For pulmonary aspiration to occur, sufficient gastric content must be present in the stomach, the protective function of the lower oesophageal sphincter has to be overcome and upper airway reflexes must be suppressed or absent. The basal gastric secretion and acidity is not changed in pregnancy. Overall, the evidence indicates that there is a delay in gastric emptying of water in the first trimester compared with the nonpregnant state, but no difference with water or solids in the second and third trimesters of pregnancy. In patients scheduled for elective caesarean delivery, the pre-operative ingestion of a carbohydrate drink, as advocated as part of enhanced recovery after caesarean delivery, leads to no difference in the cross-sectional area of the gastric antrum. Further, the Sip Til Send approach has been found to be noninferior to standard fasting with regard to the cross-sectional area of the gastric antrum and results in beneficial patient reported effects. In women in labour without systemic opioids and without epidural analgesia, gastric emptying was delayed with water and solids, and it was slowed even more with water in the presence of systemic opioids. Importantly, the use of epidural analgesia in labour increased gastric emptying, but not to levels observed in the nonpregnant phase. Clear fluids are likely to be well tolerated in labour, but the intake of solid food remains a concern. In the postpartum period, relative to the nonpregnant state, no difference in gastric emptying with water has been shown. Gastric ultrasound can be performed with the indication, acquisition, interpretation and medical management (I-AIM) framework. The indications for gastric ultrasound in obstetrics include caesarean delivery under general anaesthesia. Once past the first trimester of pregnancy, acquisition involves the semirecumbent and right lateral semirecumbent positions and an awareness of the differences on gastric ultrasound between nonpregnant and pregnant women. The contents of the stomach can be interpreted with qualitative and quantitative evaluation. In qualitative examination, the Perlas system of grading may be used. In quantitative examination, using the threshold of 1.5 ml kg -1 , measurement of the gastric cross-sectional area as more than 608 mm 2 in the semirecumbent position, 719 mm 2 in the right lateral position and 960 mm 2 in the right lateral semirecumbent position suggest the presence of a full stomach. In elective caesarean delivery with general anaesthesia, the observation of high-risk gastric contents on ultrasound may influence obstetric anaesthetists to postpone the caesarean delivery or reconsider the anaesthetic technique should the indication for general anaesthesia be relative rather than absolute. If no high-risk stomach contents are seen on gastric ultrasound, this may influence obstetric anaesthetists in their choice of induction method: either a modified rapid sequence induction; a standard general anaesthetic induction; full rapid sequence induction and secure the airway with a supraglottic airway rather than tracheal tube. In elective and emergency caesarean deliveries, the information gained from gastric ultrasound might be useful in the setting of failed tracheal intubation.

Neonates and infants are among the most vulnerable populations to undergo procedures necessitating general anaesthesia and are at risk for postoperative neurological complications. The objective of this study was to assess the association between interventions for intra-operative physiologic instability and the development of postoperative neurological complications in a cohort of neonates and infants undergoing operative and nonoperative procedures.

The effect of flow-controlled ventilation (FCV) as compared with volume-controlled ventilation (VCV) on oxygenation and respiratory system mechanics in patients undergoing one-lung ventilation (OLV) is unknown.

Neuraxial anaesthesia is commonly used for caesarean delivery, but intra-operative sensations such as pain, pressure and touch remain frequent and may affect patient experience.

Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) are at risk for peri-operative complications, often linked to endothelial dysfunction. The Endothelial Activation and Stress Index (EASIX) has shown potential in predicting outcomes in various patient cohorts.

Liquid fasting durations often exceed current recommendations, resulting in patient discomfort.

Evidence-based peri-operative practices can deliver improved patient outcomes, but their benefits may be limited by obstacles to implementation into routine practice. A multicentre randomised controlled trial demonstrated a reduction in the incidence of moderate-severe acute kidney injury after cardiac surgery using a biomarker-guided renal care bundle, however these measures are not a routine part of clinical practice.

Processed electroencephalography is widely used to assess depth of anaesthesia and to titrate anaesthetics, thereby increasing the quality of recovery. However, the processed electroencephalogram is influenced by technical, patient, and anaesthetic factors. Adding information from the frontal real-time raw electroencephalogram may help to overcome these limitations.

The air-test, which involves reducing the fraction of inspiratory oxygen (FiO2) to 21% and monitoring pulse oximetry haemoglobin saturation (SpO2), has previously been used to guide intra-operative ventilation strategies. However, it is unclear how often the air-test is positive (defined as an SpO2 decrease below 97% during ventilation with an FiO2 of 21%) in general surgery patients, and if a positive air-test is associated with the development of postoperative pulmonary complications (PPCs).