Successful treatment of severe dysrhythmias in infants with respiratory syncytial virus infections: two cases and a literature review

OBJECTIVES: To describe severe myocardial manifestations in two infants with respiratory syncytial virus infection and to review published literature reporting cardiac involvement in patients with respiratory syncytial virus disease. DESIGN: Case report and literature review. SETTING: Tertiary care pediatric intensive care unit (ICU). PATIENTS: Two infants admitted to the pediatric ICU for dysrhythmias and severe myocardial dysfunction and infected with respiratory syncytial virus. INTERVENTIONS: Conventional cardiovascular, antidysrhythmic, and respiratory support, as well as extracorporeal membrane oxygenation and high-frequency oscillatory ventilation. MEASUREMENTS AND MAIN RESULTS: Both patients had respiratory syncytial virus infections and clinical evidence of severe myocarditis, with dysrhythmias, cardiomegaly, and cardiogenic shock. Both infants survived their hospitalizations. To our knowledge, these two patients are the first reported cases of myocarditis in infants with respiratory syncytial virus infection. CONCLUSIONS: Severe myocardial dysfunction and dysrhythmias may accompany respiratory syncytial virus infection in some infants and may be reversible with aggressive supportive therapy.     

氨法脱硫中的氨逃逸和硫酸铵气溶胶现象

分析在氨法脱硫工程中出现氨逃逸和硫酸铵气溶胶的机理,提出防止或减轻氨逃逸和硫酸铵气溶胶现象的办法。     

Mathematical models of diffusion-limited gas bubble dynamics in tissue

Mathematical models of bubble evolution in tissue have recently been incorporated into risk functions for predicting the incidence of decompression sickness (DCS) in human subjects after diving and/or flying exposures. Bubble dynamics models suitable for these applications assume the bubble to be either contained in an unstirred tissue (two-region model) or surrounded by a boundary layer within a well-stirred tissue (three-region model). The contrasting premises regarding the bubble-tissue system lead to different expressions for bubble dynamics described in terms of ordinary differential equations. However, the expressions are shown to be structurally similar with differences only in the definitions of certain parameters that can be transformed to make the models equivalent at large tissue volumes. It is also shown that the two-region model is applicable only to bubble evolution in tissues of infinite extent and cannot be readily applied to bubble evolution in finite tissue volumes to simulate how such evolution is influenced by interactions among multiple bubbles in a given tissue. Two-region models that are incorrectly applied in such cases yield results that may be reinterpreted in terms of their three-region model equivalents but only if the parameters in the two-region model transform into consistent values in the three-region model. When such transforms yield inconsistent parameter values for the three-region model, results may be qualitatively correct but are in substantial quantitative error. Obviation of these errors through appropriate use of the different models may improve performance of probabilistic models of DCS occurrence that express DCS risk in terms of simulated in vivo gas and bubble dynamics.     

Monitoring of health research by ethics committees

AIMS: All health related research carried out within New Zealand requires appraisal from an accredited ethics committee. The purpose of this project was to pilot an active monitoring programme and to assess the effectiveness of such a programme for future monitoring by ethics committees. METHODS: In this qualitative study interviews were undertaken by representatives from the Wellington and Manawatu-Whanganui ethics committees with principal investigators for sixteen research proposals which had been given ethical approval from the appropriate ethics committee. Issues discussed during the interviews included the protocol and any changes to the methods or research personnel, recruitment of participants, issues arising from informed consent, reporting of adverse events, funding and payment to researchers. Researchers were given the opportunity to provide feedback on the ethical review process and suggestions for improvement. RESULTS: The most significant deviation from the approved protocol concerned access to patient information. Some minor discrepancies between the approved protocols and subsequent research undertaken and the requirements for extending ethical approval of projects beyond the initial approval date were also discussed. CONCLUSIONS: The monitoring programme fulfilled an educational role, providing an opportunity for information sharing between ethics committees and researchers. An active monitoring programme by an ethics committee can detect deviations from the approved protocol beyond the current requirements for researchers to provide annual progress reports. Future monitoring should include, where relevant, access to consent forms and patients' notes.     

Seasonal and acute changes in adrenocortical responsiveness in an arctic-breeding bird

The Lapland longspur, Calcarius lapponicus, times its breeding season so that chicks hatch coincident with the brief period of food abundance in the high arctic. This synchronization requires that all reproductive activities occur in over a much shorter period than at lower latitudes. Because of the known influence of stress hormones on delaying breeding in temperate-zone birds and the detrimental effects of such delays in the arctic, we expected the performance of the hypothalamic-pituitary-adrenal (HPA) axis of arctic-breeding birds to show less sensitivity to environmental stress than their mid-latitude counterparts. We found that adrenocortical responsiveness to the standardized stress of capture and handling, measured by taking five serial blood samples for corticosterone during the course of a 1-hr period, was similar to many temperate passerines and was also similar both between male and female longspurs and between the migratory and reproductive phases. However, the profile of plasma corticosterone during capture stress was significantly damped in longspurs sampled as they began their postnuptial molt. In addition, we had the opportunity to examine endocrine responses to a natural environmental stress in 1989 during a 3-day snowstorm which concealed available food resources. During this storm longspurs formed progressively larger flocks each day, with females abandoning incubation duties by the third day. Birds captured during the storm showed highly significant increases in both the rate of plasma corticosterone increase during capture and the peak postcapture level compared with birds sampled before the storm. This increased adrenal potential suggests increased activity of the HPA axis in response to severe conditions and is reminiscent of the response to fasting. Although the storm occurred during incubation, and reproductive hormone levels had begun to decline, we measured significant reductions in luteinizing hormone in both males and a subset of females captured during the storm.