This retrospective cohort study suggests that a small proportion of elective surgical patients may present with a full stomach despite the recommended duration of fasting. Further research is needed to establish the clinical implications of these findings in the elective setting. At present, the clinical role of gastric ultrasound continues to be for the evaluation of gastric contents to guide management when the risk of aspiration is uncertain or unknown.

Background: The physiological changes of pregnancy can increase the risk of peri-partum pulmonary aspiration. There is limited objective information regarding gastric volumes in pregnant patients. The aim of this cohort study was to characterise prospectively the range of gastric-fluid volume in term non-labouring pregnant patients compared with a historical cohort of non-pregnant females. Methods: Fasted non-labouring term pregnant patients scheduled for elective Caesarean delivery underwent a standardised gastric ultrasound examination. Gastric content was evaluated qualitatively (type of content), semiquantitatively (Perlas grades), and quantitatively (volume). The antral cross-sectional area and volume were compared with those of a retrospective cohort of non-pregnant females from the same institution. Descriptive statistics were used to describe the central tendency through mean and median values. Dispersion was evaluated with standard deviation and inter-quartile range, and the higher end of the distribution as 95th percentile. Results: Non-labouring pregnant (59) and non-pregnant (81) subjects were studied. The range of estimated total gastricfluid volume (P¼0.96) and volume per body weight (P¼0.78) was not significantly different between cohorts. An estimated volume of 115 ml (102e143) vs 136 ml (106e149) and volume per body weight of 1.4 ml kg À1 (1.2e2.8) vs 2.0 ml kg À1 (1.5e2.7) corresponded to the 95th percentile (95% confidence interval) values in the pregnant and non-pregnant cohort, respectively. Conclusions: Baseline gastric volume of non-labouring pregnant patients at term is not significantly different from that of non-pregnant females. This information will be helpful to interpreting findings of gastric point-of-care ultrasound in obstetric patients.

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Purpose of review This review focuses on the use of point-of-care ultrasound (PoCUS) in the obstetric context for airway management and assessment of aspiration risk, the placement of neuraxial blocks and the diagnosis and follow-up of cardiorespiratory dysfunction. Recent findings Gastric ultrasound is a useful aspiration risk assessment tool in pregnant patients. Total gastric fluid assessment models and specific cut-offs between high-risk and low-risk stomachs are presented. Airway assessment is useful to detect specific changes in pregnancy and to guide airway management. Handheld ultrasound devices with automated neuraxial landmark detection capabilities could facilitate needle placement in the future. Lung and cardiac ultrasonography is useful in the management of preeclampsia, pulmonary arterial hypertension and peripartum cardiomyopathy. Summary Owing to its noninvasiveness, ease of accessibility and lack of exposure to radiation, PoCUS plays an increasing and essential role in aspiration risk assessment, airway management, neuraxial anaesthesia and cardiorespiratory diagnosis and decision-making during pregnancy.

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