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The investigation and management of patients with life threatening haemoptysis is a common clinical problem in South African Hospitals. Establishing the aetiology and origin of the haemorrhage and treating these patients is both difficult and expensive in terms of human and financial resources. The purpose of this study was to identify common local aetiologies for severe haemoptysis, review the investigation and treatment of these patients at Wentworth Hospital, Durban and to formulate a plan of management. Retrospective and prospective studies of consecutive patients treated at Wentworth Hospital were performed. In the prospective study a new embolic material gelatin linked acryl microspheres (embospheres) was used for bronchial artery embolization (BAE). The study demonstrated a change in the spectrum of aetiologies of haemoptysis, from bronchiectasis following tuberculosis to destructive pneumonias. The chest radiograph was always the initial imaging investigation but was found to be inaccurate in detecting the origin of the bleeding. High resolution computed tomography of the lungs (HRCT) was the single best investigation to detect the cause and origin of the haemoptysis. HRCT detected focal bronchiectasis and intracavitatory aspergillomas that were undetected on the chest radiograph. Pleural thickening detected on CT was a good indicator of the presence of transpleural collaterals. The major limitation with HRCT was that it could not be performed if the patient was too dyspnoeic to cooperate during the scan. The role of bronchoscopy appears limited in patients with severe haemoptysis to those patients who are potential surgical candidates. I found that bronchoscopy was not accurate in detecting the source of bleeding in the few patients in which it was performed. Bronchial arteriography remains the gold standard in the detecting the source of haemorrhage. Bleeding sites were detected on angiography in the presence of focal hypervascularity, neovascularity and the presence of broncho-pulmonary shunts. Bronchial arteries were hypertrophied in bronchiectasis but were normal in size in some patients who had acute pneumonias. Bronchial artery embolization was the treatment of choice for severe haemoptysis in the patients studied. The use of gelatin cross linked micro spheres has significantly improved the initial success rate following the procedure with less complications compared to the use of polyvinyl alcohol particles (PVA). It is important to identify systemic transpleural collaterals at arteriography and to embolize them to reduce recurrent haemoptysis. Patients with aspergillomas responded well to embolization. Recurrent haemoptysis remains the major limitation of BAE but is reduced with the use of micro spheres as embolic agents and thorough embolization of systemic collaterals on the affected side. Surgical resection was an option for a limited number of patients with focal disease in one lung and good respiratory reserve. The major limitation of the study was the absence of long term follow up to detect those patients with late recurrent haemoptysis. / Thesis (D. Med.)-University of Natal, Durban, 2003.

Bibliography: leaves 181-201 / 201, [ca. 75] leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1987

published_or_final_version / Medicine / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Paediatrics and Adolescent Medicine / Master / Master of Philosophy

Hypoxia is a common feature of many respiratory disorders including acute severe asthma, chronic obstructive pulmonary disease and pneumonia. Hypoxia also occurs during sleep - disordered breathing in conditions such as sleep hypoventilation syndrome and sleep apnea. In most respiratory diseases hypoxia is coupled with increased respiratory load. Compensatory protective mechanisms are activated to oppose these impediments to respiration. However, hypoxia is associated with impaired neurocognitive function and recent studies have demonstrated that hypoxia suppresses respiratory load perception in healthy individuals and asthma patients. These recent findings raise the possibility that a variety of protective physiological reflex responses to increased respiratory load may be impaired during periods of hypoxia. The effects of hypoxia on several of these protective responses and possible mechanisms of respiratory sensory depression by hypoxia are explored in the experiments outlined in this thesis. In the first study, the respiratory related evoked potential ( RREP ) was used to investigate the mechanisms underlying hypoxia - induced suppression of respiratory load sensation in healthy individuals. As a positive control the effects of hypoxia on respiratory load perception to inspiratory resistive loads were also measured. The amplitude of the first and second positive peaks ( P1 and P2 ) of the RREP were significantly reduced during hypoxia. P1 is thought to reflect the arrival of the ascending respiratory signals to the somatosensory area of the cortex. The perceived magnitude of externally applied inspiratory resistive loads was also reduced during hypoxia. These data provide further support that hypoxia suppresses respiratory load perception and suggest that this is mediated, at least in part, by suppression of respiratory afferent information prior to its arrival at the cortex. In the second study, the effects of acute sustained hypoxia on the cough reflex threshold and cough tachyphylaxis to inhaled capsaicin were explored in healthy individuals. Acute sustained hypoxia suppressed cough reflex sensitivity to inhaled capsaicin. This finding raises the possibility that the cough reflex, important for protecting the lungs from inhalation or aspiration of potentially injurious substances and for clearing excess secretions, may be impaired during acute exacerbations of hypoxic - respiratory disease. In the third study, reflex responses of the genioglossus and scalene muscles to brief pulses of negative airway pressure were compared between hypoxia and normoxia during wake and sleep in healthy males in the supine position. Cortical RREPs to the same stimuli were also examined under these conditions. The genioglossus is the largest upper airway ( UA ) dilator muscle and can be reflexively augmented in response to negative UA pressure. A diminished response of this muscle during sleep has been postulated to be a contributing mechanism to obstructive sleep apnea ( OSA ) in individuals with an anatomically narrow UA. Cortical activation ( i.e. arousal ) to sudden airway narrowing in OSA is an important protective response to help restore ventilation during an obstructive event. In this study, genioglossus reflex responses to negative pressure pulse stimuli were maintained during mild overnight hypoxia. Conversely, reflex inhibition of the scalene muscle to the same stimuli was prolonged during hypoxia. In addition, a previously undescribed morphology of the genioglossus negative pressure reflex consisting of activation followed by suppression was observed with greater suppression during sleep than wake. The amplitude of the P2 component of the RREP was also significantly reduced during hypoxia. In summary, the potential mechanisms underlying hypoxia - induced suppression of respiratory load sensation and the effects of hypoxia on several protective respiratory responses have been investigated in healthy subjects. The potential implications of these findings for patients with hypoxic - respiratory disease are discussed. / Thesis (Ph.D.)--School of Molecular and Biomedical Science, 2006.

Pasteurella multocida causes diseases in many animal species including fowl cholera, a septicemic disease of poultry and other birds. Pathogenesis of the disease has been studied by many investigators by the systemic administration of the organism in poultry. However, only a few studies have been done as to the respiratory pathogenesis of the organism. The objective of the study was to investigate the fate of P. multocida after the intratracheal administration in turkeys The fate of four strains of Pasteurella multocida was studied after their intratracheal inoculation in young adult turkeys. Viable bacterial counts were made in respiratory tissues as well as in the liver, spleen and blood at 6 and 9 hrs after the inoculation of approximately 10⁹ viable organisms of each strain. A virulent, encapsulated strain, P-1059, invaded systemically by 6 hrs postinoculation (PI) and multiplied vigorously in all tissues and organs examined. A blue colony mutant of P-1059, T-325, which does not possess a thick layer of capsule, as well as CU vaccine strain, invaded the parenchymal organs, but did not show significant increase in viable counts at 9 hrs PI compared with at 6 hrs PI. Another vaccine strain, M-9, also invaded blood and internal organs by 6 hrs PI, however, its viable counts showed no significant change between 6 and 9 hrs PI, or in some tissues significant decrease at 9 hrs PI. The results indicate that all the four strains possess high capacity to invade respiratory tissues with varying capacity to persist in host tissues. The lesions caused by two strains of Pasteurella multocida (P-1059 and M-9) were observed after their intratracheal inoculation in young adult turkeys. The lesions were observed in the respiratory organs at 0, 0.25, 0.5, 1, 2, 3, and 6 hrs after inoculation of approximately 10⁹ viable organisms of each strain. Both virulent strain, P-1059 and non-virulent vaccine strain, M-9, have capacity to invade and multiply in the tissues examined. Macroscopicly, the lesions in the lung and in the airsac were found as early as 1 hr PI, including the infected lung was foamy and the airsac became cloudy. They became more severe by 2 to 6 hrs PI. Microscopicly, hecerophiles were present, occasionally, in the lung, trachea and airsac by 0 to 1 hr after inoculation. Then they became more severe by 2 to 6 hrs PI. By 6 hrs PI, there were diffuse heterophiles infiltration in the trachea, lung, anc airsac. The lung vascular was edema. The trachea ciliate and mucous gland was cystic or hyperplasia, and the airsac shewed increased in thickness and cloudiness. These results of study indicate that the lesion caused by P-1059 and vaccine strain, M-9, were not significantly different. / Graduation date: 1992

published_or_final_version / Dentistry / Master / Master of Orthodontics