Gestion des voies aériennes supérieures en fin d’accouchement : enquête de pratique

Prevalence and factors associated with high-risk gastric contents in women admitted to the maternity unit for childbirth: a prospective multicentre cohort study

BACKGROUND

This multicentre prospective observational study sought to determine the prevalence and the factors associated with high-risk gastric contents in women admitted to the maternity unit for childbirth, and to identify the clinical situations in which ultrasound assessment of gastric contents would be most helpful (i.e. when the prevalence of high-risk gastric contents is close to 50%).

METHODS

Ultrasound assessments of gastric contents were performed within the first hour after admission to the maternity unit. The prevalence of high-risk gastric contents was calculated and variables associated with high-risk gastric contents were identified using logistic regression analyses.

RESULTS

A total of 1003 parturients were analysed. The prevalence of high-risk gastric contents was 70% (379/544; 95% confidence interval: 66-74%) in women admitted in spontaneous labour and 65% (646/1003; 95% confidence interval: 61-67%) in the whole cohort. Lower gestational age, increased fasting duration for solids, and elective Caesarean delivery were independently associated with reduced likelihood of high-risk gastric contents. In women admitted in spontaneous labour and in the whole cohort, the prevalence of high-risk gastric contents ranged from 85% to 86% for fasting duration for solids <6 h, 63%-68% for fasting 6-8 h, 54%-55% for fasting 8-12 h, and 47%-51% for fasting ≥12 h.

CONCLUSIONS

Around two-thirds of parturients had high-risk gastric contents within the first hour after admission to the maternity unit. Our results suggest that gastric emptying for solids continues in labouring women, and that gastric ultrasound would be most helpful when fasting duration is ≥8 h.

Ultrasound assessment of gastric contents prior to placental delivery: A prospective multicentre cohort study

BACKGROUND

There is ongoing debate regarding the optimal general anaesthetic technique for manual removal of the placenta after vaginal delivery. Using ultrasound examination of the gastric antrum, this study aimed to assess the change in gastric contents during vaginal delivery and to determine the prevalence of stomach at risk for pulmonary aspiration in the immediate postpartum period before placental delivery.

METHODS

In this prospective multicentre cohort study, antral ultrasonography was performed at full cervical dilatation within the thirty minutes preceding the beginning of expulsive efforts and after vaginal birth, before placental delivery. High-risk gastric content was defined as the visualisation of any solid content in the antrum or antral cross-sectional area in the semi-recumbent position (SR-CSA) > 608 mm².

RESULTS

Twenty-six women were included and analysed. There was a significant decrease in both the proportion of patients with solid gastric content and the SR-CSA between the two-ultrasound examinations. Twenty-one patients (80.8%) exhibited a decrease in the SR-CSA during vaginal delivery. The prevalence of stomach at risk for pulmonary aspiration was significantly lower after vaginal delivery than before vaginal delivery (23.1% vs. 57.7%, P = 0.0004).

CONCLUSION

Our results suggest that gastric emptying is at least partially preserved during vaginal birth. Nevertheless, almost a quarter of women did have high-risk gastric content in the immediate postpartum period. Point-of-care antral ultrasonography may be of interest for the fast assessment of the gastric content status when a general anaesthesia is required for manual removal of retained placenta.

Prevalence and prediction of higher estimated gastric content in parturients at full cervical dilatation: A prospective cohort study

BACKGROUND

Emergent obstetrical procedures may require general anaesthesia in parturients at full cervical dilatation or immediately after vaginal birth. This study aimed to determine the prevalence and the predictive factors of higher estimated gastric content in parturients at full cervical dilatation with epidural analgesia and allowed to drink during the labour, and to assess the ability of the antral area measured in the semirecumbent position (SR-CSA) to identify higher estimated gastric content in this setting.

METHODS

This prospective observational study was conducted between December 2016 and July 2017. Ultrasonographic examination of the antrum was performed at full cervical dilatation, within the hour preceding the beginning of expulsive efforts. Higher estimated gastric content was defined when solid content was observed and/or if the calculated gastric fluid volume was >1.5 mL/kg.

RESULTS

Seventeen of 62 parturients (27%) presented higher estimated gastric content. Maximal pain intensity during the last hour of labour and time interval between the insertion of the epidural catheter and ultrasonographic examination were significantly increased in parturients with higher estimated gastric content. The threshold value of the SR-CSA to identify a higher estimated gastric content was 393 mm² , with sensitivity = 88% and specificity = 87%.

CONCLUSION

Around a quarter of parturients with epidural analgesia and free access to clear fluids during labour presented higher estimated gastric content at full cervical dilatation. The SR-CSA may be of interest for the fast ultrasound assessment of the gastric content status in case of emergent obstetrical procedures at full cervical dilatation.

Ultrasound assessment of gastric content in the immediate postpartum period: a prospective observational descriptive study

INTRODUCTION

Pulmonary aspiration of gastric contents in pregnant women undergoing general anesthesia or sedation/analgesia in the peripartum period is a feared complication in obstetric anesthesia. We assessed the changes in antral cross-sectional area (CSA) with ultrasonography in laboring women and in the immediate postpartum period.

PATIENTS AND METHODS

In an observational study in a university-affiliated maternity, gastric ultrasonography examinations were performed in non-consecutive laboring women, after epidural analgesia insertion and after childbirth. Assessment of antral CSA, difficulty of performance on a numerical scale, and factors that could influence gastric content were noted. A cut-off value of 381 mm² was taken for the diagnosis of empty stomach.

RESULTS

One hundred women were enrolled in the study. Median antral CSA was 469 mm² [25th-75th] [324-591] after epidural insertion and 427 mm² [316-574] after delivery. Antral CSA was ≥ 381 mm² in 59 of 90 women (65%) after epidural insertion vs. 48 of 100 women (48%) after delivery (P = 0.59). Median variation of antral CSA between two measurements was 36 mm² [-42 to 114]. Gastric ultrasonography was significantly more difficult to perform during labor than immediately post-delivery (median difficulty score 5 [2-7] vs. 2 [1-4], P < 0.0001). No risk factors (pain, anxiety, diabetes, smoking) were significantly associated with the occurrence of full stomach post-delivery.

CONCLUSION

This study demonstrated that 48% of parturients in the immediate postpartum period presented an antral CSA ≥ 381 mm² , cut-off being accepted for diagnosis of empty stomach and emphasizes the need for re-assessing before any general anesthetic procedure.

[Obstetric anaesthesia for instrumental vaginal delivery]

The aim of the anaesthesia for instrumental delivery is to provide optimal operation conditions for the obstetrician, appropriate maternal comfort, altogether with safety for the mother and her foetus. The type and location for this intervention are chosen individually for each case according to the indication, the risk of caesarean section and the local specificities. The general safety recommendations for obstetric anaesthesia apply in every case. Since an epidural analgesia is often already working, this type of anaesthesia is the most frequently used for the extractions. A spinal anaesthesia is a logical choice where an epidural in sot yet working. The pudendal block is a second line choice and the general anaesthesia remains as the last alternative in acute emergencies, in cases of failed regional anaesthesia or when the mother refuses any other anaesthesia despite proper information or proves unable to cooperate.