3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Anaesthetists' knowledge of appropriate adrenaline administration in three clinical scenarios(2016-10-12) Anamourlis, Prodromos ChristopherLack of knowledge and clinical experience in the event of an emergency are a lethal combination. Adrenaline is the drug of choice for resuscitation during cardiovascular collapse. Incorrectly dosing patients with adrenaline can lead to death by overdose or by undertreating the emergent condition. This highlights the importance, not only of resuscitation protocols but also the physician’s knowledge of and adherence to such guidelines. Research has consistently shown that physicians commonly make dosing mistakes during emergencies concerning adrenaline. Identifying whether or not this is due to a deficit in knowledge is important in understanding how to improve the outcomes of patients in such emergencies. The aim of this study was to determine the knowledge of anaesthetists working in the Department of Anaesthesiology at the University of the Witwatersrand regarding the appropriate administration of adrenaline for anaphylaxis, cardiac arrest and inotropic infusions. This was a prospective, contextual, descriptive study on a sample of anaesthetists working in the Department of Anaesthesiology at the University of the Witwatersrand. Anaesthetists who were willing to participate in the study were given a brief introduction to the study and a questionnaire to complete regarding adrenaline doses in three different clinical scenarios. Data collection took place during February 2014 and June 2014. Anaesthetists’ knowledge of adrenaline was analysed using descriptive and inferential statistics. The knowledge of Wits anaesthetists regarding adrenaline use in cardiac arrest, anaphylaxis and as an infusion, is inadequate. A total of 104 anaesthetists answered the questionnaire (n=104). The pass rate for the questionnaire was 14% (n=15). The median score for the questionnaire was 50%. A statistically significant difference was found between the pass rates of those anaesthetists who had attained an ACLS course and those who had not (p=0.0339). A weak correlation was found between anaesthetists knowledge and years of anaesthetic experience (r=0.2460). When comparing the knowledge of anaesthetists between different professional designations, a statistically significant difference was found between the intern groups’ knowledge and the consultants (33% vs 67%: p=0.0013). The study questionnaire uncovered major knowledge deficits in Wits anaesthetists, and revealed that ACLS certification improved knowledge in anaesthetists. This study warrants educational intervention and future investigation into knowledge improvement.Item Systolic chamber function in rats with exercise-induced compared to pathological cardiac dilation(2009-04-17T12:12:51Z) Anamourlis, Prodromos ChristopherABSTRACT In pathological left ventricular hypertrophy (LVH) with a normal intrinsic myocardial function, eccentric chamber remodelling (cardiac dilatation) can produce a right shift in systolic pressure-volume (P-V) relations (systolic chamber dysfunction). Whether comparable degrees of cardiac dilatation in physiological (exercise-induced eccentric left ventricular remodelling) and pathological LVH produce similar effects on chamber function has not been determined. Hence, the aim of my thesis was to determine the impact of cardiac dilatation on systolic chamber function in chronically exercised rats with comparable increases in cardiac diastolic volumes as those produced by two rat models of pathological dilatation. Methods: Two models of cardiac dilatation were used, namely: (1) a model of pathological cardiac hypertrophy and dilatation (induced by chronic β-adrenoreceptor agonist administration to either Sprague-Dawley or spontaneously hypertensive rats), and (2) a model of physiological cardiac hypertrophy and dilatation (induced in Sprague-Dawley rats by 4-5 months of voluntary running activity on exercise wheels). 33 Sprague-Dawley rats were placed on spontaneous running wheels for 4-5 months (Exer group) and 24 Sprague-Dawley sedentary control rats (Con group) were placed individually in normal rat cages. To induced pathological dilatation, the β-agonist, isoproterenol (ISO) was administered daily to Sprague-Dawley rats for 7 months (SD-ISO, n=10) and to spontaneously hypertensive rats (SHR) for 4-5 months (SHR+ISO, n=22). Saline was administered daily to controls (SD, n=10; SHR, n=21) and to normotensive Wistar Kyoto rats (WKY, n=17). In isolated, perfused heart preparations, left ventricular (LV) dilatation was determined from the diastolic pressure-volume (P-V) relation and the volume intercept of the diastolic P-V relation (LV V0). Systolic chamber function was assessed by comparing LV developed pressures at specific filling volumes. Intrinsic systolic myocardial function was determined from the slope of the LV systolic developed stress-strain relation (myocardial systolic elastance). Results: ISO adminstered to SD and to SHR rats produced cardiac dilatation [LV V0 (ml): SD 0.20±0.01, SD-ISO 0.27±0.02, p<0.005; SHR 0.21±0.01, SHR-ISO 0.30±0.01, p<0.001], systolic chamber dysfunction (decrease in left ventricular developed pressures at incremental filling volumes) but normal intrinsic systolic myocardial function. Habitual exercise resulted in a right shifted LV diastolic P-V relation and an increased LV V0 (Exer 0.22±0.01, Con 0.18±0.01, p<0.005). In exercised rats (Exer-dilated, n=10) with equivalent dilatation as SD-ISO and SHR-ISO (LV V0 within 95% CI of SD-ISO and SHR-ISO), despite comparable LV diastolic P-V relations and LV V0 values (0.28±0.01); both systolic chamber function and intrinsic systolic myocardial function were normal. Conclusions: These data provide evidence to indicate that as compared to pathological dilatation, a similar extent of exercise-induced dilatation does not produce the same adverse effects on systolic chamber function.