Gastric point-of-care ultrasound (PoCUS) during pregnancy and the postpartum period: a systematic review

Anesthesia for reproductive healthcare from start to finish: a narrative review

Assisted reproductive techniques, second-trimester abortions, and postpartum tubal sterilizations present anesthesia care teams with unique challenges. These highly time-sensitive procedures have unique physiologic, pharmacologic, and psychosocial considerations. A lack of relevant consensus guidelines on anesthesia care exists to address many of these procedure-specific challenges. Additionally, legal restrictions can limit trainee access to learning opportunities in some geographical areas. The review outlines anesthetic considerations and management for patients undergoing assisted reproductive procedures, second trimester abortions, and postpartum tubal sterilizations. We detail unique barriers and psychosocial considerations and offer suggestions to aid anesthesia care providers in providing safe and compassionate reproductive care.

Point-of-care ultrasound in obstetric anesthesia clinical practice

PURPOSE OF THE REVIEW

Point-of-care ultrasound (POCUS) is increasingly recognized as a valuable tool in obstetric anesthesia. This review synthesizes key studies and reviews published within the last 2 years on its application in clinical practice with relevant supporting literature.

RECENT FINDINGS

Handheld ultrasound-assisted neuraxial block placement modestly reduces periprocedure time compared with landmark-based techniques. Devices with integrated three-dimensional or artificial intelligence-guided software may improve first-attempt success, particularly in obese patients. Focused cardiac ultrasound has gained interest as a potential tool for predicting postspinal hypotension through predelivery inferior vena cava collapsibility assessment. POCUS is also valuable for evaluating shock and cardiovascular compromise, aiding in the diagnosis and clinical management of amniotic fluid embolism and maternal cardiomyopathy. Gastric ultrasound can be performed qualitatively, aids aspiration risk assessment, and can be used in studies evaluating drug effects on gastric contents and antral cross-sectional area. Robust training programs are essential to equip obstetric anesthesiologists with sustainable POCUS skill sets.

SUMMARY

POCUS is associated with reduced neuraxial block placement times, provides critical hemodynamic data in patients with amniotic fluid embolism and cardiomyopathy, and allows gastric content evaluation for aspiration risk assessment. Expanding structured training and research is crucial to maximizing its clinical utility.

Gastric POCUS, an emergent tool in the assessment of perioperative fasting: Narrative review

Pulmonary aspiration during anaesthesia induction is a serious adverse event that can lead to catastrophic consequences for the patient, including death. Preoperative fasting has so been assessed on the basis of the clinical history and fasting schedules recommended by clinical guidelines. This assessment is not objective, since the presence or absence of gastric contents cannot be guaranteed. Gastric point of care ultrasound (POCUS) is an objective, simple, and rapid method for assessing fasting prior to anaesthesia induction that stratifies risk and aids in decision-making. The aim of this review is to summarize the existing literature on gastric POCUS in the assessment of preoperative fasting. For this purpose, the Pubmed and Embase were searched for relevant studies published between 2014 and 2024.

Glucagon-like peptide-1 receptor agonists in peri-operative care: Dispelling myths and unveiling insights with essential considerations for anaesthesiologists

With the growing use of glucagon-like-peptide-1 (GLP-1) receptor (GLP-1R) agonists as anti-obesity medication it is becoming increasingly important to examine its consequences in the peri-operative period. GLP-1R agonists are known for their effects of glucose-lowering and gastroparesis the latter causing some safety concerns regarding induction of anaesthesia, more specifically the risk of pulmonary aspiration. This article gathers the available evidence on this subject in addition to the already established guidelines. Current evidence makes us assume there is indeed an increased level of gastroparesis, but there are no studies to date with evidential confirmation of a presumed elevated risk of pulmonary aspiration. Future perspectives should focus on the actual risk of pulmonary aspiration and the possible implementation of ultrasound in the preoperative assessment.

Very low monomethyl fumarate exposure via human milk: a case report-a contribution from the ConcePTION project

Introduction

While breastfeeding is recommended, knowledge regarding medicine transfer to human milk and its safety for nursing infants is limited. Only one paper has previously described dimethyl fumarate (DMF) transfer during breastfeeding in two patients at 5 and 6 months postpartum, respectively. The current case report describes maternal pharmacokinetic data of monomethyl fumarate (MMF), the active metabolite of DMF, and infant exposure estimations of MMF at 3 months postpartum.

Methods

A 32-year-old Caucasian woman started DMF therapy (120 mg, 2x/day) for multiple sclerosis at 3 months postpartum, after weaning her infant from breastfeeding. On day 99 after birth, the patient collected four milk samples over 24 h after 6 days of treatment at the initial dose. Additionally, a single maternal blood sample was collected to calculate the milk-to-plasma (M/P) ratio. The samples were analyzed using liquid chromatography coupled with the mass spectrometry method.

Results

A wide range of measured steady-state concentrations of MMF (5.5-83.5 ng/mL) was observed in human milk samples. Estimated daily infant dosage values for MMF, calculated with 150 and 200 mL/kg/day human milk intake, were 5.76 and 7.68 μg/kg/day, and the relative infant doses were 0.16 and 0.22%. The observed mean M/P ratio was 0.059, similar to the M/P ratio predicted using the empirical Koshimichi model (0.06).

Discussion

Combining this case report with the two previously described cases, the estimated infant exposure is low, albeit with relevant intra- and inter-patient variabilities. Research should further focus on infant exposure and safety.

Anesthetic recommendations for maternal and fetal safety in nonobstetric surgery: a balancing act

PURPOSE OF REVIEW

Nonobstetric surgery during pregnancy is associated with maternal and fetal risks. Several physiologic changes create unique challenges for anesthesiologists. This review highlights physiologic changes of pregnancy and presents clinical recommendations based on recent literature to guide anesthetic management for the pregnant patient undergoing nonobstetric surgery.

RECENT FINDINGS

Nearly every anesthetic technique has been safely used in pregnant patients. Although it is difficult to eliminate confounding factors, exposure to anesthetics could endanger fetal brain development. Perioperative fetal monitoring decisions require an obstetric consult based on anticipated maternal and fetal concerns. Given the limitations of fasting guidelines, bedside gastric ultrasound is useful in assessing aspiration risk in pregnant patients. Although there is concern about appropriateness of sugammadex for neuromuscular blockade reversal due its binding to progesterone, preliminary literature supports its safety.

SUMMARY

These recommendations will equip anesthesiologists to provide safe care for the pregnant patient and fetus undergoing nonobstetric surgery.

Advances in foetal anaesthesia

Nowadays, widespread antenatal ultrasound screenings detect congenital anomalies earlier and more frequently. This has sparked research into foetal surgery, offering treatment options for various conditions. These surgeries aim to correct anomalies or halt disease progression until after birth. Minimally invasive procedures can be conducted under local anaesthesia (with/without maternal sedation), while open mid-gestational procedures necessitate general anaesthesia. Anaesthesia serves to prevent maternal and foetal pain, to provide immobilization, and to optimize surgical conditions by ensuring uterine relaxation. As early as 12 weeks after conception, the foetus may experience pain. Thus, in procedures involving innervated foetal tissue or requiring foetal immobilization, anaesthetic drugs can be administered directly to the foetus (intramuscular or intravenous) or indirectly (transplacental) to the mother. However, animal studies have indicated that exposure to prenatal anaesthesia might impact foetal brain development, translating these findings to the clinical setting remains difficult.

Investigating gastrointestinal disorders in pregnancy

This article reviews anatomical and physiological changes and alterations in reference intervals for laboratory tests in healthy pregnancy, pertinent to investigation of the gastrointestinal system. The safety of procedures and radiological investigations relevant to the investigation of gastrointestinal disorders in pregnancy are also reviewed.

Point of Care Abdominal Ultrasound

Abdominal pain is a common emergency department complaint, and point-of-care ultrasound (POCUS) of the abdomen is increasingly being utilized to evaluate clinical manifestations. It aids in accurate diagnoses and assists in procedures, particularly in emergency and critical care settings. Imaging is often required to confirm the etiology of abdominal pain. POCUS provides the benefit of avoiding radiation exposure and enables quicker diagnosis compared to computed tomography scans. There is growing evidence of the diagnostic accuracy for numerous abdominal POCUS applications, including appendicitis, intussusception, diverticulitis, gastric ultrasound and contrast-enhanced ultrasound.

Evaluation of the 'Sip Til Send' regimen before elective caesarean delivery using bedside gastric ultrasound: A paired cohort pragmatic study

BACKGROUND

Pre-operative fasting is routinely advocated to avoid pulmonary aspiration. The European Society of Anaesthesiology and Intensive Care (ESAIC) recommends a fasting period of 2 h for liquids before surgery. Liberal drinking policies such as the 'Sip Til Send' are a suggested alternative to maintain hydration before surgery.

OBJECTIVES

To compare residual gastric volumes in fully fasted nonlabouring parturients before elective caesarean delivery with the 'Sip Til Send' with water liberal drinking protocol. Our hypothesis was the 'Sip Til Send' would be noninferior to standard fasting at minimising the residual gastric volume immediately before surgery.

DESIGN

A paired cohort prospective observational pragmatic study using gastric ultrasound, analysed by an operator blinded to the fasting status of each scan.

SETTING

A tertiary maternity hospital in Dublin, Ireland. The study was conducted between January and June 2023.

PARTICIPANTS

Pregnant women about to undergo elective caesarean delivery who had followed ESAIC fasting guidelines before admission.

INTERVENTIONS

Each participant underwent two pairs (semi-recumbent and the semi-recumbent right lateral positions) of standardised ultrasound examinations of the gastric antrum: the order of these scans was randomised. The first pair of scans occurred on admission before the 'Sip Til Send' protocol commenced, the other pair just before spinal anaesthesia for caesarean delivery, after a variable time following the 'Sip Til Send' protocol.

MAIN OUTCOME MEASURE

The primary outcome was the difference in antral cross-sectional area (CSA) between the fully fasted women on admission and the same women after following the 'Sip Til Send' protocol until just before spinal anaesthesia.

RESULTS

Fifty-eight women were randomised for the study: 55 and 54 scans in the semi-recumbent position on admission, and 55 and 54 scans in the right lateral position just before spinal anaesthesia. The mean differences (95% CI) in CSA in the semi-recumbent and RL positions were 0.07 (-0.39 to 0.53) cm 2 and 0.04 (-0.60 to 0.68) cm 2 , respectively. Since the of 95% CIs did not cross the predefined noninferiority margin of 0.88 cm 2 , 'Sip Til Send' was noninferior to fully fasting in in terms of the antral CSA.

CONCLUSION

The 'Sip Til Send' protocol of liberal hydration with water was noninferior to standard fasting prior to elective caesarean delivery.

TRIAL REGISTRY NUMBER

NCT05783427 ClinicalTrials.gov.

Pre-operative gastric ultrasound in patients at risk of pulmonary aspiration: a prospective observational cohort study

Point-of-care gastric sonography offers an objective approach to assessing individual pulmonary aspiration risk before induction of general anaesthesia. We aimed to evaluate the potential impact of routine pre-operative gastric ultrasound on peri-operative management in a cohort of adult patients undergoing elective or emergency surgery at a single centre. According to pre-operative gastric ultrasound results, patients were classified as low risk (empty, gastric fluid volume ≤ 1.5 ml.kg-1 body weight) or high risk (solid, mixed or gastric fluid volume > 1.5 ml.kg-1 body weight) of aspiration. After sonography, examiners were asked to indicate changes in aspiration risk management (none; more conservative; more liberal) to their pre-defined anaesthetic plan and to adapt it if patient safety was at risk. We included 2003 patients, 1246 (62%) of which underwent elective and 757 (38%) emergency surgery. Among patients who underwent elective surgery, 1046/1246 (84%) had a low-risk and 178/1246 (14%) a high-risk stomach, with this being 587/757 (78%) vs. 158/757 (21%) among patients undergoing emergency surgery, respectively. Routine pre-operative gastric sonography enabled changes in anaesthetic management in 379/2003 (19%) of patients, with these being a more liberal approach in 303/2003 (15%). In patients undergoing elective surgery, pre-operative gastric sonography would have allowed a more liberal approach in 170/1246 (14%) and made a more conservative approach indicated in 52/1246 (4%), whereas in patients undergoing emergency surgery, 133/757 (18%) would have been managed more liberally and 24/757 (3%) more conservatively. We showed that pre-operative gastric ultrasound helps to identify high- and low-risk situations in patients at risk of aspiration and adds useful information to peri-operative management. Our data suggest that routine use of pre-operative gastric ultrasound may improve individualised care and potentially impact patient safety.

The role of gastric ultrasound in anaesthesia for emergency surgery: A review and clinical guidance

BACKGROUND

The timing and technique of anaesthesia are challenging in patients with a history of recent food intake. The presence of gastric contents increases the risk of aspiration, potentially resulting in acute lung injury, pneumonia, or death. Delayed gastric emptying complicates the estimation of aspiration risk. Surprisingly, there are no fasting guidelines for emergency surgery. Point-of-care gastric ultrasound is a time-efficient, cost-efficient and accurate bedside tool with which to estimate residual gastric content and to guide decision-making in airway management and timing of general anaesthesia. This review summarises the prevailing concepts of ultrasound-guided gastric content assessment for emergency surgery.

METHODS

Medline and Embase databases were searched for studies using ultrasound for the evaluation of gastric content in adults scheduled for emergency surgery.

RESULTS

Five prospective observational studies representing 793 emergency surgery patients showed that the incidence of 'full stomach' was between 18 and 56% at the time of induction. Risk factors for a full stomach before emergency surgery were abdominal or gynaecological/obstetric surgery, high body mass index and morphine consumption. No correlation between preoperative fasting time and the presence of a full/empty stomach was found. No deaths due to aspiration were reported.

CONCLUSION

The preoperative presence of gastric content before emergency surgery is high and the estimates used for clinical management are unreliable. This review demonstrates that gastric ultrasound is a valuable tool for evaluating gastric content. A flow chart for medical decision-making using gastric ultrasound before emergency surgery was developed to assist in clinical decision-making. The validity and practical applicability should be assessed in future studies.

General anaesthesia for nonobstetric surgery during pregnancy: A narrative review

Nonobstetric surgery may be required in up to 1% of pregnancies. Most common procedures are urgent abdominal surgeries requiring general anaesthesia. Maintaining normal maternal physiology during anaesthesia is vital. Left lateral tilt position prevents aortocaval compression and preserves normal venous return. Preparation for a difficult airway is required in all obstetric patients due to the known anatomical and physiological changes. Aspiration prophylaxis and a rapid sequence induction are traditionally recommended to avoid the (probably overestimated) risk of aspiration. Although the minimum alveolar concentration (MAC) of volatile anaesthetic agents is reduced by 30 to 40%, awareness occurs more frequently in the obstetric population. Maternal outcomes from surgery are comparable with those of nonpregnant women, but increased incidences of foetal loss, preterm delivery, low birth weight and caesarean section have been reported. Although animal studies have observed impaired foetal brain development after antenatal exposure to anaesthesia, the translational value of these studies remain controversial. Clinical evidence is nearly absent. Withholding urgent/essential procedures is certainly more threatening than proceeding with the surgery. To increase the safety of mother and foetus, nonurgent or nonessential procedures should be postponed until after delivery, and if procedures cannot wait, locoregional anaesthesia should be used if possible. Where general anaesthesia cannot be avoided, the duration of exposure should be kept to a minimum. This narrative review summarises the literature of the past 20 years concerning the anaesthetic management and outcomes of nonobstetric surgery under general anaesthesia during pregnancy.

Evaluation of gastric contents using ultrasound in full-term pregnant women fasted for 8 h: a prospective observational study

BACKGROUND

We aimed to evaluate the gastric volume and contents after an 8-h fasting period in full-term, non-laboring, pregnant women following a standardized meal.

METHODS

In this prospective observational study, we included full-term pregnant women scheduled for elective cesarean delivery. The participants were instructed to fast after a standardized meal (apple juice, bread, and cheese). Participants were scanned in the semi-recumbent and right-lateral positions 8 h after the standardized meal. The primary outcome was the proportion of patients with gastric volume > 1.5 mL kg^-1 calculated by two equations. Secondary outcomes included the antral cross-sectional area and gastric volume. Data are expressed as frequency (%, 95% confidence interval [CI]), mean ± standard deviation (95% CI of the mean), or median (quartiles) as appropriate.

RESULTS

Forty-one women were available for the final analysis. For the primary outcome, one participant (2.4%, 95% CI of 0.06 to 12.8%) had gastric volume > 1.5 mL kg^-1, and none had solids in the antrum. For the secondary outcomes, the mean (95% CI of the mean) of the antral cross-sectional area was 2.11 ± 0.72 (1.88 to 2.34) cm² and 4.08 ± 1.80 (3.51 to 4.65) cm² during the semi-recumbent and right-lateral position, respectively. The median (quartiles) gastric volume was 0.53 (0.32, 0.66) mL kg^-1 and 0.33 (0.13, 0.52) mL kg^-1 as estimated by Perlas et al. and Roukhomovsky et al. equations, respectively.

CONCLUSION

After 8-h fasting following a standardized meal, full-term pregnant non-laboring women are less likely to have a high residual gastric volume.