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Thawing of fresh frozen plasma (FFP) in South Africa is not standardized and thawing at high temperatures may cause clotting factor activation and disseminated intravascular coagulation (DIC). This research project studies the in-vitro effects of thawing FFP at various temperatures on coagulation. Twenty units of FFP were each divided into 4 satellite bags which were respectively thawed at 22ºC, 37ºC, 45ºC and 60ºC and tested for Fibrinogen, DDimers, PT, PTT, r value, Alpha Angle and Maximum Amplitude (MA). FFP thawed at 60ºC showed significant differences suggesting clotting factor inactivation. FFP thawed at 45ºC showed significantly elevated D-Dimers. Clotting factors thawed at 22ºC may be partially inactivated. High thawing temperatures may activate and then denature the factors therein. Twenty two degrees may partially inactivate FFP until it is warmed to body temperature. The clinical implications and recommendations of this study are to thaw FFP at 37ºC.

Paediatric Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency Syndrome (AIDS) remain a significant health care challenge in South Africa. Oral health and coagulation are only two of the many problems experienced by HIV positive paediatric patients. This research report began with an observation that known HIV positive paediatric patients bled more than known HIV negative paediatric patients or those with unknown HIV status while undergoing dental extractions at Charlotte Maxeke Johannesburg Academic Hospital. The observation prompted a prospective, contextual, descriptive study looking at the coagulation profile (platelet count and thromboelastogram (TEG) profile (reaction time (r-time), clot formation time (Ktime), alpha angle (α-angle) and maximum amplitude (MA)), CD4 counts and percentages and observed clinical bleeding in HIV negative, HIV positive not on antiretroviral treatment (ARVs) and HIV positive on ARVs paediatric patients presenting for dental extraction. Over a two year period 47 HIV negative, 12 HIV positive not on ARVs and 17 HIV positive on ARVs paediatric patients were enrolled in the study using a consecutive, convenience sampling method. Each paediatric patient was given a standard inhalational general anaesthetic using sevoflurane and during intravenous cannulation the researcher drew blood from each child for analysis. A senior dentist from the Department of Paediatric Dentistry assessed bleeding in all cases. The data obtained for each of the three study groups was compared using a oneway analysis of variance followed by pair wise comparison using the Bonferroni adjustment to address multiplicity. To deal with the big standard deviations and skewed data a one-way analysis of variance for ranks tested for differences between the groups. No statistically significant differences were found when comparing the groups for platelet count (p = 0.2087), TEG r-time (p = 0.4738), TEG K-time (p = 0.6967), TEG α-angle (p = 0.7948) or TEG MA (p = 0.2982). There was a statistically significant difference between the HIV negative and HIV positive not on ARVs groups (p = 0.000 and 0.004) and HIV positive on ARVs and HIV positive not on ARVs groups (p = 0.000 and 0.001) when comparing CD4 count and percentage. Patient groups were compared with respect to bleeding complications using the Fisher’s exact test. There was no statistically significant difference in observed bleeding between the three groups of paediatric patients. The entire HIV positive group was then compared for bleeding, and using the Welch t-test, adjusting for unequal variances it was found that there was statistically, significantly more bleeding in the HIV positive children with lower CD4 counts regardless of treatment with ARVs (p = 0.0129). These results were also confirmed using the Wilcoxon rank-sum test (p = 0.0335). Although this study showed statistically significant bleeding in HIV positive paediatric patients with lower CD4 counts, the tests of coagulation used in the study were unable to define the underlying pathogenesis. Further research into coagulation in HIV positive paediatric patients is needed.

212 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (M.D.)--University of Adelaide, Dept. of Medicine, 1973

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Thesis--Leyden. / Summary in Dutch. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.

published_or_final_version / Pathology / Doctoral / Doctor of Philosophy