Simulation-based training in obstetric anesthesia: an update.

In this update we explore the current applications of simulation in obstetric anesthesia, describe what is known regarding its impacts on care and consider the different settings in which simulation programs are required. We will introduce practical strategies, such as cognitive aids and communication tools, that can be applied in the obstetric setting and share ways in which a program might apply these tools. Finally, we provide a list of common obstetric emergencies essential for a program's curriculum and common teamwork pitfalls to address within a comprehensive obstetric anesthesia simulation program.

Baseline parameters for rotational thromboelastometry in healthy labouring women: a prospective observational study.

OBJECTIVE: The aim of this study was to establish rotational thromboelastometry (ROTEM® ) baseline parameters in labouring women at term gestation. The secondary aim was to compare these reference ranges with those from previous studies on labouring women and from the manufacturer. DESIGN: A prospective, observational study. SETTING: Tertiary referral hospital. PARTICIPANTS: Healthy women in labour. METHODS: Ethics approval was granted for an opt-out recruitment approach. ROTEM® testing was performed in labouring women at term gestation. Women with any condition affecting coagulation were excluded. ROTEM® Delta reference ranges were derived by calculating the 2.5% and 97.5% centiles for INTEM/EXTEM/FIBTEM parameters including amplitude at 5 minutes (A5), coagulation time (CT) and maximum clot firmness (MCF). MAIN OUTCOME MEASURES: ROTEM® parameters were measured in labouring women before delivery. The following tests were performed: FIBTEM, EXTEM and INTEM. RESULTS: One hundred and twenty-one women met the inclusion criteria, with a mean (± SD) age of 29.6 ± 5.4 years and median (interquartile range) gestation of 39.4 weeks (37.4-40.4 weeks). Seventy-five (62.0%) women were nulliparous and 71 (58.7%) delivered vaginally. The median and interquartile ranges for selected ROTEM® parameters were: FIBTEM A5, 21 mm (IQR 18-23 mm); EXTEM A5, 55 mm (52-58 mm); and EXTEM CT, 52 seconds (48-56 seconds). CONCLUSIONS: The FIBTEM/EXTEM/INTEM amplitudes were higher than the manufacturer's reference ranges for non-obstetric patients. The FIBTEM MCF upper and lower limits were higher and the EXTEM/INTEM CT was shorter and narrower in range. This study provides reference ranges for ROTEM® values in healthy labouring women at term gestation with uncomplicated pregnancies. TWEETABLE ABSTRACT: This is the first study to report on ROTEM® reference ranges with over 120 healthy labouring women of normal weight at term gestation.

Baseline parameters for rotational thromboelastometry (ROTEM®) in healthy pregnant Australian women: a comparison of labouring and non-labouring women at term.

BACKGROUND: Rotational thromboelastometry (ROTEM®) is a point-of-care coagulation test. Reference ranges in non-labouring women have recently been established from a cohort of women presenting for elective caesarean delivery using the recommended minimum sample size of 120. This study aimed to present baseline parameters for labouring and non-labouring women and to compare the mean values of these ROTEM® parameters. METHODS: Ethical approval was granted for an opt-out recruitment approach for labouring women and written consent was obtained from non-labouring women (data published previously). ROTEM® testing was performed in these two cohorts at term gestation. Women with any condition affecting coagulation were excluded. ROTEM® Delta reference ranges were derived by calculating the 2.5 and 97.5 percentiles for INTEM/EXTEM/FIBTEM amplitude at 5 min (A5), coagulation time (CT), maximum clot firmness (MCF) and clot formation time (CFT). RESULTS: One hundred and twenty-one labouring and 132 non-labouring women met inclusion criteria. The mean values for selected ROTEM® parameters for labouring and non-labouring women respectively were: FIBTEM A5, 21.05 and 19.7 mm (P=0.008); EXTEM A5, 54.8 and 53.2 mm (P=0.025); and EXTEM CT, 52.2 and 53.7 s (P=0.049). Significant differences between the groups were observed in measures of clotting onset and clot firmness. CONCLUSIONS: We demonstrated a significant decrease in the mean time-to-clotting onset in labouring women compared with non-labouring women. Mean values for measures of clot firmness were greater in labouring women. In comparison to previously established ROTEM® baseline parameters for non-labouring women, this study provides evidence that there is greater hyper-coagulability in labouring women.

Reducing post-caesarean delivery surgical site infections: a narrative review.

Surgical site infection complicates 1-10% of caesarean deliveries. With the rate of caesarean delivery increasing, it is important to identify effective measures of preventing surgical site infection and to consider their impact on maternal and neonatal outcomes. Compelling evidence supports the use of prophylactic antibiotics, prior to skin incision, to reduce surgical site infection. However, there remain international variations in terms of the recommended agent, dose and body weight-adjusted dosing. Advances in wound dressings are an evolving area of interest and surgical technique can influence outcomes. This narrative review explores pharmacological and non-pharmacological methods of preventing surgical site infection following caesarean delivery.

Baseline parameters for rotational thromboelastometry (ROTEM®) in healthy women undergoing elective caesarean delivery: a prospective observational study in Australia.

BACKGROUND: Formal reference ranges for rotational thromboelastometry (ROTEM®) in pregnancy have not been obtained in the recommended minimum sample size of 120. This prospective observational study aimed to establish baseline parameters in an Australian population of women undergoing elective caesarean delivery. The secondary aim was to compare these reference ranges with those from prior studies and the manufacturer. METHODS: Women undergoing elective caesarean delivery at term were included if they were at term, of normal body mass index and had no conditions affecting coagulation. ROTEM® reference ranges were derived by calculating the 2.5 and 97.5 percentiles for INTEM/EXTEM/FIBTEM amplitude at 5 minutes (A5), amplitude at 15 minutes (A15), coagulation time (CT), maximum clot firmness (MCF), and clot formation time (CFT). RESULTS: Of 202 women screened, 132 met the inclusion criteria, having a mean age of 32.7 ±â€¯5.0 years and median body mass index of 23.8 kg/m2 (interquartile range 21.5-26.4). The reference ranges for selected ROTEM® parameters were as follows: FIBTEM A5 (13-28 mm), FIBTEM CT (40-74 s), FIBTEM MCF (16-34 mm), EXTEM A5 (39-66 mm), EXTEM CT (43-69 s), INTEM A5 (38-63 mm). CONCLUSIONS: ROTEM® reference ranges for women with uncomplicated term pregnancies were reported as per the International Federation of Clinical Chemistry. The FIBTEM MCF and FIBTEM/EXTEM/INTEM amplitudes were higher in comparison to the manufacturer's reference ranges for the non-obstetric population. The EXTEM CT was shorter than the non-obstetric reference ranges. These ranges show an increase in coagulability during normal pregnancy compared to the non-pregnant reference ranges.

Increasing body mass index and abdominal subcutaneous fat thickness are associated with increased skin-to-epidural space distance in pregnant women.

BACKGROUND: Body mass index does not indicate the distribution of adipose tissue. Central adiposity may be measured using ultrasound measurement of subcutaneous fat thickness. This study determined if the abdominal subcutaneous fat thickness measured correlated with skin-to-epidural space distance at delivery, and compared this with the booking body mass index. METHODS: We analysed a sub-set of participants from a single-centre, prospective cohort study that assessed the relationship between subcutaneous fat thickness and maternity outcomes. Abdominal subcutaneous fat thickness measurements were obtained during the routine fetal anomaly scan. The skin-to-epidural space distance was obtained in those having epidural or combined spinal-epidural analgesia. Linear regression was used to test for strength of association and adjusted R2 values calculated to determine if subcutaneous fat thickness or body mass index was more strongly associated with skin-to-epidural space distance. RESULTS: The 463 women had a median (IQR) booking body mass index of 25.0 kg/m2 (21.8-29.3) and subcutaneous fat thickness of 16.2 mm (13.0-21.0). The median (IQR) skin-to-epidural space distance was 5.0 cm (4.5-6.0). Both parameters significantly correlated with skin-to-epidural space distance (r=0.53 and 0.68 respectively, P <0.001). Adjusted linear regression coefficient (95% CI) for subcutaneous fat thickness was 0.09 (0.08 to 0.11), R2=0.30 and for body mass index 0.12 (0.11 to 0.13), R2=0.47. CONCLUSIONS: Booking body mass index had a stronger relationship with skin-to- epidural space distance at delivery than subcutaneous fat thickness, explaining 47% of the variation in the skin-to-epidural distance.

A review of blood pressure measurement in obese pregnant women.

Blood pressure monitoring is a critical component of antenatal, peripartum and postnatal care. The accurate detection and treatment of abnormal blood pressure during pregnancy is essential for the optimisation of maternal and neonatal outcomes. Increasing maternal obesity in western populations is well documented. The presence of a large arm circumference in obese pregnant women may lead to difficult and inaccurate blood pressure measurements. Difficulties measuring blood pressure in non-pregnant obese patients are well described. In the literature, the problem is uncommonly mentioned in relation to pregnant patients. This topic review will discuss the importance and challenges of blood pressure measurement in pregnancy. The currently available equipment for blood pressure monitoring in pregnancy will be identified and the process of validating devices described. The limitations of the current validation protocols in pregnancy will be highlighted. It is concluded that a pregnancy-specific validation protocol is required: this would facilitate the introduction of new technology for use in high-risk pregnant women. More accurate blood pressure measurement has the potential to improve the diagnosis and management of abnormal blood pressure in pregnancy and influence maternal and neonatal outcomes.

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.

Anaesthetic management of obese parturients: what is the evidence supporting practice guidelines?

Increasing rates of obesity in western populations present management difficulties for clinicians caring for obese pregnant women. Various governing bodies have published clinical guidelines for the care of obese parturients. These guidelines refer to two components of anaesthetic care: anaesthetic consultation in the antenatal period for women with a body mass index (BMI) ≥ 40 kg/m2 and the provision of early epidural analgesia in labour. These recommendations are based on the increased incidence of obstetric complications and the predicted risks and difficulties in providing anaesthetic care. The concept behind early epidural analgesia is logical-site the epidural early, use it for surgical anaesthesia and avoid general anaesthesia if surgery is required. Experts support this recommendation, but there is weak supporting evidence. It is known that the management of labour epidurals in obese women is complicated and that women with extreme obesity require higher rates of general anaesthesia. Anecdotally, anaesthetists view and apply the early epidural recommendation inconsistently and the acceptability of early epidural analgesia to pregnant women is variable. In this topic review, we critically appraise these two practice recommendations. The elements required for effective implementation in multidisciplinary maternity care are considered. We identify gaps in the current literature and suggest areas for future research. While prospective cohort studies addressing epidural extension ('top-up') in obese parturients would help inform practice, audit of local practice may better answer the question "is early epidural analgesia beneficial to obese women in my practice?".

Anaesthetists' experiences with the early labour epidural recommendation for obese parturients: a qualitative study.

Caring for obese pregnant women presents challenges for all medical professionals. Despite a lack of supporting evidence, expert opinion and international guidelines suggest early labour epidural insertion for obese women. Anecdotally this is not supported by all anaesthetists. This qualitative study explored the experiences of anaesthetists regarding early epidural analgesia in obese parturients, to answer the research question: Are anaesthetists consistent in how they apply early epidural analgesia in obese parturients? Personal in-depth interviews with 42 specialist anaesthetists working in south-east Queensland, Australia, were completed between February and April, 2015. Leximancer™ text analysis software applied a validated algorithm to the data to identify themes and concepts. The major themes were explored by the first author to answer the research question. Three major themes were identified: the demands associated with caring for obese women; concern regarding the anaesthetic technique used in obese women; and the importance of communication with obstetric staff. Disagreement regarding interpretation and application of early epidural analgesia was identified within this group of anaesthetists. These anaesthetists were inconsistent in how they interpreted and applied early epidural analgesia for obese parturients, with some questioning the validity of the practice. The combination of uncertainty, urgency and technical difficulty presented by obese parturients provoked anxiety in these clinicians, particularly the anticipation of unplanned general anaesthesia. Consistent anaesthetic practice could improve the implementation of early epidural analgesia in obese parturients.

Developments in labour analgesia and their use in Australia.

Since the introduction of chloroform for labour analgesia in 1847, different methods and medications have been used to relieve the pain of labour. The use of heavy sedative medication in the early 1900s was encouraged by enthusiastic doctors and by women empowered by the women's suffrage movement in America. Nitrous oxide by inhalation has been used in Australia since the 1950s and improved methods of administration have made this method of analgesia safe and practical. Caudal epidural analgesia and lumbar epidural analgesia were first made popular in America and by the 1970s these techniques were more widely available in Australia. In 1847, physicians and the public were unsure whether relieving labour pains was the 'right' thing to do. However, many medical and social changes have occurred thanks to the clinical connection between Australia and the United Kingdom and those first settlers to land on Australian shores. Thanks to this historical connection, in today's Australia there is no question that women should use analgesia as a pain relief if they wish. Currently, the majority of women worldwide use some form of analgesia during labour and different methods are widely available. This paper discusses the four milestones of the development of obstetric analgesia and how they were introduced into patient care in Australia.

The effect of antenatal anaesthetic consultation on maternal decision-making, anxiety level and risk perception in obese pregnant women.

BACKGROUND: Obese parturients are recognised as high risk and an antenatal anaesthetic consultation is recommended. The potential positive and negative effects of this consultation have not been investigated. This prospective observational study aimed to determine if antenatal anaesthetic consultation affects decisional conflict, anxiety scores or risk perception in obese women planning vaginal delivery. METHODS: Eligible women had a body mass index of > or = 35 kg/m2, planning a vaginal delivery, aged > or = 18 years and able to complete a questionnaire presented in English. Before their anaesthetic consultation, women completed a written decisional conflict questionnaire, the Six-Point Short Form of the Speilberger State-Trait Anxiety Inventory and two questions regarding risk perception. All questions were repeated by telephone consultation two weeks later. Independent samples t-tests were used to detect differences between pre and post-test scores. RESULTS: Of 114 women recruited, 89 completed the protocol and were analysed. Women had a mean ±SD age of 29.4±5.2 years and body mass index of 43.6±5.6 kg/m2. Decisional conflict scores were significantly lower after the consultation (30.04 vs. 16.54, P<0.001). Anxiety scores were lower (9.41 vs. 8.49, P=0.002) but this was not clinically significant. Only 19.1% of women felt their health was at risk in pregnancy; this did not change after the consultation. Thirteen women changed their preference toward epidural analgesia (P=0.01). DISCUSSION: Our results support the current practice of referral of obese parturients for anaesthetic consultation, but demonstrate that most women remain unaware of the risks of obesity in pregnancy despite anaesthetic consultation.

Effect of an anaesthesia information video on preoperative maternal anxiety and postoperative satisfaction in elective caesarean section: a prospective randomised trial.

Video-based patient information supplementing clinician interview has been shown to reduce anxiety and improve satisfaction in patients undergoing procedures. In Queensland more than 90% of caesarean sections are performed under regional anaesthesia. We aimed to assess the effect of using an information video about neuraxial blockade in patients having regional anaesthesia for elective caesarean section. Subjects were randomised to undergo usual care (Group C), or to view a video and undergo usual care (Group V). Subjects completed the Spielberger State-Trait Anxiety Inventory preoperatively and the Maternal Satisfaction with Caesarean Section Score questionnaire postoperatively. Satisfaction with, and duration of the preoperative anaesthetic interview, were noted. One-way analysis of variance (ANOVA) and Chi-squared tests were used in statistical analysis. One-hundred and forty three subjects were randomised and 110 completed the protocol and analysis. Group C and Group V were similar in terms demographic and anaesthesia data. There was no difference in anxiety score (41.2 versus 39.8, P=0.50), maternal satisfaction score (118.5 versus 122.7, P=0.22) or interview duration (16.3 versus 15.8 min, P=0.69) between the two groups. The use of an anaesthesia information video does not reduce preoperative anxiety or increase the duration of the anaesthetic interview. Maternal satisfaction with neuraxial blockade for elective caesarean is high and not improved by an anaesthesia information video.

Practice patterns for predicted difficult airway management and access to airway equipment by anaesthetists in Queensland, Australia.

A postal survey was conducted to investigate difficult airway management, training and equipment availability among Fellows of the Australian and New Zealand College of Anaesthetists in Queensland. The survey aimed to determine practise patterns for predicted difficult airways and investigate equipment availability. Participants were asked to nominate an induction method, intubation method and airway adjunct for each of the five difficult airway scenarios. The cases consisted of one elective and four emergency scenarios. Availability of difficult airway devices in their institution was also assessed, as well as demographics of practice and airway-related maintenance of professional standards participation. There were 454 surveys distributed and 250 returned (response rate 55%). Direct laryngoscopy and flexible fibreoptic intubation were the most commonly selected techniques for all five cases. Difficult intubation trolleys were available to 98% of responders. Certain types of equipment (such as fibreoptic bronchoscopes and cricothyroidotomy kits) were available less frequently in private institutions. We recommend a standardisation of difficult airway management equipment and an on-going training program to provide support for anaesthetists in all locations.

The origins of the sniffing position and the Three Axes Alignment Theory for direct laryngoscopy.

The Three Axes Alignment Theory and the sniffing position for direct laryngoscopy are the anatomical basis for direct laryngoscopy. This position has been one of the hallmarks of airway management and yet its development is based on a small number of descriptive texts published between 1852 and 1944. This paper explores the origins of direct laryngoscopy and how the sniffing position came to be described. The seemingly incongruent techniques of the rigid bronchoscopist and direct laryngoscopist are discussed from an historical perspective.