe in the maltose-containing groups and correlated with decreased pHi. CONCLUSION: Vasoconstriction occurred in all groups but was more severe in the low P50 + 8% maltose group. Maltose-containing solutions caused respiratory acidosis, decreased pHi, and histologic evidence of mucosal injury. Pyridoxalated hemoglobin polyoxyethylene conjugate without maltose was a superior resuscitation solution in this swine model.

Placental 11 beta-hydroxysteroid dehydrogenase activity in normotensive and pre-eclamptic pregnancies.

Apparent mineralocorticoid excess and licorice induced hypertension, both hypertensive disorders, have been attributed to a defect in the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD), which interconverts cortisol to cortisone. Therefore, we undertook this study to determine the role of human placental 11 beta-HSD activity in preeclampsia, which is a hypertensive disorder in pregnancy. 11 beta-HSD activities were determined in placentas of 17 normotensive and 11 preeclamptic patients matched for gestational age at 34-42 weeks. Cortisol levels in umbilical venous and arterial sera were also determined for both groups. Statistical analysis was performed using Student's t-test, significance at p < 0.05. 11 beta-dehydrogenase (oxidation activity of 11 beta-HSD) activity was significantly lower in placentas of preeclamptic compared to normotensive patients (0.19 +/- 0.09 vs. 0.26 +/- 0.08 mmoles/min/placenta, p = 0.02). Cortisol level in umbilical cord blood was significantly higher in the preeclamptic group (14.99 +/- 14.08 vs. 6.71 +/- 3.69 g/dL, p = 0.02). The decreased 11 beta-HSD activity is accompanied by an expected increase in umbilical cord blood cortisol level and decrease in fetal weight. This enzyme may play an important role in influencing fetal growth.

Anterior cruciate ligament injury and reconstruction among university students.

The consequences of athletic injuries extend beyond the musculoskeletal system. Depression, anger, and tension have been observed in athletes with athletic injuries. It was hypothesized that among student athletes, the psychologic impact of injury may be seen as a drop in academic performance. Thirty-eight students who had an anterior cruciate ligament injury and subsequent reconstruction were evaluated retrospectively by academic transcript and questionnaire to measure their academic performance before their injury, in the semester of their injury, and in the semester after their surgery. The patients were compared with randomly selected undergraduate control subjects. To evaluate any effect of the timing of the surgery on academic performance, the patients were separated into two groups, according to the timing of their reconstruction: those who had surgery during the academic semester, and those who elected to wait for a school break. There was a significant drop in grade point average of 0.3 grade points during the semester of injury among all injured students. Compared with those who had surgery during a break, the students who had surgery during the semester received more frequently the grade of failure (6% versus 0%) or incomplete (33% versus 9%). These students also missed more school days (10.5 days versus 1.5 days) and examinations (2.2 examinations versus 0.1 examinations). Only 47% of students who had surgery during the semester were satisfied with their decision for surgical timing, compared with 96% satisfied with the timing during an academic break. Acute anterior cruciate ligament rupture, and surgical reconstruction during an academic semester, have a significant academic effect in university students.

Analysis of failed surgical management of fractures of the base of the fifth metatarsal distal to the tuberosity: the Jones fracture.

Failure of surgical management of fractures of the base of the fifth metatarsal distal to the tuberosity is uncommon. Only one such failure has been reported in the literature to date. The purpose of this article is to present the clinical course of 11 patients with failure of surgically managed jones fractures reviewed by the senior author (J.S.T.). Surgical management was complicated by delayed union in three patients, refracture in seven patients, and nonunion in one patient. The 11 procedures were divided between two established techniques: (1) intramedullary screw fixation (N = 6) and (2) inlaid corticocancellous bone graft (N = 5). In the six intramedullary fixation procedures, using other than a 4.5-mm ASIF malleolar screw for internal fixation correlated with failure. In the five inlaid bone graft procedures, undersized corticocancellous grafts and incomplete reaming of the medullary canal correlated with failure. Also, after both procedures, early return to vigorous physical activity is believed to have played a role in delayed union and refracture.

Magnetic resonance imaging of knee disorders. Clinical value and cost-effectiveness in a sports medicine practice.

To prospectively evaluate the clinical value of magnetic resonance imaging of the knee in a referral sports medicine practice, we performed a three-part study. First, we asked 72 consecutive patients a series of clinically relevant questions regarding the ordering of their magnetic resonance imaging scans. Second, we asked the treating physicians at our center if the magnetic resonance imaging findings changed the diagnosis or treatment. Third, we compared the clinical evaluation with the findings on magnetic resonance imaging scans for 37 patients who had arthroscopic confirmation. From the physician's perspective, in only three cases would the results of the scan have changed the diagnosis. Information from the scans was judged to contribute to patient treatment in only 14 of 72 patients. Finally, comparison of clinical evaluation and magnetic resonance imaging findings with findings during arthroscopic procedures showed that clinical evaluation had a sensitivity and specificity of 100% for diagnosis of anterior cruciate ligament injuries, whereas magnetic resonance imaging was 95% sensitive and 88% specific. For isolated meniscal lesions, the clinical assessment had a sensitivity and specificity of 91% compared with 82% and 87%, respectively, for magnetic resonance imaging. For evaluation of articular surface damage, the predictive value of a positive test was 100% for clinical assessment and 33% for the magnetic resonance imaging. We conclude that magnetic resonance imaging is overused in the evaluation of knee disorders and not a cost-effective method for evaluating injuries when compared with a skilled examiner. Clinical assessment equals or surpasses the magnetic resonance imaging in accuracy.