| 1. |
- Karlsson, Adam, et al.
(författare)
-
Predicting mortality among septic patients presenting to the emergency department-a cross sectional analysis using machine learning
- 2021
-
Ingår i: BMC Emergency Medicine. - : BioMed Central. - 1471-227X. ; 21:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Sepsis is a life-threatening condition, causing almost one fifth of all deaths worldwide. The aim of the current study was to identify variables predictive of 7- and 30-day mortality among variables reflective of the presentation of septic patients arriving to the emergency department (ED) using machine learning.Methods: Retrospective cross-sectional design, including all patients arriving to the ED at Sodersjukhuset in Sweden during 2013 and discharged with an International Classification of Diseases (ICD)-10 code corresponding to sepsis. All predictions were made using a Balanced Random Forest Classifier and 91 variables reflecting ED presentation. An exhaustive search was used to remove unnecessary variables in the final model. A 10-fold cross validation was performed and the accuracy was described using the mean value of the following: AUC, sensitivity, specificity, PPV, NPV, positive LR and negative LR.Results: The study population included 445 septic patients, randomised to a training (n = 356, 80%) and a validation set (n = 89, 20%). The six most important variables for predicting 7-day mortality were: "fever", "abnormal verbal response", "low saturation", "arrival by emergency medical services (EMS)", "abnormal behaviour or level of consciousness" and "chills". The model including these variables had an AUC of 0.83 (95% CI: 0.80-0.86). The final model predicting 30-day mortality used similar six variables, however, including "breathing difficulties" instead of "abnormal behaviour or level of consciousness". This model achieved an AUC = 0.80 (CI 95%, 0.78-0.82).Conclusions: The results suggest that six specific variables were predictive of 7- and 30-day mortality with good accuracy which suggests that these symptoms, observations and mode of arrival may be important components to include along with vital signs in a future prediction tool of mortality among septic patients presenting to the ED. In addition, the Random Forests appears to be a suitable machine learning method on which to build future studies.
|
|
| 2. |
- Stassen, Willem, et al.
(författare)
-
A Prehospital Randomised Controlled Trial in South Africa : Challenges and Lessons Learnt
- 2019
-
Ingår i: African Journal of Emergency Medicine. - : Elsevier. - 2211-419X. ; 9:3, s. 145-149
-
Tidskriftsartikel (refereegranskat)abstract
- The incidence of cardiovascular disease and STEMI is on the rise in sub-Saharan Africa. Timely treatment is essential to reduce mortality. Internationally, prehospital 12 lead ECG telemetry has been proposed to reduce time to reperfusion. Its value in South Africa has not been established. The aim of this study was to determine the effect of prehospital 12 lead ECG telemetry on the PCI-times of STEMI patients in South Africa. A multicentre randomised controlled trial was attempted among adult patients with prehospital 12 lead ECG evidence of STEMI. Due to poor enrolment and small sample sizes, meaningful analyses could not be made. The challenges and lessons learnt from this attempt at Africa's first prehospital RCT are discussed. Challenges associated with conducting this RCT related to the healthcare landscape, resources, training of paramedics, rollout and randomisation, technology, consent and research culture. High quality evidence to guide prehospital emergency care practice is lacking both in Africa and the rest of the world. This is likely due to the difficulties with performing prehospital clinical trials. Every trial will be unique to the test intervention and setting of each study, but by considering some of the challenges and lessons learnt in the attempt at this trial, future studies might experience less difficulty. This may lead to a stronger evidence-base for prehospital emergency care.
|
|
| 3. |
- Stassen, Willem, et al.
(författare)
-
A Retrospective Geospatial Simulation Study of Helicopter Emergency Medical Services' Potential Time Benefit Over Ground Ambulance Transport in Northern South Africa.
- 2023
-
Ingår i: Air Medical Journal. - : Elsevier. - 1067-991X .- 1532-6497. ; 42:6, s. 440-444
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: One of the most important benefits of helicopter emergency medical services (HEMS) is a time benefit, either through expedited access to the casualty or a reduction in the transport time to definitive care. However, HEMS utilization does not come without risk to the public and crew or at an insignificant cost. Cost is an essential consideration for health policy decisions, especially in low- to middle-income countries, such as South Africa. The aim of this study was to determine whether there is a time benefit of HEMS dispatch in South Africa compared with simulated driving time. A secondary aim was to determine the distance from the incident site to the hospital at which a time benefit can be guaranteed.METHODS: A retrospective study was undertaken by comparing the prehospital times of patients who underwent HEMS transportation with simulated ground emergency medical services (GEMS) transportation times. Handwritten patient records of actual flights were reviewed and analyzed. The actual flight times recorded were used to calculate the helicopter transport time, activation to scene time, scene time, and scene to hospital time. Times were assigned based on a nonsimultaneous dispatch model, as is used in South Africa. For each helicopter mission, Google Maps (Google Inc, Mountain View, CA) was used to simulate the fastest ground route from the same location of the incident to the same receiving hospital corrected for typical traffic trends. The actual HEMS and simulated GEMS times were compared using the paired t-test. Linear regression analysis was performed to determine a minimum driving distance at which HEMS provides a time benefit.RESULTS: A total of 118 HEMS transports were analyzed, the majority of which were trauma related (n = 115, 97%). HEMS transport resulted in a mean time deficit of -15 minutes (95% confidence interval, -18 to -11; P < .05) compared with simulated GEMS drive times. After regression, HEMS transport provides a time benefit at a driving distance greater than 119 km.CONCLUSION: The current study demonstrated that there was rarely a time benefit for actual primary emergency responses when HEMS was used compared with simulated driving time of GEMS transport. Using a nonsimultaneous dispatch model, a time benefit only occurs when the driving distance from the incident site to the hospital is greater than 119 km. There is an urgent need to critically evaluate HEMS utilization in the South African context.
|
|
| 4. |
- Stassen, Willem, et al.
(författare)
-
Barriers and facilitators to implementing coronary care networks in South Africa : a qualitative study
- 2020
-
Ingår i: African Health Sciences. - : NISC - National Inquiry Services Centre. - 1680-6905 .- 1729-0503. ; 20:1, s. 338-350
-
Tidskriftsartikel (refereegranskat)abstract
- Background: ST-elevation myocardial infarction (STEMI) is on the rise in sub-Saharan Africa. South Africa consistently fails to deliver timely reperfusion to these patients, possibly due to under-developed coronary care networks (CCN).Objectives: To determine the current perceived state of CCNs, to determine the barriers to optimising CCNs and to suggest facilitators to optimising CCNs within the South African context.Methods: A qualitative descriptive approach was employed, by performing two structured in-depth and two focus group interviews (n=4 and 5, respectively), inviting a purposely heterogeneous sample of 11 paramedics (n=4), doctors (n=5), and nurses (n=2) working within different settings in South African CCNs. Recorded interviews were transcribed verbatim and subjected to content analysis.Results: Participants described an under-resourced, unprioritised and fragmented CCN with significant variation in performance. Barriers to CCN optimisation resided in recognition and diagnosis of STEMI, transport and treatment decisions, and delays. Participants suggested that thrombolysing all STEMI patients could facilitate earlier reperfusion and that pre-hospital thrombolysis should be considered. Participants highlighted the need for regionalised STEMI guidelines, and the need for further research.Conclusion: Numerous barriers were highlighted. Healthcare policy-makers should prioritise the development of CCNs that is underpinned by evidence and that is contextualised to each specific region within the South African health care system.
|
|
| 5. |
- Stassen, Willem
(författare)
-
Coronary care networks in the resource-limited setting : systems of care in South Africa
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND: Owing to an epidemiological transition observed throughout Sub- Saharan Africa, South Africa is experiencing an increase in the incidence of myocardial infarction. ST-elevation myocardial infarction (STEMI) occurs commonly in South Africa and at much younger ages than observed elsewhere in the world. Emergent treatment in the form of coronary reperfusion is required to reduce morbidity and mortality following STEMI. Political and socio-economic factors have led to large disparities in emergency healthcare access for many South Africans. Well organised networks of care (coronary care networks, CCNs) that seamlessly integrate prehospital care, in-hospital assessment and percutaneous coronary intervention is recommended to reduce mortality for these patients. CCNs are underdeveloped and under-studied in South Africa. To this end, the aims of this project was to examine the current state of Coronary Care Networks in South Africa, a low- to middle income country and to provide recommendations for future development of such networks. METHODS: This project was comprised of four studies. Study I was a cross-sectional descriptive study that aimed at determining the current PCI-capable facilities in South Africa and sought correlations between the resources, population, poverty and insurance status using Spearman’s Rho. Study II utilised proximity analysis to determine the average drive times of South African municipal wards (geopolitical subdivisions used for electoral purposes) to the closest PCI-capable facility for each South African province. It further determined the proportion of South Africans living within one and two hours respectively, from such a facility. Study III combined data obtained from Studies I and II with network optimisation modelling to propose an optimised reperfusion strategy for patients with STEMI, based on proximity, using the North West province as a case study. Finally, Study IV employed qualitative methodology to determine the barriers and facilitators to developing CCNs in South Africa by performing interviews with individuals working with the South African contexts of coronary care. RESULTS: South Africa has 62 PCI-capable facilities, with most PCI-facilities (n=48; 77%) owned by the private healthcare sector. A disparity exists between the number of private and state-owned PCI-facilities when compared to the poverty (r=0.01; p=0.17) and insurance status of individuals (r=-0.4; p=0.27) (Study I). This means that reperfusion by PCI is likely inaccessible to many despite approximately, 53.8% and 71.53% of the South African population living within 60 and 120 minutes of a PCI facility (Study II). Yet, we provide an efficient and swift model that provides a recommendation for the best reperfusion strategy even in the instance of a large amount of ward data with these additional constraints. This model can be run in realtime and can guide reperfusion decisions at the bedside or form the basis of regional reperfusion guidelines, and CCN development priorities (Study III). When considering the local CCN, we found an under-resourced CCN that is not prioritised by policymakers and displays considerable variation in performance based on time of day and geographic locale. Specific barriers to the development of CCNs in South Africa included poor recognition and diagnosis of STEMI, inappropriate transport and treatment decisions, and delays. Facilitators to the development of CCNs were regionalised STEMI treatment guidelines, further research and prehospital thrombolysis programmes (Study IV). CONCLUSION: South Africa has a shortage of PCI facilities. Even in areas with high concentrations of PCI facilities. In addition, many patients may not be able to access care due to socio-economic status. When considering proximity alone, most South Africans are able to access PCI within guideline timeframes. Despite this, prehospital thrombolysis should still be considered in some areas – as demonstrated by a novel approach that combines geospatial analysis and network optimisation modelling. This approach is able to efficiently determine the optimum reperfusion strategy for each geographic locale of South Africa. Current CCNs in South Africa are under-resourced, over-burdened and not prioritised. Future efforts should aim at improving STEMI recognition and diagnosis to decrease delays to reperfusion. The findings described should be considered and integrated into a future model of CCNs within South Africa, towards improving reperfusion times and finally morbidity and mortality.
|
|
| 6. |
- Stassen, Willem, et al.
(författare)
-
Helicopter Emergency Medical Services in Trauma Does Not Influence Mortality in South Africa
- 2020
-
Ingår i: Air Medical Journal. - : Elsevier. - 1067-991X .- 1532-6497. ; 39:6, s. 479-483
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Sub-Saharan Africa carries a large trauma burden. Helicopter emergency medical services (HEMS) have been suggested to reduce prehospital time and mortality. It is not clear whether HEMS infers a mortality benefit over ground transport in South Africa. This study aimed to determine whether HEMS improved 30-day mortality over ground emergency medical services (GEMS).METHODS: A retrospective, case-control study was undertaken for major trauma patients transported to a private trauma center in Johannesburg. A 1-year cohort of HEMS patients was extracted and matched to GEMS patients based on mechanism, injury severity or percentage of the total body surface area burned, age, sex, and comorbidities. The odds ratio (OR) for 30-day mortality was calculated to determine the risk of death.RESULTS: A total of 822 cases (HEMS: 272 [33%], GEMS: 550 [67%]) were reviewed. We included 410 patients in the matched cohort with equal distribution between transportation modes. The OR for mortality in the total cohort was 2.69 (95% confidence interval, 1.6-4.6; P = .003) for HEMS patients, whereas in the matched cohort the OR was 1.35 (95% confidence interval, 0.5-3.4; P = .503) for patients transported by HEMS.CONCLUSION: In a matched cohort of major trauma patients, HEMS does not seem to improve mortality over GEMS. These results might reflect the South African HEMS dispatch model.
|
|
| 7. |
- Stassen, Willem, et al.
(författare)
-
Telephonic description of sepsis among callers to an emergency dispatch centre in South Africa
- 2020
-
Ingår i: African Journal of Emergency Medicine. - : Elsevier. - 2211-419X. ; 10:2, s. 64-67
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Sepsis is an acute, life-threatening condition caused by a dysregulated systemic response to infection. Early medical intervention such as antibiotics and fluid resuscitation can be life-saving. Diagnosis or suspicion of sepsis by an emergency call-taker could potentially improve patient outcome. Therefore, the aim was to determine the keywords used by callers to describe septic patients in South Africa when calling a national private emergency dispatch centre.Methods: A retrospective review of prehospital patient records was completed to identify patients with sepsis in the prehospital environment. A mixed-methods design was employed in two-sequential phases. The first phase was qualitative. Thirty cases of sepsis were randomly selected, and the original call recording was extracted. These recordings were transcribed verbatim and subjected to content analysis to determine keywords of signs and symptoms telephonically. Once keywords were identified, an additional sample of sepsis cases that met inclusion and exclusion criteria were extracted and listened to. The frequency of each of the keywords was quantified.Results: Eleven distinct categories were identified. The most prevalent categories that were used to describe sepsis telephonically were: gastrointestinal symptoms (40%), acute altered mental status (35%), weakness of the legs (33%) and malaise (31%). At least one of these four categories of keywords appeared in 86% of all call recordings.Conclusion: It was found that certain categories appeared in higher frequencies than others so that a pattern could be recognised. Utilising these categories, telephonic recognition algorithms for sepsis could be developed to aid in predicting sepsis over the phone. This would allow for dispatching of the correct level of care immediately and could subsequently have positive effects on patient outcome.
|
|
| 8. |
- Stassen, Willem, et al.
(författare)
-
The application of optimisation modelling and geospatial analysis to propose a coronary care network model for patients with ST-elevation myocardial infarction
- 2020
-
Ingår i: African Journal of Emergency Medicine. - : Elsevier BV. - 2211-419X. ; 10:Suppl 1, s. S18-S22
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe incidence of myocardial infarction is increasing in South Africa. Prompt treatment is indicated to reduce mortality. One way of expediting treatment is to set up regional referral recommendations that can guide prehospital providers on the best reperfusion strategy for a particular patient. A coronary care network model for patients who present with ST-elevation myocardial infarction is proposed, using the North West province, of South Africa as a case study.MethodsGeospatial analysis with network optimisation modelling was applied, to determine which strategy (prehospital thrombolysis, in-hospital thrombolysis or percutaneous coronary intervention) was most appropriate for patients presenting within each of the municipal wards of the North West province.ResultsAn efficient and swift recommendation for the optimal reperfusion strategy is obtained using the current model, even in the instance of a large amount of ward data with additional constraints. For most municipal wards (204, 53%) percutaneous coronary intervention is the preferred reperfusion strategy based on proximity. For the remainder of the wards prehospital (138, 36%) or in-hospital (44, 11%) thrombolysis is recommended.ConclusionA scalable and efficient method of determining the optimal reperfusion strategy for a patient presenting with ST-elevation myocardial infarction in the North West province, is presented. This approach can serve as a model which can be applied to other settings and can form the basis of regional coronary care network development priorities and resource allocations.
|
|
