The blood–brain barrier (BBB) is a dynamic barrier essential for central nervous system interstitial fluid separation from circulating blood. This dynamic separation ensures maintenance of neuronal microenvironment homeostasis against that of the everchanging in solutes and toxin concentration in circulating blood. The blood–brain barrier structure is complex, it has multiple contributors, such as specialised blood microvascular endothelium, neurons, astrocytes and pericytes. Transfer of essential nutrients to the brain and waste products from the brain to circulating blood is tightly regulated and facilitated by a large surface area and specialised transport systems. It is not only the physical characteristics of the barrier that assist in maintenance of neuronal microenvironment, biochemical substances and the high trans endothelial electrical resistance also play a major role. Circumventricular organs are those parts of the central nervous system lacking the blood–brain barrier. These are essential for optimum central nervous system interaction with circulating blood directly or using neurotransmitters. Primary or secondary central nervous system pathological states, such as infective and noninfective causes, directly or indirectly induce biochemical mediators that may disrupt and alter blood–brain barrier structure and function. Understanding of the blood–brain barrier anatomy and physiology assists in developing treatment methods to overcome degenerative and pathological states negatively affecting the central nervous system.

Open-heart surgery is the leading cause of neuronal injury in the perioperative state, with some patients complicating with cerebrovascular accidents and delirium. Neurological fallout places an immense burden on the psychological well-being of the person affected, their family, and the healthcare system. Several randomised control trials (RCTs) have attempted to identify therapeutic and interventional strategies that reduce the morbidity and mortality rate in patients that experience perioperative neurological complications. However, there is still no consensus on the best strategy that yields improved patient outcomes, such that standardised neuroprotection protocols do not exist in a significant number of anaesthesia departments. This review aims to discuss contemporary evidence for preventing and managing risk factors for neuronal injury, mechanisms of injury, and neuroprotection interventions that lead to improved patient outcomes. Furthermore, a summary of existing RCTs and large observational studies are examined to determine which strategies are supported by science and which lack definitive evidence. We have established that the overall evidence for pharmacological neuroprotection is weak. Most neuroprotective strategies are based on animal studies, which cannot be fully extrapolated to the human population, and there is still no consensus on the optimal neuroprotective strategies for patients undergoing cardiac surgery. Large multicenter studies using universal standardised neurological fallout definitions are still required to evaluate the beneficial effects of the existing neuroprotective techniques.

Background: Fasting guidelines in paediatric patients aim to prevent regurgitation and aspiration during anaesthesia. The European Society of Anaesthesiology and Intensive Care recommends a 2-h fasting period for carbohydrate-containing fluids. Aim: This study aimed to compare gastric residual volumes (GRVs) in children at three time intervals after preoperative consumption of an oral carbohydrate-rich drink (OCD). Setting: This study was conducted at Charlotte Maxeke Johannesburg Academic Hospital. Methods: This prospective, single-centre study was conducted from November 2023 to April 2024 and included paediatric patients aged 2–18 years undergoing elective orthopaedic procedures who adhered to fasting guidelines and consumed 3 mL/kg of an OCD. Gastric residual volume was assessed with ultrasound at baseline, 1- and 2-h intervals post-ingestion. Statistical analyses were performed to evaluate changes in GRV between children and the change in each child over time. Results: Thirty-three children were included in the study. The study found no significant differences in mean GRV across the three time points, with all values remaining below the safe aspiration threshold of 1.5 mL/kg. Qualitative assessments showed that GRV decreased below baseline levels by 2 h. One-third of patients reported thirst preoperatively, but none experienced intraoperative hypoglycaemia or postoperative nausea or vomiting. Conclusion: The consumption of a modest volume of an OCD up to 1 h before surgery did not significantly increase GRV in paediatric patients. Contribution: These findings support the safety of preoperative carbohydrate intake at 1 h preoperatively, aligning with recent guidelines that advocate for reduced fasting times to enhance patient outcomes.

Background. Coronavirus disease‐2019 (COVID‐19) is associated with a heightened inflammatory response, leading to thromboembolic events that influence patient outcomes. Complex anticoagulation strategies are often required to mitigate these complications. However, severe illness combined with such strategies may be associated with bleeding at multiple sites. Objectives. To describe the incidence of bleeding and venous thromboembolism (VTE) in critically ill COVID‐19 patients receiving anticoagulation. Secondary objectives were to determine the incidence of transfusion in bleeding patients, and the association between inflammatory markers, coagulation parameters, and bleeding and/or VTE. Length of intensive care unit (ICU) stay and patient outcomes in the same cohort were also investigated. Methods. Participants included adult patients with confirmed COVID‐19 by positive polymerase chain reaction (PCR), admitted to the ICU from 1 April 2020 to 30 April 2021. A p‐value of <0.05 was considered statistically significant. Results. The study population comprised 103 patients. The anticoagulant of choice was low‐molecular‐weight heparin at therapeutic doses (median 80 mg/day). Bleeding occurred in 39.8% (n=41) of patients, predominantly from the oral mucosa (20.4%; n=21) and the gastrointestinal tract (13.6%; n=14). Of the patients who bled, 46.3% (n=19) received blood transfusions. Two patients (1.9%) developed grade 1 deep vein thrombosis. The median length of ICU stay was 7 days. Survival dropped below 50% (n=51) after 10 days of admission, and 25% (n=25) of patients survived beyond 28 days. Overall mortality was high at 65.0% (n=67). Conclusion. COVID‐19‐positive critically ill patients receiving therapeutic anticoagulation exhibited an increased incidence of bleeding, accompanied by a high mortality rate.