Does obesity complicate regional anesthesia and result in longer decision to delivery time for emergency cesarean section?

Conversion to general anesthesia and intravenous supplementation during intrapartum cesarean delivery with an indwelling epidural catheter: a retrospective study

BACKGROUND

Intraoperative pain during cesarean delivery with or without conversion to general anesthesia has been shown to negatively impact maternal and perinatal morbidity. Efforts to reduce these adverse events are a recent focus of obstetric anesthesia care. We aimed to assess rates of and risk factors for conversion to general anesthesia and intraoperative pain during intrapartum cesarean delivery with an indwelling epidural catheter in our academic center.

METHODS

In this retrospective cohort study, all women undergoing cesarean delivery with an indwelling epidural catheter between January 2017 and June 2022 were included. Labor epidural analgesia was provided according to a standardized protocol, and conversion to epidural anesthesia was achieved in the operating room before surgery. We determined the conversion rate to general anesthesia and associated risk factors. Second, we examined the rate of administration of analgesics/sedatives and related risk factors in cesarean cases that were not converted to general anesthesia.

RESULTS

Among the 1192 women undergoing intrapartum cesarean delivery with epidural anesthesia, there were 97 cases with conversion to general anesthesia (8.1%), of which 87 (89.7%) were due to a failed epidural. Higher age, higher weight, and higher gestational age were associated with decreased odds of conversion to general anesthesia. Higher gravidity and longer surgical time were associated with increased odds. An emergent indication was not associated with conversion to general anesthesia. Intravenous analgesic/sedative supplementation occurred in 141 cases (12.9%). Higher age was associated with decreased odds of supplementation, and longer surgical time was associated with increased odds.

CONCLUSION

In our tertiary academic center, the rate of intraoperative conversion to general anesthesia and administration of analgesic/sedative medication among women undergoing intrapartum cesarean delivery with epidural anesthesia was relatively high. Emergency cesarean delivery was not associated with either of the above endpoints.

Maternal and perinatal outcomes in nulliparous women with a booking body mass index exceeding 50 kg/m2

BACKGROUND

Women with a body mass index (BMI) >35 kg/m2 carry an increased obstetric risk; however, the experience of the Class IV and above obese nulliparous women is less understood.

AIMS

To describe maternal and perinatal outcomes in nulliparous women of booking BMI > 50 kg/m2.

MATERIALS AND METHODS

A cohort study of 48 nulliparous women who delivered between 2015 and 2019 in a tertiary hospital and had a booking BMI > 50 kg/m2. Obstetric outcome data was collated via electronic and written patient records. The relationship between mode of delivery and BMI was assessed using direct logistic regression. Multiple pregnancies and severe congenital malformations (n = 3) were excluded.

RESULTS

The mean booking BMI was 53.7 kg/m2 (SD 4.05) and mean maternal age was 30.4 years (SD = 5.7). Comorbidities included asthma (43%), essential hypertension (20%) and diabetes (61%). Antenatally, accuracy was compromised in 80% of morphology scans (n = 35). In the perinatal period, 33 women (68.8%) were induced compared to a spontaneous onset of labour in two (4.1%) women. There were nine elective caesarean sections (CS), five of which were for breech presentation. Of those who intended on vaginal delivery (n = 35), 51% (n = 18) had an emergency CS. In these women, the risk of CS increased by a factor of 1.36 for every one point increase in BMI > 50 kg/m2. The average gestational age was 37.5 weeks (SD 2.4) with 14% (n = 6) experiencing preterm deliveries. The incidence of babies born >90th percentile for gestational age was 15 (34%).

CONCLUSION

Increased BMI impairs maternal and perinatal outcomes and significantly increases the risk of emergency CS. BMI > 50 kg/m2 is associated with higher-level interventions and obstetric complications.

Using machine learning to identify quality-of-care predictors for emergency caesarean sections: a retrospective cohort study

OBJECTIVES

Emergency caesarean sections (ECS) are time-sensitive procedures. Multiple factors may affect team efficiency but their relative importance remains unknown. This study aimed to identify the most important predictors contributing to quality of care during ECS in terms of the arrival-to-delivery interval.

DESIGN

A retrospective cohort study. ECS were classified by urgency using emergency categories one/two and three (delivery within 30 and 60 min). In total, 92 predictor variables were included in the analysis and grouped as follows: 'Maternal objective', 'Maternal psychological', 'Fetal factors', 'ECS Indication', 'Emergency category', 'Type of anaesthesia', 'Team member qualifications and experience' and 'Procedural'. Data was analysed with a linear regression model using elastic net regularisation and jackknife technique to improve generalisability. The relative influence of the predictors, percentage significant predictor weight (PSPW) was calculated for each predictor to visualise the main determinants of arrival-to-delivery interval.

SETTING AND PARTICIPANTS

Patient records for mothers undergoing ECS between 2010 and 2017, Nordsjællands Hospital, Capital Region of Denmark.

PRIMARY OUTCOME MEASURES

Arrival-to-delivery interval during ECS.

RESULTS

Data was obtained from 2409 patient records for women undergoing ECS. The group of predictors representing 'Team member qualifications and experience' was the most important predictor of arrival-to-delivery interval in all ECS emergency categories (PSPW 25.9% for ECS category one/two; PSPW 35.5% for ECS category three). In ECS category one/two the 'Indication for ECS' was the second most important predictor group (PSPW 24.9%). In ECS category three, the second most important predictor group was 'Maternal objective predictors' (PSPW 24.2%).

CONCLUSION

This study provides empirical evidence for the importance of team member qualifications and experience relative to other predictors of arrival-to-delivery during ECS. Machine learning provides a promising method for expanding our current knowledge about the relative importance of different factors in predicting outcomes of complex obstetric events.

Defining the decision-to-delivery interval at caesarean section: narrative literature review and proposal for standardisation

The decision-to-delivery interval is a widely used term at non-elective caesarean section. While the definition may appear self-evident, there is no universally agreed consensus about when this period begins and ends. We reviewed the literature for original research utilising the terms 'decision-to-delivery', 'decision-to-incision' or 'incision-to-delivery' and examined definitions used for decision, delivery, incision, as well as any additional time intervals that were assessed. Our analysis demonstrated an inconsistent non-standardised approach to defining these intervals, which might have clinical practice and medicolegal ramifications. We propose that the decision-to-delivery interval should be defined as follows: the interval between the time at which the senior obstetrician makes the decision that a caesarean section is required and the time at which the fetus (or first fetus in the case of multiples) is delivered. The decision time should ideally be recorded contemporaneously in the medical notes or partogram.

Guideline No. 392-Pregnancy and Maternal Obesity Part 2: Team Planning for Delivery and Postpartum Care

OBJECTIVE

This guideline will review key aspects in the pregnancy care of women with obesity. Part I will focus on Preconception and Pregnancy Care. Part II will focus on Team Planning for Delivery and Postpartum Care.

INTENDED USERS

All health care providers (obstetricians, family doctors, midwives, nurses, anaesthesiologists) who provide pregnancy-related care to women with obesity.

TARGET POPULATION

Women with obesity who are pregnant or planning pregnancies.

EVIDENCE

Literature was retrieved through searches of Statistics Canada, Medline, and The Cochrane Library on the impact of obesity in pregnancy on antepartum and intrapartum care, maternal morbidity and mortality, obstetric anaesthesia, and perinatal morbidity and mortality. Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to September 2018. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALIDATION METHODS

The content and recommendations were drafted and agreed upon by the authors. Then the Maternal-Fetal Medicine Committees peer reviewed the content and submitted comments for consideration, and the Board of the Society of Obstetricians and Gynaecologists of Canada (SOGC) approved the final draft for publication. Areas of disagreement were discussed during meetings at which time consensus was reached. The level of evidence and quality of the recommendation made were described using the Evaluation of Evidence criteria of the Canadian Task Force on Preventive Health Care.

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in these guidelines may increase obstetrical provider recognition of the issues affecting pregnant individuals with obesity, including clinical prevention strategies, communication between the health care team, the patient and family as well as equipment and human resource planning. It is hoped that regional, provincial and federal agencies will assist in the education and support of coordinated care for pregnant individuals with obesity.

GUIDELINE UPDATE

SOGC guideline will be automatically reviewed 5 years after publication. However, authors can propose another review date if they feel that 5 years is too short/long based on their expert knowledge of the subject matter.

SPONSORS

This guideline was developed with resources funded by the SOGC.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Anesthesia for Urgent Cesarean Section

Cesarean section (CS) is a common surgical procedure worldwide. The anesthesiologist is responsible, together with obstetrician and neonatologist, for safe perioperative management. A continuum of risk exists for urgent CS. The decision-to-delivery interval is an important audit tool, to ensure international standards are upheld and good outcomes for mother and neonate are achieved. Urgent CS may be performed under either GA or RA, with benefits and risks attributable to each. Specific clinical scenarios require an individualized approach to anesthesia, including hemorrhage, hypertensive disorders, cardiac disease, the difficult airway and fetal compromise. Ongoing training is integral to the provision of safe anesthesia.

Directive clinique No 392 - Grossesse et obésité maternelle Partie 2 : Planification en équipe de l'accouchement et soins post-partum

OBJECTIF

La présente directive clinique aborde les aspects essentiels des soins prénataux chez les femmes atteintes d'obésité. La partie 1 porte sur la préconception et les soins prénataux. La partie 2 porte sur la planification en équipe de l'accouchement et les soins post-partum. UTILISATEURS CONCERNéS: Tous les fournisseurs de soins de santé (obstétriciens, médecins de famille, sages-femmes, infirmières, anesthésiologistes) qui prodiguent des soins relatifs à la grossesse auprès de femmes atteintes d'obésité.

POPULATION CIBLE

Femmes atteintes d'obésité qui sont enceintes ou prévoient le devenir. DONNéES PROBANTES: Des recherches ont été menées en consultant les ressources de Statistique Canada, de Medline et de Cochrane Library en vue d'en tirer la littérature relativement aux effets de l'obésité durant la grossesse sur les soins prénataux et intrapartum, la morbidité et la mortalité maternelles, l'anesthésie obstétricale ainsi que sur la morbidité et la mortalité périnatales. Seuls les résultats de revues systématiques, d'essais cliniques randomisés ou comparatifs et d'études observationnelles ont été retenus. Aucune restriction de date ou de langue n'a été employée. Les recherches ont été mises à jour régulièrement, et les résultats ont été incorporés à la directive clinique jusqu'en septembre 2018. Nous avons également tenu compte de la littérature grise (non publiée) obtenue sur les sites Web d'organismes d'évaluation des technologies de la santé et d'autres organismes pertinents, dans des collections de directives cliniques et des registres d'essais cliniques, et auprès d'associations nationales et internationales de médecins spécialistes. MéTHODES DE VALIDATION: Le contenu et les recommandations ont été rédigés et acceptés par les auteurs. Les membres du comité de médecine fœto-maternelle ont ensuite passé en revue le contenu et formulé des commentaires aux fins d'examen. Enfin, le conseil d'administration de la Société des obstétriciens et gynécologues du Canada (SOGC) a approuvé la publication de la version définitive de la directive. Les points de désaccord ont été abordés lors de réunions pour enfin arriver à un consensus. La qualité des données et des recommandations a été déterminée à l'aide des critères d'évaluation décrits par le Groupe d'étude canadien sur les soins de santé préventifs. AVANTAGES, PRéJUDICE ET COûTS: La mise en place des recommandations des présentes directives peut améliorer la reconnaissance des fournisseurs de soins obstétricaux relativement aux problèmes qui touchent les personnes enceintes atteintes d'obésité, notamment au moyen de stratégies de prévention clinique; de la communication entre l'équipe de soins de santé, la patiente et la famille; et de la planification de l'équipement et des ressources humaines. Il est à espérer que les organismes régionaux, provinciaux et fédéraux participeront à la formation et au soutien en matière de soins coordonnés pour les personnes enceintes atteintes d'obésité. MISE à JOUR DE LA DIRECTIVE CLINIQUE: Les directives de la SOGC sont automatiquement passées en revue 5 ans après leur publication. Les auteurs peuvent toutefois proposer une autre date de réévaluation s'ils croient qu'une période de 5 ans est trop courte ou trop longue en fonction de leurs connaissances du sujet à titre d'experts en la matière.

PROMOTEURS

La présente directive a été élaborée à l'aide de ressources financées par la SOGC. DéCLARATIONS SOMMAIRES: RECOMMANDATIONS.

Spinal and epidural sufentanil and fentanyl in early labour

BACKGROUND AND AIM

The analgesic effect on labour pain of either spinal or epidural sufentanil or fentanyl was tested in a total of 80 primiparous parturients at an early phase of the delivery. The aim of the study was to compare the level of analgesia achieved within 20 minutes.

METHODS

The parturients were randomly assigned to groups receiving either spinal sufentanil (5 µg), epidural sufentanil (20 µg), spinal fentanyl (20 µg) or epidural fentanyl (100 µg), whereafter the parturients were monitored for reported pain during contraction and side effects for 30 minutes. The primary outcome was the level of analgesia achieved within 20 minutes, while the secondary outcome was the time until the administration of the first epidural bolus.

RESULTS

At baseline, the mean maximum pain VAS was 86 (84-89) mm. At 20 minutes after spinal sufentanil, epidural sufentanil, spinal fentanyl or epidural fentanyl, the maximum VAS was 19 (7-31), 45 (32-59), 25 (10-39) or 52 (40-63) mm, respectively (P < .01 spin vs epid groups). There were no differences in efficacy between spinal or epidural sufentanil and fentanyl. The mean (95% CI) time to the activation of epidural analgesia was 151 (111-192), 130 (93-168), 177 (121-234) and 112 (80-143) minutes after spinal sufentanil, epidural sufentanil, spinal fentanyl and epidural fentanyl, respectively.

CONCLUSIONS

In terms of a reduction of VAS score at 20 minutes, epidural sufentanil or fentanyl provide 63% and 60% of the analgesic effect of the corresponding spinal analgesia. Epidural sufentanil or fentanyl could be used in situations in which spinal/CSE administration is not possible or desired.

A conceptual framework for the impact of obesity on risk of cesarean delivery

Cesarean deliveries accounted for 32.2% of nearly 4 million births in the United States in 2014. Obesity affects a third of reproductive-age women and is associated with worse cesarean delivery outcomes. Studies have shown that increasing maternal body mass index correlates linearly with cesarean delivery rates, but little is known about the potential mediating and moderating mechanisms. Thus, a conceptual framework for understanding how obesity correlates with risk of cesarean delivery is crucial to determining safe ways to reduce the cesarean delivery rate among obese gravidas. Based on an extensive review and synthesis of the literature, we present a conceptual framework that posits how obesity may operate through several pathways to lead to a cesarean delivery. Our framework explores the complexity of obesity as an exposure that operates through potential mediating pathways, a moderator of cesarean delivery risk, and a covariate with other cesarean delivery risk factors. Among nulliparas, obesity appears to operate through 3 main proximal mediating mechanisms to increase risk of cesarean delivery including: (1) preexisting comorbidities and obstetric complications; (2) a slower progression of first-stage labor, potentially increasing the risk of cesarean delivery secondary to failure to progress; and (3) a prolongation of pregnancy, which is associated with risk of maternal postdates. For multiparas, a fourth proximal mediator of prior uterine scar may also increase cesarean delivery risk. Distal mediating mechanisms, which operate through one of the proximal mechanisms, may include an induction of labor or planned prelabor cesarean delivery. Obesity may also moderate the likelihood of cesarean delivery by interacting with clinician-level or hospital-level factors. Future research should assess the validity of this framework and seek to understand the relative contributions of each potential pathway between obesity and cesarean delivery. This will allow for evidence-based recommendations to reduce preventable cesareans among obese women by targeting modifiable mediators and moderators of the relationship between obesity and increased risk of cesarean delivery.

Epidural extension failure in obese women is comparable to that of non-obese women

BACKGROUND

Management of labor epidurals in obese women is difficult and extension to surgical anesthesia is not always successful. Our previous retrospective pilot study found epidural extension was more likely to fail in obese women. This study used a prospective cohort to compare the failure rate of epidural extension in obese and non-obese women and to identify risk factors for extension failure.

METHODS

One hundred obese participants (Group O, body mass index ≥ 40 kg/m² ) were prospectively identified and allocated two sequential controls (Group C, body mass index ≤ 30 kg/m² ). All subjects utilized epidural labor analgesia and subsequently required anesthesia for cesarean section. The primary outcome measure was failure of the labor epidural to be used as the primary anesthetic technique. Risk factors for extension failure were identified using Chi-squared and logistic regression.

RESULTS

The odds ratio (OR) of extension failure was 1.69 in Group O (20% vs. 13%; 95% CI: 0.88-3.21, P = 0.11). Risk factors for failure in obese women included ineffective labor analgesia requiring anesthesiologist intervention, (OR 3.94, 95% CI: 1.16-13.45, P = 0.028) and BMI > 50 kg/m² (OR 3.42, 95% CI: 1.07-10.96, P = 0.038).

CONCLUSION

The failure rate of epidural extension did not differ significantly between the groups. Further research is needed to determine the influence of body mass index > 50 kg/m² on epidural extension for cesarean section.