Digital cardiac defibrillator tester

The cardiac defibrillator is the most commonly used instrument in hospital, ambulance and industry for resuscitation after electrocution or cardiac arrest. Defibrillation involves the application of a short pulse of electric current (4–10ms) through the chest of the patient; it has been demonstrated that the required energy is a function of the patient's weight. A knowledge of the performance of a defibrillator is essential; front panel meters, although calibrated in joules, read capacitor voltage only, and a loss of capacitance is not easily detected in use. We have had personal experience of this loss on several occasions. Commercial defibrillator testers employ analogue circuitry and are no more reliable in calibration than defibrillators themselves. This paper discusses the design of a microprocessor-based defibrillator analyser which has a performance far superior to existing testers. It gives an absolute digital readout of the energy delivered into a standard 50 Ω load, the peak defibrillating voltage, and the rise time of the defibrillator output wave. Facilities are also provided for storage of the defibrillator output waveform, so that the profile can be examined on an oscilloscope.     

Nickel cadmium batteries in defibrillators

This article describes the failure mechanisms of nickel cadmium batteries. The design of suitable battery chargers for defibrillators is discussed. It is argued that the life of nickel cadmium battery packs can be significantly extended without impairing safety if appropriate testing is carried out. Results of tests on a set of 10 defibrillator packs removed from service after a period of two years are presented.     

A syringe pump tester

The equipment described allows the accuracy of a syringe pump to be tested quickly and conveniently. A digital micrometer assembly clips in place of the disposable syringe and transmits readings to a separate unit which displays flow rates in ml/h. Initial readings of pump output are given in 30 s, with readings to a higher accuracy within 4 min.     

A megawatt defibrillator for transchest defibrillation of heavy subjects

The design and performance characteristics of a high-energy (5000J) defibrillator are described. The instrument was constructed for the purpose of obtaining strength duration curves for transchest defibrillation of very heavy subjects. To date, the heaviest subject that has been defibrillated is a 270 kg horse.     

The content of cadmium,cobalt and nickel in laryngeal carcinoma

Introduction

The aim of the study was to determine the content of cadmium (Cd), cobalt (Co) and nickel (Ni) in the samples from laryngeal carcinoma in comparison with the level of these elements in the samples of healthy mucous membrane from the same larynx.

Material and methods

The study was conducted on 43 patients with laryngeal carcinoma. The levels of Cd, Co, and Ni in carcinoma and healthy control tissues was determined by inductively coupled plasma optical emission spectrometry (ICP – OES) using sequential spectrometer.

Results

No significant differences were found between the levels of the Cd, Co, and Ni in laryngeal carcinoma vs tissues without carcinoma. However, it was noted that the concentration of Cd in tumors of patients with metastases to cervical lymph nodes was significantly higher than in tumors without metastases. The content of Co was significantly higher in more advanced laryngeal tumors: in stage-T4 than in stage T3. It is of interest that the levels of Cd, Co and Ni were significantly higher in tumors in patients from rural than urban areas.

Conclusions

The imbalance in the level of nickel, cadmium and cobalt in laryngeal cancer may be due to a changed cellular metabolism in the cancer process. However, the results of our study reveal the significant differences in the concentration of these metals between patients from urban and rural areas which suggests that this fact may be related to environmental or occupational factors and therefore it requires further study.     

A.C. Cardiac defibrillator performance

An adequate expression of the desired characteristics is necessary for the assessment of commercially-available and privately-made defibrillators., The wide range of electrical performance of such units demands simple methods for measurement and possible modification. Observed performance characteristics are compared and subsidiary points of design mentioned. A simple instantaneous-electrode-current monitor is shown to be clinically useful and capable of giving rapid estimates of tissue resistance. It is also useful for assessment of defibrillator design and operation.     

A rapid and simple scheme for confirmation of salmonella tester strain phenotype

A simple scheme has been developed for confirming the phenotype of the standard set of Salmonella typhimurium tester strains. This scheme employs a series of filter paper discs impregnated with diagnostic mutagens or bacterial toxins. Up to 6 diagnostic discs can be placed on a petri dish to test a single Salmonella strain. The Salmonellae are distinguished by their responses to ampicillin, crystal violet, nitrofurantoin, 9-aminoacridine, 4-nitro-o-phenylenediamine and sodium azide.     

除颤器性能检测及其质量分析方法

通过使用除颤能量测试仪对除颤器进行性能测试,在获取大量质量数据的基础上,研究探讨了除颤器质量数据的分析方法,并使用该方法对能量数据进行分析,从而对除颤器的除颤性能做出质量评价.     

Ultrastructural changes in rat lungs exposed to combinations of cadmium, zinc, copper, and nickel

The morphological effects of single intratracheal intubation of cadmium oxide (CdO) with oxides of zinc (Zn), copper (Cu), and nickel (Ni) at their threshold limit values on alveolar macrophages and type II cells were studied. The combinations used were: CdO + ZnO (0.1 mg + 5.0 mg); CdO + CuO (0.1 mg + 0.2 mg); and CdO + NiO (0.1 mg + 1.0 mg). Rats sacrificed after one week recovery period showed distinct morphological changes. Alveolar macrophages and type II cells exposed to CdO and ZnO showed an increase in number, shape, and size of vacuolar phagolysosomes. Multivesicular bodies and lamellar bodies were also seen, as well as the lack of distinct nucleoli. The CdO/CuO combination showed an increase in the number of dense vacuolar phagolysosomes and large aggregates of multivesicular bodies. Hypertrophy of mitochondria was also evident in this combination. The CdO/NiO combination showed more distinctive changes compared to the other two combinations in lysosomes, membranous whorls, multivesicular bodies, residual bodies, and number of mitochondria. Our findings using combination exposures of CuO and ZnO with CdO indicate the existence of competitive inhibition resulting in some form of protective action. On the other hand, the CdO/NiO exposure seemed to be additive showing structural modifications, premature aging, faster degeneration, and release of abnormal membrane structures.     

Screening for Parkinson's disease with response time batteries: A pilot study

Background  

Although significant response time deficits (both reaction time and movement time) have been identified in numerous studies of patients with Parkinson's disease (PD), few attempts have been made to evaluate the use of these measures in screening for PD.     

A portable mains-operated d.c. defibrillator of unusual design

The philosophy, design and operation of a portable defibrillator are described. The instrument is mains-operated but dispenses with a high-voltage transformer, and employs electrolytic capacitors. The weight is about 11 kg not including electrodes.