Do ethnic and socio-economic inequalities in mortality vary by region in New Zealand? An application of hierarchical Bayesian modelling

We hypothesised that ethnic and socio-economic inequality in mortality might vary by region in New Zealand. Linked 2001–2004 census-mortality data were stratified by region (District Health Boards or DHBs), sex, age and ethnic groups, and income quintiles. To accommodate data sparseness, and to achieve accurate estimates of DHB-specific mortality rates and rate ratios by ethnicity and income, we used hierarchical Bayesian methods. To aid presentation of results, we used posterior mortality rates from the models to calculate directly standardised rates and rate ratios, with credible intervals. Māori-European/Other mortality rate ratios were often similar across DHBs, but Waitemata and Canterbury DHBs (both predominantly urban areas with low Māori population) had significantly lower rate ratios. In contrast, Bay of Plenty and Waikato DHBs (heterogeneous by both ethnicity and socio-economic position) had significantly higher rate ratios. There was little variation in mortality inequalities by income across DHBs. Examining the underlying rates for ethnic and income groups separately, there were significant variations across DHBs, but these were often correlated such that the ethnic or income rate ratio was similar across DHBs. The application of hierarchical Bayesian allowed more definitive conclusions than routine empirical methods when comparing small populations such as social groups across regions. The range of hierarchical Bayesian estimates of Māori mortality and Māori:European rate ratios across regions was considerably narrower than empirical standardisation estimates.     

Clinical judgement of near pupil responses provides a useful indicator of focusing ability in children with cerebral palsy

Accommodation is often reduced in cerebral palsy (CP). Knowledge about accommodative facility is valuable when investigating a child's visual needs and developing strategies for education. With normal accommodation, changing focus from distance to near results in pupil constriction. We compared quality of near pupil responses (NPR) with objective measures of accommodative function obtained with dynamic retinoscopy (DR) to investigate the utility of NPR in indicating accommodative facility. NPR and accommodative function of 90 children with CP (56 males, 34 females; median age 11y, range 4-18y) were assessed. A total of 93% of participants had spastic CP (71.3% bilateral involvement, 28.7% hemiplegia). The severity of motor impairment ranged from very mild (n=7) to severe (no independent walking, n=28). NPR was classified subjectively as normal, reduced, or absent and compared with DR measures of accommodative response. A total of 9.8% of pupil responses were judged absent, 25.6% reduced, and 64.6% normal. Participants with reduced or absent pupil responses demonstrated significantly poorer levels of accommodation with DR (one-way analysis of variance p<0.01). Sensitivity and specificity of NPR in identifying participants with reduced accommodation were 83% (95% confidence interval [CI] 65.5-92.4%) and 72% (95% CI 58.4-82.0%) respectively. NPR provides a rapid, useful indicator of accommodative function in children with CP.     

Is steroid therapy ever of benefit to patients in the intensive care unit going into septic shock

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was, is steroid therapy ever of benefit to patients in the intensive care unit going into septic shock? Using the reported search 1505 papers were identified. Fourteen papers represented the best evidence on the subject. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study comments and weaknesses were tabulated. Recent guidelines from the Surviving Sepsis Campaign recommend using stress doses of corticosteroids for septic shock regardless of adrenal function. All patients undergoing cardiothoracic surgery are at risk of developing septic shock. The 14 papers demonstrated that 28-day mortality is unaffected by hydrocortisone, however, the time to shock reversal is significantly reduced. Steroids reduced inflammatory mediators (IL-6, IL-8 and CRP) and neutrophil activation whilst maintaining neutrophil phagocytic functions. Haemodynamically, they increased systemic vascular resistance (SVR) and mean arterial pressure (MAP) and reduced heart rate (HR) and glomerular permeability. We conclude that steroids have no effect on mortality but shorten time to shock reversal, therefore they have a limited capacity in septic shock patients. Their immunological and haemodynamic effects cannot be discounted and could benefit patients in severe septic shock with adrenal insufficiency.     

Current concepts review: total ankle arthroplasty

Many orthopaedic surgeons had abandoned the use of first and second generation total ankle arthroplasties due to unacceptably high complication and failure rates as compared to arthrodesis. Recently, there has been renewed interest in ankle joint replacement as longer term outcome studies have become available, and the FDA has approved several more designs. With the introduction of two new FDA approved implants in November 2006, options for surgeons interested in total ankle arthroplasty have greatly expanded. There continues to be much debate within the orthopaedic community as to indications, patient selection, and optimal component design. This review aims to provide orthopaedists with an overview of the currently available implants and literature.     

A novel role for MNTB neuron dendrites in regulating action potential amplitude and cell excitability during repetitive firing

Principal cells of the medial nucleus of the trapezoid body (MNTB) are simple round neurons that receive a large excitatory synapse (the calyx of Held) and many small inhibitory synapses on the soma. Strangely, these neurons also possess one or two short tufted dendrites, whose function is unknown. Here we assess the role of these MNTB cell dendrites using patch-clamp recordings, imaging and immunohistochemistry techniques. Using outside-out patches and immunohistochemistry, we demonstrate the presence of dendritic Na⁺ channels. Current-clamp recordings show that tetrodotoxin applied onto dendrites impairs action potential (AP) firing. Using Na⁺ imaging, we show that the dendrite may serve to maintain AP amplitudes during high-frequency firing, as Na⁺ clearance in dendritic compartments is faster than axonal compartments. Prolonged high-frequency firing can diminish Na⁺ gradients in the axon while the dendritic gradient remains closer to resting conditions; therefore, the dendrite can provide additional inward current during prolonged firing. Using electron microscopy, we demonstrate that there are small excitatory synaptic boutons on dendrites. Multi-compartment MNTB cell simulations show that, with an active dendrite, dendritic excitatory postsynaptic currents (EPSCs) elicit delayed APs compared with calyceal EPSCs. Together with high- and low-threshold voltage-gated K⁺ currents, we suggest that the function of the MNTB dendrite is to improve high-fidelity firing, and our modelling results indicate that an active dendrite could contribute to a 'dual' firing mode for MNTB cells (an instantaneous response to calyceal inputs and a delayed response to non-calyceal dendritic excitatory postsynaptic potentials).     

Alcohol self-administration acutely stimulates the hypothalamic-pituitary-adrenal axis, but alcohol dependence leads to a dampened neuroendocrine state

Clinical studies link disruption of the neuroendocrine stress system with alcoholism, but remaining unknown is whether functional differences in the hypothalamic-pituitary-adrenal (HPA) axis precede alcohol abuse and dependence or result from chronic exposure to this drug. Using an operant self-administration animal model of alcohol dependence and serial blood sampling, we show that longterm exposure to alcohol causes significant impairment of HPA function in adult male Wistar rats. Acute alcohol (voluntary self-administration or experimenter-administered) stimulated the release of corticosterone and its upstream regulator, adrenocorticotropic hormone, but chronic exposure sufficient to produce dependence led to a dampened neuroendocrine state. HPA responses to alcohol were most robust in 'low-responding' non-dependent animals (averaging < 0.2 mg/kg/session), intermediate in nondependent animals (averaging approximately 0.4 mg/kg/session), and most blunted in dependent animals (averaging approximately 1.0 mg/kg/session) following several weeks of daily 30-min self-administration sessions, suggesting that neuroendocrine tolerance can be initiated prior to dependence and relates to the amount of alcohol consumed. Decreased expression of corticotropin-releasing factor (CRF) mRNA expression in the paraventricular nucleus of the hypothalamus and reduced sensitivity of the pituitary to CRF may contribute to, but do not completely explain, neuroendocrine tolerance. The present results, combined with previous studies, suggest that multiple adaptations to stress regulatory systems may be brought about by excessive drinking, including a compromised hormonal response and a sensitized brain stress response that together contribute to dependence.     

Choreathetoid movement as an unusual presentation of subdural haematoma

Summary  Subdural haematomas can present with a wide variety of symptoms. An atypical presentation can be movement disorders. The key feature is that the history of onset is more rapid than with neurological conditions such as Parkinson’s disease. The symptoms can also be an acute worsening of pre-existing disorder. The case discussed involved an 80 year old woman with bilateral choreathetoid movements attributed to a unilateral chronic subdural haematoma. The haematoma was surgically drained and the symptoms resolved. Sporadic reports of similar cases of movement disorders associated with subdural haematomas exist in the literature, but rarely do unilateral haematomas present with bilateral symptoms. Pressure effects, neurotransmitter abnormality and ischaemia have been postulated as reasons for this type of presentation. Unexplained and sudden movement disorders might warrant imaging to rule out a subdural haematoma as the cause. Correspondence: Mrs. G. Pickett, Salford Royal Hospital, Stott Lane, Salford M6 8HD, UK.     

Three-year results of mandated work hour restrictions: attending and resident perspectives and effects in a community hospital

In response to the Accreditation Council of Graduate Medical Education mandated resident work hour restrictions, our residency program used a night float system in 2003. We undertook a survey of attending staff and residents to assess its effects on patient care and resident education. An anonymous survey was administered to attending staff and residents 1 year and 3 years after work hour restrictions took effect. The areas of disagreement include: beneficial effect on education (residents vs faculty: in 2004, 87% vs 22%, respectively, P = 0.02; in 2006, 71% vs 22%, P = 0.03); beneficial effect on patient care (in 2004, 53% vs 10%, P = 0.03); and compromised continuity of care (in 2004, 27% vs 70%, P = 0.04; in 2006, 7% vs 89%, P = 0.0002). One area of agreement was that residents' quality of life had improved. Both disagreed that more errors were being made and that work hour restrictions should be mandated on practicing surgeons. Attending staff and residents have deeply held opinions regarding the effects of work hour restrictions. This reflects a continuing dissatisfaction with providing patient care and educating residents under a set of requirements that solely addresses resident sleepiness and fatigue.     

Blunt liver injury in children and adults: is there really a difference?

Hepatic injuries are increasingly managed nonoperatively with the availability of adjunctive procedures such as angiography, ERCP, and percutaneous drainage. Although extensively discussed in the adult population, little has been reported on outcomes and management of pediatric liver injury. Retrospective review of all patients with blunt liver injuries admitted to an adult Level I trauma center and pediatric trauma center within the same community was performed from 2004 to 2006. The necessity for operation, adjuncts to nonoperative management, and outcome were collected and compared for the pediatric (PED) (<18 years of age) versus the adult (> or = 18 years of age) injured patients. There were 389 liver injuries identified (PED = 90, adult = 299); 25 per cent of adult injuries were greater than or equal to grade III, while 23 per cent of PED injuries were high-grade injuries. Each group of patients had similar rates of primary operative intervention: adult patients (18%) versus PED patients (16%). Adjunctive therapies were rarely used in the PED patients with only one patient requiring a percutaneous drain and one patient undergoing ERCP twice. Conversely, the adult patient group required eight percutaneous drains, 15 angiograms, 6 ERCPs and 14 laparoscopic abdominal washout procedures. ICU and hospital LOS were 25 per cent and 33 per cent lower in the adult population for high-grade injuries. The overall mortality rates were similar at 7 per cent (PED) and 9 per cent (adult). Liver-related mortality was 50 per cent (3/6 deaths) in the PED group with no liver-related deaths in the adult group (27 deaths). Adult patients with blunt liver injury were no more likely to sustain high grade liver injuries than PED patients. Furthermore, adult and PED patients underwent similar rates of operative intervention and primary liver procedures. Adult patients used adjunctive measures as part of their nonoperative management more frequently, but both subsets had similar length of hospital stays and low overall mortality. A higher rate of liver-related mortality was seen in the PED population. Overall, PED patients seemed to sustain fewer liver related complications necessitating invasive procedures despite similar injury patterns.