Reducing breakthrough pain during labour epidural analgesia: an update

The Efficacy of Dural Puncture Epidural Performed by 27-gauge Whitacre Needle in Labour Epidural Analgesia: Randomized Single-Blinded Controlled Study

Objective

Dural puncture epidural technique is refinement of standard epidural technique. Its goal is to overcome drawbacks of standard epidural. We assessed whether dural puncture epidural technique performed by 27-gauge spinal needle would provide higher quality of labour epidural analgesia by using 10 mL epidural bolus of 0.125% bupivacaine. Additionally, the impact of dural puncture epidural on epidural analgesia onset, course of labour and occurrence of maternal side effects was examined.

Methods

We designed prospective, randomized, single-blind study. A total of 76 healthy nulliparous parturients were randomly allocated to dural puncture or standard epidural group. After identification of epidural space, spinal Whitacre needle was used for dural puncture. Intrathecal drug administration was omitted at that point. Both groups received a bolus of local anaesthetic mixture, followed by a continuous infusion of diluted local anaesthetic via epidural catheter. Pain was assessed by numeric pain rating scale. The number of top-ups and mode of delivery were recorded in both groups.

Results

After 10 minutes, there was a statistically significant difference in numeric pain rating scale ≤3 reported (P=0.028), with 97.4% subjects in dural puncture epidural group achieving adequate analgesia after 10 minutes. There was no statistically significant difference in the number of additional boluses, time to delivery, Bromage scale achieved or maternal outcomes between groups.

Conclusion

Dural puncture epidural technique appears to be effective in providing faster onset of epidural analgesia. However, the need for additional boluses remains unchanged. It can be safely used in obstetrics, without deleterious effect on the course of labour.

A randomized double-blinded study assessing the dose-response of ropivacaine with dexmedetomidine for maintenance of labor with epidural analgesia in nulliparous parturients

Background: The combination of ropivacaine and dexmedetomidine has been used as an epidural analgesic for inducing labor. However, there is limited data regarding the administration of epidural analgesia for labor maintenance, hence, this study aimed to determine the optimum concentration through dose-response curves of ropivacaine plus dexmedetomidine, which could be used along with the Programmed Intermittent Epidural Bolus (PIEB) technique. Methods: One hundred parturients were randomized into 4 groups who were administered four different doses of ropivacaine (dexmedetomidine at 0.4 μg mL-1): 0.04%, 0.06%, 0.08%, and 0.1%. The primary outcome that was determined included the proportion of patients experiencing breakthrough pain during their 1st stage of labor. Breakthrough pain was described as a visual analog scale [VAS] score of >30 mm, requiring supplemental epidural analgesia after the administration of at least one patient-controlled bolus. The effective concentration of analgesia that was used for labor maintenance in 50% (EC50) and 90% (EC90) of patients were calculated with the help of probit regression. Secondary outcomes included epidural block characteristics, side effects, neonatal outcomes, and patient satisfaction. Results: The results indicated that the proportion of patients without breakthrough pain was 45% (10/22), 55% (12/22), 67% (16/24), and 87% (20/23) for 0.04%, 0.06%, 0.08%, and 0.10% doses of the analgesic that were administered, respectively. The EC50 value was 0.051% (95% confidence interval [CI], 0.011%-0.065%) while the EC90 value was recorded to be 0.117% (95% CI, 0.094%-0.212%). Side effects were similar among groups. Conclusion: A ropivacaine dose of 0.117% can be used as epidural analgesia for maintaining the 1st stage of labor when it was combined with dexmedetomidine (0.4 μg mL-1) and the PIEB technique. Clinical Trial Register: https://www.chictr.org.cn/index.aspx, identifier ChiCTR2200059557.

Automated mandatory bolus versus basal infusion for maintenance of epidural analgesia in labour

BACKGROUND

Epidural analgesia is often used for pain relief during labour and childbirth, and involves administration of local anaesthetics (LA) into the epidural space resulting in sensory blockade of the abdomen, pelvis, and perineum. Epidural opioids are often co-administered to improve analgesia. Administration of epidural medications can be accomplished by basal infusion (BI) or automated mandatory bolus (AMB). With BI, medications are administered continuously, while AMB involves injecting medications at set time intervals. Patient-controlled epidural analgesia (PCEA) on top of AMB or BI enables patients to initiate additional boluses of epidural medications.  The superior method of delivering epidural medications would result in lower incidence of pain requiring anaesthesiologist intervention (breakthrough pain). Also, it should be associated with lower incidence of epidural-related adverse effects including caesarean delivery, instrumental delivery (use of forceps or vacuum devices), prolonged duration of labour analgesia, and LA consumption. However, clear evidence of the superiority of one technique over the other is lacking. Also, differences in the initiation of epidural analgesia such as combined spinal-epidural (CSE) (medications given into the intrathecal space in addition to the epidural space) compared to epidural only, and medications used (types and doses of LA or opioids) may not have been accounted for in previous reviews.  Our prior systematic review suggested that AMB reduces the incidence of breakthrough pain compared to BI with no significant difference in the incidence of caesarean delivery or instrumental delivery, duration of labour analgesia, and LA consumption. However, several studies comparing AMB and BI have been performed since then, and inclusion of their data may improve the precision of our effect estimates.

OBJECTIVES

To assess the benefits and harms of AMB versus BI for maintaining labour epidural analgesia in women at term.

SEARCH METHODS

We searched CENTRAL, Wiley Cochrane Library), MEDLINE, (National Library of Medicine), Embase(Elseiver), Web of Science (Clarivate), the WHO-ICTRP (World Health Organization) and ClinicalTrials.gov (National Library of Medicine) on 31 December 2022. Additionally, we screened the reference lists of relevant trials and reviews for eligible citations, and we contacted authors of included studies to identify unpublished research and ongoing trials.

SELECTION CRITERIA

We included all randomised controlled studies that compared bolus dosing AMB with continuous BI during epidural analgesia. We excluded studies of women in preterm labour, with multiple pregnancies, with fetal malposition, intrathecal catheters, those that did not use automated delivery of medications, and those where AMB and BI were combined.

DATA COLLECTION AND ANALYSIS

We used standard methodology for systematic review and meta-analysis described by Cochrane. Primary outcomes included: incidence of breakthrough pain requiring anaesthesiologist intervention; incidence of caesarean delivery; and incidence of instrumental delivery. Secondly, we assessed the duration of labour; hourly LA consumption in bupivacaine equivalents, maternal satisfaction after fetal delivery, and neonatal Apgar scores.  The following subgroup analyses were chosen a priori: epidural alone versus CSE technique; regimens that used PCEA versus those that did not; and nulliparous versus combination of nulli- and multi-parous women. We used the GRADE system to assess the certainty of evidence associated with our outcome measures.

MAIN RESULTS

We included 18 studies of 4590 women, of which 13 enrolled healthy nulliparous women and five included healthy nulli- and multiparous women. All studies excluded women with preterm or complicated pregnancies. Techniques used to initiate epidural analgesia differed between the studies: seven used combined spinal epidural, 10 used epidural, and one used dural puncture epidural (DPE). There was also variation in analgesics used. Eight studies utilised ropivacaine with fentanyl, three used ropivacaine with sufentanil, two utilised levobupivacaine with sufentanil, one used levobupivacaine with fentanyl, and four utilised bupivacaine with fentanyl. Most of the studies were assessed to have low risk of randomisation, blinding, attrition, and reporting biases, except for allocation concealment where eight studies were assessed to have uncertain risk and three with high risk. Our results showed that AMB was associated with lower incidence of breakthrough pain compared to BI (risk ratio (RR) 0.71; 95% confidence interval (CI) 0.55 to 0.91; I2 = 57%) (16 studies, 1528 participants), and lower hourly LA consumption in bupivacaine equivalents (mean difference (MD) -0.84 mg/h; 95% CI -1.29 to -0.38, I2 = 87%) (16 studies, 1642 participants), both with moderate certainty. AMB was associated with an estimated reduction in breakthrough pain incidence of 29.1% (incidence 202 per 1000, 95% CI 157 to 259), and was therefore considered clinically significant. The incidence of caesarean delivery (RR 0.85; 95% CI 0.69 to 1.06; I2 = 0%) (16 studies, 1735 participants) and instrumental delivery (RR 0.85; 95% CI 0.71 to 1.01; I2 = 0%) (17 studies, 4550 participants) were not significantly, both with moderate certainty. There was no significant difference in duration of labour analgesia (MD -8.81 min; 95% CI -19.38 to 1.77; I2 = 50%) (17 studies, 4544 participants) with moderate certainty. Due to differences in the methods and timing of outcome measurements, we did not pool data for maternal satisfaction and Apgar scores. Results reported narratively suggest AMB may be associated with increased maternal satisfaction (eight studies reported increased satisfaction and six reported no difference), and all studies showed no difference in Apgar scores. WIth the exception of epidural alone versus CSE which found significant subgroup differences in LA consumption between AMB and BI, no significant differences were detected in the remaining subgroup analyses.

AUTHORS' CONCLUSIONS

Overall, AMB is associated with lower incidence of breakthrough pain, reduced LA consumption, and may improve maternal satisfaction. There were no significant differences between AMB and BI in the incidence of caesarean delivery, instrumental delivery, duration of labour analgesia, and Apgar scores. Larger studies assessing the incidence of caesarean and instrumental delivery are required.

Peri-operative anaesthetic management of women with obesity

Obesity in women is prevalent and growing at an alarming pace worldwide, resulting in significant healthcare and socioeconomic consequences. Obesity is a multisystemic disease that is associated with numerous comorbidities, particularly sleep-disordered breathing, hypertension, coronary artery disease, pulmonary hypertension, thromboembolism, and diabetes mellitus. Additionally, obesity poses several peri-operative challenges including difficulty with airway management and mechanical ventilation, challenges with intravenous access or regional blocks, the need for modified anaesthetic drug dosing, the requirement for correctly sized and rated equipment, and appropriate post-operative monitoring. Therefore, early multidisciplinary planning is crucial to identify and address important peri-operative and clinical issues. Parturients with obesity are especially at high risk due to the additional physiological changes and obstetric comorbidities associated with obesity. Antenatal anaesthetic consultation along with close communication and collaboration within the multidisciplinary team are important to improve maternal and neonatal safety.

Perceived stress during labor and its association with depressive symptomatology, anxiety, and pain catastrophizing

Perceived stress is a dimension of the maternal stress response, however little data is available on perceived stress levels and its associated psychological risk factors during labor. In this secondary data analysis from a prospective study evaluating epidural regimens, we investigated the potential associations between depressive symptomatology, anxiety, and pain catastrophizing with perceived stress during labor. Healthy nulliparous adult women with term singleton pregnancies requesting for epidural analgesia in early labor were included. Assessments were administered after epidural analgesia and adequate pain relief were achieved. Perceived stress (Perceived Stress Scale, PSS, high PSS ≥ 16), depressive symptomatology (Edinburgh Postnatal Depression Scale, EPDS, high EPDS ≥ 10), and pain catastrophizing (Pain Catastrophizing Scale, PCS, high total PCS ≥ 25) were assessed as categorical variables. Additionally, anxiety (State-trait Anxiety Inventory, STAI), PCS total and its subscales (rumination, magnification and helplessness) were analyzed as continuous variables. Univariate and multivariable logistic regression models were used to identify factors associated with high PSS. Of 801 women included, 411 (51.9%) had high PSS. High EPDS (OR 2.16, 95%CI 1.36–3.44), increasing trait anxiety (OR 1.17, 95%CI 1.14–1.20), and increasing pain magnification (OR 1.12, 95%CI 1.05–1.19) were independently associated with high PSS. Depressive symptomatology, trait anxiety, and pain magnification were associated with perceived stress during labor, providing impetus for future research aimed at detecting and alleviating stress and its psychological or pain association factors.

Peripartum optimization and coordination of collaborative care practice: a critical role for the obstetric anesthesiologist in combating maternal morbidity and mortality

PURPOSE OF REVIEW

Antenatal anesthesia clinics remain uncommon despite the rising incidence of maternal morbidity and mortality in the United States. The purpose of the present review is to outline the major considerations and challenges surrounding antenatal anesthetic evaluation.

RECENT FINDINGS

Data from the general surgical population would suggest a mortality benefit associated with preoperative anesthesia evaluation, although no such data exists in the obstetric population.Robust systems for case ascertainment and referral are needed. Recent publications on obstetric comorbidity indices may provide useful tools to ascertain high-risk parturients for a referral to antenatal obstetric anesthesiology clinics and higher levels of maternal care. Major obstetric organizations have identified and laid out criteria for maternal level of care. Anesthesiology resources also play a role in these designations and can help triage patients to facilities with appropriate resources.

SUMMARY

Obstetric anesthesiologists have a critical role not only in preoperative patient optimization but also in coordinating multidisciplinary care for optimal patient outcomes.

Obesity in women: anaesthetic implications for peri-operative and peripartum management

The prevalence, healthcare and socio-economic impact of obesity (defined as having a body mass index of ≥ 30 kg.m^-2 ) are disproportionately higher in women than men. A combination of biological and social factors, including the adaptation of energy homeostasis to the increased demands of pregnancy and lactation and poor access to healthy foods or exercise facilities, contribute to the increasing prevalence of obesity in women. Obesity-related physiological changes stem from mass loading and increased metabolism of adipose tissue, as well as secretion of bioactive substances from adipocytes leading to chronic low-grade inflammation. As a result, obesity is associated with increased risks of: infertility; malignancy; sleep-disordered breathing; cardiovascular disease; diabetes; and thromboembolism. Hence, obese women are at markedly increased risk of peri-operative morbidity and mortality and require comprehensive evaluation and targeted comorbidity optimisation by a multidisciplinary team. In addition to routine obstetric challenges, pregnancy in women with obesity further exacerbates the above risks, making multidisciplinary management starting at pre-conception even more important. Weight loss, lifestyle management and optimisation of comorbidity are the cornerstone of reducing obesity-related risks. The anaesthetist plays a vital role within the multidisciplinary team by emphasising weight loss as part of pre-operative comorbidity optimisation, formulation of individualised peri-operative management plans, supervising postoperative care in the high dependency or intensive care settings and providing safe labour analgesia and careful peripartum management for obese parturients.

Prediction of breakthrough pain during labour neuraxial analgesia: comparison of machine learning and multivariable regression approaches

INTRODUCTION

Risk-prediction models for breakthrough pain facilitate interventions to forestall inadequate labour analgesia, but limited work has used machine learning to identify predictive factors. We compared the performance of machine learning and regression techniques in identifying parturients at increased risk of breakthrough pain during labour epidural analgesia.

METHODS

A single-centre retrospective study involved parturients receiving patient-controlled epidural analgesia. The primary outcome was breakthrough pain. We randomly selected 80% of the cohort (training cohort) to develop three prediction models using random forest, XGBoost, and logistic regression, followed by validation against the remaining 20% of the cohort (validation cohort). Area-under-the-receiver operating characteristic curve (AUC), sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were used to assess model performance.

RESULTS

Data from 20 716 parturients were analysed. The incidence of breakthrough pain was 14.2%. Of 31 candidate variables, random forest, XGBoost and logistic regression models included 30, 23, and 15 variables, respectively. Unintended venous puncture, post-neuraxial analgesia highest pain score, number of dinoprostone suppositories, neuraxial technique, number of neuraxial attempts, depth to epidural space, body mass index, pre-neuraxial analgesia oxytocin infusion rate, maternal age, pre-neuraxial analgesia cervical dilation, anaesthesiologist rank, and multiparity, were identified in all three models. All three models performed similarly, with AUC 0.763-0.772, sensitivity 67.0-69.4%, specificity 70.9-76.2%, PPV 28.3-31.8%, and NPV 93.3-93.5%.

CONCLUSIONS

Machine learning did not improve the prediction of breakthrough pain compared with multivariable regression. Larger population-wide studies are needed to improve predictive ability.

Enhanced recovery after cesarean delivery: a challenge for anesthesiologists

Enhanced recovery after cesarean (ERAC) delivery is an evidence-based, multi-disciplinary approach throughout pre-, intra-, post-operative period. The ultimate goal of ERAC is to enhance recovery and improve the maternal and neonatal outcomes. This review highlights the role of anesthesiologist in ERAC protocols. This review provided a general introduction of ERAC including the purposes and the essential elements of ERAC protocols. The tool used for evaluating the quality of ERAC (ObsQoR-11) was discussed. The role of anesthesiologist in ERAC should cover the areas including management of peri-operative hypotension, prevention and treatment of intra- and post-operative nausea and vomiting, prevention of hypothermia and multi-modal peri-operative pain management, and active pre-operative management of unplanned conversion of labor analgesia to cesarean delivery anesthesia. Although some concerns still remain, ERAC implementation should not be delayed. Regular assessment and process improvement should be imbedded into the protocol. Further high-quality studies are warranted to demonstrate the effectiveness and efficacy of the ERAC protocol.