Browsing by Author "Wilson, Graeme"

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    Open Access
    A prospective study of paediatric preoperative fasting times at Red Cross War Memorial Children's Hospital
    (2021) Kouvarellis, Alison; Wilson, Graeme; Biccard, Bruce; van der Spuy, Karen
    Background. Fasting for liquids and solids is recommended prior to procedures requiring anaesthesia, to reduce the risk of pulmonary aspiration. Children often experience excessive fasting, which is associated with negative physiological and behavioural consequences, and patient discomfort. The duration of preoperative fasting in children in South Africa is unknown. Objectives. The aim of this study was to determine the compliance with fasting guidelines and fasting times of children prior to elective procedures performed under anaesthesia at a paediatric hospital in Cape Town, South Africa. The primary focus was fasting for clear liquid. The study also intended to identify the most common reasons for prolonged clear liquid fasting. Methods. Over a seven-week period, we prospectively captured fasting times of consecutive patients undergoing elective surgical, medical and radiological procedures at Red Cross War Memorial Children's Hospital (RCWMCH). Measurement outcomes were defined as the period from the last clear liquid, milk or solid feed to the start of anaesthesia. For analysis of compliance with preoperative fasting guidelines, institutional preoperative fasting target limits were established based on the standard 6-4-2 hour guideline. Results. The study included 721 elective paediatric cases. The mean (SD) fasting time for clear liquids (n=585) was 8.0 (4.8) hours, with an adherence rate of 25.5% (95% confidence interval (CI) 22-29%) to the institutional target of 2 to 4 hours. The mean (SD) fasting times for breast milk (n=92), formula milk (n=116) and solid feeds (n=560) were 7.1 (2.8), 8.8 (2.8) and 13.9 (3.6) hours respectively. The factors associated with clear liquid fasting >4 hours were: inadequate fasting instructions, poor adherence to fasting orders, procedural delays and fasting to promote theatre flexibility. Conclusion. This study demonstrates that children in a South Africa hospital experience excessive fasting times prior to elective procedures. To reduce fasting durations and improve the quality of perioperative care, quality improvement (QI) interventions are required to create an adaptable fasting system which allows individualised fasting. Improving preoperative fasting times in children is the responsibility of all health care professionals in the multi-disciplinary management team.
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    Effect of a histidine-tryptophane-ketoglutarate solution on coagulation as measured by a thromboelastogram
    (2016) Kabambi, Kasandji Freddy; Wilson, Graeme
    Background: The Histidine-tryptophan-ketoglutarate (HTK) solution is cardioplegic solution that confers myocardial protection during periods of ischemia in heart surgery. It has the advantage of allowing a longer protection and it is especially the preferred cardioplegic solution in complex paediatric heart surgery like transposition of great vessels. This has also been used in organ transplant as a preservative solution. Recently concern has been raised over its safety because of the increased incidence of transplant failure due to thrombosis in individuals whose transplanted organ were preserved with HTK solution. The main purpose of this study was to establish whether the HTK solution in the dose and volume used for myocardial protection during paediatric heart surgical procedures increases the thrombotic risk of patients. Patient and methods: This study was an experimental study conducted at the coagulation laboratory of the department of anaesthesia of the University of Cape Town. The human research ethical committee of this university approved this study. Twenty healthy individual were recruited for this study and each one of them read and signed the consent form before being enrolled for the study. The exclusion criteria were any known coagulopathy, liver diseases, alcoholism, kidney disease and intake of any drugs known to impair the coagulation. Ten millilitre of blood was drawn from the volunteer at the coagulation laboratory. The blood was diluted with either HTK solution or St Thomas' cardioplegic solution at 9:1 ratio to mimic the hemodilution due to HTK solution in paediatric population. The effect on coagulation was assessed by means of thromboelastography run on the native blood and each dilution separately. Results: The difference in the magnitude of change from baseline in r-time between the HTK solution and Saint Thomas' solution (mean difference 0.49 min) (p 0.014) was statistically significant. There was no statistically significant change in MA between the HTK solution and St Thomas' solution (mean difference -2.13 mm) (p 0.165). Compared to native blood there were no significant change in r-time with the HTK solution (mean -0.215 min), the same with St Thomas' solution. Compared to native blood, there was significant change in maximum amplitude with the HTK solution (mean 1.38 mm) the same with St Thomas' solution (mean 3.51). Although the difference in the magnitude of in R time change between HTK solution and St Thomas' was statistically significant, it is clinically not relevant. The data did not show a trend that might become significant with large sample. All variables showed a slight tendency towards decreased coagulation in the diluted samples, but not of sufficient magnitude to be clinically important. Our goal was the use of a dilution that is clinically relevant in the context of paediatric cardiac surgery. Conclusion: The results of this study suggest the HTK solution at 10% dilution does not cause significant changes in coagulation parameters. In comparison to normal saline, there were a tendency toward hypocoagulation. More research in this field is needed to clarify the pathophysiologic pathways of thrombosis observed in these transplants.
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    Paediatric out-of-theatre procedural sedation at a tertiary children's hospital: A prospective observational study
    (2021) Lapere, Cherese; Gray, Rebecca; Wilson, Graeme
    Background: This tertiary referral centre is one the largest paediatric hospitals in Africa. Despite an increasing number of surgical and diagnostic procedures being performed annually, a formal out-of-theatre sedation service does not exist. Procedural sedation and analgesia (PSA) is an important adjunct in behavioural management for invasive procedures in children. Objective: A prospective, observational study was performed at RCWMCH, aimed primarily at defining the number of cases of PSA performed outside the operating theatre. Methods: Data was collected from all procedural out-of-theatre sedations performed over a period of three months, including ward patients and out-patient departments. All children < 13 years of age were included. Results: A total of 639 sedations were performed. Of these sedations, 288 (45.0%) paper responses were captured and analysed. The reported incidence of desaturation was 4.2% (12/288), laryngospasm 0.3% (1/288) and nausea and vomiting 2.4% (6/288). Three cases required conversion to general anaesthetic, and three cases were abandoned due to inadequate sedation. In 16.3% (47/288) of cases the clinician was an operator sedationist (the same person performing the sedation and the procedure). In 90.6% of cases the intravenous route was utilized, with dexmedetomidine, ketamine and propofol being the three most commonly used agents. Conclusion: 639 PSA events were recorded in 3 months. The 288 events analysed were safely performed with minimal serious reported events. These results compare favourably with international studies and provide quantitative evidence as a prelude to setting up a dedicated sedation service at our facility.
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    Platelet function Analyzer; closure times in children with congenital cyanotic heart disease A prospective observational pilot study
    (2020) Kempe, Laura Jessica; Wilson, Graeme
    Objectives: To establish the median and interquartile range or the mean and standard deviation for closure times , with the CADP and CEPI cartridges for children with CCHD and to compare this to normal children. Design: Prospective observational pilot study Setting: Red Cross War Memorial Children's Hospital (RCWMCH) in association with the University of Cape Town Participants: Children between birth and 16 years old diagnosed with CCHD presenting for corrective or palliative cardiothoracic surgical procedures Interventions: 0.8ml of whole blood obtained from the participants was pipetted into both the CEPI and CADP cartridges and analyzed by the PFA machine. Closure times for both cartridges were obtained and recorded on the data collection form. Results: 40 successful CADP samples and 39 successful CEPI cartridges were analysed. Of the total 40 valid CADP samples there was left skewed distribution , the median was 114.50 seconds with an interquartile range from 87.25 seconds to 153.75 seconds. Of the total 39 valid CEPI samples the data was normally distributed to give a mean of 175.38 and a standard deviation of 74.998. Both of which are not significantly different from the typical normal ranges obtained with 3.2% trisodium citrate ; 55–112 s for CADP and 79–164 s for CEPI (Harrison 2005). However, when compared to the normal ranges quoted by Carcao et al for neonates and children, there was a significant prolongation for both the CEPI and CADP samples in the neonates and children with CCHD Conclusion: This is a pilot study and limited by small sample sizes obtained due to time limitation. Further research would be needed to further assess whether the PFA could be used to guide platelet replacement in this population.