Transcutaneous carbon dioxide measurements in anesthetized apneic patients with BMI > 35 kg/m2

Transcutaneous carbon dioxide measurement (TcCO2) offers the ability to continuously and non-invasively monitor carbon dioxide (CO2) tensions when end-tidal monitoring is not possible. The accuracy of TcCO2 has not been established in anesthetized apneic patients with obesity. In this secondary publication, we present a methods comparison analysis of TcCO2 with the gold standard arterial PCO2, in adult patients with body mass index (BMI) > 35kg/m2 who were randomized to receive high flow or low flow nasal oxygenation during post-induction apnea. Agreement between PaCO2 and TcCO2 at baseline, the start of apnea and the end of apnea were assessed using a non-parametric difference plot. Forty-two participants had a median (IQR) BMI of 52 (40-58.5) kg/m2. The mean (SD) PaCO2 was 33.9 (4.0) mmHg at baseline and 51.4 (7.5) mmHg at the end of apnea. The bias was the greatest at the end of apnea median (95% CI, 95% limits of agreement) 1.90 mmHg (-2.64 to 6.44, -7.10 to 22.90). Findings did not suggest significant systematic differences between the PaCO2 and TcCO2 measures. For a short period of apnea, TcCO2 showed inadequate agreement with PaCO2 in patients with BMI > 35 kg/m2. These techniques require comparison in a larger population, with more frequent sampling and over a longer timeframe, before TcCO2 can be confidently recommended in this setting.

Analysis of anaesthesia incidents during caesarean section reported to webAIRS between 2009 and 2022

Anaesthesia for caesarean section occurs commonly and places specific demands on anaesthetists. We analysed 469 narratives concerning anaesthesia for caesarean section, entered by Australian and New Zealand anaesthetists into the webAIRS incident reporting system between 2009 and 2022. As expected, compared with the remaining 8978 database entries, the 469 incidents were more likely to be emergency cases (relative risk (RR) 1.95), more likely to occur between 18:00 and 22:00 hours (RR 1.81) and between 22:00 and 07:59 hours (RR 4.40) and more likely to be undertaken using neuraxial anaesthesia (RR 9.18). Most incidents involved more than one event. The most commonly reported incidents included intraoperative neuraxial anaesthesia complications (180, 38%), medication errors or issues (136, 29%), equipment issues (49, 10%), obstetric haemorrhage (38, 8%), maternal cardiac arrests (28, 6%), endotracheal tube issues (28, 6%) and neonatal resuscitation (24, 5%). Inadequate neuraxial block, reported in 95 incidents, was the most common intraoperative neuraxial complication. Allergic reactions, reported in 30 incidents, were the most common medication issue, followed by 17 associated with oxytocin and 16 syringe swaps. Thirty-eight reports included significant maternal haemorrhage, with eight of those incidents including maternal cardiac arrest. There was one maternal death and eight incidents with neonatal deaths reported, affecting nine neonates. Problems with intraoperative neuraxial anaesthesia were the most commonly reported events. Implementation of specific strategies are encouraged to enhance preparation for conversion to general anaesthesia and to mitigate medication errors, particularly those relating to oxytocic use and neuraxial anaesthesia medications.

Nitrous Oxide Use in Australian Health Care: Strategies to Reduce the Climate Impact

Nitrous oxide is a useful inhaled analgesic. Due to its high global warming potential and ozone-depleting properties, the nitrous oxide emissions related to health care are being increasingly scrutinized. In this narrative review, we will discuss the clinical uses of nitrous oxide relevant to anesthetists, in addition to its contribution as a greenhouse gas. Using available data from Australia, we will explore potential strategies for reducing the impact of those emissions, which are likely to be applicable in other countries. These include destruction of captured nitrous oxide, minimizing nitrous oxide waste and reducing clinical use. Anesthesia clinicians are well placed to raise awareness with colleagues and consumers regarding the environmental impact of nitrous oxide and to promote cleaner alternatives. Reducing use is likely to be the most promising reduction strategy without large-scale changes to infrastructure and subsequent delay in action.

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.

A retrospective observational study of patient analgesia outcomes when regional anaesthesia procedures are performed by consultants versus supervised trainees

At teaching hospitals, consultants must provide effective supervision, including appropriate selection of teaching cases, such that the outcomes achieved by trainees are similar to that of consultants. Numerous studies in the surgical literature have compared patient outcomes when surgery is performed by consultant surgeons or surgical trainees but, to our knowledge, none exist in the field of anaesthesia. We aimed to compare analgesia outcomes of regional anaesthesia when performed by supervised trainees versus consultants. We designed a retrospective observational study using registry data. The primary outcome was inadequate analgesia, defined as a numerical rating scale (NRS) for pain >5 reported at any time in the post-anaesthesia care unit (PACU). Secondary outcomes included the maximum pain NRS, pain experienced in the PACU, and the requirement for systemic opioid analgesia in the PACU. Of the 1814 patients analysed, the primary proceduralist was a consultant for 514 (28.3%) patients and a trainee for 1300 (71.7%) patients. All trainees were supervised by an on-site consultant. There were no statistically significant differences between consultants and supervised trainees in terms of the primary outcome (NRS >5 in 24.9% and 24.5% of patients, respectively; P = 0.84) and secondary outcomes. Compared to trainees, consultants had a slightly higher rate of patients with a body mass index >30 kg/m², an American Society of Anesthesiologists Physical Status Classification of 3 or 4, nerve blocks performed under general anaesthesia, paravertebral/neuraxial blocks and blocks with perineural catheter placement. Regional anaesthesia performed by supervised trainees can achieve similar analgesia outcomes to consultant-performed procedures.

The Effect of Dexmedetomidine on Postanesthesia Care Unit Discharge and Recovery: A Systematic Review and Meta-Analysis

BACKGROUND

Current evidence on the effect of dexmedetomidine in early postoperative recovery is limited. We conducted a systematic review to evaluate the effect of dexmedetomidine on the length of stay (LOS) and recovery profile in postanesthesia care unit (PACU) patients.

METHODS

The study protocol is registered on International Prospective Register of Systematic Reviews (PROSPERO; CRD42021240559). No specific funding or support was received. We conducted searches in MEDLINE, Embase, PubMed, and Cochrane Library to March 31, 2021 for peer-reviewed randomized controlled studies comparing adult patients who received intravenous dexmedetomidine and placebo undergoing noncardiac, nonneurosurgical procedures under general anesthesia. All studies reporting statistics relating to the duration of stay in the recovery ward or PACU, the primary outcome, were included. We performed individual random-effect meta-analysis on the primary and secondary outcomes (time to extubation, emergence agitation, cough, pain, postoperative nausea and vomiting, shivering, residual sedation, bradycardia, and hypotension) using Stata version 17.0. Evidence was synthesized as mean difference (MD) and risk ratio (RR) for continuous and dichotomous variables, respectively. The quality of evidence was assessed using the revised Cochrane risk-of-bias tool for randomized trials (RoB 2) tool and Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Thirty-three studies including 2676 patients were eligible for analysis. All studies had low risk or some concerns of overall bias and provided low-to-high certainty evidence for all studied outcomes. Dexmedetomidine was not associated with a significantly increased PACU LOS (MD, 0.69 minute; 95% confidence interval [CI], -1.42 to 2.81 minutes). It was associated with a statistically but not clinically significant prolonged time to extubation (MD, 1 minute; 95% CI, 0.32-1.68 minutes). Dexmedetomidine was associated with significantly reduced incidence of emergence agitation (RR, 0.38; 95% CI, 0.29-0.52), cough (RR, 0.69; 95% CI, 0.61-0.79), pain (RR, 0.50; 95% CI, 0.32-0.80), postoperative nausea and vomiting (RR, 0.54; 95% CI, 0.33-0.86), and shivering (RR, 0.24; 95% CI, 0.12-0.49) in PACU. There was an increased incidence of hypotension (RR, 5.39; 95% CI, 1.12-5.89) but not residual sedation (RR, 1.23; 95% CI, 0.20-7.56) or bradycardia (RR, 5.13; 95% CI, 0.96-27.47) in the dexmedetomidine group.

CONCLUSIONS

The use of dexmedetomidine did not increase the duration of PACU LOS but was associated with reduced emergence agitation, cough, pain, postoperative nausea and vomiting, and shivering in PACU. There was an increased incidence of hypotension but not residual sedation or bradycardia in PACU.

Rotational thromboelastometry (ROTEM® ) in gestational diabetes mellitus and coagulation in healthy term pregnancy: A prospective observational study in Australia

BACKGROUND

Rotational thromboelastometry (ROTEM^® ) is a point-of-care test of coagulation. ROTEM^® -defined hypercoagulability has been identified in pregnant women and in non-pregnant patients with diabetes mellitus. Pregnancy is known to be a hypercoagulable state, but the influence of gestational diabetes mellitus (GDM) on coagulation is unknown.

AIM

The aim of this study was to assess the combined effect of pregnancy and GDM on coagulation using ROTEM^® and to compare this to healthy pregnant women presenting for elective caesarean delivery.

MATERIALS AND METHODS

Ethics approval was granted for recruitment of women presenting for elective caesarean delivery. Women with pre-existing conditions affecting coagulation were excluded. Group N included health pregnant women at term and Group G included pregnant women at term with GDM. Data regarding GDM management and glycaemic control were collected. Poor glycaemic control was defined by markers of accelerated fetal growth and elevated fasting or postprandial blood glucose levels. The ROTEM^® parameters (extrinsically activated thromboelastometric test (EXTEM) / fibrin polymerisation test (FIBTEM) amplitude at five minutes, coagulation time, maximum clot firmness and clot formation time) were compared between the two groups using Student's t-test.

RESULTS

There were 75 women in Group N and 21 women in Group G. Mean age and median body mass index values were comparable for both groups. There were no statistical differences found between the EXTEM and FIBTEM parameters analysed for the two groups.

CONCLUSIONS

There was no association between GDM and increased hypercoagulability as demonstrated by ROTEM^® parameters in healthy pregnant women presenting for elective caesarean delivery at term.

The effect of transnasal humidified rapid-insufflation ventilator exchange (THRIVE) versus nasal prongs on safe apnoea time in paralysed obese patients: a randomised controlled trial

BACKGROUND

Evidence is lacking regarding the efficacy of Optiflow transnasal humidified rapid-insufflation ventilator exchange (THRIVE™) in obese patients. We compared the impact of this technique at 70 L min^-1 with 4 L min^-1 oxygen via nasal prongs on safe apnoea times of paralysed obese patients.

METHODS

We randomised adults with a BMI >35 kg m^-2 undergoing elective bariatric surgery. While apnoeic and paralysed, Group T received 70 L min^-1 oxygen via Optiflow THRIVE™. Group N received nasal prong oxygen at 4 L min^-1. The primary outcome was time to SpO₂ ≤95% while apnoeic, with a 360 s cut-off. This was analysed by applying a time-to-event analysis.

RESULTS

Forty-two patients were included. The median (inter-quartile range) BMI was 44.8 kg m^-2 (40.0-50.0) in Group T and 42.0 kg m^-2 (39.3-45.1) in Group N. Median (inter-quartile range) time to SpO₂ ≤95% in Group T was 356 (165 to ≥360) s and in Group N, 210 (160-270) s. Using a survival analysis framework, median time-to-event in Group T was 356 s (95% confidence interval 165 s-upper limit not defined) and 210 s (95% confidence interval 160-242 s) (P=0.049) in Group N.

CONCLUSIONS

Compared with oxygen delivered via nasal prongs at 4 L min^-1, oxygen delivery via Optiflow THRIVE™ at a flow rate of 70 L min^-1 can prolong safe apnoea time, however, the results are statistically inconclusive. Optiflow THRIVE™ did decrease the rate of reduction in Pa_o2 during apnoea.

CLINICAL TRIAL REGISTRATION

ANZCTR 12618000445279.

Obesity, metabolic syndrome, and inflammation: an update for anaesthetists caring for patients with obesity

Our understanding of chronic inflammation in obesity is evolving. Suggested mechanisms include hypoxia of adipose tissue and a subsequent increase in circulating cytokines. It is now known that adipose tissue, far from being an inert tissue, produces and secretes multiple peptides that influence inflammation and metabolism, including substrates of the renin-angiotensin-aldosterone system (RAAS). RAAS blocking antihypertensive medication and cholesterol-lowering agents are now being evaluated for their metabolic and inflammation-modulating effects. Surgery also has pro-inflammatory effects, which may be exacerbated in patients with obesity. This narrative review will summarise the recent literature surrounding obesity, metabolic syndrome, inflammation, and interplay with the RAAS, with evidence-based recommendations for the optimisation of patients with obesity, prior to surgery and anaesthesia.

Upper limb dimensions in adults presenting for elective surgery - implications for blood pressure measurement

Background

Arm conicity is associated with non-invasive blood pressure (NIBP) measurement error and may be avoided by using finger cuffs. Predicting arm conicity may help decisions regarding NIBP measurement techniques.

Methods

We obtained upper limb measurements of adults presenting to the Pre-Anesthetic Clinic to determine: the suitability of arm and finger cuff sizes; the best anthropometric predictor of arm conicity based on the right arm slant angle; the incidence of a right arm slant angle < 83 degrees. Right mid-arm circumference (MAC) was compared to recommended cuff sizes and finger circumference compared to available cuffs. Slant angle was calculated from the measurements obtained. Linear regression was used to determine the better predictor of right arm slant angle. Correlation coefficients were calculated and R² values compared.

Results

Four hundred fifty-four patients participated and 453 had cone-shaped arms. One participant (0.2, 95% CI 0.0–1.2) had a MAC outside the recommended cuff range. Twenty-five participants (5.5, 95% CI 3.6–8.0) had a middle finger circumference greater than the largest ClearSight™ cuff. Body mass index (BMI), weight and right MAC all had low to moderate correlation with right arm slant angle (r = − 0.49, − 0.39, − 0.48, all p < 0.001) and regression revealed R² values of 0.24, 0.15 and 0.23. Six participants (1.3, 95% CI 0.5–2.9) had a slant angle < 83 degrees.

Conclusion

Current NIBP equipment caters for most patients, based on the traditional measure of MAC. The utility of finger cuffs is limited by cuff size. BMI and right MAC showed the most promise in predicting arm conicity.

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.

Perioperative Blood Pressure Monitoring in Patients With Obesity

Blood pressure monitoring plays a key part in the preoperative, intraoperative, and postoperative care of all patients. In patients with obesity, hypertension indicates increased metabolic and surgical risk and may signal the presence of significant medical comorbidities, including obstructive sleep apnea. Avoidance of hypertension postoperatively is necessary to minimize bleeding risk after surgery. Hypotension in the postoperative period may be the first sign of significant complications that require urgent management. With the problem of being overweight or obese now affecting two-thirds of adults in Western countries, the proportion of patients with obesity in perioperative environments is similarly increasing. Detection of aberrations in blood pressure is contingent on the accuracy of blood pressure measurement methods. Patients with obesity tend to have a large arm circumference and "cone-shaped arms." Standard blood pressure cuffs fit such patients poorly, and this compromises the accuracy of measurements. Alternatives to arm blood pressure cuffs, some made specifically for individuals with obesity, have been evaluated but are not widely available to clinicians. This focused narrative review will discuss the relevance of hypertension management in the care of patients with obesity, highlight the currently available methods for perioperative monitoring of blood pressure, and explore the opportunities that exist to improve the perioperative blood pressure care in patients with obesity undergoing surgical procedures.

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.

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.

Arm and finger measurements in the third trimester: Implications for blood pressure measurement

OBJECTIVES

To obtain arm and finger measurements of women ≥32 weeks gestation to determine: the requirement for different arm cuff sizes; the suitability of available finger cuffs in this population; the best predictor of arm conicity; the frequency of cuff placement on the forearm or leg.

STUDY DESIGN

Prospective observational pilot study.

MAIN OUTCOME MEASURES

Right and left mid-arm circumference (MAC) and to compare these to the recommended cuff sizes; right and left finger circumference; right and left arm conicity; the responses of women to a three-point Likert scale regarding cuff placement.

RESULTS

Measurements were obtained for 450 women at an Australian tertiary hospital with a median (IQR) gestation of 35.7 (34.0-37.0); 299 (66.4%) were Caucasian and 35 (7.8%) had gestational hypertension. The median (IQR) body mass index (BMI) was 29.6 kg/m² (26.2-33.4), range 18.0-62.2. Median (IQR) right MAC was 29.9 cm (27.4-33), range 19.6-53.2. Based on right MAC, 58 (12.9%) required a large cuff and 6 (1.3%) a thigh cuff. Maximum right finger circumference was 7.0 cm. BMI, weight and right MAC were positively correlated with right arm conicity: r = 0.51, 0.42 and 0.45, p < 0.001 for all. R² for each were 0.26, 0.17 and 0.20. Fourteen (3.1%) reported cuff placement on the forearm or leg.

CONCLUSIONS

A small percentage of women are likely to be unsuited to traditional arm cuffs. Available finger-cuffs would suit this population. BMI could potentially be used to select women with cone-shaped arms for future studies of alternative devices.

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.

Successful Resuscitation of Maternal Cardiac Arrest With Disseminated Intravascular Coagulation Guided by Rotational Thromboelastometry and Transesophageal Echocardiography

We present a case of maternal cardiac arrest during an elective cesarean delivery. Transesophageal echocardiography identified a large pulmonary artery mass, and guided resuscitation efforts. After return of spontaneous circulation, the patient developed disseminated intravascular coagulation with massive hemorrhage. Blood product selection and volume replacement were guided by rotational thromboelastometry and transesophageal echocardiography, respectively. Correction of coagulopathy was observed clinically and confirmed by rotational thromboelastometry. The patient fully recovered without neurological deficit.

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.

What is the failure rate in extending labour analgesia in patients with a body mass index ≥ 40 kg/m(2)compared with patients with a body mass index < 30 kg/m(2)? a retrospective pilot study

BACKGROUND

Early utilisation of neuraxial anaesthesia has been recommended to reduce the need for general anaesthesia in obese parturients. The insertion and management of labour epidurals in obese women is not straight-forward. The aim of this pilot study was to compare the failure rate of extension of epidural analgesia for emergency caesarean section, in pregnant women with a body mass index (BMI) ≥ 40 kg/m(2), to those with a BMI < 30 kg/m(2). The results will be used to calculate the sample size of a planned prospective study.

METHODS

In this retrospective, (1:1) case-control pilot study, obese subjects and control subjects were selected from the obstetric database, if they delivered between January 2007 and December 2011. All subjects used epidural analgesia during labour and subsequently required anaesthesia for Category 1 or 2 Caesarean Section. Data was extracted from the patient medical record. Failure to extend was analysed using liberal and restrictive definitions. Chi-square or Fisher's exact tests were used to detect differences between groups. Multiple logistic regression was used to examine variables predictive of extension failure.

RESULTS

There were 63 subjects in each group. The mean BMI of the obese group was 45.4 (5.8) kg/m(2) and 23.9 (3.0) kg/m(2) in the control group. The odds ratio for failure to extend the existing epidural blockade (liberal definition) was 2.48 (95 % CI:1.02 - 6.03) for the obese group compared with the control group (adjusted for age, parity and gestation). Using the restrictive definition, the odds ratio for failure in the obese group was 6.78 (95 % CI:1.43 - 32.2). The combination of respiratory co-morbidity and gestational diabetes significantly predicted extension failure. Surgical time and epidural complications on labour ward were significantly greater in the obese group.

CONCLUSIONS

In this small retrospective cohort, patients with a BMI ≥ 40 kg/m(2) were significantly more likely to fail epidural extension for caesarean section. The presence of respiratory co-morbidity and gestational diabetes were significant predictors of extension failure; their clinical relevance requires further evaluation.

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.