Preoperative testing and medical therapy intervention to improve perioperative outcomes in noncardiac surgical patients.

Introduction: Cardiovascular disease is the leading cause of death worldwide and a growing concern in low-and-middle income countries, including those in Africa. Patients with cardiovascular disease often have poorly managed chronic conditions in the African setting, which impacts their outcome when they present for non-cardiac surgery. This cohort has an increased risk of perioperative cardiovascular complications. This series of studies explored evidence-based perioperative cardiovascular management strategies in patients with high-risk cardiac comorbidities presenting for non-cardiac surgery. Methods: This was achieved through five objectives which formed five separate but interconnected research studies. The first objective was to study the approach of natriuretic peptide-directed medical therapy in non-surgical patients to inform development of a preoperative protocol in surgical patients through a systematic review. The second objective was to conduct systematic review on exercise therapy in nonsurgical patients to inform development of a preoperative protocol in surgical patients. The third objective was to define the population who would need optimisation before surgery in the Western Cape, South Africa through a prospective observational study of risk stratification. The fourth objective was to explore the broader applicability of perioperative cardiovascular management of high-risk patients by examining cardiovascular outcomes after surgery on the African continent (a sub-study of a larger African cohort study). The fifth objective was to produce national guidelines on cardiovascular risk stratification in a South African and African surgical population. Main results: The systematic reviews showed potential utility for exercise therapy in the optimisation of cardiac patients for non-cardiac surgery. Medical therapy optimisation guided by natriuretic peptide testing did not demonstrate a consistent reduction in natriuretic peptides, but did support a potential mortality benefit in non-surgical patients. The cohort of cardiac patients presenting for non-cardiac surgery in the Western Cape carries significant cardiac risk and needs perioperative cardiovascular management. This was confirmed by the rate of adverse cardiovascular outcomes reported on the African continent. These data supported the development of context-specific national cardiovascular risk stratification guidelines. Conclusion: The cardiovascular burden and risk for perioperative cardiovascular complications presents a challenge in low- and middle-income countries like South Africa, and more broadly Africa. This is a growing phenomenon which needs the collaborative effort of perioperative physicians and the implementation of evidence-based strategies in perioperative cardiovascular management

Natriuretic peptide-directed medical therapy: a systematic review

Abstract Natriuretic peptides (NP) are strongly associated with perioperative cardiovascular events. However, in patients with raised NP, it remains unknown whether treatment to reduce NP levels prior to surgery results in better perioperative outcomes. In this systematic review and meta-analysis, we investigate NP-directed medical therapy in non-surgical patients to provide guidance for NP-directed medical therapy in surgical patients. The protocol was registered with PROSPERO (CRD42017051468). The database search included MEDLINE (PubMed), CINAHL (EBSCO host), EMBASE (EBSCO host), ProQuest, Web of Science, and Cochrane database. The primary outcome was to determine whether NP-directed medical therapy is effective in reducing NP levels within 6 months, compared to standard of care. The secondary outcome was to determine whether reducing NP levels is associated with decreased mortality. Full texts of 18 trials were reviewed. NP-directed medical therapy showed no significant difference compared to standard care in decreasing NP levels (standardized mean difference − 0.04 (− 0.16, 0.07)), but was associated with a 6-month (relative risk (RR) 0.82 (95% confidence interval (CI) 0.68–0.99)) reduction in mortality

The role of cardiac rehabilitation using exercise to decrease natriuretic peptide levels in non-surgical patients: a systematic review

Abstract Exercise is recommended in patients with cardiac failure. In the perioperative patient, exercise is also gaining popularity as a form of prehabilitation. In this meta-analysis, we examine if exercise is able to reduce natriuretic peptide levels. Natriuretic peptide (NP) has strong prognostic ability in identifying patients who will develop adverse postoperative cardiovascular outcomes. The protocol was registered with PROSPERO (CRD42017051468). The database search included MEDLINE (PubMed), CINAHL (EBSCO host), EMBASE (EBSCO host), ProQuest, Web of Science, and Cochrane database. The primary outcomes were to determine whether exercise therapy was effective in reducing NP levels as compared to control group, the shortest time period required to reduce NP levels after exercise therapy, and whether reducing NP levels decreased morbidity and mortality. Full texts of 16 trials were retrieved for this review. Exercise therapy showed a significant reduction in natriuretic peptide levels between the intervention and control groups (SMD − 0.45, 95% CI − 0.88 to − 0.03) with significant heterogeneity between the included trials. This was also shown in the within a 12-week period

National priorities for perioperative research in South Africa

BACKGROUND. Perioperative research is currently unco-ordinated in South Africa (SA), with no clear research agenda. OBJECTIVE. To determine the top ten national research priorities for perioperative research in SA. METHODS. A Delphi technique was used to establish consensus on the top ten research priorities. RESULTS. The top ten research priorities were as follows: (i) establishment of a national database of (a) critical care outcomes, and (b) critical care resources; (ii) a randomised controlled trial of preoperative B-type natriuretic peptide-guided medical therapy to decrease major adverse cardiac events following non-cardiac surgery; (iii) a national prospective observational study of the outcomes associated with paediatric surgical cases; (iv) a national observational study of maternal and fetal outcomes following operative delivery in SA; (v) a steppedwedge trial of an enhanced recovery after surgery programme for (a) surgery, (b) obstetrics, (c) emergency surgery, and (d) trauma surgery; (vi) a stepped-wedge trial of a surgical safety checklist on patient outcomes in SA; (vii) a prospective observational study of perioperativeoutcomes after surgery in district general hospitals in SA; (viii) short-course interventions to improve anaesthetic skills in rural doctors; (ix) studies of the efficacy of simulation training to improve (a) patient outcomes, (b) team dynamics, and (c) leadership; and (x) development and validation of a risk stratification tool for SA surgery based on the South African Surgical Outcomes Study (SASOS) data. CONCLUSIONS. These research priorities provide the structure for an intermediate-term research agenda.The workshop was funded by the Discipline of Anaesthesiology and Critical Care, University of KwaZulu-Natal.http://www.samj.org.zaam2016Anaesthesiolog

An evaluation of severe anesthetic-related critical incidents and risks from the South African paediatric surgical outcomes study : a 14-day prospective, observational cohort study of pediatric surgical patients

SUPPLEMENTARY MATERIAL 1 : The South African Paediatric Surgical Outcomes Study (SAPSOS): A 14-day prospective, observational cohort study of paediatric surgical patients.SUPPLEMENTARY MATERIAL 2 : South African Paediatric Surgical Outcomes Study (SAPSOS) : Operating Room case record form.SUPPLEMENTARY MATERIAL 3 : Supplemental Tables and Figures.BACKGROUND : Severe anesthetic-related critical incident (SARCI) monitoring is an essential component of safe, quality anesthetic care. Predominantly retrospective data from low- and middle-income countries (LMICs) report higher incidence but similar types of SARCI compared to high-income countries (HIC). The aim of our study was to describe the baseline incidence of SARCI in a middle-income country (MIC) and to identify associated risk for SARCI. We hypothesized a higher incidence but similar types of SARCI and risks compared to HICs. METHODS : We performed a 14-day, prospective multicenter observational cohort study of pediatric patients (aged <16 years) undergoing surgery in government-funded hospitals in South Africa, a MIC, to determine perioperative outcomes. This analysis described the incidence and types of SARCI and associated perioperative cardiac arrests (POCAs). We used multivariable logistic regression analysis to identify risk factors independently associated with SARCI, including 7 a priori variables and additional candidate variables based on their univariable performance. RESULTS : Two thousand and twenty-four patients were recruited from May 22 to August 22, 2017, at 43 hospitals. The mean age was 5.9 years (±standard deviation 4.2). A majority of patients during this 14-day period were American Society of Anesthesiologists (ASA) physical status I (66.4%) or presenting for minor surgery (54.9%). A specialist anesthesiologist managed 59% of cases. These patients were found to be significantly younger (P < .001) and had higher ASA physical status (P < .001). A total of 426 SARCI was documented in 322 of 2024 patients, an overall incidence of 15.9% (95% confidence interval [CI], 14.4–17.6). The most common event was respiratory (214 of 426; 50.2%) with an incidence of 8.5% (95% CI, 7.4–9.8). Six children (0.3%; 95% CI, 0.1–0.6) had a POCA, of whom 4 died in hospital. Risks independently associated with a SARCI were age (adjusted odds ratio [aOR] = 0.95; CI, 0.92–0.98; P = .004), increasing ASA physical status (aOR = 1.85, 1,74, and 2.73 for ASA II, ASA III, and ASA IV–V physical status, respectively), urgent/emergent surgery (aOR = 1.35, 95% CI, 1.02–1.78; P = .036), preoperative respiratory infection (aOR = 2.47, 95% CI, 1.64–3.73; P < .001), chronic respiratory comorbidity (aOR = 1.75, 95% CI, 1.10–2.79; P = .018), severity of surgery (intermediate surgery aOR = 1.84, 95% CI, 1.39–2.45; P < .001), and level of hospital (first-level hospitals aOR = 2.81, 95% CI, 1.60–4.93; P < .001). CONCLUSIONS : The incidence of SARCI in South Africa was 3 times greater than in HICs, and an associated POCA was 10 times more common. The risk factors associated with SARCI may assist with targeted interventions to improve safety and to triage children to the optimal level of care.The Jan Pretorius Research Fund, South African Society of Anaesthesiologists; Discipline of Anaesthesiology and Critical Care, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal; Department of Anaesthesia and Perioperative Medicine, Groote Schuur Hospital and University of Cape Town; Department of Anaesthesia, University of the Witwatersrand; and Paediatric Anaesthesia Community of South Africa.https://journals.lww.com/anesthesia-analgesia/pages/default.aspxhj2023Anaesthesiolog

Development of a clinical prediction model for in-hospital mortality from the South African cohort of the African surgical outcomes study

BACKGROUND : Data on the factors that influence mortality after surgery in South Africa are scarce, and neither these data nor data on risk-adjusted in-hospital mortality after surgery are routinely collected. Predictors related to the context or setting of surgical care delivery may also provide insight into variation in practice. Variation must be addressed when planning for improvement of risk-adjusted outcomes. Our objective was to identify the factors predicting in-hospital mortality after surgery in South Africa from available data. METHODS : A multivariable logistic regression model was developed to identify predictors of 30-day in-hospital mortality in surgical patients in South Africa. Data from the South African contribution to the African Surgical Outcomes Study were used and included 3800 cases from 51 hospitals. A forward stepwise regression technique was then employed to select for possible predictors prior to model specification. Model performance was evaluated by assessing calibration and discrimination. The South African Surgical Outcomes Study cohort was used to validate the model. RESULTS : Variables found to predict 30-day in-hospital mortality were age, American Society of Anesthesiologists Physical Status category, urgent or emergent surgery, major surgery, and gastrointestinal-, head and neck-, thoracic- and neurosurgery. The area under the receiver operating curve or c-statistic was 0.859 (95% confidence interval: 0.827–0.892) for the full model. Calibration, as assessed using a calibration plot, was acceptable. Performance was similar in the validation cohort as compared to the derivation cohort. CONCLUSION : The prediction model did not include factors that can explain how the context of care influences post-operative mortality in South Africa. It does, however, provide a basis for reporting risk-adjusted perioperative mortality rate in the future, and identifies the types of surgery to be prioritised in quality improvement projects at a local or national level.http://link.springer.com/journal/268hj2022AnaesthesiologyMaxillo-Facial and Oral SurgerySurger

Methemoglobin as a marker of acute anemic stress in cardiac surgery

Summary: Biological evidence supports plasma methemoglobin as a biomarker for anemia-induced tissue hypoxia. In this translational planned substudy of the multinational randomized controlled transfusion thresholds in cardiac surgery (TRICS-III) trial, which included adults undergoing cardiac surgery requiring cardiopulmonary bypass with a moderate-to-high risk of death, we investigated the relationship between perioperative hemoglobin concentration (Hb) and methemoglobin; and evaluated its association with postoperative outcomes. The primary endpoint was a composite of death, myocardial infarction, stroke, and severe acute kidney injury at 28 days. We observe weak non-linear associations between decreasing Hb and increasing methemoglobin, which were strongest in magnitude at the post-surgical time point. Increased levels of post-surgical methemoglobin were associated with a trend toward an elevated risk for stroke and exploratory neurological outcomes. Our generalizable study demonstrates post-surgical methemoglobin may be a marker of anemia-induced organ injury/dysfunction, and may have utility for guiding personalized approaches to anemia management. Clinicaltrials.gov registration NCT02042898

The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

Background: The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications. Methods: ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery. Results: The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784. Conclusions: This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance. © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.Medical Research Council of South Africa gran