S. M. Kinsella

A prospective audit of regional anaesthesia failure in 5080 Caesarean sections

Anaesthesia for Caesarean section was audited over a 5 year period: 5080 cases were performed using spinal 63%, epidural top‐up 26%, combined spinal‐epidural 5% and primary general anaesthesia 5%. The rate of general anaesthesia conversion of regional anaesthesia was 0.8% for elective and 4.9% for emergency Caesarean section compared to Royal College of Anaesthetists targets of 1% and 3%. The rate of conversion of regional to general anaesthesia in category 1 Caesarean section was 20%. A total of 8% of women had general anaesthesia when both primary general and conversion of regional anaesthesia were combined. The rate of failure to achieve a pain‐free operation was 6% with spinals, 24% with epidural top‐up and 18% with combined spinal‐epidural. Besides the type of anaesthesia and operative urgency, other factors associated with pre‐operative failure of regional anaesthesia included body mass index, no previous Caesareans, and indication for Caesarean of acute fetal distress or maternal medical condition. Inadequacy of pre‐operative anaesthetic block and duration of surgery were important risk factors for intra‐operative failure. For spinal anaesthesia, use of a spinal opioid was associated with less pre‐operative failure. For epidural top‐up anaesthesia, lower epidural top‐up volume was associated with less pre‐operative failure, and use of adrenaline was associated with both less pre‐operative and intra‐operative failure. The rate of serious adverse incidents was 1 : 126 with general anaesthesia and 1 : 501 with regional anaesthesia.

Maternal cardiovascular consequences of positioning after spinal anaesthesia for Caesarean section: left 15° table tilt vs. left lateral

Sixty healthy women undergoing elective Caesarean section were randomly allocated to either a measured 15° left table tilt position (n = 31) or full left lateral position (n = 29) for a 15‐min period after spinal blockade. Arm and leg blood pressure, ephedrine requirements, symptoms, fetal heart rate, cord gases and Apgar scores were recorded. Mean ephedrine requirements and incidence of hypotension were similar in the two groups. Arm systolic arterial pressure over time was similar in both groups, but leg systolic arterial pressure over time was significantly lower in the tilt group (p < 0.001); the mean leg systolic arterial pressure was lower for all 15 sequential recordings in the tilt group, reaching statistical significance (p < 0.05) at 4, 5, 6 and 8 min. Differences in maternal nausea, vomiting and bradycardia and fetal outcome were not statistically significant. Following spinal anaesthesia, even a true 15° left table tilt position is associated with aortic compression.

Category-1 caesarean section: a survey of anaesthetic and peri-operative management in the UK*

A national survey of anaesthetic and peri‐operative management of category‐1 caesarean section was sent to 245 consultant‐led maternity units. There was a 70% response rate. The median (IQR [range]) general anaesthetic rate was 51% (29%–80% [6%–100%]), 12% (9%–16% [3%–93%]), 4% (2%–5% [<1%–18%]), for category‐1 caesarean section, categories 1–3 (non‐elective/emergency) and category‐4 (elective) caesarean section, respectively. The main operating theatre for caesarean section is on the delivery suite in 151 (88%) units, and 112 (66%) units also have a second theatre in the same location. One hundred and thirty‐nine (81%) use the standard urgency classification described in the NICE caesarean section guideline. However, only 72 (42%), 24 (14%), and 16 (9%) units comply with this guideline’s recommended decision‐delivery intervals for category‐1 (≤ 30 min), category‐2 (≤ 30 min) and category‐3 (≤ 75 min) caesarean sections, respectively. Practice in the smaller units was similar to that in the larger units, although there was less availability of a dedicated anaesthetist, intra‐uterine resuscitation guidelines and operating theatres on the delivery suite in the smaller units.

Anaesthetic deaths in the CMACE (Centre for Maternal and Child Enquiries) Saving Mothers’ Lives report 2006–08

‘There are lies, damned lies, and statistics’. The above comment derives from a statistic, but is it accurate? And if inaccurate, how did this 2010 headline from a respectable newspaper, quoting an original paper in The Lancet [2], come to be written? National maternal mortality statistics have been collected in the UK for over 150 years, and the Maternal Death Enquiry (MDE) celebrated its 50th anniversary in 2002 [3]. There is a well-deserved pride in the accuracy of the figures, and major efforts are made to count all cases. Thus, for instance, there was a 22% increase in deaths from the 1991–93 to the 1994–96 reports, owing to the application of computerised searches of death certificate data to identify cases that had not initially been linked to pregnancy [4]. However, the internationally used measure of Maternal Mortality Ratio (MMR) is defined differently. The MMR numerator uses death certificate data, and includes direct and indirect deaths, but not coincidental or late deaths. In the latest report, 155 out of 261 maternal deaths were identified on death certificates, but an additional 106 cases came to the attention of the Centre for Maternal and Child Enquiries (CMACE) via professionals and CMACE regional managers [5]. Furthermore, the denominator used for the MMR is all live births, whereas for the MDE, the denominator is all maternities in the UK. Thus, this report quotes two UK maternal death rates, the maternal mortality rate of 11.4 per 100 000 maternities and the MMR of 6.7 per 100 000 live births – a striking difference. This report shows statistically significant decreases in the overall UK maternal mortality rate and deaths directly related to pregnancy, and narrowing in the excess mortality related to area of residence and partner’s unemployment. The strength of the MDE lies in the active changes that the Government and professionals have made to improve the status quo: in the earliest years, haemorrhage, sepsis and anaesthesia; then thromboembolism and suicide; and more recently, a focus on those with social isolation or other underprivileged circumstances. The narrowing of this excess mortality may show that active measures to address health risks have been successful. However, when taking a wider overview of mortality over one or two decades, large percentage fluctuations in the numbers are seen, and it is possible that the decreases noted in the current report may not be sustained. This is not to denigrate the specific attempts that are being made in these areas, but to caution that the task of improving maternal safety is unrelenting, especially with the increasing prevalence of a number of risk factors in the population.

Reporting of 'hypotension' after epidural analgesia during labour. Effect of choice of arm and timing of baseline readings.

We studied 20 women in labour to see how reporting ‘hypotension’ after obstetric epidural analgesia is affected by position of the blood pressure cuff and baseline definition. Blood pressure was recorded from both arms simultaneously while the woman was semirecumbent and then in the left lateral position. Three readings were then taken after epidural bupivacaine, one left lateral and the remainder right lateral. Before the epidural, blood pressure in the dependent arm in the lateral position was similar to blood pressure in either arm in the semirecumbent position and an average of 10 mmHg (systolic) and 14 mmHg (diastolic) higher than blood pressure in the uppermost arm (p ≤ 0.00005). This difference persisted in both lateral positions as epidural analgesia became established. Choosing different definitions of hypotension, baselines and arm to measure blood pressure resulted in ‘hypotension rates’ between 0% and 75%. For blood pressure measurement in the lateral position, the blood pressure cuff should be placed on the dependent arm.

International consensus statement on the management of hypotension with vasopressors during caesarean section under spinal anaesthesia

1 Consultant, Department of Anaesthesia, St Michael’s Hospital, Bristol, UK 2 Professor, Department of Anesthesiology, Stanford University School of Medicine, Stanford, CA, USA 3 Professor Emeritus, Department of Anaesthesia and Peri-operative Medicine, University of Cape Town, Cape Town, South Africa 4 Senior Consultant, Department of Anaesthesia, Hamad Women’s Hospital, Doha, Qatar 5 Clinical Associate Professor, Department of Anaesthesia and Pain Medicine, King Edward Memorial Hospital for Women, Subiaco, Australia 6 Professor, D epartement d’Anesth esie-R eanimation, Hôpital Antoine B ecl ere, Clamart, France 7 Assistant Professor, Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA 8 Professor and Senior Consultant, Department of Women’s Anaesthesia, KKWomen’s and Children’s Hospital, Singapore 9 Chair, Department of Anesthesiology, UZ Leuven, Leuven, Belgium 10 Professor of Anesthesiology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium 11 Consultant, Department of Anaesthesia and Intensive Care Medicine, King’s College Hospital NHS Foundation Trust, London, UK

Position, position, position – terminology during stomach ultrasound in pregnant women

pation: An observational study. Anesthesia and Analgesia 2012; 114: 987– 92. 37. Hiller KN, Karni RJ, Cai C, Holcomb JB, Hagberg CA. Comparing success rates of anesthesia providers versus trauma surgeons in their use of palpation to identify the cricothyroid membrane in female subjects: a prospective observational study. Canadian Journal of Anesthesia 2016; 63: 807–17. 38. Howard-Quijano KJ, Huang YM, Matevosian R, Kaplan MB, Steadman RH. Video-assisted instruction improves the success rate for tracheal intubation by novices. British Journal of Anaesthesia 2008; 101: 568–72, e1. 39. Stringer KF, Bajenov S, Yentis SM. Training in airway management. Anaesthesia 2002; 57: 967–83. 40. McGuire B, Dalton AJ. Sugammadex, airway obstruction, and drifting across the ethical divide: a personal account. Anaesthesia 2016; 71: 487–92. 41. Cook TM, MacDougall-Davis SR. Complications and failure of airway management. British Journal of Anaesthesia 2012; 109: i68–i85. 42. Mathieu JE, Heffner TS, Goodwin GF, Salas E, Cannon-Bowers J-A. The influence of shared mental models on team process and performance. Journal of Applied Psychology 2000; 85: 273–83. 43. Weingart SD, Levitan RM. Preoxygenation and prevention of desaturation during emergency airway management. Annals of Emergency Medicine 2012; 59: 165–75, e1. 44. Sakles JC, Mosier JM, Patanwala AE, Arcaris B, Dicken JM. First pass success without hypoxemia is increased with the use of apneic oxygenation during rapid sequence intubation in the Emergency Department. Academic Emergency Medicine 2016; 23: 703–10.

The case for invasive placebo – is the devil in the detail?

In this issue of Anaesthesia we publish a paper by Kumar et al. evaluating the effect of pre-operative stellate ganglion block on postoperative tramadol consumption following surgery to fixate upper limb fracture [1]. This research study was prompted by the 2011 case series from McDonnell et al. that showed a marked benefit of stellate ganglion block performed for similar indications with respect to postoperative pain scores and analgesic requirements [2]. Two editorials accompanied McDonnell et al.’s paper; one discussed the potential for modulation of acute somatic pain by the autonomic nervous system [3], and the other called for robust substantiation of the findings before such an approach was incorporated into routine clinical practice [4]. Kumar et al. have now performed a randomised, doubleblind, placebo-controlled study to address the latter point. Subjects received a 3-ml stellate ganglion injection of either lidocaine 2% or saline before general anaesthesia and surgery. The authors report a statistically significant and clinically relevant reduction in tramadol consumption, administered via patientcontrolled analgesia, over the first 24 h postoperatively. There are two conventional ways of assessing the benefit of an analgesic intervention: measuring pain scores and/or recording analgesic usage (preferably with a patient-controlled analgesia system rather than administered if and when requested). Whilst pain scores are commonly used as a research tool, a statistically significant difference in pain scores may translate poorly to an actual clinical benefit for the patient. Furthermore, pain scores are also hampered by intraand inter-individual variation in scoring, making a change in median pain scores across a group difficult to interpret. In contrast, use of analgesics can be used as a surrogate marker for pain, if one assumes that the patient is ‘titrating’ the analgesic dose to provide an acceptable level of analgesia. Whilst this is not a direct evaluation of subjective pain, it reflects the patient experience, as the reduced use of analgesic medication can be thought to represent a reduction in the pain experienced. In addition, it addresses an important non-specific aspect of managing pain, also inherent in the concept of multi-modal analgesia: that of a reduction in analgesic doses in order to reduce side-effects. The aim of the optimal analgesic package is to get the best analgesia for the least ‘cost’, if we consider cost to include not just the financial tariff but also complexity and time, side-effects and risks. Therefore Kumar et al.’s study aims to address two questions. The first is the usefulness of stellate ganglion block before upper limb surgery in reducing postoperative pain as reflected by a reduction in selfadministered analgesic requirements. The second, and possibly more important question, is its exploration of the relationship between the autonomic nervous system, nociception and acute pain.

Preparation for the difficult airway

References 1. Nørskov AK, Wetterslev J, Rosenstock CV, et al. Prediction of difficult mask ventilation using a systematic assessment of risk factors vs. existing practice–a cluster randomised clinical trial in 94,006 patients. Anaesthesia 2017; 72: 296–308. 2. Nørskov AK, Wetterslev J, Rosenstock CV, et al. Effects of using the simplified airway risk index vs. usual airway assessment on unanticipated difficult tracheal intubation–a cluster randomized trial with 64,273 participants. British Journal of Anaesthesia 2016; 116: 680–9. 3. Pandit JJ, Heidegger T. Putting the ‘point’ back into the ritual: a binary approach to difficult airway prediction. Anaesthesia 2017; 72: 283–8. 4. Nørskov AK, Rosenstock CV, Lundstrøm LH. Lack of national consensus in preoperative airway assessment. Danish Medical Journal 2016; 63: pii a5278.

Obstetric difficult and failed tracheal intubation guidelines - a reply.

the technique and maintain expertise. We agree with Dalton and Rodney that the term ‘gold standard’ is unhelpful because how can all anaesthetists achieve this when there are simply not enough opportunities? We still believe that fibreoptic intubation has its place in certain situations, such as in patients with abnormal anatomy and/or have predictors of difficult bag/valve/mask ventilation where safety is paramount, but that it should no longer be considered the ‘gold standard’ for difficult airway management because not all difficult airways are the same. Like all specialised techniques, a skilled specialist should use it in an appropriate situation.