Thesis (Ph. D.)--University of Sydney, 2001. / Title from title screen (viewed Apr. 24, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Dept. of Paediatrics and Child Health, Faculty of Medicine. Includes bibliographical references. Also available in print form.

Thesis (M.S.P.H.)--University of Michigan, 1940.

Thesis (M.S.P.H.)--University of Michigan, 1940.

Cough is a common symptom of both acute and chronic respiratory illness. It is poorly understood and treatment options are sparse. One reason is that there are few validated objective measures of cough frequency and severity. In this thesis I have further validated the Leicester Cough Monitor, an automated cough detection system capable of detecting coughs over 24 hours. I have demonstrated that automated cough numbers were similar to those derived from the gold standard of manual counting in healthy adults and in patients with respiratory disease. Cough frequency was then measured using the Leicester Cough Monitor and was almost 16 fold higher in patients with respiratory diseases compared to healthy controls. In the population as a whole there was a correlation between cough frequency and the induced sputum neutrophil count. I then conducted a randomised, placebo controlled, double blind, parallel group trial of low dose erythromycin taken daily for 3 months in 30 patients with unexplained chronic cough. Active treatment was associated with a reduction in the sputum neutrophil count but no difference in cough counts or other measures of cough severity. Also, there is no information on the natural history of unexplained chronic cough. In a longitudinal study of 42 patients with unexplained chronic cough followed up for at least 7 years, I found that cough, measure by the cough visual analogue score, improved in 25 percent. Unexpectedly, patients had an abnormally rapid fall in FEV1, whether cough improved or not. Finally, the assessment of health related quality of life is important in people with acute cough in order to evaluate potential therapies. I have shown that that the minimal important clinical difference in the Leicester Cough Questionnaire for those with acute cough is 2.5 and this will aid in the interpretation of treatment trials.

Thesis (M. P. H.)--University of Hong Kong, 2005. / Also available in print.

Thesis (M.S.P.H.)--University of Michigan, 1933.

Thesis (M.S.P.H.)--University of Michigan, 1933.

Thesis (M.P.H.)--University of Hong Kong, 2005.

Background: One population prone to aspiration pneumonia and impaired cough is the postoperative patient. Postoperative pneumonia is the third most common complication among surgical patients after urinary tract and wound infections (Wren, Martin, Yoon, & Bech, 2010). A patient who has their surgical course complicated by aspiration pneumonia has increased morbidity, increased length of hospital stay and places greater demands on the health system. Mortality rates are cited as high as 70% (Wren, et al., 2010). Despite the prevalence of postoperative pneumonia and the high morbidity and mortality rates, little is known about the effect of anaesthesia on swallowing and airway protection. This study investigated the effect of clinical doses of fentanyl on suppressed cough reflex in healthy participants. Materials and Methods: After receiving ethical approval, 14 young, healthy participants gave informed written consent and completed the study protocol. Each participant received a total of 2 mcg/kg of fentanyl in four doses administered at five-minute intervals. Fentanyl effect site concentrations (ESC) were estimated using a standard pharmacokinetic model. During the administration period, suppressed cough response testing (SCR) with nebulised citric acid was performed after each fentanyl dose. Citric acid was presented in increments of 0.2M from each participant’s baseline cough response until a present-strong response was achieved. During the post-administration period, SCR was compared with reducing effect site concentrations to determine the time course for resolution of cough suppression. Results: Suppressed cough threshold increased and decreased in parallel with modeled fentanyl effect site concentrations. Mean citric acid concentration increased from 0.5M at baseline to 0.6M after 0.5 mcg/kg of fentanyl, 0.7 M after 1 mcg/kg of fentanyl, 0.9M after 1.5 mcg/kg of fentanyl and 1.2M after 2 mcg/kg of fentanyl. Predicted effect site concentrations after final doses of fentanyl (2 mcg/kg) were 1.89 ng/mL (1.81-1.96), well within the range seen clinically in the postoperative period. After the final dose of fentanyl, participants had on average 3.4 increments of change in their cough response (at increments of 0.2M). Conclusion: SCR testing with citric acid is sensitive enough to mirror changes in fentanyl ESC in healthy, young participants. The degree of reflex suppression seen has been associated with an 8-fold increase in aspiration risk in the general medical patient with dysphagia (Miles, Moore, McFarlane, Lee, Allen, Huckabee, 2013). Further research into the application of SCR in the postoperative period may help clinical decisions regarding safety to commence oral intake.

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