Browsing by Author "Dyer, Robert"

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    Open Access
    A multicentre cross-sectional descriptive study evaluating the cardiovascular risk profile of preoperatively identified patients with hypertension
    (2021) Govender, Sarisha; Rayner, Brian; Dyer, Robert
    Background. The prevalence of hypertension in adults in South Africa (SA) is 35%. Hypertension is the most important modifiable risk factor for cardiovascular (CV) and chronic kidney disease (CKD) in subSaharan Africa. However, 49% of people are unaware of their blood pressure status. Screening for hypertension prior to surgery provides a unique opportunity to diagnose and treat affected individuals. Furthermore, assessing overall CV risk identifies patients at highest risk for complications, and improves the utilisation of scarce resources. Objective. To evaluate the CV risk profile of hypertensive patients in the adult population of the Western Cape Province presenting for elective non-cardiac, non-obstetric surgery. Methods. This report documents the CV risk profile of patients recruited to the HASS-2 study (Hypertension and Surgery Study 2), which was undertaken in seven Western Cape hospitals. Patients were screened for hypertension and pharmacological treatment was initiated or adjusted in patients with stages 1 and 2 disease. Stage 3 patients were referred to a physician. In the present substudy, patients with stages 1 and 2 hypertension were assessed for associated CV risk factors, the presence of target organ damage, and documented CV or kidney disease; they received an overall risk stratification according to the 2018 European Society of Cardiology and the European Society of Hypertension Guidelines. Results. Sixty-one patients with stage 1 and 12 with stage 2 hypertension were analysed. Established CV disease was present in 13.7% of the study population, and CKD (eGFR <60 ml/min) in 10.8%. Seventy-one percent of the study group had a raised body mass index, and 55.9% underlying metabolic syndrome. Prediabetes and diabetes were present in 16.1% and 14.5% respectively. According to the 2018 European guidelines, 34.7% were at moderate, 33.3% at high and 16.7% at very high risk for a CV event in the following 10 years. Conclusions. The perioperative period is a critical time during which surgeons, nurses and anaesthetists can influence patients' CV risk of adverse events. This involves appropriate screening, education and treatment. In this study population, nearly 9 out of 10 elective surgical patients with stage 1 or 2 hypertension had CV risk factors placing them at moderate to very high risk. The simultaneous assessment of these additional CV risk parameters, in addition to diagnosis and management of hypertension, may further decrease the health and financial burden in resource-limited facilities in SA, and improve CV outcomes.
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    Myocardial injury after non-cardiac surgery: A prevalence study
    (2018) Coetzee, Ettienne; Biccard, Bruce; Dyer, Robert
    Background Worldwide, the number of patients suffering from surgical complications account for a significant burden on healthcare systems. Myocardial injury after non-cardiac surgery (MINS) is a new entity that has recently been identified as an independent risk factor associated with 30-day all-cause mortality. The risk of death increases approximately 10 fold following MINS in the perioperative period. Diagnosing myocardial injury in nonsurgical patients often relies on specific symptomatology and clinical findings combined with special investigations. However, in surgical patients, more than 80% of patients with postoperative myocardial injury will be asymptomatic, and hence the majority of diagnoses will be missed. Studies identifying the prevalence and risk factors for MINS have been conducted in countries with a different surgical population to South Africa. The primary outcome of this study was to investigate the prevalence of MINS after non-cardiac, elective, elevated risk surgery in South Africa. Methods Patients undergoing elevated risk, elective, non-cardiac surgery ≥ 45 years of age were enrolled via convenience sampling. The new 5th generation, high sensitivity cardiac troponin T (hscTnT) blood test was used to identify MINS. Blood samples were taken between 24 to 72 hours after surgery. Exclusion criteria included patients with known renal disease, a recent cardiac event, pulmonary embolism or sepsis. Results A total of 244 patients were included in the study. The prevalence of MINS was 4.9% (95% CI 2.2-7.6) which was not significantly different (p=0.078) to reports from international prospective observational studies. Conclusion Elective, elevated risk surgical patients in South Africa have a similar incidence of MINS when compared to patients from international studies. As the risk profile of South African patients is significantly lower than other similar international observational studies, it is possible that the prevalence of MINS is more common in South Africa, when patients are adjusted for cardiovascular risk profile. The burden of MINS on public health morbidity is therefore likely to be proportionally more in South Africa when compared to international reports. This may suggest that the calibration of international cardiovascular risk prediction models is incorrect for South African patients, or there are confounding comorbidities which should be included in South African cardiovascular risk prediction models. Larger studies are required to confirm this hypothesis however, and should also aim to address the need for appropriate cardiovascular risk predicting models in South Africa, to ensure timeous identification of patients at risk of MINS.
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    Overcoming language barriers using an information video on spinal anesthesia for cesarean section: implementation and impact on maternal anxiety
    (2021) Purcell-Jones, Jessica M A; Duys, Rowan; Dyer, Robert
    Background It is unknown whether the implementation of an information video on spinal anesthesia for caesarean section, narrated in a patient's first language, reduces anxiety, increases satisfaction, and improves doctor-patient communication if there is a language barrier. In South Africa most doctors speak English, and patients Xhosa, with educational and cultural disparities existing in many doctor-patient interactions. Methods One hundred and seventy-five Xhosa patients scheduled for elective cesarean section were enrolled in the study. The first 92 patients received “usual care” verbal explanations of the spinal anesthesia procedure (control group); the next 83 patients watched a spinal anesthesia information video (intervention group), narrated in Xhosa. Videos were displayed using smartphones. Maternal anxiety was assessed before and after spinal explanation, using a Numerical Visual Analog Anxiety Scale (NVAAS). A difference in post-explanation NVAAS score of 1.5 points between intervention and control groups was regarded as clinically significant. Patient satisfaction was assessed using the Maternal Satisfaction Scale for Cesarean Section (MSSCS). Results The mean (SD) age (31.5 (5.2) and 32.1 (5.4) years) and pre-explanation NVAAS score (4.2 (3.2) and 4.0 (3.0)) of the intervention and control groups respectively, showed no difference at baseline. The mean (SD) post-explanation decrease in NVAAS score was greater in the intervention- than in the control group (1.6 (3.5) versus .7 (2.3), P = .046, unadjusted mean difference .9 points (95% CI .02 to 1.8)). A linear regression model for the post-explanation NVAAS score showed that the intervention effect was significantly associated with the pre-explanation score (P = .002), adjusted for age and English fluency. Patients with pre-explanation NVAAS scores ³ 5 showed a statistically significant intervention effect. There was no significant difference in patient satisfaction between the intervention and control groups. The smartphone was an accessible and convenient display medium for the video. Ninety nine percent of patients exposed to the intervention would recommend watching the video prior to the procedure. Conclusion In this pilot study, lower NVAAS scores were observed in anxious patients, when a Xhosa information video was used to ameliorate challenges posed by a doctor-patient language barrier. It is easily implemented and demonstrates a novel use of mobile health technology. The study provides baseline data to inform sample size calculations for future studies. A high level of patient recommendation for the video suggests that this is an agreeable practice.
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    The association between perioperative risk factors and the method of anaesthesia, and maternal and neonatal outcomes following caesarean delivery in Africa: a sub-study of a 7-day prospective observational cohort study
    (2022) Gerber, Carmen; Biccard, Bruce; Dyer, Robert; Bishop, David
    Background Maternal and neonatal mortality is high in Africa. The African Surgical Outcomes Study found that maternal mortality following caesarean delivery in Africa is 50 times higher than in highincome countries, and independently associated with obstetric haemorrhage and anaesthesia complications. Methods A sub-study was conducted of a seven-day, international, prospective, observational cohort study of patients undergoing caesarean delivery in Africa. The aims were to determine the association between preoperative risk factors and the method of anaesthesia, and to examine the association between method of anaesthesia and i) pre- and post-delivery hypotension, ii) severe anaesthesia complications, iii) maternal mortality, and iv) neonatal mortality. In addition, the association was examined between pre-delivery intraoperative hypotension and neonatal outcomes. The primary outcomes were maternal and neonatal in-hospital mortality censored at 30 days. Secondary outcomes were a composite of four severe anaesthesia complications, the association between method of anaesthesia and intraoperative hypotension, and that between hypotension and neonatal outcomes. Findings 3709 patients who received spinal (2968, 80%) or general anaesthesia (GA) (741, 20%) were recruited from 183 hospitals in 22 African countries from February to May 2016. Maternal mortality was higher with GA than spinal anaesthesia (11/729, 1.5%, versus 9/2881, 0.3%, p = 0.001), as was neonatal mortality (65/662, 9.8% versus 73/2669, 2.7%, p < 0.001). Independent predictors of GA as the method for caesarean delivery included gestational age, American Society of Anaesthesiologists (ASA) category, emergency surgery, eclampsia, placenta praevia, placental abruption, and ruptured uterus. Spinal anaesthesia was administered to 48/94 (51.1%) patients with eclampsia, 12/28 (42.9%) with cardiac disease, 14/19 (73.7%) with preoperative sepsis, 48/76 (63.2%) with antepartum haemorrhage, 30/55 (54.5%) with placenta praevia, 33/78 (42.3%) with placental abruption and 12/29 (41.4%) with a ruptured uterus. There was no association between method of anaesthesia and intraoperative hypotension. There was no association between pre-delivery hypotension and neonatal mortality, cardiopulmonary resuscitation, or Apgar scores at 1 and 5 minutes. Conclusion Analysis of a large cohort of patients undergoing anaesthesia for caesarean delivery in Africa, showed that a larger proportion than in high-income countries received GA, and indicated which patients were more likely to require GA. GA was associated with maternal mortality, neonatal mortality, and severe anaesthesia complications. Spinal anaesthesia was often administered to patients with eclampsia or at high risk for obstetric haemorrhage. Focussed training in the principles of selection of method of anaesthesia, and specifically in the skills of safe GA, are recommended.
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    The prevalence of substance use in anaesthesia practitioners in South Africa
    (2020) van Der Westhuizen, Justine; Dyer, Robert; Nejthardt, Marcin
    Introduction: Substance abuse has twice the mortality in United States anaesthesia- than non-anaesthesia residents. Since no data exist, the primary objective of this cross-sectional study was to establish the prevalence of substance use in South African anaesthesia practitioners. Secondary objectives were to compare the prevalence in male and female practitioners, and in private- and state practice anaesthetists. Years of experience and level of training were explored as possible risk factors for hazardous or harmful use. Method: Participants completed a self-administered, validated WHO questionnaire, run for ten days surrounding the 2018 South African Society of Anaesthesiologists (SASA) congress. All doctors practicing anaesthesia in South Africa were eligible. Recruitment was via an email link sent to all SASA members, as well as a web-based link at the congress. Results: A total of 1961 SASA members and 113 non-members (anaesthesiologists, registrars and non-specialists) were invited to participate (total 2074). There were 434 responses (response rate 20.9%, margin of error 4.18%); 364 were suitable for analysis. The most commonly lifetime-used substances were alcohol (92.8%), tobacco (42.3%), cannabis (34.7%), and sedatives (34.4%). Questionnaire scores defined low-, medium- and high-risk categories according to substance use during the previous 3 months. Sedative (12.6%) and alcohol (12.1%) users were deemed to be at moderate risk. The prevalence of opioid use was 1.9% (n=7). Prevalence of substance use was similar in male and female practitioners, as well as in those working in private practice or in state hospitals. Conclusion: The prevalence of current use of alcohol and sedatives is of major concern. A significant proportion of respondents were assessed to be at moderate risk of hazardous or harmful substance use. Gender and practice setting have little impact on substance use. Wellness efforts should be aimed at all anaesthesia practitioners in South Africa.