Thesis (MScPhysio (Physiotherapy))--University of Stellenbosch, 2007. / Study Aim: To describe the profile and selected outcomes of CABG patients admitted in the Cape metropolitan area. Design: A prospective descriptive study design with a multicentre observational approach was followed. Method: All patients undergoing isolated CABG surgery, whether elective or emergency, during a three-month period (15 August–15 November 2005) were included in the study. Demographic data, pre-operative medical status, intra-operative, as well as post-operative information were collected using a self-designed structured initial assessment form (SIA). Means and standard deviations were calculated where applicable. Relationships between different variables were analyzed by means of: ANOVA, correlations, linear and logistic regressions. Where it appeared that the ANOVA assumptions were violated, non-parametric bootstrap techniques were employed. Results: Two hundred and forty five patients were admitted to the seven hospitals which provide CABG surgery in the Cape metropolitan area in the allotted period. The profile of patients admitted to private and state institutions were similar. The mean age of the sample was 60 (±10). The mean LOS of the total cohort was 12 (±5.5) days, with patients in the state hospitals staying longer 13.4 days (± 7.1). Patients who were older than 60 were twice as likely to have a LOS >12days (odds ratio = 2.49; 95% confidence interval = 1.33 to 4.65). The development of a pleural effusion or pneumothorax was associated with an increased LOS (p<0.01). At least one PPC was reported in 65% of the population. A mortality rate of only 3% was reported. Conclusion: Patients in this cohort were younger than in developed countries. An age greater than 60 years was a predictor of an LOS >12days in the current cohort. Patients were most likely to develop a PPC on day three after CABG surgery. Physiotherapeutic intervention, if any, would be well aimed at those patients older than 60 years of age. Screening of patients in the first three post-operative days for the development of PPCs is also advised.

Thesis (MScPhysio)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Aim: The aim of this study is to determine if the addition of a pre-extubation recruitment manoeuvre to standard care is safe and will improve lung compliance and subsequent PaO2/FiO2 (PF ratio) after extubation in postoperative coronary artery bypass graft surgery patients. Design: Prospective, triple blind, randomised, controlled trial. Method: This study was conducted in a private hospital in the Northern suburbs of Cape Town, South Africa. All patients admitted between 03/10/2010 and 22/11/2011, for uncomplicated elective coronary artery bypass graft (CABG) surgery were eligible for inclusion into the study. Patients were randomly allocated into either the intervention group or the control group. The intervention group received a gradual build-up lung recruitment manoeuvre (RM). The primary outcome was PaO2/FiO2 (PF ratio). The secondary outcomes were safety and static lung compliance. ICU length of stay (LOS) and hospital LOS were also recorded. The pre-RM hemodynamic stability of the patient was checked before the intervention and repeated at 5 minutes after the intervention by the nursing sister. Data to calculate static lung compliance was captured at the same time. Criteria for safety and discontinuation of the RM were monitored during the intervention by the principle investigator only. Results: Of the 69 patients eligible for the study 47 were randomly allocated into the intervention group (n=22) and control group (n=25) respectively. Groups were the same at baseline with regards to sex, pulmonary risk, sedation and surgical procedures. The RM could be completed in all patients. The prior defined criteria for discontinuation of the RM were not reached in any of the patients. No adverse effects were noted. The PaO2/FiO2 (PF ratio) decreased significantly in both groups from pre-surgery measurements compared to when measured before the RM (p<0.001). There was a tendency noted for the intervention group to return to pre-surgery measurements of PF ratio within 12 hours after extubation when compared to the control group. There was no significant difference between the groups from extubation to 24 hours (p = 0.6). The static compliance improved at 5 minutes following the RM (p<0.001) and remained improved until extubation (p<0.001) for the intervention group. No difference was noted in the static compliance of the control group over the same time period. The mean hospital length of stay for the intervention group was 8.61 (95% confidence interval 7.26 to 9.96 days) and 10.08 (95% confidence interval 8.52 – 11.63 days) for the control group. Conclusion: A gradual recruitment manoeuvre at 30cmH2O 30minutes before extubation significantly improved static lung compliance within 5 minutes with no adverse hemodynamic side effects. There was noted maintained improved PF ratio at extubation or immediately afterwards for the intervention group and no difference in the PF ratio between the intervention group and control group. / AFRIKAANSE OPSOMMING: Doel: Die doel van hierdie studie is om te bepaal of die toevoeging van ’n pre-ekstubasie herwinningstegniek tot standaard sorg veilig is, en of dit longvervormbaarheid en gevolglike PaO2/FiO2 (PF-verhouding) na ekstubasie in post-operatiewe kroonaaromleidingchirurgiepasiënte sal verbeter. Ontwerp: Prospektiewe, trippel-blinde, ewekansige, gekontroleerde proefneming. Metode: Hierdie studie is uitgevoer in ’n privaat hospitaal in die noordelike voorstede van Kaapstad, Suid-Afrika. Alle pasiënte wat tussen 03/10/2010 en 22/11/2011 gehospitaliseer is vir ongekompliseerde elektiewe kroonaaromleidingchirurgie, kon in aanmerking kom vir die studie. Pasiënte is op ewekansige wyse ingedeel in die intervensie- en kontrolegroepe. ’n Geleidelike-opbou-van-druk-longherwinningstegniek (HT) is op die intervensiegroep toegepas. Die primêre uitkoms was die PaO2 /FiO2 (PF-verhouding). Die sekondêre uitkoms was veiligheid en statiese longvervormbaarheid. ISE-verblyf en hospitaalverblyf is ook genoteer. Die navorsingsassistent het data van bestaande eenheiddokumentasie geneem. Die pre-HT-hemodinamiese stabiliteit van die pasiënte is gemonitor voor en weer 5 minute na die intervensie. Inligting om die statiese longvervormbaarheid te bereken is terselfdertyd genoteer. Kriteria vir veiligheid en vir die staking van die HT is gemonitor tydens uitvoering deur die primêre ondersoeker en die verpleegkundige. Resultate: Van die 69 pasiënte wat in aanmerking kon kom vir die studie is 47 op ewekansige wyse ingedeel in die intervensiegroep (n=22) en die kontrolegroep (n=25). Die groepe was dieselfde by die basislyn. Die herwinningstegniek kon volledig op alle pasiënte uitgevoer word. Die vooraf gedefinieerde kriteria vir staking van die HT is met geen pasiënte bereik nie. Geen nadelige uitwerking is genoteer nie. Die PaO2 /FiO2 (PF-verhouding) het beduidend verminder in beide groepe van pre-operatiewe metings in vergelyking met meting voor die HT (p<0.001). ‘n Neiging is genoteer dat die intervensiegroep binne 12 uur na ekstubasie tot pre-chirurgie PF-metings teruggekeer het. Daar was geen merkbare verskil tussen die groepe vanaf ekstubasie tot 24 uur (p=0.6) nie. Die statiese vervormbaarheid het verbeter teen 5 minute na HT (p<0.001) en het verbeter gebly tot ekstubasie (p<0.001) vir die intervensiegroep. Daar was geen verskil in die statiese vervormbaarheid van die kontrolegroep nie. Die gemiddelde hospitaalverblyf vir die intervensiegroep was 8.61 (95% betroubaarheidsinterval 7.26 tot 9.96 dae) en 10.08 (95% betroubaarheidsinterval 8.52 – 11.63 dae) vir die kontrolegroep. Gevolgtrekking: ’n Geleidelike herwinningstegniek teen 30cmH2O 30 minute voor ekstubasie het statiese longvervormbaarheid beduidend verbeter binne 5 minute, met geen nadelige hemodinamiese newe-effekte nie. Daar was geen verskil in die oksigenasie-indeks tussen die intervensie- en kontrolegroep na ekstubasie nie.

Thesis (MA)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: It is well known that coronary bypass graft surgery influences the psycho-social adjustment of the patient, but little is known about the effect of bypass surgery on the family members of the patient. The primary aim of this study was to assess the effect of coronary bypass graft surgery on certain aspects of the marital relationship and family functioning of the patient. The secondary aim was to determine which coping strategies families used during the two months after the operation. An experimental pre-test and post-test research design was used. Data during the first measure was collected by means of Biographical, Enriching and Nurturing Relationship Issues, Communication and Happiness (ENRICH)- and Family Adaptability and Cohesion Evaluation Scale-II (FACES II)-questionnaires, which were completed by the patient, the spouse of the patient and the eldest child still living with the parents. ENRICH-, FACES 11-and Family Crisis Oriented Personal Evaluation Scales (F-COPES)-questionnaires were used during the second measure which was conducted two months after the operation. The results indicated that bypass surgery affected the patients' marital satisfaction and communication negatively and changed their attitudes toward the division of new roles in the marriage and family. Bypass surgery had a further negative influence on the emotional bonding of the patients and their spouses with other members of the family. The patients' adaptability regarding new challenges facing the family was also negatively affected. The patients in the experimental group who were still working also showed a greater decline than the retired patients with regards to some of the measured variables. The coping strategies most often used by the families were the seeking of spiritual support and the reframing of the problem. Correlation coefficients between changes in the marital and family variables of the patient and the coping strategies used indicated that if passive appraisal was used, the patients' marital satisfaction would decrease and if reframing of the problem was used, the patients' adaptability regarding new challenges facing the family would increase. / AFRIKAANSE OPSOMMING: Alhoewel kroonaarsiektes die psigo-sosiale aanpassing van die pasiënt beïnvloed, bestaan daar min inligting oor die invloed wat kroonaarhartomleidingchirurgie op die huweliksverhouding en gesinsfunksionering van die pasiënt het. Die doel van hierdie ondersoek is om te bepaal hoe kroonaarhartomleidingchirurgie sekere aspekte van die pasiënt se huweliks- en gesinslewe beïnvloed. Verder het die ondersoek ten doelom te bepaal watter coping-strategieë die gesin post-operatief gebruik. Daar is van 'n eksperimentele voor- en na-metingnavorsingsontwerp gebruik gemaak. Data is ingesamel met Biografiese, Enriching and Nurturing Relationship Issues, Communication and Happiness (ENRICH)- en Family Adaptability and Cohesion Evaluation Scale-II (FACES II)-vraelyste wat gedurende 'n voormetingsgeleentheid deur die pasiënt, huweliksmaat van die pasiënt en oudste kind wat nog in die huis bly, voltooi is. Die na-meting, wat bestaan het uit die voltooing van ENRICH-, FACES 11-en Family Crisis Oriented Personal Evaluation Scales (F-COPES)-vraelyste, het twee maande na die operasie plaasgevind. Die resultate toon dat kroonaarhartomleidingchirurgie die pasiënte se huwelikstevredenheid en -kommunikasie nadelige beïnvloed het en 'n veranderinge in hul houding oor die rolverdeling in die huwelik en gesin teweeg gebring het. Verder het die operasie 'n nadelige effek op die pasiënte en hul huweliksmaats se gevoel van emosionele binding met ander gesinslede gehad. Die pasiënte se vermoë om by nuwe eise en uitdagings wat aan die gesin gestel word aan te pas, is ook nadelig beïnvloed. Verder is bevind dat die werkende pasiënte 'n groter verandering as die afgetrede pasiënte ten opsigte van sekere van die gemete veranderlikes getoon het. Die coping-strategieë wat die meeste deur die gesinne gebruik is, is die soeke na geestelike ondersteuning en die herdefiniëring van die probleem. Die resultate het ook aangedui dat as passiewe waardering as coping-strategie gebruik word, die pasiënte se tevredenheid met hul huwelik sal afneem. Verder sal gesinne se vermoë om by nuwe eise en uitdagings wat aan die gesin gestel word aan te pas, toeneem indien herdefiniëring van die probleem as coping-strategie gebruik word.

The intent of this research was to identify if the degenerative changes within arteries in the endometrium (endometrial angiopathies) correlate with degenerative changes in the uterine arteries and can be used as a predictor of increased risk for uterine artery rupture (UAR). With this objective specimens from 20 mares that died from uterine artery rupture and 21 control mares that died from unrelated causes were obtained from cases submitted to the University of Kentucky Veterinary Diagnostic Laboratory (UKVDL) over a two-year period. Postmortem specimens of each mare were collected from the left and right uterine arteries at the origin, bifurcation, and distal to the bifurcation as well as full thickness uterine wall sections at five different sites. An additional sample was taken from the uterine artery at the site of rupture in the affected mares. Tissue samples were immersed in 10% neutral buffered formalin, routinely processed, and stained with hematoxylin and eosin, Masson’s Trichrome, and Verhoeff´s Van Gieson histochemical stains as well as a smooth muscle-actin immunohistochemical marker. Elastosis, fibrosis, and vascular smooth muscle cell degeneration were identified in this study as potential contributors of vascular degeneration and a scoring system was developed to differentiate the degrees of severity of these specific degenerative changes within the intima and media of the vascular wall. Based on the scoring system, sections of uterine arteries and endometrial arterioles were blindly examined and the scored changes recorded for statistical analysis. Although the degenerative changes in endometrial and uterine arteries were similar within each group, the results could not not be used to predict an increased risk for UAR. Furthermore, we determined the major changes in vascular pathology of the affected uterine arteries and show there is a significant difference in degenerative changes between specific layers of the vascular wall.

published_or_final_version / Community Medicine / Master / Master of Public Health

published_or_final_version / abstract / Mechanical Engineering / Doctoral / Doctor of Philosophy

Atherosclerosis and related cardiovascular diseases (CVDs) are amongst the largest causes of morbidity and mortality in the developed world, causing considerable monetary pressure on public health systems worldwide. Atherosclerosis is characterised by the build up of vascular plaque in medium and large arteries and is a direct precursor to acute vascular syndromes such a myocardial infarction, stroke or peripheral arterial diseases. The causative factors leading to CVD still remain relatively poorly understood, but are becoming increasingly identifiable as a dysfunction of the endothelial cells that line the arterial wall. It is well known that the endothelium responds to the prevailing fluid mechanic (i.e. haemodynamic) environment, which plays a crucial role in the localised occurrence of atherosclerosis near vessel bends and bifurcations. In these areas, disturbed haemodynamics lead to flow separation and very low wall shear stress (WSS), which directly affects the functionality of the endothelium and impedes the transport of important blood borne agonists and antagonists. Detailed full field measurements assessing complex haemodynamics are sparse and consequently this thesis aims to address some of the important questions related to arterial haemodynamics and CVD by performing in-vitro flow measurements in physiologically relevant conditions. In particular, this research develops and uses state-of-the-art Particle Image Velocimetry (PIV) techniques to measure three-dimensional velocity and WSS fields in scaled models of the human carotid artery. For this purpose, the necessary theoretical and experimental concepts are developed and in-depth analyses of the underlying factors affecting the local haemodynamics and their relation to CVD are carried out. In the first part, a methodology for the construct of transparent hydraulic flow phantoms from medical imaging data is developed. The arterial geometries are reproduced in optically clear silicone and the flowing blood is modelled with a refractive index matched blood analogue. Subsequently, planar and Stereo-PIV techniques are developed and verified. A novel interfacial PIV (iPIV) technique is introduced to directly measure WSS by inferring the velocity gradient from the recorded particle images. The new technique offers a maximal achievable resolution of 1 pixel and therefore removes the resolution limit near the wall usually associated with PIV. Furthermore, the iPIV performance is assessed on a number of numerical and experimental test cases and iPIV offers a significantly improved measurement accuracy compared to more traditional techniques. Subsequently, the developed methodologies are applied in three studies to characterise the velocity and WSS fields in the human carotid artery under a number of physiological and experimental conditions. The first study focuses on idealised vessel geometries with and without disease and establishes a general understanding of the haemodynamic environment. Secondly, a physiological accurate vessel geometry under pulsatile flow conditions is investigated to provide a more realistic representation of the true in-vivo flow conditions. The prevailing flow structure in both cases is characterised by flow separation, strong secondary flows and large spatial and temporal variations in WSS. Large spatial and temporal differences exist between the different geometries and flow conditions; spatial variations appear to be more significant than transient events. Thirdly, the three-dimensional flow structure in the physiological carotid artery model is investigated by means of stereoscopic and tomographic PIV, permitting for the first time the measurement of the full 3D-3C velocity field and shear stress tensor in such geometries. The flow field within the model is complex and three-dimensional and inherently determined by the vessel geometry and the build up of an adverse pressure gradient. The main features include strong heliocoidal flow motions and large spatial variations in WSS. Lastly, the physiological implications of the current results are discussed in detail and reference to previous work is given. In summary, the present research develops a novel and versatile PIV methodology for haemodynamic in vitro studies and the functionality and accuracy is demonstrated through a number of physiological relevant flow measurements.

Cognitive impairment in coronary artery disease (CAD) patients can predict poorer quality of life, dementia, and increased mortality. This study aimed to determine the association between long-term cortisol elevations and cognitive function in CAD patients. Participants were recruited at the beginning of a 1 year cardiac rehabilitation program and followed forward. Composite Z-scores were computed from tests measuring memory and executive function at baseline and 1 year. Cortisol deposition (3 months) was measured from a 20 mg, 3 cm hair sample. Analyses of covariance showed less improvement in memory function (F1,50=4.721, p=0.035) but not executive function (F1,49=0.318, p=0.575) in patients dichotomized into a high cortisol group based on a previously established reference range. Prolonged cortisol elevation may be associated with cognitive changes in subjects with CAD.

Cognitive impairment in coronary artery disease (CAD) patients can predict poorer quality of life, dementia, and increased mortality. This study aimed to determine the association between long-term cortisol elevations and cognitive function in CAD patients. Participants were recruited at the beginning of a 1 year cardiac rehabilitation program and followed forward. Composite Z-scores were computed from tests measuring memory and executive function at baseline and 1 year. Cortisol deposition (3 months) was measured from a 20 mg, 3 cm hair sample. Analyses of covariance showed less improvement in memory function (F1,50=4.721, p=0.035) but not executive function (F1,49=0.318, p=0.575) in patients dichotomized into a high cortisol group based on a previously established reference range. Prolonged cortisol elevation may be associated with cognitive changes in subjects with CAD.

In this thesis I present a microfluidic platform developed to control dissolved gases and monitor dissolved oxygen concentrations within the microenvironment of isolated small blood vessels. Dissolved gas concentrations are controlled via permeation through the device substrate material using a 3D network of gas and liquid channels. Dissolved oxygen concentrations are measured on-chip via fluorescence quenching of an oxygen sensitive probe embedded in the device. Dissolved oxygen control was validated using the on-chip sensors as well as a 3D computational model. The platform was used in a series of preliminary experiments using olfactory resistance arteries from the mouse cerebral vascular bed. The presented platform provides the unique opportunity to control dissolved oxygen concentrations at high temporal resolutions (<1 min) and monitor dissolved oxygen concentrations in the microenvironment surrounding isolated blood vessels.