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Biomedical subjects

D P Spence

Publications and source records attributed to D P Spence.

8 recordsLinked to original sources
PubMed1992

A mask to modify inspired air temperature and humidity and its effect on exercise induced asthma.

BACKGROUND: Heat and moisture loss from the respiratory tract during exercise are important triggers of exercise induced asthma. METHODS: A new heat and moisture exchange mask has been developed which both recovers exhaled heat and water and has a sufficiently low resistance for use during exercise. The effect of the mask on inspired air temperature was studied in four normal subjects. Eight asthmatic subjects performed identical exercise protocols on three separate days, breathing room air through a conventional mouthpiece, a dummy mask, and the new heat and moisture exchange mask. Seven different asthmatic subjects exercised while breathing cold air at -13 degrees C through a dummy or active mask. RESULTS: All subjects found the new mask comfortable to wear. The mean inspired temperature when the mask was used rose to 32.5 (1.4) degrees C when normal subjects breathed room air at 24 degrees C and to 19.1 (2.7) degrees C when they inhaled subfreezing air at -13 degrees C. The heat and moisture exchange mask significantly reduced the median fall in forced expiratory volume in one second (FEV1) after exercise to 13% (range 0-49%) when asthmatic subjects breathed room air compared with 33% (10-65%) with the dummy mask and 28% (21-70%) with the mouthpiece. The fall in FEV1 when the asthmatic subjects breathed cold air was 10% (0-26%) with the heat and moisture exchange mask compared with 22% (13-51%) with the dummy mask. CONCLUSION: Use of a heat and moisture exchange mask can raise the inspired temperature and humidity and ameliorate the severity of exercise induced asthma. The mask may be of practical value in non-contact sport or for people working in subzero temperatures.

Adolescent↗
PubMed1992

Effect of methacholine induced bronchoconstriction on the spectral characteristics of breath sounds in asthma.

BACKGROUND: Analysis of breath sounds by digital techniques offers an attractive non-invasive method of monitoring changes in airway calibre. Asthmatic breath sounds have been analysed and related to changes in forced expiratory volume in one second (FEV1). METHODS: Bronchoconstriction was induced with methacholine in six asthmatic subjects on two occasions and changes in FEV1 and breath sound spectra were measured. RESULTS: Audible wheeze appeared after a mean (SE) fall in FEV1 of 35% (6.3%) but the level was not reproducible within patients. The mean and median frequency of the spectra of breath sounds correlated with the percentage of predicted FEV1 (r = -0.5 and -0.6 respectively; p < 0.001). Inclusion of the quartile frequencies in a stepwise multiple regression reduced the residual variance by a further 9%. CONCLUSION: Detecting changes in airway calibre by this method of sound analysis so far produces qualitative data only and will not yield quantitative data in individual patients.

Asthma↗
PubMed1990

The rhetorical voice of psychoanalysis.

The rhetorical voice of psychoanalysis has a long history and has only recently come to be seen as a special feature of the theory. Its beginnings can be found in Freud's earliest pleadings for the usefulness of metaphor and analogy, although he felt that they were largely provisional and would eventually be replaced by more durable concepts. We have begun to see problems in replacing the central metaphors; the rhetorical base of psychoanalysis may be more enduring than we thought. While our metaphors may never provide epistemic access to the stuff of the mind, they can and do point to specific clinical encounters. Ways must be found to expand our rhetorical treasure chest and develop language even better suited to our concepts and observations.

Freudian Theory↗
PubMed1986

When interpretation masquerades as explanation.

The principal goal of the clinical interpretation (and of the larger clinical narrative) is to bring about insight and change in the patient, and not to present a reasoned argument that relies on public data and shared rules of evidence and logic. When the clinical account is transposed to the public domain and presented as a form of explanation, it is no longer designed for the benefit of one individual but must now be accessible to all. We are still under the shadow of Freud's five famous cases which are literary landmarks of exposition and persuasion. As a result, we are less sensitive to what happens when interpretations are substituted for explanations. The time has come to develop a new genre and a new mode of clinical reporting that would allow the reader to participate in the argument, allow him to evaluate the proposed links between evidence and conclusion (instead of relying on the authority of the analyst-author), and open up the clinical report to the possibilities of refutation, disconfirmation, and falsification.

Austria↗