Hypotension during spinal anaesthesia for Caesarean section in a resource limited setting: towards a consensus definition

Background: Intraoperative hypotension following spinal anaesthesia for Caesarean section is associated with maternal morbidity and mortality. Because of inconsistent definitions the reported incidence of hypotension varies between 7% and 74%, making it almost impossible to set standard targets. Developing and adopting a clinically significant threshold for intraoperative hypotension will allow for benchmarking, comparison between studies, and consistency in guidelines and recommendations. Methods: Common definitions for spinal hypotension were first identified from a recent systematic review of the literature and a consensus statement on spinal hypotension. These definitions were applied to haemodynamic data taken from a prospective interventional obstetric spinal hypotension study conducted at Edendale Hospital, to determine the incidence of hypotension when applying these different thresholds. Finally, a definition was proposed based on these incidences and a review of the relevant literature. Results: Fifteen different definitions were identified. These were then applied to the study population with a resultant incidence of hypotension ranging from 15.8% to 91.4%. Based on a literature review of obstetric and other relevant perioperative and critical care medicine, targeting a mean arterial pressure > 70 mmHg and systolic blood pressure > 100 mmHg is recommended, and it is proposed that the lowest absolute values at which vasopressor therapy should be initiated are a mean arterial blood pressure < 65 mmHg or systolic blood pressure < 90 mmHg. Optimally, practitioners should maintain systolic blood pressure at greater than 90% of the baseline pre-spinal anaesthesia value. Conclusion: This study confirmed a wide variation in the incidence of obstetric spinal hypotension in a South African setting, depending on the definition used. An absolute threshold for intervention with vasopressor and an optimal target relative to baseline blood pressure are suggested. Further work is required to establish the effect of the adherence to these recommendations on important maternal and foetal outcomes

Preoperative anaemia and clinical outcomes in the South African surgical outcomes study

Background.In high-income countries, preoperative anaemia has been associated with poor postoperative outcomes. To date, no large study has investigated this association in South Africa (SA). The demographics of SA surgical patients differ from those of surgical patients in the European and Northern American settings from which the preoperative anaemia data were derived. These associations between preoperative anaemia and postoperative outcomes are therefore not necessarily transferable to SA surgical patients.Objectives. The primary objective was to determine the association between preoperative anaemia and in-hospital mortality in SA adult non-cardiac, non-obstetric patients. The secondary objectives were to describe the association between preoperative anaemia and (i) critical care admission and (ii) length of hospital stay, and the prevalence of preoperative anaemia in adult SA surgical patients.Methods. We performed a secondary analysis of the South African Surgical Outcomes Study (SASOS), a large prospective observational study of patients undergoing inpatient non-cardiac, non-obstetric surgery at 50 hospitals across SA over a 1-week period. To determine whether preoperative anaemia is independently associated with mortality or admission to critical care following surgery, we conducted a multivariate logistic regression analysis that included all the independent predictors of mortality and admission to critical care identified in the original SASOS model.Results. The prevalence of preoperative anaemia was 1 727/3 610 (47.8%). Preoperative anaemia was independently associated with in-hospital mortality (odds ratio (OR) 1.657, 95% confidence interval (CI) 1.055 - 2.602; p=0.028) and admission to critical care (OR 1.487, 95% CI 1.081 - 2.046; p=0.015).Conclusions. Almost 50% of patients undergoing surgery at government-funded hospitals in SA had preoperative anaemia, which was independently associated with postoperative mortality and critical care admission. These numbers indicate a significant perioperative risk, with a clear need for quality improvement programmes that may improve surgical outcomes. Long waiting lists for elective surgery allow time for assessment and correction of anaemia preoperatively. With a high proportion of patients presenting for urgent or emergency surgery, perioperative clinicians in all specialties should educate themselves in the principles of patient blood management

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 stepped-wedge 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 perioperative outcomes 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