Browsing by Author "Myburgh, Adriaan"

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    Open Access
    Design of a Novel Video-Assisted Tube Over Tube Rigid Bronchoscope for the Removal of Foreign Bodies from the Bronchi Following Aspiration
    (2022) McEwan, Sarah Ann; Sivarasu, Sudesh; Myburgh, Adriaan
    Foreign body aspiration (FBA) is a prevalent occurrence in the paediatric population. FBA is when a foreign body (FB) is inhaled accidentally into the airways. The location of the FB may differ according to each patient, but in most cases, the FB is found in the right bronchial tree. FBA symptoms are often misdiagnosed, resulting in late discovery of the obstruction. There is an increase in difficulty to remove a FB, dependent on how long it remains within the airway. This poses a greater risk to the patient, fatality or other serious long-term complications. Currently, FBs are removed using a bronchoscope in conjunction with a pair of forceps. The two types of bronchoscopes used currently are the flexible and rigid bronchoscopes. The rigid scope is preferred for FB removal due to better control and clear visuals of the air way and an array of forceps ends. The costly flexible scope is more difficult to use and is used in cases where radiological findings of a FB are inconclusive. During insertion of the scope, no ventilation is supplied to the patient, posing a high risk of hypoxia. Both instruments require considerable skill and extensive training, limiting the procedure applicability. The difficulty experienced when handling the current instruments and the high risk of hypoxia are motivations for a product redesign. Therefore, this study aims to design and develop a novel video-assisted tube-over-tube rigid bronchoscope to remove foreign bodies from the airways following aspiration, whilst providing constant ventilation and visualisation of the airway. The redesign compromises of several subsystems: the rigid bronchoscope (and attached camera), ventilation connector tube and an uncuffed endotracheal tube (ETT). These subsystems were designed to ensure constant ventilation throughout the insertion of the bronchoscope, whilst providing real-time imaging of the airways. The design incorporated a guiding mechanism to increase the usability further. A testing protocol was performed on a Laerdal airway management trainer using the designed device, named the ‘Re-Aspire' device and its competitor, the Karl Storz rigid bronchoscope. The testing participants were a group of anaesthesiologists who have had prior training in bronchoscopy, but do not practise the procedure. A common FB was placed inside the airway of the trainer, and both scopes were used to retrieve it. The facilitator timed the procedure and observed the participants. Post testing, each participant was interviewed about the functionality of each device and completed a system usability scale. A total of 34 attempts of FB removal was recorded for the rigid bronchoscope compared to 14 attempts for the Re-Aspire device. As hypothesised, the estimated average hypoxic time was more than double for the rigid bronchoscope compared to that of the Re-Aspire device. According to the system usability scale, the Re-Aspire device resulted in a higher average system usability score. These results demonstrated that the Re Aspire device has a higher perceived ease of use and system satisfaction according to the user's perspective. Therefore, achieving all the stated testing hypotheses. However, the design of the device can be improved to increase the usability and efficacy further.
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    Open Access
    The influence of delayed sample processing time on the PO₂ values in critically ill patients with sepsis-induced leukocytosis
    (2017) Pretorius, Petrus Rohan; Myburgh, Adriaan
    Background: The ability to correctly measure the partial pressure of Oxygen is one of the fundamental test that influence clinical decision making in a septic ICU patient. The study examined the extent of error over time, from collection to processing, when measuring blood gas samples for PO₂, PCO₂, pH, in critically-ill patients with sepsis and metabolically active leucocytosis > 12 000/mm³ and compares it with a control, where immersing it in ice has stopped metabolism. Methods: Thirty septic ICU patients with confirmed leucocytosis > 12 000/mm³, who had routine arterial blood analysed was included in the study. Blood form the standard PICO50 radiometer arterial blood sampler (2ml) syringe was decanted into two 1ml Glass syringes that was pre-heparinised with 1ml Heparin 1000U - all excess Heparin removed. One syringe was cooled with ice slurry and tested as a control at 60 minutes The other syringe was used to repeatedly analyse the sample at 0,10, 30 and 60 minutes. The syringes were sealed with plastecine and a glass capillary tube was use to decant the sample just prior to analysis to fit the analyser. Samples were processed using an ABL 800 blood gas analyser. Results: The mean absolute difference in PO₂ at 10 minutes was -0.94 kPa (95% CI: -1.48 to -0.4 kPa), at 30 minutes -2.42 kPa (95% CI: -3.10 to -1.75 kPa) and at 60 minutes -4.44 kPa (95% CI: -5.54 to -3.34 kPa). The relative difference in pO₂ at 10 minutes was -4.98% (95% CI: -8.12 to -1.84%), at 30 minutes -13.79% (95% CI: -17.40 to -10.17%) and 60 minutes -25.46% (95% CI: -30.97 to -19.95%). The absolute difference in PO₂ at 60 minutes on Ice was - 0.31 kPa. Conclusion: Delayed blood gas analysis in Septic ICU patients with a raised WCC > 12 000/mm³, results in statistical and possible clinical significant abnormality in the pO₂, that progressively worsens with time. After 10 minutes there was a 5% change, at 30 minutes a 14% change and there was a 25% change from baseline PO₂ at 60 minutes. The magnitude of change with statistical mixed linear models shows the rate of decline to be of the magnitude of 1% per minute. So at 60 minutes, the ratio change is 0.7313859 (0.9948 to the power of 60).This deviation may alter clinical decision making.
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    Quadruple valve replacement in a patient with severe rheumatic heart disease
    (2018-06-01) Adembesa, Isaac; Myburgh, Adriaan; Swanevelder, Justiaan
    We present a patient with rheumatic heart disease involving all the heart valves. An intraoperative transoesophageal echocardiography confirmed severe mitral stenosis, severe aortic regurgitation, severe tricuspid regurgitation and stenosis, and severe pulmonary stenosis. The patient underwent successful quadruple valve replacement during a single operation at the Groote Schuur Hospital, Cape Town, South Africa.