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Biomedical subjects

J H Kerr

Publications and source records attributed to J H Kerr.

At least 19 recordsLinked to original sources

Cognition and mood in relation to the performance of squash tasks.

The purpose of this investigation was to determine the role of cognition and mood in the performance of squash tasks, with particular reference to attention and self-reported arousal and stress. Volunteer male subjects (n = 40), divided into three ability groups, 'skilled', 'average' and 'novice', were required to perform two squash tasks with different degrees of difficulty. Order of presentation of the tasks was controlled. Results indicated that subjects completing the easier squash task first performed better on the subsequent difficult task than those subjects who completed the more difficult task first. No differences in scores across tasks were found for subjects completing the tasks in reverse order. Performance was related to level of skill. Furthermore, significant differences in attentional style were revealed when average subjects were compared with skilled and novice players. Skilled players were also found to exhibit significantly different personality characteristics from novice players. Specifically, skilled players exhibited higher levels of extraversion and appeared less neurotic. For the average and novice groups, reports of high levels of stress accompanied those of high levels of arousal and these remained constant throughout the experiment. By contrast, for the skilled group low levels of stress accompanied high levels of arousal. The results are discussed in terms of the effects of these cognitive and mood factors on performance and a suggested direction for future research is offered.

Adolescent

Effects of telic dominance and metamotivational state on squash task performance.

Measures of telic dominance and metamotivational state were obtained from 40 volunteer males grouped on the basis of their playing ability, before and after the performance of squash tasks. Utilising a mixed-blocks design, which controlled for order of task, subjects were required to perform two squash tasks of differing difficulty. Significant differences between groups on performance were obtained, confirming the ability classification, but no significant differences in telic dominance were found. Significant increases in mood response in the telic direction were found on pre- and posttask scores. A significant decrease in discrepancy scores (preferred arousal minus felt arousal) obtained pre- and posttask was noted, together with a significant interaction between skill level and in arousal discrepancy pre- and posttask. In all cases trends were least for the most skilled group.

Adolescent

Cognitive intervention with elite performers: reversal theory.

Noticeable in the literature associated with the application of psychology to the area of sport and sports performance in particular has been the increasing frequency of references to the use of cognitive intervention in the sports context. Currently utilised in clinical psychology and behavioural medicine, and receiving increasing attention in sports psychology, are a number of intervention techniques primarily oriented towards altering the individual's level of arousal. These techniques, which have been advocated for use by sports performers as an aid to adapting and coping during competition, have been largely concerned with arousal reduction. This paper presents an alternative approach, the case of reversal theory, a new general theory of psychology concerned with motivation, and emphasises the conceptual implications of this new approach for the use of cognitive intervention techniques in sport.

Arousal

Use of "bollards" to improve patient access during intensive care.

Permanent floor-mounted "bollards" have been installed in three Intensive Care Areas in the Oxford Teaching Hospitals. Each brings services to one bed and, because access around the head is greatly improved in comparison with the conventional arrangement with the head next to the wall, facilitates both emergency and routine care and improves the safety of the working environment for staff and patients. Differences between the bollards installed in the three units are described and the advantages and disadvantages of each discussed. It is concluded that a bollard should be located to the left of the head of the bed and that it should be about 1100 mm high and 500 mm square. At least two oxygen and vacuum outlets, one air outlet, six electric power sockets and connections for monitoring cables should be provided on the bollard with further power sockets on the adjacent wall. A length of equipment rail mounted across the head of the bed supports the suction equipment required for oral and respiratory tract care and storage space is provided on and below the work surface which is mounted on the wall behind the head of the bed.

Critical Care

The experience of arousal: a new basis for studying arousal effects in sport.

Sports psychologists have for some time put forward the inverted-U-hypothesis as a useful working model of the relationship between arousal and performance. Although some emphasis in the sports psychology literature has been placed on the limitations of the hypothesis, generally the notion of an optimal level of arousal has been well received. A few authors have been less tolerant of the arguments put forward in the inverted-U-hypothesis and the restrictions of its theoretical stance. Sports psychologists have been slow to suggest or adopt diverse theoretical perspectives and consequently little real progress has been made. The danger is that this approach has become widely accepted almost without question. This review paper attempts to sum up the current position and, based on recent work, recommend alternative interpretations of arousal effects in sport.

Arousal

Relationships between inspired oxygen concentration and venous admixture during nitrous oxide-oxygen-halothane anaesthesia.

The inspired oxygen concentration (F/O2) was changed on 43 occasions at about 30-min intervals in 13 patients during artificial ventilation with mixtures of nitrous oxide (N2O), oxygen and halothane. Ventilator settings remained unchanged for each patient and at the end of each period, samples of arterial and central venous blood (and, in six patients, pulmonary arterial blood) and inspired and expired gases were collected. Oxygen tension was measured with a dedicated electrode shown to be unaffected by N2O. Venous admixture (Qva/Qt) was calculated at each F/O2. There was a highly significant correlation between the direction of change of F/O2 and that of Qva/Qt, irrespective of whether F/O2 increased or decreased. In 10 patients, there was a progressive increase in Qva/Qt as F/O2 increased above 40%, and in all patients Qva/Qt on nearly 100% oxygen was greater than that measured at the next lowest concentration (60-80%). These results are at variance with the pattern of behaviour predicted from the "critical Va/Q" theory and support the concept of an oxygen-dependent redistribution of perfusion.

Adult

Automatic blood pressure monitors. A clinical evaluation of five models in adults.

Five automatic blood pressure monitors were evaluated by comparing their values with almost simultaneous blood pressure readings from radial artery catheters. A total of 583 comparisons were made on 48 patients. Statistical analysis was performed on the pooled comparisons of systolic and diastolic pressure for each monitor. Agreement between the pressure measurements was variable between both patients and machines. For systolic pressure, two machines (Copal and Sentron) had correlation coefficients of over 0.9 while for the other machines (Dinamap 845XT, Narco and Vitastat 9001S) the values lay between 0.7 and 0.8. The steepest regression lines were also found with the Copal (0.93) and Sentron (0.86) data, but the other machines had considerably flatter slopes (0.55 to 0.67). The intercepts on the Y axes ranged from +14.1 (Copa) to +50.1 (Dinamap). In clinical use, popularity of the different machines reflected the degree to which the machine reproduced the behaviour of the direct pressure measurement.

Adult

Unilateral high frequency jet ventilation. Reduction of leak in bronchopleural fistula.

A young alcoholic presented with severe bilateral bronchopneumonia, which required prolonged treatment with intermittent positive pressure ventilation. High airway pressures were necessary for effective gas exchange. A recurrent tension pneumothorax led to a persistent bronchopleural fistula which resulted in hypercarbia and hypoxaemia despite the use of large minute volumes. Surgical resection was not considered feasible because of extensive local infection. Asynchronous independent lung ventilation was instituted, using a double-lumen endobronchial tube. A considerable leak still occurred through the bronchopleural fistula, and it was only when high frequency jet ventilation was substituted to the fistula-containing lung that the leak was virtually abolished, while improving gas exchange. High frequency jet ventilation in bronchopleural fistula is of potential benefit.

Adult

Paratracheal abscess after tracheostomy.

Mediastinal abscess formation in the paratracheal region is a complication of tracheostomy that has previously been only sparsely reported. We present a case which highlights this complication and illustrates some of the diagnostic difficulties with which it may be associated. In this case septicaemia-developed as a secondary complication and diagnosis of the abscess was dangerously delayed because the radiographic appearance masqueraded as a left upper lobe consolidation and because its rarity led to a low index of suspicion.

Abscess

Extradural diamorphine in the control of pain following lumbar laminectomy.

Catheters were inserted into the extradural space under direct vision at the time of surgery for prolapsed intervertebral disc or lumbar canal stenosis. In the post-operative period, diamorphine (3 mg in 5 ml water) was injected through the catheter when patients requested analgesia. In only four of 49 patients was significant pain relief not achieved after extradural diamorphine injection. In four other patients it was not possible to use this method of analgesia throughout the two post-operative days as planned. As judged by the improved mobility and by grading on a linear analogue pain scale, the quality of analgesia achieved was better than after intramuscular papaveretum (10-20 mg) and extradural diamorphine was requested less frequently. There were no serious side-effects in the patients studied, although the technique was not used in patients over 55 years of age. Extradural diamorphine appeared to be less effective in two patients who had undergone re-explorations.

Adolescent

Pheochromocytoma in the modern context.

The hypertensive patient faces an uncertain future. Therefore a search for those cases in which the condition is potentially curable is eminently worth while and has become increasingly productive because of the specific diagnostic aids now available and because of the present safety of surgical intervention. Detection and localization of a pheochromocytoma allows a planned surgical approach. Correction of hypovolemia preoperatively ensures a safe course postoperatively. The use of blocking agents pre- and peroperatively prevents the hazardous hypertensive crises and arrhythmias that were a part of early surgical experience. Monitoring of central venous and arterial pressures as well as the electrocardiographic tracing during the operation permits prophylactic therapy when necessary. On the basis of a series of 31 patients the authors compare many aspects of the current management with earlier experience of pheochromocytoma in the same institution. The incidence of extra-adrenal lesions (3.8%), multicentric tumours (3.8%) and malignant change (11.5%) was lower in this group of patients than that usually reported. Abdominal exploration remains the approach of choice in most cases. Treatment of the solitary pheochromocytoma has become straightforward. However, management of the familial syndromes and the malignant from of the disease still requires careful scrutiny.

Adrenal Gland Neoplasms

Thermographic assessment of peripheral arterial occlusion.

Infra-red thermography was used to confirm the observation that the temperature differences between corresponding areas of skin on opposing hands are normally minimal and to demonstrate that the skin temperature of the hand distal to an occluded radial or brachial artery was lower than that of the contra-lateral hand. Temperature differences between the two hands decreased with time and had disappeared by the time that recannulation of the occluded artery, gauged by the modified "Allen" test, had occurred. Thermography is a simple and noninvasive technique and provides a useful indicator of the incidence and progress of peripheral arterial occlusion such as that which may follow arterial cannulation.

Arterial Occlusive Diseases