The association between epidural labour analgesia and postpartum depression: a randomised controlled trial.

There is conflicting evidence regarding the association between epidural labour analgesia and risk of postpartum depression. Most previous studies were observational trials with limited ability to account for confounders. We aimed to determine if epidural analgesia was associated with a significant change in the incidence of postpartum depression in this randomised controlled trial. We enrolled women aged 21-50 years old with a singleton fetus ≥ 36 weeks gestation. Patients were advised regarding available labour analgesic modalities during enrolment (epidural block; intramuscular pethidine; nitrous oxide; or intravenous remifentanil). On request for analgesia, patients were offered the modality that they had been allocated randomly to first. Blinded investigators recorded patient and obstetric characteristics within 24 h of delivery and assessed for postpartum depression at 6-10 weeks following delivery using the Edinburgh Postnatal Depression Scale (score ≥ 13 considered positive for postpartum depression). The modified intention-to-treat population consisted of all patients who received any form of labour analgesia, while per-protocol consisted of patients who received their randomised modality as their first form of labour analgesia. Of 881 parturients allocated randomly (epidural n = 441, non-epidural n = 440), we analysed 773 (epidural n = 389, non-epidural n = 384); 62 (15.9%) of women allocated to epidural group developed postpartum depression compared with 65 (16.9%) women allocate to the non-epidural group. There were no significant differences in the incidence of postpartum depression between the two groups (adjusted risk difference (95%CI) 1.6 (-3.0-6.3%), p = 0.49). Similar results were obtained with per-protocol analysis (adjusted risk difference (95%CI) -1.0 (-8.3-6.3%), p = 0.79). We found no significant difference in the risk of postpartum depression between patients who received epidural labour analgesia and those who utilised non-epidural analgesic modalities.

Risk factors for persistent pain after breast cancer surgery: a multicentre prospective cohort study.

Identifying factors associated with persistent pain after breast cancer surgery may facilitate risk stratification and individualised management. Single-population studies have limited generalisability as socio-economic and genetic factors contribute to persistent pain development. Therefore, this prospective multicentre cohort study aimed to develop a predictive model from a sample of Asian and American women. We enrolled women undergoing elective breast cancer surgery at KK Women's and Children's Hospital and Duke University Medical Center. Pre-operative patient and clinical characteristics and EQ-5D-3L health status were recorded. Pain catastrophising scale; central sensitisation inventory; coping strategies questionnaire-revised; brief symptom inventory-18; perceived stress scale; mechanical temporal summation; and pressure-pain threshold assessments were performed. Persistent pain was defined as pain score ≥ 3 or pain affecting activities of daily living 4 months after surgery. Univariate associations were generated using generalised estimating equations. Enrolment site was forced into the multivariable model, and risk factors with p < 0.2 in univariate analyses were considered for backwards selection. Of 210 patients, 135 (64.3%) developed persistent pain. The multivariable model attained AUC = 0.807, with five independent associations: age (OR 0.85 95%CI 0.74-0.98 per 5 years); diabetes (OR 4.68, 95%CI 1.03-21.22); pre-operative pain score at sites other than the breast (OR 1.48, 95%CI 1.11-1.96); previous mastitis (OR 4.90, 95%CI 1.31-18.34); and perceived stress scale (OR 1.35, 95%CI 1.01-1.80 per 5 points), after adjusting for: enrolment site; pre-operative pain score at the breast; pre-operative overall pain score at rest; postoperative non-steroidal anti-inflammatory drug use; and pain catastrophising scale. Future research should validate this model and evaluate pre-emptive interventions to reduce persistent pain risk.

Hyperbaric vs. isobaric bupivacaine for spinal anaesthesia for elective caesarean section: a Cochrane systematic review.

Both isobaric and hyperbaric bupivacaine have been used for spinal anaesthesia for elective caesarean section, but it is not clear if one is better than the other. The primary objective of this systematic review was to determine the effectiveness and safety of hyperbaric bupivacaine compared with isobaric bupivacaine administered during spinal anaesthesia for elective caesarean section. We included 10 studies with 614 subjects in the analysis. There was no evidence of differences either in the risk of conversion to general anaesthesia, with a relative risk (95%CI) of 0.33 (0.09-1.17) (very low quality of evidence), or in the need for supplemental analgesia, the relative risk (95%CI) being 0.61 (0.26-1.41) (very low quality of evidence). There was also no evidence of a difference in the use of ephedrine, the amount of ephedrine used, nausea and vomiting, or headache. Hyperbaric bupivacaine took less time to reach a sensory block height of T4, with a mean difference (95%CI) of -1.06 min (-1.80 to -0.31). Due to the rarity of some outcomes, dose variability, use of adjuvant drugs and spinal technique used, future clinical trials should look into using adequate sample size to investigate the primary outcome of the need for supplemental analgesia.

A case series of vital signs-controlled, patient-assisted intravenous analgesia (VPIA) using remifentanil for labour and delivery.

Intravenous remifentanil patient-controlled analgesia can be used during labour as an alternative to epidural analgesia. Adverse effects of opioids, including hypoxia and bradycardia, may lead to maternal morbidity and mortality. We devised an interactive feedback system based on a clinical proportional algorithm, to continuously monitor for adverse effects to enhance safety and better titrate analgesia. This vital signs-controlled, patient-assisted intravenous analgesia with remifentanil used a prototype delivery system linked to a pulse oximeter that evaluated maternal oxygen saturation and heart rate continuously. With this system, we detected oxygen saturation < 95% for more than 60 s in 15 of 29 subjects (52%); and heart rate < 60 min-1 for more than 60 s in 7 of 29 subjects (24%) during use. The system automatically responded appropriately by reducing the dosages and temporarily halting remifentanil administration, thus averting further hypoxia and bradycardia.

Common variants of catechol-O-methyltransferase influence patient-controlled analgesia usage and postoperative pain in patients undergoing total hysterectomy.

Catechol-O-methyltransferase (COMT) gene polymorphisms and haplotypes have been associated with both experimental and clinical pain phenotypes. In this prospective study, we investigated the association of three common polymorphisms with experimentally induced pressure pain, postoperative pain and amount of self-administered morphine in 973 patients who underwent scheduled total hysterectomy. DNA extracted from peripheral blood was genotyped for three COMT polymorphisms by Taqman assay or a PCR-based method. In the overall sample, rs4633 and rs4680 were significantly associated with morphine use, whereas rs4818 was associated with time-averaged pain scores. Statistically significant associations were found between COMT rs4633 and rs4680 genotypes and the amount of morphine self-administered through a patient-controlled analgesia pump. For rs4818, the only statistically significant association was with time-averaged pain scores. Haplotype analysis showed statistically significant association of the low pain sensitivity haplotype with time-averaged pain scores; and average pain sensitivity haplotype with total morphine and weight-adjusted morphine.

Assessment of an updated double-vasopressor automated system using Nexfin for the maintenance of haemodynamic stability to improve peri-operative outcome during spinal anaesthesia for caesarean section.

Hypotension occurs commonly during spinal anaesthesia for caesarean section, associated with maternal and fetal adverse effects. We developed a double-vasopressor automated system with a two-step algorithm and continuous non-invasive haemodynamic monitoring using the Nexfin device. The system delivered 25 µg phenylephrine every 30 s when systolic blood pressure was between 90% and 100% of baseline, or 2 mg ephedrine at this blood pressure range and heart rate < 60 beats.min(-1) ; and 50 µg phenylephrine or 4 mg ephedrine when systolic blood pressure was < 90% of baseline with the same heart rate criterion. Fifty-seven women received standardised spinal anaesthesia. Twenty-seven (47.4%) had at least one reading of hypotension defined as systolic blood pressure < 80% baseline. Systolic blood pressure was within 20% of the baseline in a mean (SD) of 79.8 (20.9)% of measurements. Fifty-three (93.0%) women required phenylephrine before delivery while 10 (17.5%) required ephedrine. Six women (10.5%) experienced nausea and three (5.3%) vomited. The system was able to achieve a low incidence of maternal hypotension with good maternal and fetal outcomes.

Closed-loop double-vasopressor automated system vs manual bolus vasopressor to treat hypotension during spinal anaesthesia for caesarean section: a randomised controlled trial.

Hypotension necessitating vasopressor administration occurs commonly during caesarean section under spinal anaesthesia. We developed a novel vasopressor delivery system that automatically administers phenylephrine or ephedrine based on continuous non-invasive arterial pressure monitoring. A phenylephrine bolus of 50 µg was given at 30-s intervals when systolic blood pressure fell < 90% of baseline; an ephedrine bolus of 4 mg was given instead if systolic pressure fell < 90% of baseline together with a heart rate < 60 beats.min(-1). The control group used manual boluses of either phenylephrine 100 µg or ephedrine 8 mg, administered at 1-min intervals based on the same thresholds for systolic pressure and heart rate. This randomised, controlled, double-blinded trial involved 213 healthy women who underwent elective caesarean delivery under spinal anaesthesia using 11 mg hyperbaric bupivacaine with 15 µg fentanyl and 100 µg morphine. The automated vasopressor group had better systolic pressure control, with 37/106 (34.9%) having any beat-to-beat systolic pressure reading < 80% of baseline compared with 63/107 (58.9%) in the control group (p < 0.001). There was no difference in the incidence of reactive hypertension, defined as systolic pressure > 120% of baseline, with 8/106 (7.5%) in the automated vasopressor group vs 14/107 (13.1%) in the control group, or total dose of vasopressors. The automated vasopressor group had lower median absolute performance error of 8.5% vs control of 9.8% (p = 0.013), and reduced incidence of nausea (1/106 (0.9%) vs 11/107 (10.3%), p = 0.005). Neonatal umbilical cord pH, umbilical lactate and Apgar scores were similar. Hence, our system afforded better control of maternal blood pressure and reduced nausea with no increase in reactive hypertension when compared with manual boluses.

Novice learners' perspectives on obstetric airway crisis decision-making training using virtual reality simulation.

BACKGROUND: Current training on managing an obstetric difficult airway crisis is likely inadequate, as real-life opportunities to practice are rare. Frequent simulation training sessions could be helpful but are resource intensive. Virtual reality (VR) simulation training may be a potential tool to complement existing simulation curricula. METHODS: In this pilot qualitative study, a VR simulation scenario of an obstetric airway crisis was designed to test the decision-making of novice learners rotating through obstetric anesthesia training. Individual interviews were conducted pre-VR to assess learning needs and post-VR to assess perspectives on utilizing the VR teaching tool. The interviews were transcribed and thematically analyzed. RESULTS: Twenty-one residents were recruited and participated in the study. Analysis of pre-VR interviews identified three major themes, including gaps in the current curriculum, lack of confidence in managing obstetric difficult airway crises, and recognition that simulation is resource intensive. Post-VR interview themes revealed that VR could be helpful in learning decision-making under stress. Suggested improvements included better video and audio quality, and adding haptic feedback and potential multiplayer features in the future. CONCLUSION: We identified the advantages of VR simulation and its potential as an intervention to address gaps in our curriculum. Areas of improvement were identified for more effective future implementation.

Education in obstetric anesthesiology: an international approach.

Competency-based training and active teaching methods are increasingly becoming accepted and utilized in medical schools and hospitals, and obstetric anesthesiology training is expected to follow this process. This article summarizes current modalities of obstetric anesthesiology training in five countries from various parts of the world. Analysis of these curricula shows that implementation of new educational methods is variable, incomplete, and lacking in data related to patient outcomes. Research in assessments and practical applications are required to avoid wide ranges of educational strategies.

Closed-loop double-vasopressor automated system to treat hypotension during spinal anaesthesia for caesarean section: a preliminary study.

Hypotension occurs in most caesarean sections under spinal anaesthesia, necessitating vasopressor administration. However, the optimal dosing regimen remains unclear. We have developed a novel vasopressor delivery system that automatically administers phenylephrine or ephedrine based on continuous non-invasive blood pressure monitoring. This prospective cohort study recruited 55 healthy women under standardised spinal anaesthesia with 2.2 ml hyperbaric bupivacaine 0.5%, 15 µg fentanyl and 100 µg morphine. A 50-µg phenylephrine bolus was given at 1-min intervals when systolic blood pressure fell below 90% of baseline, and a 4-mg ephedrine bolus was given when hypotension developed with bradycardia (heart rate <60 beats.min(-1) ). Systolic blood pressure was within 20% of baseline in 88% of all measurements. Six patients (11%) had one or more measurements above 120% of baseline (1% of all measurements), whereas 36 (65%) had at least one reading below 80% of baseline (11% of total measurements). The system maintained systolic blood pressure at a mean (SD) of -9.1 (7.0)% below baseline, with 5.4 (2.5)% fluctuation. Two patients (4%) experienced pre-delivery nausea. All 5-min Apgar scores were 9.

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.

Rescue supraglottic airway devices at caesarean delivery: What are the options to consider?

Tracheal intubation is considered the gold standard means of securing the airway in obstetric general anaesthesia because of the increased risk of aspiration. Obstetric failed intubation is relatively rare. Difficult airway guidelines recommend the use of a supraglottic airway device to maintain the airway and to allow rescue ventilation. Failed intubation is associated with a further increased risk of aspiration, therefore there is an argument for performing supraglottic airway-guided flexible bronchoscopic intubation (SAGFBI). The technique of SAGFBI has a high success rate in the non-obstetric population, it protects the airway and it minimises task fixation on repeated attempts at laryngoscopic tracheal intubation. However, after failed intubation via laryngoscopy, there is a lack of specific recommendations or indications for SAGFBI in current obstetric difficult airway guidelines in relation to achieving tracheal intubation. Our narrative review explores the issues pertaining to airway management in these cases: the use of supraglottic airway devices and the techniques of, and technical issues related to, SAGFBI. We also discuss the factors involved in the decision-making process as to whether to proceed with surgery with the airway maintained only with a supraglottic airway device, or to proceed only after SAGFBI.

Determining competence in performing obstetric combined spinal-epidural procedures in junior anesthesiology residents: results from a cumulative sum analysis.

BACKGROUND: The epidural anesthesia technique is a challenging skill to master. The Accreditation Council for Graduate Medical Education (ACGME) stipulates that anesthesiology residents must complete 40 epidural procedures by the end of junior residency. The rationale is unknown. The aim of this prospective study was to determine the minimum case experience required to demonstrate competence in performing obstetric combined spinal-epidural procedures among junior residents, using an objective statistical tool, the cumulative sum (CUSUM) analysis. METHODS: Twenty-four residents, with no prior experience performing epidurals, sequentially recorded all obstetric combined spinal-epidural procedures as a 'success' or 'failure', based on study criteria. Individual CUSUM graphs were plotted, with acceptable and unacceptable failure rates set at 20% and 35%, respectively. The number of procedural attempts necessary to demonstrate competence was determined. RESULTS: Twenty-four residents (mean (SD) age 29 (2) years) participated in the study. Median (IQR) number of procedures was 78 (66-85), with a median (IQR) success rate of 86% (82-89%). Nineteen of 24 residents required a median (IQR) of 40 (33-50) attempts to demonstrate competence. Five did not achieve procedural competence in the training period. The CUSUM graphs highlighted performance trends that required intervention. CONCLUSION: Competence was achieved by 19/24 residents after the ACGME-required case experience of 40 combined spinal-epidural procedures, based on a predefined acceptable failure rate of 20%. In our experience, CUSUM analysis is useful in monitoring technical performance over time and should be included as an adjunct assessment method for determining procedural competence.

Considerations and strategies in the organisation of obstetric anaesthesia care during the 2019 COVID-19 outbreak in Singapore.

The provision of safe obstetric anaesthesia services is essential during the COVID-19 global outbreak. The identification of the 'high-infection risk' parturient can be challenging especially with the rapidly changing risk criteria for COVID-19 'cases'. A multidisciplinary taskforce is required to review the infection control protocols and workflows for managing the parturient for labour analgesia and for caesarean section in order to minimize infection risk to healthcare staff and other parturients. A constant review of such processes is needed to enhance efficiency and to optimise use of finite resources. Good communication between health officials, institutional leadership and ground staff is essential for the dissemination of information.

Association of renin-angiotensin-aldosterone system genetic polymorphisms with maternal hypotension during spinal anaesthesia for caesarean delivery: a retrospective cohort study.

BACKGROUND: Unless prevented, hypotension occurs in up to 80% of normotensive women undergoing spinal anaesthesia for caesarean delivery. Renin-angiotensin-aldosterone system genetic polymorphisms have been associated with hypertensive disease, but few studies investigated effects on blood pressure regulation under spinal anaesthesia. We postulated that these polymorphisms increased vasodilation and maternal hypotension during spinal anaesthesia. METHODS: A retrospective secondary analysis of data from four prospective trials with similar inclusion/exclusion criteria evaluating phenylephrine/ephedrine delivery systems during spinal anaesthesia for elective caesarean delivery. Angiotensin type-1 receptor (AT1R) (A1166C), angiotensin-converting enzyme (ACE) (I/D), and aldosterone synthase CYP11B2 (C344T) polymorphisms were identified from stored specimens. The associations between the polymorphisms and hypotension (systolic blood pressure <80% of baseline), and vasopressor use, were determined by univariable and multivariable regression. RESULTS: Of 556 patients, 378 (68.0%) had hypotension. The AC/CC genotypes of AT1R (A1166C) were associated with hypotension by univariable analysis (OR 2.70, 95% CI 1.38 to 5.28, P=0.004]) and multivariable analysis (OR 3.65, [95% CI 1.68 to 7.94, P=0.004]) after adjustment for age, race, intravenous fluid volume, and block height. No difference in vasopressor use or adverse maternal or fetal outcomes were noted. Baseline characteristics were similar, with the exception of higher baseline blood pressure, block height, and intravenous fluid volume in the hypotensive group. There was no significant association between ACE and CYP11B2 polymorphisms and hypotension. CONCLUSION: AC/CC genotypes of AT1R (A1166C) polymorphism were associated with maternal hypotension under spinal anaesthesia for caesarean delivery. An association with cardiovascular indices and high-risk parturients should be examined.

Exploring the challenges of task-centred training in obstetric anaesthesia in the operating theatre environment.

BACKGROUND: Task-centred learning forms the basis of procedural training in obstetric anaesthesia. We observed that our residents were not building their competence from experiential practice in the operating theatre. We used a broad-based framework to explore the challenges encountered by the residents and clinical supervisors in the learning and teaching of obstetric anaesthesia. METHODS: The study was conducted at the KK Women's and Children's Hospital, Singapore, from 1 December 2016 to 30 June 2017. A semi-structured interview format was used in the focus group and individual interviews. Information collection continued until data saturation was reached. The interviews were analysed and the challenges were identified. Fourteen residents and five clinical supervisors participated in the focus group and individual interviews respectively. FINDINGS: The operating theatre constituted a stressful learning and teaching environment for the participants. Five categories of challenges were identified: (1) clinical conditions, (2) concerns about maternal risk and outcomes, (3) reluctance of the residents to vocalise their learning needs, (4) poor feedback, and (5) lack of opportunities for inter-professional practice. These collective challenges reduced the quality of task-centred learning and the effectiveness of supervisor teaching. We described some strategies to overcome these challenges (dedicated trainee lists, obstetric anaesthesia reflective diary, active mentoring system and in-situ simulation). CONCLUSIONS: Our study described the challenges of obstetric anaesthesia training in the operating theatre environment in an Asian healthcare setting. Research is needed on the influence of supervisors' concern about maternal risks and their teaching behaviours.

Incidence and risk factors for epidural re-siting in parturients with breakthrough pain during labour epidural analgesia: a cohort study.

INTRODUCTION: Epidural re-siting is one of the significant events during labour epidural analgesia that may result in decreased patient satisfaction. The aim of our study was to investigate the incidence of and factors associated with epidural re-siting in parturients using epidural analgesia, with an emphasis on those with breakthrough pain. METHODS: A retrospective cohort study of 10170 parturients who received labour epidural analgesia. The primary outcome was the incidence of epidural re-siting (binary data). Univariate and multivariate logistic regression analysis were performed to find associated risk factors for re-siting. RESULTS: Less than 1% (0.85%, 86/10170) of the women in the study had their epidural re-sited. Amongst the subset of women with breakthrough pain, the incidence of epidural re-siting was higher (4.7%, 68/1454). Most of the women who had their epidural re-sited had experienced breakthrough pain (79%, 68/86). Amongst all parturients, the presence of breakthrough pain (OR=21.31), hypotension (OR=4.18) and venous puncture (OR=2.74) were significantly associated with re-siting. Amongst the parturients with breakthrough pain who required epidural re-siting, lower cervical dilatation (OR=0.81), higher number of episodes of breakthrough pain (OR=1.83) and patchy block (OR=4.37) were significantly associated with re-siting. The areas-under-curves of two multivariate models were 0.894 and 0.806 respectively. CONCLUSION: In our institution, the incidence of epidural catheter re-siting was low in all patients. However, the majority of patients whose catheters were re-sited had exhibited breakthrough pain. The risk factors associated with the need for re-siting of catheters in all patients differed from those who had breakthrough pain.