Inspiratory aerodynamic valving occurs in the ostrich, Struthio camelus lung: a computational fluid dynamics study under resting unsteady state inhalation.

In the avian lung, inhaled air is shunted past the openings of the medioventral secondary bronchi (MVSB) by a mechanism termed 'inspiratory aerodynamic valving' (IAV). Sizes and orientations of the trachea (Tr), syrinx (Sx), extrapulmonary primary bronchus (EPPB), intrapulmonary primary bronchus (IPPB), MVSB, mediodorsal secondary bronchi (MDSB), lateroventral secondary bronchi (LVSB) and the ostium (Ot) were determined in the ostrich, Struthio camelus. Air flow was simulated through computationally generated models and its dynamics analysed. The 'truncated normal model' (TNM) consisted of the Tr, Sx, EPPB, IPPB, MVSB and the Ot. For the 'inclusive normal model' (INM), the MDSB and the LDSB were added. Variations of these models included the 'truncated MVSB1 rotated model' (T(MVSB1)RM), the 'truncated constriction fitted model' (TCFM) and the 'inclusive MVSB1 rotated model' (I(MVSB1)RM). In the TNM, the T(MVSB1)RM and the TCFM, the air flow exited through the MVSB while for the INM and the I(MVSB1)RM, very little of it did: IAV did not occur in the partial models. In the I(MVSB1)RM, rotating the MVSB1 clockwise did not affect IAV. The incomplete models may be faulty because the velocity/pressure profiles in different parts of the interconnected airways form an integrated functional continuum in which different parts of the system considerably impact on each other.

Transvenous cardioverter defibrillator lead malfunction due to terminal connector damage in pectoral implants.

Lead failure places patients with implantable cardioverter defibrillators (ICD) at risk for sudden cardiac death or results in delivery of inappropriate shocks. This study describes a mechanism of lead malfunction occurring at the junction of the terminal ring with the conductor coil of the rate sensing terminal connector in one specific model of a transvenous ICD lead. We detected the problem in a population of 179 patients with a mean age of 61 +/- 10 years and a mean lead implant duration of 16 +/- 11 months. All patients underwent pectoral ICD implantation using a submuscular approach. The implanting physician chose to place the ICD on the left side in 155 patients (87%) and on the right side in 24 patients (13%). Cephalic vein cutdown provided central venous access in 147 patients (82%), and subclavian vein puncture provided access in 32 patients (18%). Follow-up examination detected lead failure in six patients (3.5% over 31 months) due to insulation damage with or without conductor coil fracture at the junction of the terminal ring and conductor coil of the IS-1 rate sense terminal. We detected lead disruption 17 +/- 9 months (range 5-31 months) after implantation. Multiple nonsustained arrhythmia episodes exhibiting nonphysiologic intervals associated with noisy rate sensing electrograms during pocket manipulation led to discovery in three patients. The other three patients presented with inappropriate device discharges confirmed by stored high-energy lead electrograms showing normal rhythm. Pacing lead impedance abnormally dropped in two patients. Impedance remained stable in the other four patients. In conclusion, the generator pocket represents an important site of ICD transvenous lead vulnerability. Lead failure may result from conductor coil and/or insulation disruption at the interface with the rate sensing terminal connector.

Developing national health information in Australia.

Two significant developments in the past two years have given impetus to development of health information in Australia. In March 1993, the former National Minimum Data Set was revised and published as the National Health Data Dictionary. Second, establishment of an agreement in June 1993, between the Commonwealth and State/Territory government health authorities, the Australian Bureau of Statistics, and the Australian Institute of Health and Welfare initiated a process of working cooperatively to develop national health information. Australia, like many other countries, suffers from inconsistent health data definitions, lack of timely data, poor data quality, gaps in data coverage, and barriers to accessing the data. The National Health Information Agreement [1] came into effect on June 1, 1993 and seeks to provide a national framework and processes to improve national health information, that is, information on health of the population; determinants of the population's health; provision and utilization of health promotion and disease prevention programs and health services including: outcomes and outputs, resource use and costs, access by and distribution to population groups; relationships between these elements; and the language necessary to facilitate provision of services and collection of national health information. The major implementation mechanism of the Agreement is a rolling three-year National Health Information Work Program of national health information activities. The activities range from development work on standard hospital charts of accounts, on health outcome measures, and on new collections such as outpatients to improved definitions and the enhancement of existing collections such as mental health and vital statistics. The Work Program is published annually. A first priority is to improve the data collections available. This is being achieved through the setting of national data definitions and standards. The Agreement recognizes the National Health Data Dictionary (NHDD) as the authoritative set of national definitions and is a significant initiative aimed at improving Australia's health information. The dictionary is the repository of the agreed common language, use of the definitions facilities the description and comparison of health and health services nationally [2]. The National Health Data Dictionary currently covers institutionally provided health care, the national health labor force, and is expanding to cover other major areas, including outpatient services, community care, and mental health. The NHDD is reviewed and maintained by the National Health Data Committee and the overall coordination of definition development projects and publication is undertaken by the Institute. The placement of an agreed definition in the NHDD does not automatically mean that it has a place in a national data collection. The use of the dictionary definition will allow comparison by and between service providers. In order for a data item to be eligible for inclusion in a national minimum data set, the definition of that item must be contained in the NHDD. During the first three months of 1995, the Australian Institute of Health and Welfare will conduct a national project to develop a model for the health system in Australia. The model will provide a common vocabulary and information architecture in order to facilitate better quality health information, and consequently better health for Australians. It is expected that the development of the model will bring several benefits including facilitating the more rapid and accurate assembly of appropriate clinical information to support improved customer service and outcomes, provide a mechanism for achieving better quality information, reduce the costs of data collection; provide enabling mechanisms for the integration of systems via data standards and reduce the costs of acquiring information systems through reduced development and tailoring costs for suppliers. (abst