Intra-operative hypotension – how low should you go?

The February issue of Anaesthesia attempts to answer the age-old question plaguing anaesthetists – what blood pressure should we be targeting and how much does it matter? We are delighted to present the first publication from the iHype study – a prospective cohort study designed and conducted by the Research and Audit Federation of Trainees (RAFT). Data from 4750 patients aged >65 y were collected over a 48 h period. They found intra-operative hypotension, and its many different definitions, to be common, with incongruence between the blood pressure anaesthetists say they will treat and their actual treatment threshold. This study is a great example of what trainee research networks can achieve and how they are a relatively untapped resource. The podcast discussion with the authors is a must for any budding trainee researcher on how to plan and perform such a large and effective study. The associated editorial highlights the discrepancy between blood pressure recordings and explores why we feel may feel the need to “fudge” the anaesthetic chart. With electronic recording becoming more prevalent in the future there may be nowhere to hide! 

Figure 1 Thresholds at which anaesthetists give vasopressor treatments and their intended treatment thresholds. Y-axis denotes the proportion of patient episodes/respondents given the defining threshold on the x-axis for (a) absolute mean arterial pressure; (b) absolute systolic blood pressure; (c) relative change in mean arterial pressure from pre-operative blood pressure; and (d) relative change in systolic blood pressure from pre-operative blood pressure.

The effect of intra-operative hypotension on acute kidney injury, postoperative mortality and length of stay following emergency hip fracture surgery is a neat single centre study investigating the incidence of intra-operative hypotension in a vulnerable group. Interestingly, they did not find an association with intra-operative hypotension and acute kidney injury. However, delay to surgery was associated with increased mortality. North Shore Hospital Anaesthetic department do use electronic intra-operative recording and the MAP was (truly) rarely below 65mmHg in their cohort. 

Why does blood pressure drop during anaesthesia and is there anything we can do to predict which patients will be most affected? The editorial by Frandsen et al. goes back to basic physiology and highlights the often forgotten about autonomic system – it is not all about intra-vascular volume. Anaesthesia causes both sympatholysis and vagolysis. If a patient already has pre-existing autonomic dysfunction, despite adequate fluid volume, anaesthesia could and does provoke hypotension and cardiac instability. By using pre-operative markers of vagal tone, such as heart rate variability, can we identify high risk patients and tailor our anaesthesia accordingly?

The pandemic has sharpened and exacerbated health and social inequalities globally. There is no doubt that patients of non-white ethnicity have poorer outcomes from SARS-CoV-2 infection. The underlying cause for this is likely to be multi-factorial but there has been anxiety that pulse oximetry is less accurate in patients with darker skin pigmentations. Wiles et al. performed a retrospective observational study to address this important concern. They compared SaO2 and SpO2 measured concurrently in patients on different ethnicities and reassuringly found no clinically significant difference. However, as mentioned in the accompanying editorial – is ethnicity the correct question to be asking, and should we actually be comparing skin pigmentation levels in order to accurately validate the use of pulse oximetry in different groups? The inclusion of different ethnic groups in both clinical research and validation studies of commercial monitoring is improving, but this topic highlights the need for both patients and medical staff to be confident that what we are both doing and using to monitor patients in different diseases is correct for all patients. 

Figure 2 Bland-Altman plot paired measurements of oxygen saturation by arterial blood gas analysis and peripheral oxygen saturation in 194 patients with COVID-19 pneumonitis who were admitted to critical care for non-invasive respiratory support. Patient ethnic origin is shown by the colour of each datum (White = yellow; Asian = purple; Black = light blue; and Other = green). The solid line represents the bias between the two measurements, the dashed line represents the limits of agreement (bias ± 1.96 SD) and the dotted line represents the 95%CI for the limits of agreement. (a) shows all paired measurements and (b) shows only those measurements when the patient was hypoxaemic (defined as SaO2 ≤94%).

The pandemic has also made us aware of the vital importance of oxygen and how hypoxic patients do not always look the same! However, aside from being able to sketch out the oxygen dissociation curve, our actual understanding of oxygen physiology is limited. Slingo and Pandit present a narrative review aiming to introduce hypoxia-inducible factor and oxygen sensing pathways to the wider clinical community. The ability of cells to detect and respond to varying oxygen concentrations relies on a complex cascade. Manipulation of this pathway may have many clinical implications, including targeted oxygen therapy. This fascinating review also highlights the requirement for more basic science research in anaesthesia.

Figure 3 Several hundred genes are direct transcriptional targets of HIF, and are involved in diverse cellular and physiological processes in order to optimise oxygen supply and demand. A few examples are given here that will be of direct interest to clinicians in anaesthesia and critical care. VEGF, vascular endothelial growth factor; TF, transferrin; EPO, erythropoietin; Hb, haemoglobin; Hct, haematocrit; EDN1, endothelin 1; NOS, nitric oxide synthase; GLUT 1, glucose transporter 1; LDH, lactate dehydrogenase; PDK1, pyruvate dehydrogenase kinase 1.

The expanding field of peri-operative medicine is changing the focus of anaesthesia research. Along with clinical shared decision-making, patient involvement in study design is improving and with that the need for outcomes that are important for patients. Days alive and at home (DAH) is one such outcome that neatly encompasses the many factors of the post-operative journey for a patient. Ferguson et al. surveyed patients and found the minimal clinically important difference to be 3 days, with an early discharge and being discharged to home rated as important. This is important work that will guide study design in future trials. Indeed Moore et al. used a similar patient-centred outcome measure (days alive and out of hospital) to audit the implementation of the WHO Surgical Safety Checklist.

None of the above research into patient outcomes however is important if we do not have a world in which to practice anaesthesia! In light of COP26 in Glasgow in November the World Federation of Societies of Anaesthesiologists has produced a consensus statement on the principles of environmentally-sustainable anaesthesia. The main points are that patient safety should not be compromised and healthcare systems should be mandated to reduce their contributions to global heating in order to limit global heating to 1.5℃ by 2050. There is a lack of scientific evidence to underpin these guidelines and further work and investment is needed to ensure that we protect our world and current and future generations.

Elsewhere we also have a feasibility study on the use of cryoprecipitate in post-partum haemorrhage. Finally, we are recruiting! We have adverts for a Trainee FellowEditor-in-Chief and three Editors posts at Anaesthesia Reports! Join us!

Cara Hughes and Andrew Klein

Current evidence for peri-operative and critical care management of the brain

What better way to see in any new year than with a brand-new Anaesthesia Special Supplement! This year, it is all about the peri-operative and critical care management of the brain, which has been guest edited by Dr Jugdeep Dhesi and Professor Alana Flexman. Flexman and Tung begin by appraising outcomes used in neuroanaesthesia and neurocritical care. They call for a shift towards PROMS as well as perspectives from LMICs, and the tools are available now – we just have to use them. Dhesi and Moppett discuss the implications of the older brain in peri-operative care and ask – what should we do? As we most things, there is no one right answer and no ‘magic bullet’, but one of the key themes appearing throughout the issue is of multidisciplinary thinking and working. The first review seems to have caught the imagination of our followers already, which looks at the implications of nocebo. This is a key paper that could potentially change practice, but not everyone will agree, as many of the nocebos in use are enshrined in practice already (Fig. 1). Time now for phrases such as ‘bee sting’ and ‘sharp scratch’ to be thought of as clumsy verbal relics of the past? We think so!

Figure 1 Overview of the neurobiology of the nocebo effect. PONV, postoperative nausea and vomiting; ACTH, adrenocorticotrophic hormone; CCK, cholecystokinin; PFC, prefrontal cortex; ACC, anterior cingulate cortex; HPA, hypothalamic–pituitary–adrenal axis; PAG, peri-aqueductal gray.

Stubbs et al. use a stereotyped peri-operative journey to highlight the decision-making points where the expertise of professionals from across the peri-operative medicine team may play an important role for patients with chronic subdural haematoma. The key point is that most patients are managed outside neuroscience centres, and more research is needed to improve the associated care pathways. Peri-operative neurocognitive disorders are the most common complication experienced by older individuals undergoing anaesthesia and surgery. Evered et al. discuss the clinical and practical implications of peri-operative neurocognitive disorder on patients, and possible pathways for identifying at-risk individuals and assessment of modifiable factors.Possible mechanisms include: neurodegenerative disease; inflammation; neuronal damage; and frailty. No longer should we refer to patients as ‘pleasantly confused’ as arguably, there is nothing pleasant about delirium. 

There is much emerging evidence of COVID-19-associated delirium, and White and Jackson have brought it all together for us. They describe how it differs from ‘classical’ delirium, as well as potential mechanisms and practical approaches to management (Fig. 2). It turns out that it is more prevalent, longer lasting and associated with worse outcomes. The management remains the same, except for distressing end of life agitation where the need for higher-than-normal doses of sedatives may be required. One area of persistent controversy in neuroanaesthesia relates to the mode of anaesthesia and its relation with outcomes for mechanical thrombectomy. Dinsmore and Tan review the evidence, and suggest more important targets such as blood pressure management, diagnosis and timely management

Figure 2 Lived experience of delirium for patients, staff and families.

Is anyone using POCUS for acute brain injury? Dinsmore and Venkatraghavan describe the techniques and applications for and provide evidence of its utility in guiding clinical management both in the peri-operative period and on ICU. They list the commonly used acoustic windows and the structures that are visible. They argue it is an effective, non-invasive, safe and readily available technique for the rapid assessment of cerebral anatomy and cerebral haemodynamics. Will it become an alternative routine imaging technique? The results seem comparable. Most doctors will encounter status epilepticus in their carrer. Migdady et al. discuss the definitions of status epilepticus, evidence behind treatment regimens at various stages, treatment goals, outcomes and the role for newer drugs. Implementing early, evidence-based treatment modalities is important to prevent mortality and complications from prolonged status epilepticus, and this paper is arguably of important relevance for all!

Figure 3 Treatment timeline of convulsive status epilepticus. *intramuscular (IM) or buccal (depending on availability) preferred in patients without i.v. access. Diazepam can be used if lorazepam and midazolam are not available. ABC, airway, breathing and circulation; IV, intravenous; AED, anti-epileptic drug; CBC, complete blood count; CMP, complete metabolic panel; CT, computed tomography; EEG, electroencephalogram; MRI, magnetic resonance imaging; KD, ketogenic diet; rTMS, repetitive transcranial magnetic stimulation; and VNS, vagal nerve stimulator.

Have you been busy with COVID-19 over the last few years and missed the most recent CPD relevant to the management of traumatic brain injury? Fear not, Matt Wiles has reviewed the recent evidence and brought it all together. In summary, there are few clear therapeutic interventions that are associated with meaningful improvements in mortality, or more importantly, neurological outcome. The early administration of TXA appears to offer a clinically important early mortality benefit and early tracheostomy appears to be of value. Kayambankadzanja et al. review pragmatic sedation strategies to prevent secondary brain injury in low-resource settings, which is common. They emphasise the importance of analgesia, the choice of drugs, the associated risks and the monitoring required for these patients in these settings. Elsewhere we have reviews of: strategies to reduce the incidence of postoperative deliriumperi-operative neurological monitoring with electroencephalography and cerebral oximetry; and the peri-operative management of patients with Parkinson’s disease

Figure 4 Summary of recent evidence-based recommendations for the management of traumatic brain injury.

We hope you enjoyed the live broadcast to accompany the issue which was seen by over 2.5k viewers! This has now been converted into a podcast which available in all the usual places. Enjoy!

Mike Charlesworth and Andrew Klein

Understanding unrecognised oesophageal intubation

Last week, we brought you a live broadcast all about the new editorial from Pandit, Young and Davies, which is available now on early view. We received some excellent commentary on Twitter, none more so than this thread from Tanya Selak. This month, Professor Pandit also argues that ‘no trace, wrong place’ does not mean ‘positive trace, right place’. It seems that a better way of thinking is that absent traces justify tube removal, and abnormal or attenuated waveforms warrant investigation to re-confirm tracheal tube position, with further management guided by the balance of risks (Fig. 1). There is much here in these contributions to think about for all those with an interest in airway management.

Figure 1 Examples of ETCO2 waveforms with suggested courses of actions for each. From left to right: normal trace; flat trace, as might arise with oesophageal intubation (notwithstanding other causes in blue section of Fig. 1a); attenuated trace (here, a maximum value < 0.2 kPa is shown; it may be higher), as might arise with CPR (pink section of Fig. 1a). This scheme applies primarily to attempted tracheal intubation during CPR but also has relevance for all other situations. With an attenuated trace, ETCO2 may be optimised by more effective CPR. So long as the trace remains attenuated, these measures may need to be repeated. FOB, fibreoptic bronchoscopy (ultrasound may also be used); ABG, arterial blood gas analysis.

Patients generate aerosols, not procedures – say scientists. But most local and national infection control policies in the UK still refer to precautions required around certain procedures, even in low risk isolated test-negative patients. The new paper from the AERATOR study group is all about manual facemask ventilation, and the results will come as no surprise to many. They found that tidal breathing and a volitional cough generate many-fold more aerosol than facemask ventilation. Another so called aerosol generating procedure is the use of nasal high flow oxygen, which is becoming increasingly important in peri-operative practice. Lyons et al. report that pre-oxygenation with high-flow nasal oxygen in combination with oxygen via a mouthpiece causes higher arterial oxygen partial pressures and lengthens the time-to-desaturation after the onset of apnoea when compared with facemask pre-oxygenation. However, Thiruvenkatarajan et al. find that in high-risk patients undergoing ERCP within the context of target-controlled infusion based propofol administration, oxygen delivery using high-flow nasal oxygen did not reduce the rate of hypoxaemia, hypercarbia and the need for major and minor airway interventions, compared with low-flow nasal plus mouthguard oxygen. In the associated editorial, Patel and El-Boghdadly discuss the case for switching to high-flow nasal oxygen in all circumstances. It seems that only when we can seamlessly transition between oxygen delivery systems, without the risk of barotrauma and with optimal monitoring, will this switch be embraced. Until then, high-flow nasal oxygen has a specifically defined role for certain indications only. 

Figure 2 Aerosol concentration measured during the experimental protocol. This shows the concentration of particles detected during baseline respiratory manoeuvres (tidal breathing and voluntary coughs), background monitoring, facemask ventilation with no leak and facemask ventilation with a leak.

In August, we were delighted to publish the COVIDSurg/GlobalSurg collaborative work on SARS-CoV-2 infection and venous thromboembolism (VTE) after surgery. They found that SARS-CoV-2 infection was independently associated with an increased incidence of postoperative VTE in patients with peri-operative and recent SARS-CoV-2 infection. Marshall and Duggan in their editorial discuss various aspects of the study as well as the effect of VTE on surgical patients, prophylaxis protocols, and how this all fits in with contemporary peri-operative risk management

Which size tracheal tube best facilitates general anaesthesia in adults? This new RCT from Cho et al. stimulated a lot of discussion on social media, with the main finding that sore throat and hoarse voice 1 and 24 h after surgery were less frequent and less severe after intubation with smaller tubes. Ventilatory mechanics were unaffected. Another controversy is the management of haematoma after thyroid surgery, but this new guideline aims to change that as the first to report the multidisciplinary management of haematoma following thyroid surgery, either in the anaesthetic or in the surgical literature. A final area of controversy is how best to define the ‘decision-to-delivery’ interval for a non-elective caesarean section. In particular, there is a wide variation as to the interpretation of when the ‘decision’ occurs, ranging from the time that the obstetrician in attendance documents the decision, to when the whole team is alerted, or to when the patient is prepared for the operating theatre. May et al. review all the relevant literature and provide a useful definition that can be used for audits, research and clinical practice.

Elsewhere we have: an observational study of surgery and general anaesthesia on sleep-wake timing; an observational study of the right supraclavicular fossa ultrasound view for correct catheter tip positioning in right subclavian vein catheterisationa non-inferiority trial of supraclavicular versus infraclavicular approach for ultrasound-guided right subclavian venous catheterisation; and a discussion of best practice for subclavian central venous access

Finally, we are looking forward to releasing our 2022 supplement in early January, which is all about the brain and implications for peri-operative practice. We will also be relaunching our popular ‘how to publish a paper’ workshop at the Winter Scientific Meeting on the 14th of January. It is free for all delegates. See you there!

Mike Charlesworth and Andrew Klein

Aerosol-generating patients, not procedures

Peri-operative literature exploded in early 2020 with much in the way of low-quality COVID-19 anecdotes, secondary analyses, reviews and reviews of reviews. Today, we are delighted to have published several excellent primary scientific experiments that challenge our now well-established and sometimes precautionary guidelines and protocols. The AERATOR study group have done it again with a paper grounded in aerosol science but with significant clinical implications for all. The message is that we should see the issue as one of ‘aerosol-generating patients’ rather than ‘aerosol-generating procedures’ (Fig. 1). However, we remain a long way from truly acknowledging test-positive awake COVID-19 patients as ‘riskier’ to care for than test-negative patients undergoing elective surgery. Thankfully, the AERATOR group have another paper coming soon to reinforce the message!

Figure 1 Aerosol measurements during supraglottic airway insertion and removal. (a) Time profile of aerosol generation from volitional coughs. Average time course of volitional coughs plotted (mean with 95%CI) showing a peak after 2 s and a rapid decay back to baseline. Individual recordings (n = 27) represented on heat map showing the total number particle concentration over time. (b) Size distribution of peak aerosol concentrations from volitional coughs (n = 27). (c) Time-course of aerosol during uneventful supraglottic airway insertions (n = 11, mean ± 95%CI); inset chart with altered y-axis to demonstrate very low concentration of particles sampled. (d) Aerosol detected during the eventful insertion showing the period of supraglottic airway removal and reinsertion; inset chart shows particle size distribution of the peak aerosol sample associated with the supraglottic airway removal, note the difference in size distribution compared with a volitional cough (b).

Obesity is increasingly prevalent in England and there is a suggestion that patients undergoing elective surgery are more likely to be obese than the general population. This new prospective observational study from Shaw et al. finds this to be the case for a population of patients in the London area, with obesity also associated with increased minor airway events. The most common of these was oxygen desaturation below 90% and the second was maintaining adequate ventilation using a supraglottic airway device. In the associated editorial, Duggan and El-Boghdadly set these results in their clinical context and remind us that data were collected before the COVID-19 pandemic. Much has since changed. They remind us of the power of observational studies in airway management: randomised trials are scarce; observational studies can change practice; and collaborative research is the future.

How best to study postoperative recovery after major surgery? There has been (rightly so!) a move away from mortality and complication rates and focus has instead shifted to functional recovery. This new multicentre prospective cohort study from Ladha et al. finds that more participants reported decline than improvement in at least one EQ-5D functional domain 30 days after surgery but not 1 y after surgery. Functional decline was associated with worse pre-operative fitness and moderate or severe postoperative complications. We have two further excellent peri-operative papers this month. First, Drake et al. report a before-and-after analysis of the introduction of a standardised maternity early warning system. They observed a significant and sustained reduction in severe maternal morbidity, and a non-significant reduction in cardiorespiratory arrest calls. Second, Awadalla et al. describe the impact of the Australian/New Zealand organisational position statement on extended-release opioid prescribing among surgical inpatients. They found it was associated with an overall decrease in opioid prescribing among surgical inpatients as well as a decrease in extended-release opioids among patients who received any opioid at two Australian hospitals (Fig. 2). In the associated editorial, Levy et al. list the problems with extended-release opioid preparations as well as strategies for their de-implementation.

Figure 2 Proportion of patients who were prescribed extended-release opioids among all surgical inpatients who received any opioid by month.

How can Never Event data be used to reflect or improve hospital safety performance? Olivarius-McAllister et al. compare annual rates of Never Events and finished consultant episodes from 2017 to 2020 by acute hospital Trust (Fig. 3). The absolute number of Never Events was correlated with workload (r2 = 0.51, p < 0.001), but the five Trusts above the upper 95% confidence limit did not have the highest number of Never Events. They argue we should focus now on reducing the mean national Never Event rate through an integrated safety strategy. In the associated editorial, Devlin and Smith describe the problems associated with Never Events, such as that they continue to happen with near certainty and can be well modelled. They argue we should try to improve by redesigning our systems to reinforce their components that create safety, rather than continuing to grant cultural and linguistic supremacy to negative and punitive approaches.

Figure 3 Correlation of 3 years’ cumulative events vs. episode in 151 Trusts (black circles). The solid red (jagged) line is the predicted number of events (rounded) from the overall mean. The dashed red lines are the 95%CIs. The grey line is the linear regression line (slope 1.6 events per 100,000 episodes; r2 0.510, p < 0.001).

Guidelines can sometimes present an editorial dilemma. This new document is an Association of Anaesthetists guideline and we are the journal of the Association. Yet, some might suggest this guideline and others are not scientific or clinical enough to warrant publication in the journal. Some initial feedback on Twitter seems to suggest we made the correct decision, as it turns out ergonomics as applied to peri-operative practice is an incredibly important topic to clinically practicing anaesthetists. For example, we received over 200 retweets and 198,532 Twitter impressions on the day of publication, which is great! The guideline is novel too, as there were, until now, no guidelines on ergonomics in the anaesthetic workplace. Much of the included evidence is from other industries which seems to suggest a need for more primary evidence in this area.

Elsewhere we have: a systematic review of intrathecal morphine for analgesia after lower joint arthroplasty; validation of the factors influencing family consent for organ donation in the UK; and editorials commenting on research in regional anaesthesia and organ donation.

Finally, this new statistics contribution describes some fundamental aspects of significance testing, which is the basis of most of what we need to know as clinicians. It is, therefore, essential reading for all, and probably one of the most useful statistics papers that we have read recently. From time-to-time, questions about shifts in practice come up. Should we scrap the p value? Should we use confidence intervals? Should we report the fragility index? Should we use a Bayesian approach? Perhaps rather than shaking up how we ‘do’ statistics, we should instead focus on better understanding. This paper helps greatly to achieve that goal for us all.

As we come towards the end of the year our focus now moves to our 2022 supplement, which will this time be all about the brain and anaesthesia! We will also be rekindling our popular ‘how to publish a paper’ workshop for the Winter Scientific Meeting 2022 which is free to all who register. We look forward to seeing you there.

Mike Charlesworth and Andrew Klein

Pre-operative isolation – friend or foe?

This month, we are delighted to publish another fantastic study from the COVIDSurg and GlobalSurg collaboratives who were recently awarded a Guinness World Record for work previously published in the journalThis new paper comes from 15,025 global authors based in over 1600 hospitals and reports data for 96,454 patients. The topic this time is pre-operative isolation, which was introduced as a precaution despite limited evidence on its benefits and harms. It aims to keep systems clean and patients safe, but is it risk free? They found that, following correction for various measured confounders, it was associated with a small but clinically important increase in postoperative pulmonary complications (Fig 1). In the associated editorial, Charlesworth and Grossman set out how this new information may help us move towards ‘COVID-19 secure’ elective surgery. If indeed pre-operative isolation is not without risk, then hospitals need to focus on how this may be tackled as well as other ways in which nosocomial transmission can be prevented.

Figure 1 Multivariable logistic regression model exploring the association between pre-operative isolation and postoperative pulmonary complications, adjusting for patient, surgery and surgical setting factors. Number in dataframe = 96,454; number in model = 96,067; missing = 387; AIC = 16,680.6; C-statistic = 0.784. Full model presented in online Supporting Information Table S4, including an interaction term of isolation and country income. Community prevalence of SARS-CoV-2 was defined as the median 14-day cumulative country case notification rate per 100,000 population during October 2020. Country income groups defined as per the World Bank classification. 

One such area where there remains room for improvement is incorporating what we now know about ‘aerosol-generating procedures’ into policy documents, guidelines and local procedures. This new study from Wilson et al. yet again shows that therapies such as high flow nasal oxygen and continuous positive airway pressure generate less aerosol as comparted with breathing, talking, exercising, shouting or coughing. Such therapies should not therefore be delayed in patients with COVID-19 and we should instead focus on ‘aerosol-generating patients’, not procedures. Also featuring this month is a new Association of Anaesthetists guideline for regional analgesia for lower leg trauma and the risk of acute compartment syndrome. This guideline generated a lot of debate on social media and the associated podcast provides some useful context. Perhaps one of the main talking points was recommendation six, which stated that neither the surgeon nor the anaesthetist has the right to veto a treatment recommended by the other. The associated editorial from Bogod and McCombe expands upon the associated controversies including aspects of patient ownership and autonomy. They also discuss the reasons why the British Orthopaedic Association were unable to endorse the final document. The editorial from Keating and Duckworth focusses on clinical aspects of the guideline with particular emphasis on the need for more monitoring in acute compartment syndrome. Such monitoring has been available now for over three decades and perhaps enables patients to receive appropriate analgesia appropriate to the circumstances.

For patients who have suffered traumatic injuries, reducing time from injury to definitive care is perceived to be associated with improved health outcomes. This new retrospective analysis of linked registry data from Lyons et al. aimed to evaluate the effect of the introduction of the Emergency Medical Retrieval and Transfer Service (EMRTS) on 30-day mortality in patients who had suffered blunt traumatic injuries (Fig. 2). After adjustment for differences in case-mix, they found a 37% reduction in the adjusted OR for 30-day mortality in patients with blunt traumatic injuries who were treated by EMRTS compared with standard pre-hospital care pathways. Hurst and Lendrum remind us of the reasons why this was not a good comparison of ground vs. helicopter emergency medical systems, but there remain some important clinical messages. For example, there is a need to include all trauma patients in national registries and establish why injured patients die in the early post-injury phase.

Figure 2 Inclusion criteria and data cleaning for the study population. EMRTS, Emergency Medical Retrieval and Transfer Service; TARN, Trauma Audit and Research Network; ISS, injury severity score; GCS, Glasgow coma scale; PMC, pre-existing medical conditions.

Postoperative sleep disturbance is perhaps more common than we think with significant consequences for patients. Earplugs and eye masks are low-cost interventions that may help, yet this is an area which has received little attention in the peri-operative literature. Leong et al. report their randomised controlled trial of effect of the use of earplugs and eye masks on the quality of sleep after major abdominal surgery. They did not find that the use of earplugs and eye masks as sleep aids on postoperative days 1–3 improved the sleep quality of patients after major abdominal surgery, nor did it affect patient satisfaction, reduce the frequency of nursing care required or reduce the incidence of delirium. We look forward to receiving more original articles in this area and there is much to be done. 

Severe pain after total hip arthroplasty can have major negative effects on recovery and mobilisation in the postoperative period. Pascarella et al. report their randomised observer-masked controlled trial of the impact of the pericapsular nerve group (PENG) block on postoperative analgesia and functional recovery following total hip arthroplasty (Fig. 3). They found that the PENG block improved postoperative analgesia following total hip replacement, and decreased pain scores and opioid consumption during the first 48 h after surgery. Time to now consider it as a valid analgesia option for fast-track hip surgery protocols? Finally, Finnerty et al. report their randomised trial of bilateral erector spinae plane block vs. no block for thoracolumbar decompressive spinal surgery. They found that the addition of intra-operative erector spinae block to multimodal analgesia improved recovery and reduced pain up to 24 h after thoracolumbar decompressive spinal surgery. Perhaps another indication for a block that has exploded in popularity despite being discovered and reported for the first time only recently

Figure 3 PENG block via a lateromedial approach. Once the needle was placed in the plane between the iliopsoas tendon (IPT) and periosteum and between the anterior inferior iliac spine (AIIS) and iliopubic eminence (IPE), the PENG block was performed by injecting 20 ml of local anaesthetic, the spread of which is visible under the iliopsoas muscle (IPM). Arrow, needle pathway; blue dashed line, local anaesthetic spread; FA, femoral artery. Asterisk, needle entry point.

Elsewhere we have: a review of oxytocin at birth and beyondan observational study of temporomandibular joint dysfunction following the use of a supraglottic airway device during general anaesthesia; and a randomised controlled trial of the effect of saline versus air for cuff inflation on the incidence of high intra-cuff pressure in paediatric MicroCuff® tracheal tubes.

Make sure you check out our top 10 papers of 2020 which we announced only last week at an excellent Annual Congress virtual conference! Congratulations to El-Boghdadly and team for winning paper of the year which was all about risks to healthcare workers following tracheal intubation of patients with COVID‐19!

Mike Charlesworth and Andrew Klein

Delivering person-centred critical care

There has been concern for some time in some areas of the UK that critical care admission is rationed according to age. This new retrospective observational study from Pugh et al., which was conceived and conducted before the outbreak of COVID-19, aimed to investigate trends in patient characteristics for adult critical care admissions in Wales between 2008-2017. They analysed 85,629 cases with the oldest cohort (≥ 80 years) accounting for 15% of critical care admissions. The proportions in each age bracket did not change over the study period. However, in contrast to several recent reports, they identified a significant decline in admissions of older patients (aged ≥ 65 years) relative to the national population, of those with comorbidity and those with a medical diagnosis (Fig. 1).

Figure 1 Rates of ICU admission per 10,000 population over time by age group with 95%CIs.

Has critical care capacity failed to keep pace with the needs of an ageing population? Lone and Suntharalingam make a case for the need to learn, adapt and ensure equity and appropriate best care for our growing cohorts of those aged > 65 years and new octogenarians. That said, the priority for many older critically unwell adults is not always survival at all costs. What will anaesthesia and peri-operative medicine look like to us when many of the current workforce are classed as an older adult in ~25 years? Fawcett and Klein discuss the implications for genomics, AI, service delivery, peri-operative medicine, green anaesthesia and radiology. The only certainty seems to be that our skills will continue to be in demand and there will inevitably be significant workforce shortages. 

Dexmedetomidine is now used widely for several indications in peri-operative practice and critical care medicine. This new randomised controlled trial from van Norden et al. is the first to investigate the effect of peri-operative administration of dexmedetomidine on the incidence of postoperative delirium in major cardiac and non-cardiac surgical patients aged > 60 years. They found that found a significant reduction in postoperative delirium to 18% from 44% when dexmedetomidine was administered as compared with placebo (Fig. 2). In the accompanying editorial from Chuan and Sanders, the biological plausibility of this finding is assessed, and dexmedetomidine might not be the much sought-after magic bullet for the prevention of postoperative.

Figure 2 Cumulative case count of delirium in dexmedetomidine (red) and placebo (blue) groups.

This new science letter from Shah et al. reports results from a retrospective cohort study of general ICU survivors in two large health regions in the UK aiming to benchmark how many patients had anaemia-specific treatment (excluding blood transfusion) initiated before hospital discharge. The key findings were: a high prevalence of anaemia at ICU discharge and subsequently hospital discharge; little active management of anaemia during this important time period; and Hb of < 100 g.l-1 was associated with prolonged hospitalisation following ICU discharge. Also in this month’s issue, van der Laan et al. report their retrospective analysis of anaemia among intensive care unit survivors and its association with days alive and at home. They found that among ICU survivors, anaemia was highly prevalent and persistent in most patients at hospital discharge. Haemoglobin concentration < 100 g.l-1 at ICU discharge was experienced by 2886 (45.4%) of ICU survivors and independently associated with five fewer days alive and at home to day 90. This association remained significant when accounting for confounders including ICU length of stay, illness severity and red blood cell transfusion, and was attributable predominantly to fewer days at home among anaemic ICU survivors. In addition, ICU discharge anaemia was also an independent predictor of ICU and hospital re-admission (Fig. 3). In the accompanying editorial, Agarwal and Karkouti discuss both studies and remind us that the findings from each might at best be hypothesis generating only. They remind us of the vast amount of work still to be done in what is becoming and increasingly important area of clinical practice.

Figure 3 Association between haemoglobin at ICU discharge and DAH90 by ICU length of stay.

We are delighted to publish a Special Article from Takla et al. in this month’s issue, which raises some difficult ethical and legal issues around the use of general anaesthesia in end-of-life care. They remind us that our speciality already has a self-declared mission to extend the role of anaesthetists beyond the operating theatre in its strategy of championing ‘peri-operative medicine’. They argue that their redefinition of the scope and reach of general anaesthesia through end-of-life care, radical though it is, would be entirely in line with that philosophy, recognising that anaesthetists have skills that can help alleviate suffering for the dying patient. Their main findings were that peri-operative lidocaine infusions of extended duration can be delivered safely and effectively in patients undergoing breast cancer surgery, and that a definitive, multicentre trial employing these design features is feasible. 

One of our most popular podcasts episodes was about the use of intravenous lidocaine in peri-operative practice released November 2020This new pilot multicentre randomised controlled trial of lidocaine infusion in women undergoing breast cancer surgery from Toner et al. enrolled 150 patients and looked at safety, effectiveness and the feasibility of a larger trial. Daliya et al. report their retrospective observational study of Opioid prescription at postoperative discharge. They were able to isolate a number of recognised risk-factors in the prescribing habits of clinicians at discharge that could contribute to a large unused pool of opioids in the community. In the accompanying editorial, Albrecht and Brummett remind us that if you cannot measure it, you cannot improve it. They argue that improvement can be made through: proper adherence to education and guidelines; by embracing simple measures such as prescription of non-opioid analgesics at regular intervals; specification on the duration of the course of immediate-release opioid tablets; avoidance of long-acting opioid formulations and compound analgesic preparations; and advice on deprescribing.

Elsewhere this month we have: a systematic review of suicide in anaesthetistsa systematic review of simulation-based team training in airway managementnew Association of Anaesthetists fire safety and evacuation guidelines; and a time-sensitivity analysis of the prognostic utility of vasopressor dose in septic shock

Finally, make sure you do not miss our next live broadcast with our Associate Editor Dr Tanya Selak chairing which is all about a new paper on the safety of day-case paediatric tonsillectomy in England from the Getting It Right First Time programme. You can tune in by coming to @Anaes_Journal (or following this link) at 1200 BST on Friday 17th September!

See you then!

Mike Charlesworth and Andrew Klein

Staff are our most valuable asset

In the UK, COVID-19 continues to impact upon the provision of all NHS services. This new serial service evaluation from Kursumovic et al. was able to measure and report on the impact on anaesthesia and critical care services in the UK between October 2020 and January 2021. Interestingly, this study made use of the NAP6 infrastructure, as the project was on hold during the pandemic. During this time, one in eight anaesthetic staff were not available for work and one in five operating theatres were closed, with activity falling significantly in those theatres that were open. During January 2021, the system was largely overwhelmed. Redeployed anaesthesia staff increased the critical care workforce by 125% and three quarters of critical care units were expanded. This all helps us to work out what happened which will hopefully mean we are better placed to respond to future pandemics. 

The survey focusses on three key factors – staff, space and stuff. In the accompanying editorial, Wong et al. argue that staff are our most valuable asset. We have all and will continue to work in new ways because of the pandemic, and there has been much focus on ways in which to combat the effects of workforce burnout. It nevertheless remains to be seen whether recommendations such as better provision of mental health support, improved pay, combating workplace bullying and delivering better workforce planning will be implemented. The arguments provided by Wong et al. are compelling and their thoughts seemed to resonate with our followers over on Twitter. For this workforce will also be the one that looks after our nation’s health for years to come. 

There have been numerous observational studies reporting on outcomes in patients with COVID-19 admitted to intensive care. This new systematic review and meta-analysis from Taylor et al. finds that increasing age, pre-existing comorbidities and greater severity of illness are associated with mortality in patients admitted to ICU with COVID-19, but male sex and increasing BMI were not. This surprising finding attracted a lot of attention on social media and with nine news outlets also featuring the study. In the associated editorial from Cook and Comporota, state the case for core datasets for critical care outcomes from COVID-19. These will not only be of benefit for this and other pandemics, but also for the major health challenges that affect ICUs across the world. 

How best to pre-oxygenate patients prior to rapid sequence intubation (RSI) continues to be debated. This new randomised controlled trial from Sjöblom aimed to compare high-flow nasal oxygen with tight-fitting facemask pre-oxygenation during RSI in patients undergoing emergency surgery in several different centres. They showed no difference in the number of patients desaturating < 93% between pre-oxygenation using high-flow nasal oxygen vs. tight facemask. Lam and Irwin ask, is high-flow nasal oxygen worth the hassle? It does seem to be safe, but it is more expensive, time-consuming, technically more difficult to prepare does not appear to have any major benefits over other accepted techniques. We need more research in specific patient groups such as obese, pregnant and high-risk patients more generally. Also this month, Sud et al. compare gastric gas volumes measured by computed tomography between high-flow nasal oxygen therapy and conventional facemask ventilation. They find that high-flow nasal oxygen does not increase gastric gas volume in fasted patients undergoing induction of anaesthesia in the supine position, which adds further support to the safety of its use. 

Figure 1 Oxygenation until 1 min after intubation. Lowest SpO2 (%) from start of pre-oxygenation until 1 min after intubation and apnoea time (s) is plotted for every patient pre-oxygenated with high-flow nasal oxygen (n = 174) or facemask (n = 175). High-flow nasal oxygen (red squares); facemask (blue dots). Desaturation was defined as SpO2 < 93% (dotted line). *No intubation time was noted. Therefore, this patient had the mean intubation time in the high-flow nasal oxygen group added to its apnoea time up until the laryngoscope passed the teeth.

Every year, > 130k patients survive an episode of critical illness in the UK. Focus on this patient group will no doubt increase as the pandemic hopefully eases. This new mixed-methods systematic review from Bench et al. finds that fatigue is common in critical illness survivors, with a prevalence ranging from 13.8–80.9%. This rises around one month following ICU discharge and improves over time but seldom resolves completely. There is a paucity of evidence on how best it should be detected or managed. In the accompanying editorial, Hosey et al. argue that we must help ICU survivors find new ways to live with chronic symptoms, with clinicians and researchers striving to design and evaluate multidisciplinary and comprehensive treatment modalities that support recovery from the ICU to home. 

Figure 2 SF-36 vitality scores over time for data from (a) observational cohort studies and (b) randomised controlled trials. Values are mean (95%CI).

The new Association of Anaesthetists 2021 recommendations for standards of monitoring during anaesthesia and recovery have now been cited 7 times and attracts an Altmetric score of > 250. Areas of controversy include new guidance on: capnography; transfer; quantitative neuromuscular monitoring; processed electroencephalogram monitoring; and electronic record keeping. They feature in this month’s issue, and they are essential reading for all. Elsewhere we have: a randomised controlled trial of deep serratus anterior plane block vs. sham block in ambulatory breast cancer surgerya narrative review of adjunctive treatments for the management of septic shocka systematic review of the association between intra-operative cardiac arrest and country Human Development Index statusan evaluation of group teaching before surgery (Fit-4-Surgery School); and a feasibility and pilot study of volatile anaesthesia and peri-operative outcomes related to cancer

Many of this month’s articles have an associated podcast which you can listen to here. It also features the most recent podcast which looks at the new COVIDSurg international prospective cohort study on the effects of pre-operative isolation on postoperative pulmonary complication rates. The paper remains free to access forever!

Mike Charlesworth and Andrew Klein

Dexamethasone for all?

Dexamethasone is a drug that has many uses for a range of indications and patient groups. This month, the results of the STRIDE randomised controlled feasibility trial are reported. Kluger et al. recruited 79 participants with hip fracture undergoing surgery and randomised to dexamethasone 20 mg or placebo. They found a number of factors that will help design and complete a larger definitive study. Although delirium was less severe in the dexamethasone group, there was no difference in terms of its incidence. We look forward to a larger definitive trial in the future which is evidently scientifically valid and feasible. In the accompanying editorial, Abraham and Neuman dissect the STRIDE study and draw their own conclusions. They highlight the need for future trials to consider the possible risks associated with steroids, such as postoperative infections. The important point is that this is an area that has not been well studied, and this trial means that trialists working in this area will be better equipped to provide the definitive evidence that we need.

The PROSPECT papers always receive a lot of attention on social media which is probably due to their pragmatic methods and clinically relevant suggestions. This new contribution is aimed at patients undergoing total hip arthroplasty with seven core evidence-based recommendations. The key difference here is that most other guidelines focus on enhanced recovery or anaesthetic technique rather than the best analgesic regimen. In the accompanying editorial, Abdallah and McCartney list what’s old, what’s new and what continues to be missing. Will new iterations include items such as day case surgery, the approach to patients with chronic pain, second- or third-line strategies and novel blocks, not in widespread use at the time of this literature search? Time will tell.

During the first COVID-19 wave in the UK, the general anaesthesia rate for caesarean sections in the north-west decreased significantlyThis new study analyses the impact of increased regional anaesthesia use during the pandemic on the decision-to-delivery interval and neonatal outcomes for category-1 caesarean sections. They conclude that the there was a small, clinically unimportant increase in decision-to-delivery interval for category-1 caesarean section during the first wave of the COVID-19 pandemic (Fig. 1). This arguably supports the safe use of regional anaesthesia for category-1 caesarean section except in those cases which warrant the most urgent delivery. Just what then is a clinically significant decision-delivery interval? Mike Kinsella sets out the evidence, the problem with general anaesthesia and considerations for rapid achievement of delivery under general anaesthesia for category-1 caesarean section with fetal compromise. He argues that 30 min, embedded in audit and clinical practice though it is, is too long for cases where there is fetal compromise. He calls for a new 20min target which should be seen as a new clinically-relevant standard. Do you agree? Let us know!

Figure 1 The significant dependency of general anaesthesia (GA) on indication ordered by neonatal morbidity is shown using non-parametric regression (median slope: 1.03% (95%CI 0.09–1.86), Spearman’s rho correlation 0.81, p = 0.022). Chi-square trend analysis shows a significant 5.6% (95%CI 4.2–7.0); p < 0.0001) change in general anaesthesia rate per ordered indication category. There is a significant use of general anaesthesia for the top four indications combined with adverse neonatal outcomes (odds ratio 3.5 (95%CI 2.2–5.4); p < 0.0001). APH, antepartum haemorrhage; CTG, cardiotocography.

The 7th UK National Audit Project has now begun, and the aim will be to advance our knowledge and understanding of peri-operative cardiac arrests. This new article from Kane et al. lists the challenges faced, such as defining peri-operative cardiac arrest, determining the scope of study and conducting the project in the era of COVID-19. You can hear all about the issues raised in the editorial and much more by listening to the podcast, which is free! One area that has been studied extensively is myocardial injury following non-cardiac surgery and the influence of remote ischaemic preconditioning (RIPC). This new 1-year follow-up from a randomised controlled trial from Ekeloef et al. finds that RIPC did not reduce the occurrence of major adverse cardiovascular events within 1 year of hip fracture surgery (Fig. 2). Looking at individual components of the primary outcome, the preventive effect of RIPC on myocardial infarction seems to hold for 1 year. 

Figure 2 Effect of remote ischaemic preconditioning on 1-year clinical outcomes expressed as hazard ratios. Error bars indicate 95%CIs. MACE, major adverse cardiac event.

This new paper from Maranhao et al. has been available on early view since late 2020 and has attracted a lot of attention on social media. They undertook a systematic review and network meta-analysis to compare spinal needles and their respective odds of post dural puncture headache. They find that the 26-G atraumatic spinal needle is the most likely needle to enable successful insertion while avoiding PDPH. Where this needle is not available, as seems to be the case in most institutions according to Twitter, they provide a rank order to help clinicians select the best among the available options. Whether an intrathecal catheter for labour analgesia reduces the incidence of post-dural puncture headache or need for an epidural blood patch has been questioned. Orbach-Zinger et al. report their literature review and clinical management recommendations for intrathecal catheter use after accidental dural puncture in obstetric patients. Although such a catheter might provide effective and satisfactory labour analgesia, there are several important complications that usually negate their use. Eight clear recommendations are provided.

Elsewhere we have: a description of the new Anaesthesia Case Report (ACRE) checklista prospective study of persistent headache and low back pain following accidental dural puncture in the obstetric populationa retrospective study of labour epidural case volume and the rate of accidental dural puncture; and a narrative review of routinely collected data and patient-centred research in anaesthesia and peri-operative care

Last but by no means least is the penultimate Contemporary Classic article in the series which tackles the 2010s. Kumar et al. have picked a paper from Blanco et al. from 2013 which was the first to describe the serratus plane block. They discuss the identification of new potential sono-anatomic targets, undertaking exploratory studies and translating this pioneering research into clinical practice. They argue the work from Blanco et al. is a classic because it taught us important lessons about how to introduce a novel and potentially useful fascial plane block into clinical practice. It also greatly influenced the expansion in ultrasound-guided block techniques, which increases the likelihood that all surgical patients may one day have access to regional anaesthesia as part of their peri-operative pain management.

Congratulations to our new trainee fellow, Dr Cara Hughes! Cara is a clinical research fellow based at the Academic Unit of Anaesthesia at the University of Glasgow. We look forward to welcoming her to the team!

Mike Charlesworth and Andrew Klein

Charting the way forward

COVID-19 has had a tremendous impact on access to healthcare services, including anaesthesia and surgery. What is the best way to proceed for those patients who have been infected with SARS-CoV-2? In this issue of AnaesthesiaEl-Boghdadly et al. outline key principles in the timing of surgery after SARS-CoV-2 infection in a multidisciplinary consensus statement supported by the Association of Anaesthetists, the Centre for Peri-operative Care, the Federation of Surgical Specialty Associations, the Royal College of Anaesthetists and the Royal College of Surgeons of England. Specific focus is afforded to symptoms and severity of disease, comorbid and functional status, priority and complexity of surgery, and anaesthetic technique. The consensus statement is informed by recent studies, such as the international prospective cohort study of the COVIDSurg and GlobalSurg Collaboratives, which was published in Anaesthesia, and which quantified mortality risk in patients with pre-operative SARS-CoV-2 infection based on the time interval between diagnosis and surgery. An accompanying editorial by Price et al. addresses the curtailment in surgical activity caused by the pandemic and its effects on the workforce, both in terms of reallocation of duties and psychological consequences. A further editorial by Stuart White asks whether a role exists for mandatory psychological assessment of those working in anaesthesia and critical care medicine during the pandemic. The impact of this pandemic on patients, healthcare workers and broader society will extend long beyond its end. 

Even in a world without COVID-19, access to safe and affordable surgical care in low- and middle-income countries can be erratic. Reliable data is essential for the evaluation and advancement of peri-operative care in these regions. In this issue, the Network for Peri-operative Critical Care reports on the establishment and initial output of an Ethiopian data registry that incorporated national surgery and quality indicators. There were 1748 care episodes in four hospitals recorded in the registry over a 12-month period, including data on anaesthetic adverse events and post-operative morbidity and mortality. In an accompanying editorial, Kluyts and Biccard discuss the role of peri-operative registries in improving the quality of care in low-resource environments and the challenges associated with their creation and interpretation.

The prevention and treatment of postoperative nausea and vomiting is one of the commonest everyday challenges faced by anaesthetists. Weibel et al. publish an abridged Cochrane network meta-analysis of the drugs used for preventing post-operative nausea and vomiting in adults after general anaesthesia (Fig. 1). Data are included from 585 trials and 97,516 participants, evaluating 44 single drugs and 51 drug combinations, making this the most comprehensive, up to date review of the evidence in this area. An accompanying editorial by Collier and Smith places these findings in the context of current anaesthesia practices and the broader challenges faced in preventing post-operative nausea and vomiting

Figure 1 Network geometry of eligible comparisons for postoperative vomiting within 24 h after surgery. The thickness of the edges is proportional to the number of included studies comparing two treatments.

As researchers continue to investigate the exact risks and benefits of apnoeic oxygenation with high-flow nasal oxygen in anaesthesia, areas of uncertainty include its merits in the paediatric population and capacity for clearance of carbon dioxide. The ability of apnoeic oxygenation with high-flow nasal oxygen to clear carbon dioxide in adults was first postulated by Patel and Nouraei in this journal in 2014. This phenomenon has not been demonstrated in paediatric patients. In this issue, Riva et al. publish their transcutaneous evaluation of carbon dioxide elevations in apnoeic children weighing 10-15 kg by comparing two oxygen flow rates.  

Regional anaesthesia also features in this issue – from assessment of the needle manipulation of novices to the role of adjunctive agents in brachial plexus blockade. Chuan et al. report the results of their randomised controlled trial examining the potential role for visuospatial ability screening in learning ultrasound-guided regional techniques. The visuospatial ability of anaesthetists, as measured by their ability to identify similar three-dimensional objects from different perspectives, was hypothesised to correlate with their ability to perform ultrasound-guided needle manipulation, which is an essential component of regional anaesthesia performance. The needling times of 140 medical students during ultrasound-guided tasks are reported, after randomisation by visuospatial ability, with some participants receiving deliberate practice and others assigned to discovery learning. Meanwhile, Sehmbi et al. report their meta-analysis of 100 trials on supraclavicular brachial plexus block characteristics when dexamethasone and dexmedetomidine are administered as adjunctive agents. The authors evaluated the effects of these agents on sensory block, motor block and analgesic duration by comparing with control supraclavicular blocks that were performed without adjuncts. The route of administration of the agents (perineural or intravenous) was incorporated into their analysis.

The bleeding post-cardiac surgery patient is both a unique haematological challenge and a commonly faced problem in cardiac intensive care units. How best to identify and manage specific deficits in coagulation, and measure the response, remains a matter of ongoing debate. This issue features a pilot randomised controlled trial comparing the use of prothrombin complex concentrate and fresh frozen plasma in adult patients who required coagulation factor replacement for bleeding within 24-hours of cardiac surgery. Elsewhere, Kataife et al. evaluate the impact of the Haemostasis Traffic Light cognitive aid on clinician performance during simulated bleeding scenarios (Fig. 2).

Figure 2 Design of the Haemostasis Traffic Light. The five steps are described (0 to 4) from left to right. Each step has its rationale and an example of an intervention (dotted line) to show how the Haemostasis Traffic Light concept may be adapted to institutional coagulation management protocols.

The dose of oxytocin administered during elective caesarean delivery has reduced over the last two decades. In this issue, Peska et al. report the results of an oxytocin dose-finding study in obese women at elective caesarean delivery, using the biased coin up-down method. The primary outcome was uterine tone as assessed by the operating obstetrician two minutes after drug administration.

Finally, in this month’s Contemporary Classics series, revisiting some notable papers that have featured in Anaesthesia in celebration of its 75th anniversary, Tim Cook, Ellen O’Sullivan and Fiona Kelly discuss the origins and impact of the 2004 Difficult Airway Society guidelines for the management of difficult tracheal intubation. To round off this issue, our popular Correspondence section has its reliable mixture of personal observations and insights along with commentary and debate surrounding recently published research in Anaesthesia.

We hope you enjoy the diverse range of topics featured in this month’s issue. Stay tuned to our twitter feed for daily updates on the journal’s articles, podcasts and live broadcasts!

Craig Lyons and Andrew Klein

Data, answers and questions

This month, we are delighted to publish a new international prospective cohort study from the COVIDSurg and GlobalSURG collaboratives. It is now our best performing paper on social media, ever, with an Altmetric score of > 2400! They studied > 140k patients in 116 countries and concluded that the risks of postoperative morbidity and mortality are greatest if patients are operated within 6 weeks of diagnosis of SARS-CoV-2 infection (Fig. 1). Their work highlights how collaboration on an international stage such as this can give us the answers we need to clinically important questions that matter to hospitals, clinicians and patients. Their work has helped formulate new guidelines which have been implemented across the UK. In the accompanying editorial, Wijeysundera and Khadaroo take us through the complexity of asking when the safest time to operate on a patient with prior SARS-CoV-2 infection is. They highlight the need for quality standards specifically tailored for these large multicentre collaborative studies. Provided that the research question, study design and team are strong and efficient, collaborative research is to be commended and must be continued.

Figure 1 Overall adjusted 30‐day postoperative mortality from main analysis and sensitivity analyses for patients having elective surgery and those patients with a reverse transcription polymerase chain reaction (RT‐PCR) nasopharyngeal swab positive result for SARS‐CoV‐2. ‘No pre‐operative SARS‐CoV‐2’ refers to patients without a diagnosis of SARS‐CoV‐2 infection. The time‐periods relate to the timing of surgery following the diagnosis of SARS‐CoV‐2 infection. Sensitivity analysis for RT‐PCR nasopharyngeal swab proven SARS‐CoV‐2 includes patients who either had RT‐PCR nasopharyngeal swab proven SARS‐CoV‐2 or did not have a SARS‐CoV‐2 diagnosis; patients with a SARS‐CoV‐2 diagnosis which was not supported by a RT‐PCR nasopharyngeal swab were not analysed. 

We have several high-quality obstetric anaesthesia papers this month, as well as a podcast. First, Odor et al. present the findings from their multicentre prospective cohort study – the direct reporting of awareness in maternity patients (DREAMY). Their main finding was that the incidence of accidental awareness during general anaesthesia (AAGA) in obstetrics, assessed by using direct questioning, is almost three times higher than previously ascertained when relying on patient self‐reports: 1 in 256 (95%CI 149–500) vs. 1 in 1200 (95%CI 714–2500). There are many other nuggets of information here of relevance to all anaesthetists, and the paper has reignited the debate about choice of anaesthetic agents for obstetric general anaesthesia as well as a range of other topics. In the accompanying editorial, Palanisamy and Paech discuss these practice changes, the associated controversies and the possible consequences of the work by Odor et al. They argue the most significant contribution is the association between AAGA and post-traumatic stress disorder, the incidence of which is broadly in keeping with previous reports in other patient populations. Therefore, early recognition of AAGA and subsequent intervention is more important now than ever.

Figure 2 Study flowchart of participant recruitment and outcome adjudications. Outcomes are stratified as accidental awareness during general anaesthesia (AAGA) and ‘No AAGA’, with ‘Unlikely AAGA’ included in the latter category. A total of six patients had screening Brice interview responses indicating suspected awareness during general anaesthesia; however, verification assessment was not able to be completed, hence insufficient evidence was available to adjudicate these reports using equivalent criteria to the remaining cases.

Second, this new randomised controlled trial from Chapron et al. finds that spinal anaesthesia with hyperbaric prilocaine induced a shorter and more reliable motor block compared with bupivacaine, administered in spinal anaesthesia for non‐breastfeeding women with uncomplicated pregnancies and undergoing elective caesarean section. The suggestion that prilocaine might be more useful than bupivacaine in this setting is sure to cause, at the very least, some raised eyebrows in the obstetric anaesthetic community. Carvalho and Sultan provide their analysis and conclude that if hyperbaric prilocaine is ever contemplated for routine use, it should be used in conjunction with a combined spinal‐epidural technique. This is so that if the surgical duration exceeded the duration of spinal anaesthesia, the epidural could be dosed to maintain anaesthesia and reduce the need for conversion to general anaesthesia. Third, Heesen et al. discuss the use of noradrenaline as compared with phenylephrine in women undergoing spinal anaesthesia for caesarean section. They highlight that the effect of noradrenaline on fetal acidosis is still unclear, but in the best case scenario it is no worse than phenylephrine. Some excellent suggestions are provided for those undertaking studies in this area. 

Sickle cell disease is one of the most common serious inherited single gene disorders worldwide and has a major impact on the health and life expectancy of the individual. These new Association of Anaesthetists guidelines were developed to highlight advances in peri‐operative care of patients with sickle cell disease, provide anaesthetists with a better understanding of sickle cell disease and to make recommendations about the organisation of care for this complex group of patients. Twelve key recommendations are provided, which are included in the infographic below. 

Elsewhere we have: a systematic review and meta-analysis of conventional landmark vs. preprocedural ultrasound for neuraxial analgesia and anaesthesia in obstetricsa systematic review of reporting quality for anaesthetic interventions in randomised controlled trialsa systematic review of melatonin for anaesthetic indications in paediatric patientsa pilot and feasibility study of postoperative wrist worn accelerometers; and an observational study of exploring the limits of prolonged apnoea with high-flow nasal oxygen

Finally, this new paper from Matt Wiles has been extremely popular on social media. He was tasked with taking on a classic paper from the 1990s and chose an article by Nolan and Wilson about tracheal intubation in patients with spinal injuries. Is manual in-line stabilisation (MILS) during tracheal intubation effective protection or harmful dogma? He presents a persuasive argument against, and urges clinicians to reflect on why they continue to choose to use MILS during tracheal intubation – is this for patient benefit, for protection against later criticism or medicolegal claims, or because ‘we have always done it this way’? Do you disagree? Send us your thoughts in a letter! We might just publish it and get Matt to respond.

Do you want to be our next journal fellow? The deadline for our next post is approaching, so make sure you start working on your application now. Previous fellows include Helen Laycock, Mike Charlesworth and Kariem El-Boghdadly, who are now all fully fledged Editors!

Mike Charlesworth and Andrew Klein