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Biomedical subjects

J G Greene

Publications and source records attributed to J G Greene.

At least 37 records · Page 2Linked to original sources
PubMed1990

Design of an optimal ventilator.

When a patient is incapable of adequate ventilation by natural processes, mechanical assistance must be provided. Ventilation assures sufficient Oxygen delivery to the organs and tissues of the body and excessive amounts of Carbon Dioxide are not permitted to accumulate. Ventilators are employed continuously or intermittently to improve the ventilation of the lungs. The present work involves design of a ventilator that virtually eliminates any work done by the patients in their breathing process. Presently available ventilators approach this level of performance but they have a few reported shortcomings. These limitations include insufficiency of inspiratory airflow and rigidity of operating cycles. The new ventilator is built around an optimal controller and its performance is based on computational capability of microprocessors. Real time measurements of volume, flow rates and pressure are managed and processed by these devices for optimal determination of controlled parameters of the ensuing respiratory cycle. These measured parameters are used for estimating the lung characteristics such as lung compliance and airway resistance. An independent microprocessor system incorporating data acquisition and processing features with scope for a number of additional capabilities such as graphic output, database and communications functions can prove very useful in health care institutions.

Biomechanical Phenomena↗
PubMed1989

Effects of alprazolam on respiratory drive, anxiety, and dyspnea in chronic airflow obstruction: a case study.

Alprazolam, an anxiolytic benzodiazepine, has a pharmacologic profile similar to that of diazepam. An intermediate half-life of 10-12 hours and a comparatively brief duration of activity relative to other anxiolytic benzodiazepines justified evaluation of a 0.5-mg test dose in an anxious patient with chronic obstructive lung disease. Subjective indexes, breath-by-breath respiratory drive response to hypercapnia, and blood alprazolam concentrations were determined before and after dosing. Subjective testing included a visual analog dyspnea scale, the state anxiety inventory, and subjective feelings visual analog scales (represented by alertness, calmness, and level of contentment). After dosing, the patient was better able to tolerate the rebreathing study technique. Statistically significant improvements in dyspnea (t - 10.20; p 0.0005), anxiety (t - 45.85; p less than 0.0001), alertness (t - 13.04; p less than 0.0001), cententedness (t - 12.27; p less than 0.0001), and calmness (t - 8.05; p less than 0.0001) occurred after alprazolam administration. Drive to breathe, as determined by mouth occlusion pressure and minute ventilation, was not statistically different before and after dosing. No adverse effects were reported or observed. Further study is warranted.

Alprazolam↗
PubMed1989

The Scottish first episode schizophrenia study. VII. Two-year follow-up. Scottish Schizophrenia Research Group.

Of 49 schizophrenic patients followed up 2 years after their first admission to hospital, 37% were well, 47% had been readmitted to hospital at some time over the 2 years, and 38% showed schizophrenic symptoms at follow-up. A poor outcome at 2 years was associated with male sex, poor outcome after the first 5 weeks of the first admission, negative schizophrenic symptoms on first admission, and a diagnosis of definite or probable schizophrenia using the Feighner criteria. Only 23% were in employment. A small double-blind discontinuation study of maintenance antipsychotic medication during the second year found more relapses in those switched to placebo medication. Repeat psychometric assessment at 2 years confirmed modest improvements found at 12 months; that is, there was no evidence of intellectual decline. Relatives showed no more psychosocial distress than that found in a normal community sample; what distress there was correlated with patients' schizophrenic symptoms.

Clinical Trials as Topic↗
PubMed1989

A comparison of esophageal and chest electrodes in studying the diaphragmatic EMG.

In exploring respiratory fatigue detection using the electromyograph (EMG), two EMG signals may be collected. One resulting from skin electrodes placed on the outside of the chest and the other from an esophageal electrode. The current trend in respiratory muscle fatigue detection is to use skin electrodes as the recipients of the diaphragmatic EMG signal. This eliminates the need of subjecting the person to a nasally inserted EMG electrode. Although it is more convenient to use this type of electrode, it does have several distinct disadvantages that must be overcome if accurate analysis is to take place. This paper compares the advantages and disadvantages of the two electromyograph detection methods and addresses the appropriate use of both.

Diaphragm↗
PubMed1987

Evaluation of a psychological treatment programme for climacteric women.

A psychological assessment and treatment programme designed for a group of climacteric women with severe and varied psychological complaints and symptoms is described and evaluated. All the women were currently experiencing stressful psychosocial difficulties within their life situation. The treatment programme comprised an educational, a counseling and a behavioural component. By the end of the sixth session of therapy, most women showed a significant improvement in their main complaint, accompanied by improvements in general symptoms and personal adjustment. Two-thirds considered that they had benefited substantially from treatment. The outcome of the treatment was considered to be encouraging in what might otherwise be considered a potentially unresponsive group of women.

Adult↗
PubMed1985

Control of exercise hyperpnea during hypercapnia in humans.

Previous studies have yielded conflicting results on the ventilatory response to CO2 during muscular exercise. To obviate possible experimental errors contributing to such variability, we have examined the CO2-exercise interaction in terms of the ventilatory response to exercise under conditions of controlled hypercapnia. Eight healthy male volunteers underwent a sequence of 5-min incremental treadmill exercise runs from rest up to a maximum CO2 output (VCO2) of approximately 1.5 l . min-1 in four successive steps. The arterial PCO2 (PaCO2) at rest was stabilized at the control level or up to 14 Torr above control by adding 0-6% CO2 to the inspired air. Arterial isocapnia (SD = 1.2 Torr) throughout each exercise run was maintained by continual adjustment of the inspired PCO2. At all PaCO2 levels the response in total ventilation (VE) was linearly related to exercise VCO2. Hypercapnia resulted in corresponding increases in both the slope (S) and zero intercept (V0) of the VE-VCO2 curve; these being directly proportional to the rise in PaCO2 (means +/- SE: delta S/ delta PaCO2, 2.73 +/- 0.28 Torr-1; delta V0/ delta PaCO2, 1.67 +/- 0.18 l . min-1 . Torr-1). Thus the ventilatory response to concomitant hypercapnia and exercise was characterized by a synergistic (additive plus multiplicative) effect, suggesting a positive interaction between these stimuli. The increased exercise sensitivity in hypercapnia is qualitatively consistent with the hypothesis that VE is controlled to minimize the conflicting challenges due to chemical drive and the mechanical work of breathing (Poon, C. S. In: Modelling and Control of Breathing, New York: Elsevier, 1983, p. 189-196).

Adult↗
PubMed1983

Bereavement and social support at the climacteric.

The relationship between life events and symptoms was examined in a general population sample of Scottish climacteric women within the framework of the concepts and methods developed in the field of life event research. It was found that at least some of the increase in symptoms at that time of life was due to the occurrence of stressful life events. This relationship was a complex one as different types of life events were associated with symptoms in a differential way. In particular, the occurrence of a bereavement involving a close family member and the consequent loss of social support, were found to be significant factors in provoking physical symptoms, but only in the presence of other life stress. These results are discussed in the context of the findings of other life event researchers.

Adult↗
PubMed1983

Reality orientation with elderly patients in the community: an empirical evaluation.

There is now good evidence that elderly mentally impaired patients can be re-orientated for time, place and person using the technique of reality orientation (RO). To date, all empirical trials demonstrating this have been carried out on elderly institutionalized patients. This technique however might be of greater value to those elderly dementing patients still living with relatives in the community but attending geriatric psychiatry day hospitals, where they could receive RO in a consistent and systematic way. The results of an empirical study of RO with a group of such patients is reported. These showed that day hospital patients could be effectively re-orientated and that concomitant with changes in level of orientation of the patients, there were parallel changes in the patients' behaviour at home, reported stress on relatives and in relatives' mood.

Aged↗
PubMed1983

The relationship between neonatal characteristics and three-month mother-infant interaction in high-risk infants.

The behavior of 4 groups of infants--healthy term, healthy preterm, sick preterm, and sick full-term--was assessed in the neonatal period using the Neonatal Behavioral Assessment Scale (NBAS). At 3 months postterm, infants and their mothers were observed and videotaped in a free-play session. Both the NBAS and mother-infant interaction data were analyzed to assess the effects of maturity (term vs. preterm), illness (sick vs. healthy), and their interaction. Results revealed that illness of the infant affected both NBAS performance and maternal behavior during the interaction at 3 moths. Infants who were ill performed poorly on the NBAS orientation dimension; this dimension was found to be significantly associated with maternal and infant behaviors at 3 months. These data demonstrate an association between early infant characteristics and subsequent mother and child interactive behaviors. They also identify postnatal illness as an important influence on the development of the mother-infant dyad.

Asphyxia Neonatorum↗
PubMed1982

Measuring behavioural disturbance of elderly demented patients in the community and its effects on relatives: a factor analytic study.

In recent years increasing interest has centered on the elderly psychogeriatric patient living in the community and the part played by relatives in supporting these patients. There is a need, however, for ways of assessing the behavioural disturbance shown by such patients at home and the effect this behaviour has on relatives. Ratings by relatives of the behaviour at home of elderly dementing patients attending a geriatric psychiatry day hospital, together with the relatives' own ratings of the degree of stress and upset being experienced were obtained. Using the technique of factor analysis was shown that the patient's behaviour and the relative's reaction could be analysed into a number of separate categories and that these were differentially related to each other. Thus, for example, personal distress in the relative was related mainly to the amount of apathetic and withdrawn behaviour shown by the patient, whereas negative feelings held by the relative towards the patient were related only to the degree of disturbance of the patient's mood. The construction of scales measuring these different aspects of patient's behaviour and relative's reaction is described.

Aged↗
PubMed1980

Life stress and symptoms at the climacterium.

Psychological and somatic symptoms presented by women in middle life are frequently attributed to the menopause. Many writers have questioned this assumption and have placed more emphasis on environmental and personality factors. Using a life event model and a multivariate analysis technique, life stress was shown to have a significantly more powerful influence on the elevation of symptoms in a normal population of women at that age than did the menopause. Furthermore, the elevation in symptoms occurred some considerable time before that event. The finding that there was no significant increase in total life stress at that time of life suggests the presence of a vulnerability or moderating factor.

Adult↗