Survey of major chronic iIlnesses and hospital admissions via the emergency department in a randomized older population in Randwick,Australia

Objective: To find out if patients with chronic illnesses living in the community are at risk of unplanned hospital admissions through emergency departments; what types of chronic illnesses may be putative risk factors; and if an increase in the number of chronic illnesses may be associated with increased risk. Methods: The survey included the completion of a standardized questionnaire for medical illnesses in a random sample of older people dwelling in the community and analysis of admission records to our hospital. The principal diagnoses for admissions were recorded. The risk factors for admissions were analysed. Results: Five hundred and twenty‐six (239 men and 287 women) people aged 55 years and over were interviewed. Musculoskeletal disorders, hypertension, gastrointestinal disorders and ischaemic heart disease were the most frequently reported of the chronic illnesses surveyed. A total number of 70 people from the survey group with a total of 115 admissions through emergency departments were recorded. Using logistic regression model, hypertension, ischaemic heart disease and age were found to be risk factors for emergency admissions amongst this group of community‐dwelling residents. The ratios were 2.03 (95% confidence interval (CI): 1.2–3.44), 2.02 (95% CI: 1.16–3.49) and 1.05 (95% CI: 1.02–1.09), respectively. Furthermore, multiple (three or more) chronic illnesses were found to be a strong predictor of hospital admission via emergency department (chi‐square = 16.647, DF = 1, P‐value < 0.001). Conclusion: We conclude that there was significant association between multiple chronic diseases and emergency admissions for older people. Of these, hypertension and ischaemic heart disease were found to be significant predictors. Age per se was found to be of borderline significance.     

Skull Flexure as a Contributing Factor in the Mechanism of Injury in the Rat when Exposed to a Shock Wave

The manner in which energy from an explosion is transmitted into the brain is currently a highly debated topic within the blast injury community. This study was conducted to investigate the injury biomechanics causing blast-related neurotrauma in the rat. Biomechanical responses of the rat head under shock wave loading were measured using strain gauges on the skull surface and a fiber optic pressure sensor placed within the cortex. MicroCT imaging techniques were applied to quantify skull bone thickness. The strain gauge results indicated that the response of the rat skull is dependent on the intensity of the incident shock wave; greater intensity shock waves cause greater deflections of the skull. The intracranial pressure (ICP) sensors indicated that the peak pressure developed within the brain was greater than the peak side-on external pressure and correlated with surface strain. The bone plates between the lambda, bregma, and midline sutures are probable regions for the greatest flexure to occur. The data provides evidence that skull flexure is a likely candidate for the development of ICP gradients within the rat brain. This dependency of transmitted stress on particular skull dynamics for a given species should be considered by those investigating blast-related neurotrauma using animal models.     

Distinct types of microglial activation in white and grey matter of rat lumbosacral cord after mid-thoracic spinal transection

The inflammatory response has been characterized in the lumbosacral segments (L4-S1) of rats after spinal transection at T8. Immune cells were identified immunohistochemically using antibodies to complement type 3 receptor, CD11b (OX-42), the macrophage lysosomal antigen, CD68 (ED1), major histocompatibility complex class II (MHC II), and CD163 (ED2), a marker of perivascular cells. One week after cord transection, OX-42+ microglial density had nearly doubled. In the white matter, microglia became enlarged, often with retracted processes. In contrast, microglia in the grey matter remained ramified although nearly half of those lying medially contained clusters of ED1+ granules. After 8 weeks, ED1+ (+/-MHC II) macrophages were prominent in regions of Wallerian degeneration extending from dorsolateral to ventral funiculi. Microglial density remained raised in grey matter, particularly in the ventral horns of L4/5. Ramified microglia expressing MHC II+ (+/-ED1) extended from deep in the dorsal columns and around the central canal to the ventral columns. More ED2+ (+/-MHC II) perivascular and meningeal cells were recruited and expressed ED1. Thus, distinct from their conversion into macrophages in the white matter, the activation of ramified microglia after degeneration in the grey matter involves expression of ED1 without morphologic transformation.     

Immune cell involvement in dorsal root ganglia and spinal cord after chronic constriction or transection of the rat sciatic nerve

Chronic constriction injury (CCI) of the sciatic nerve in rodents produces mechanical and thermal hyperalgesia and is a common model of neuropathic pain. Here we compare the inflammatory responses in L4/5 dorsal root ganglia (DRGs) and spinal segments after CCI with those after transection and ligation at the same site. Expression of ATF3 after one week implied that 75% of sensory and 100% of motor neurones had been axotomized after CCI. Macrophage invasion of DRGs and microglial and astrocytic activation in the spinal cord were qualitatively similar but quantitatively distinct between the lesions. The macrophage and glial reactions around neurone somata in DRGs and ventral horn were slightly greater after transection than CCI while, in the dorsal horn, microglial activation (using markers OX-42(for CD11b) and ED1(for CD68)) was greater after CCI. In DRGs, macrophages positive for OX-42(CD11b), CD4, MHC II and ED1(CD68) more frequently formed perineuronal rings beneath the glial sheath of ATF3+ medium to large neurone somata after CCI. There were more invading MHC II+ macrophages lacking OX-42(CD11b)/CD4/ED1(CD68) after transection. MHC I was expressed in DRGs and in spinal sciatic territories to a similar extent after both lesions. CD8+ T-lymphocytes aggregated to a greater extent both in DRGs and the dorsal horn after CCI, but in the ventral horn after transection. This occurred mainly by migration, additional T-cells being recruited only after CCI. Some of these were probably CD4+. It appears that inflammation of the peripheral nerve trunk after CCI triggers an adaptive immune response not seen after axotomy.     

Filters in autologous blood retransfusion systems affect the amount of blood cells retransfused in total knee arthroplasty: a pilot study

A pilot study was undertaken to evaluate whether filters integrated in postoperative retransfusion systems affect the amount of blood cells retransfused after total knee arthroplasty. Twenty-two consecutive patients received either the Donor retransfusion system (n=12 patients) or the Bellovac ABT retransfusion system (n=10). Both systems differ with respect to the type of filter, a Pall Lipiguard filter and a Sangopur filter, respectively. At the beginning of the retransfusion, blood samples were taken before and after the filter. The filter of the Donor system significantly decreased the amount of leukocytes and erythrocytes, whereas the filter of the Bellovac system did not. As a result the haemoglobin level of retransfused blood with the Donor system was significantly lower than with the Bellovac system. It can be concluded that the type of filter integrated in two postoperative autologous blood retransfusion systems significantly affected the amount of blood cells retransfused in patients undergoing total knee arthroplasty.