Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.640277
Title: Studies on blood pressure in obstructive sleep apnoea/hypopnoea syndrome
Author: Al-Abri, M. A. I.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2007
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Abstract:
This thesis aims to explore baroreflex sensitivity (BRS) in a randomised controlled trial. The hypothesis is that BRS is impaired in sleep apnoea patients, which might be reversed with one month of CPAP therapy. The study was designed to test for BRS in newly diagnosed OSAHS patients and perform a single blinded placebo controlled crossover trial of the effect of CPAP. Twenty-nine patients were recruited with Epworth Sleepiness Scale (ESS) of more than 10 and apnoea/hypopnoea index (AHI) was more than 15. Ten healthy control subjects were also studied. The study has shown weak difference between controls and OSAHS patients in the sequential analysis measure of BRS (P=0.05) but there was no difference with other BRS variables (P>0.05). However, the study did not show any significant difference between CPAP and placebo in terms of an effect on any measure of BRS not of 24-hour blood pressure. Even a priori sub group analyses of desaturating and compliant patients (4% Desaturating Index > 10 & CPAP use > 3.9 hour/night) showed no effect of CPAP (P>0.05). Patients did improve symptomatically with CPAP (P=0.02).The main criticisms of this study are the lack of reproducibility of the BRS measuring technique. Furthermore, relatively small sample size, may perhaps, had a negative impact on the results. The new methods were investigated further by another study, looking into the reproducibility of eth technique and the principles of BRS measurement, either the sequence as well as the spectral analysis of heart rate and systolic blood pressure. This study has revealed that spontaneous methods of BRS particularly the spectral domains are quite variables over time and thus difficult to reproduce. The third study was to assess endothelial function, as part of the process of understanding the pathogenesis of development hypertension and cardiovascular diseases in OSAHS patients and the contribution of hypoxemia in these disorders. The 24 blood pressure monitoring analysis revealed that hypoxemia is a putative predictor for hypertension.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.640277  DOI: Not available
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