Socially accountable anaesthesia

It was reported in 2006 that anaesthetists in Uganda had the facilities to deliver safe anaesthesia for adults, children and pregnant women only 23%, 13% and 6% of the time, respectively. Furthermore, only 13 physician anaesthetists were in place for a population of 29 million. Thereafter, the AAGBI established a fellowship scheme with the primary aim to increase the number of physician anaesthetists in Uganda to 50. In this month’s Anaesthesia, the much-anticipated results of this initiative are presented, analysed and discussed. A mixed-methods approach (you can read all about qualitative research here) clearly demonstrates how a partnership between two professional organisations has profoundly changed healthcare in Uganda beyond the initial goal of improving human resource capacity. Unexpected benefits include greater access to surgery, anaesthesia and intensive care, and improved standards of training and patient care.

 

The accompanying editorial by Biccard and Green-Thompson describes how, in most low and middle-income countries, the demand for care far outstrips the capacity to provide it. There seems to be a global maldistribution of anaesthetic and surgical expertise, and part of the solution could be socially accountable education of future practitioners. They argue this should produce healthcare graduates who are responsive to the social needs of the local environment. Standards of care can be concurrently formed through partnerships and innovations, such as the Lifebox initiative (more about that here). Motivated learners can then be identified and supported through fellowships and emerge as socially responsive healthcare providers, able to address the limitations of a resource-limited environment. Socially accountable anaesthesia is therefore less about transference of a system into a country and more about supporting an existing system to thrive and become sustainable, and the trainee fellowship programme in Uganda is a remarkable example of this.

 

In patients undergoing general anaesthesia, does nitrous oxide decrease, increase or have no effect on the risk of accidental awareness under general anaesthesia (AAGA)? (Read all about the recent evidence related to AAGA here!) This Cochrane systematic review of 15 RCTs finds only three cases of reported awareness in the included literature. This, together with the poor quality of evidence meant it was not possible to draw meaningful conclusions, other than that the risk of awareness with or without nitrous oxide is unknown and included trials were not powered to measure awareness as a primary outcome. Is this yet another example of a question that cannot be answered with an RCT and where we may need to rely on observational ‘big-data’ analyses? Possibly….but more on that later!

 

Gastric ultrasound as a means to assess gastric content prior to, during and following surgery seems to be an increasingly popular area of study. For example, we have recently seen studies of the risk of aspiration through regurgitation of ingested blood in children undergoing ENT surgery, gastric emptying in healthy controls as compared with patients with end-stage renal failure and assessment of the gastric antrum before and after elective caesarean section. The first of two new such studies this month is an RCT of non-labouring pregnant women in the third-trimester randomised to one of six pre-determined volumes of apple juice. Ultrasound measurements following an 8-hour fast and immediately after the drink were taken, and a model for gastric volume estimation was derived. The resultant equation is the first mathematical model to predict gastric volumes in late pregnancy using bedside point of care ultrasound, and may one-day change the way perioperative care is delivered for such patients.

 

Additionally, a prospective observational study of pre-operative gastric ultrasound assessment in children undergoing elective surgery concludes it may provide more useful information than clinical assessment alone when aiming to predict the risk of pulmonary aspiration. Should we be using gastric ultrasound in our routine clinical practice to assess the risk of aspiration pneumonitis? Van de Putte and Perlas debate what constitutes a clinically insignificant gastric volume prior to anaesthesia, and conclude we may not be far from a simple, clinically-relevant bedside tool to help us accurately assess this risk. They discuss many issues pertaining to the timing of gastric ultrasound, how it should be performed and who should be doing it? There is lots here to discuss and debate and we would very much like to hear your thoughts.

 

When designing a study, one must decide which outcomes should be measured. For example, when comparing two analgesics, should we aim to demonstrate less pain, faster recovery or shorter length of stay? Say ‘less pain’ is selected, does this equate with lower pain scores, less morphine administered, longer time between requests, or should we use patient-related functional outcomes? A systematic review of outcomes in postoperative pain studies in children and adolescents finds a worrying lack of standardisation in outcome measurements that may prevent the pooling of such studies in a meta-analysis. The authors call for a core outcome set that may improve the quality of future trials and allow for more study-to-study comparisons. With regards outcome selection for systematic reviews, Heesen et al. suggest distinctions between primary and secondary outcomes should be abandoned. They also argue that clinically useful sub-group analyses should be reported regardless of whether or not it was planned to do so. Departures from the study protocol can be easily explained retrospectively in order to provide transparency.

 

This retrospective observational study in 1,478,977 patients concludes general anaesthesia is associated with a significantly higher risk of new-onset epilepsy, more so in patients with co-existing medical conditions and those suffering postoperative complications. ‘Big-data’ observational analyses are arguably more difficult to understand and interpret than an RCT, yet we are becoming more reliant on such studies to answer the questions RCTs cannot. (You can read all about the limitations and merits of retrospective observation here.) Thankfully, Ms Method Matters is on hand to guide us in our attempts to understand this finding. She concludes that when applying the results to a hypothetical Taiwanese population, there would be one more case of epilepsy for every 1111 undergoing general rather than neuraxial anaesthesia. Despite this context, there are certain limitations that cast doubt over our ability to comment on accuracy and clinical significance. Is the risk of epilepsy greater in those receiving general or neuraxial anaesthesia? Perhaps we will never know!

 

Elsewhere this month there is a RCT of different perioperative strategies for the management of patients with type-2 diabetes undergoing non-cardiac surgery, a RCT comparing recovery characteristics for patients receiving either sugammadex or neostigmine for reversal of neuromuscular blockade, a before and after observational study of a protocol or use of the C-MAC videolaryngoscope with a Frova introducer in pre-hospital rapid sequence intubation and an observational feasibility study of a new anaesthesia drug storage tray. Finally, with the abstract deadline for #GATASM18 fast approaching, we encourage you to send us your work! We enjoy reading your abstracts and many have the potential to become full papers. We hope you enjoy the March issue as much as we did, and we look forward to discussing each paper with you on Twitter. Don’t forget, each article is free for 24 hours on the day it is tweeted!

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Mike Charlesworth

Trainee Fellow

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Andrew Klein

Editor-in-Chief

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The corridor of uncertainty

Clinical decision-making is a strong theme throughout this month’s Anaesthesia. Using the example of cricket (more about the reason for this later!) ‘the corridor of uncertainty’ is an area a bowler aims to pitch their delivery so as to induce uncertainty in the batsman’s decision to play or leave, move forward or back, and defend or attack. Whether or not the correct decision was made soon becomes clear, particularly if a wrong shot, a late movement, hesitation or indecision result in a dismissal. The clinical corridor of uncertainty is arguably no different. We are pitched complex clinical problems and our job is to use knowledge, experience and ‘heuristics’ (more about that here) to make the best decisions for our patients. In anaesthesia and critical care, we soon find out whether or not we made the right choice too! This month’s edition is packed full of clinical content to help reduce uncertainty, guide decision-making and improve care for patients.

First up is a randomised controlled trial from Chambers et al. comparing leak, tidal volume and complications for cuffed vs. uncuffed tracheal tubes in children. They conclude cuffed tubes provide better ventilation and control of respiratory mechanics, are associated with less corrective measures following intubation and result in lower rates of adverse events (Table 1). Craig Bailey argues there is good evidence cuffed tubes enable accurate end tidal measurements, reduce theatre pollution, provide more reliable control of ventilation, are less likely to be exchanged for another sized tube and reduce the incidence of postoperative sore throat and pulmonary aspiration. Of course, such recommendations challenge the accepted wisdom of the last 50 years and we would very much like to know what you think. Will your practice change? Tell us!

 

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Table 1 Peri-operative and postoperative respiratory complications for all patients by cuffed/ uncuffed groups. Values number (proportion). TT, tracheal tube

 

The 2017 Australian flu season was the worst seen for many years and so-called ‘Aussie flu’ (H3N2) is now here in the UK. The spread of influenza along with other respiratory viruses seems to be putting considerable pressure on UK hospitals, intensive care units and severe respiratory failure centres (SRFCs). For patients with severe respiratory failure, care can be escalated through referral, acceptance and transfer to a SRFC for the consideration of veno-venous extracorporeal membrane oxygenation (VV-ECMO). Gillon et al. report the results of their retrospective analysis of SRFC referrals to Guy’s and St. Thomas’ in central London. Six-month survival was 72.8% for those accepted to the service and 72.1% for those retrieved with VV-ECMO, which is higher than previously reported. Their results appear to support decision making and clinical practice at the study site and cast doubt on the use of scoring systems as compared with experienced clinical judgment. In their editorial, Charlesworth et al. distil the decision-making process for SRFC referrals into seven themes and conclude expert collaborative clinical assessment is, at present, an acceptable way to manage such referrals. If you are working in an intensive care unit this winter, there is a good chance you will care for patients with severe respiratory failure, so make sure you read these papers!

In their review article, van de Donk et al. discuss the pharmacokinetics and pharmacodynamics of sufentanil and examine its use for acute postoperative pain. They argue the sufentanil sublingual tablet system (SSTS) is effective and may even provide a future alternative to an intravenous morphine PCA system. Bantel and Laycock discuss and critique this evidence in the context of the tactics used by the pharmaceutical industry to promote gabapentin in the 1990s. They find many problems, including the publication of more reviews than original articles, ethical approvals granted by commercial review boards, methodological deficiencies and the use of ghost-writers for two manuscripts. They ask therefore, are SSTSs being promoted with the same marketing tools as used for gabapentin in the 1990s?

We often see discussions on Twitter with regards the documentation of laryngeal view as a means of recording the difficulty of intubation. In his editorial, Brian Jenkins discusses the documentation of ‘the view from the top’ in relation to an article by O’Loughlin et al., in which the accuracy and reliability of three scoring systems for reporting the glottic view at videolaryngoscopy are compared. He argues it is important to contextualise the grade recorded by documenting, as a minimum, equipment, technique, adjuncts and difficulties with obtaining a good laryngeal view. He also suggests the resultant record is an invaluable source of information for to the next operator and the recording of inaccurate or unreliable data should be regarded by all as potentially dangerous.

Continuing with the cricket theme (there was a reason we chose it!), Tavare and Pandit present their much anticipated statistically speaking article, ‘When rain stops play: a ‘Duckworth-Lewis method’ for surgical operating list productivity?’ Is it possible to compare the productivity of, for example, a cardiac theatre with two scheduled cases and a urology theatre undertaking ten operations in the same time period? It turns out we can use a well-known statistical method whose usual function is to calculate the target score for a team batting second in a limited overs match that is interrupted, typically by rain (Figure 1). In fact, the curves for operating theatre productivity are similar to the Duckworth-Lewis cricket model and the same principles seem to apply. Is working in the NHS the same as batting in the rain? The answer is educational, philosophical and entertaining, as is the article as a whole. We really enjoyed reading this one!

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Figure 1 Duckworth–Lewis performance curve relating resources (%, y-axis) to overs remaining (x-axis), as a function of wickets (isopleths). The resource % is then used to calculate the target score for the second team after an interruption.

 

Elsewhere this month we have a randomised controlled trial comparing high-flow nasal oxygen with standard management for conscious sedation during bronchoscopy, a description of real-time continuous monitoring of injection pressure at the needle tip for peripheral nerve blocks and a review of 21 years of litigation for pain during caesarean section. Finally, if you have exams on the horizon, need a paper for a journal club or simply want to become a statistics expert, we have completely re-organised and updated our special collections. Topics include cardiothoracics, guidelines, hip fractures, obstetrics, paediatrics, regional, research misconduct, statistics, reviews, training and education, and ultrasound. We hope you enjoy this month’s issue as much as we did and we look forward to discussing the articles with our followers on Twitter (each article we tweet is made #FOAMed for that day) in the next few weeks!

Mike Charlesworth, Editor Fellow

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Andrew Klein, Editor-in-Chief

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Complications of Anaesthesia

The start of a new year isn’t usually much fun. Short days, long nights, back to work and a guilt-driven desire to visit a gym and eat salad. On the other hand, it’s nearly time for the AAGBI Winter Scientific Meeting, and we recently published our free to access supplement issue, ‘Complications’! Our Friday morning session (12th January) is all about the complications of anaesthesia and it is no coincidence the two are related. First up is Dr Alastair Glossop from Sheffield discussing respiratory complications followed by Dr Guillermo Martinez from Cambridge, who will give a much-anticipated talk about cardiovascular complications. Finally, we are delighted to have Dr Heidi Doughty, a consultant in Transfusion Medicine from the NHS Blood & Transplant service, present the complications of blood transfusion. If you are registered for #WSMLondon18 please do come along and engage with us either in person or on Twitter. If you aren’t yet registered, here is the link.

If you simply cannot wait to hear from our speakers, you’re in luck, as our 2018 supplement issue is simply everything you need to know about the complications of anaesthesia. Our special issues are growing in popularity, with each allowing for a particular topic to be set out in extraordinary depth. They are an excellent educational resource that we hope contribute in some way to enhancing the care we provide for our patients. In 2017, we published ‘Monitoring in the peri-operative period’ preceded by ‘Peri-operative medicine’ in 2016 and ‘Transfusion, Thrombosis and Bleeding Management’ in 2015. ‘Complications’ is already having an impact and we hope to see lots of discussions about the articles as we tweet each one over the coming week or so.

Valchanov and Sturgess set the scene (and issue an apology to Atul Gwande!) with their editorial ‘Complications: an anaesthetist’s rather than a surgeon’s notes’. They argue the complications issue is a timely publication, as demands on anaesthetists are increasing, the population is aging, we are seeing more patients with complex comorbid conditions and therefore complications are no-doubt increasing. The culture of complications is changing too, as it is becoming more acceptable to report critical incidents and learn from these reports in an open, no-blame and shared manner.

Merry and Mitchell provide an overview of complications in anaesthesia and question whether or not there is an easy way in which they can be defined or attributed to anaesthesia. Such questions seem trivial enough, but there are no easy answers. From the perspective of human error, which is statistically inevitable, they argue the occurrence of a complication or adverse event does not always equate with a failure in care standards. Nevertheless, every effort should be made to prevent such errors from precipitating these events. This leads nicely to the systematic review from Jones et al. where the role of human factors in preventing anaesthetic complications is examined (methodologically, this is a very difficult literature search/synthesis and the authors must be congratulated!). They included 74 studies and highlight the way in which human factors have become embedded into clinical practice in anaesthesia (Figure 1 and 2). Though the relationship between human factors and anaesthesia is emphasised with the example of complex trauma in the emergency department and operating theatre, the principles are transferrable to all manner of scenarios.

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Figure 1 Human factors recognised by NAP4

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Figure 2 Human factors recognised by NAP5

 

The respiratory and cardiovascular complications of anaesthesia are core topics for all and the articles by Mills and Sellers et al. are therefore essential reading. Professor Mills sets out the evidence-base for postoperative pulmonary complications and underlines the need for more research to establish the role of postoperative CPAP, non-invasive ventilation and high-flow nasal oxygen. Although the optimum level of intraoperative PEEP is uncertain, the use of lung-protective ventilation during anaesthesia likely reduces the incidence of postoperative pulmonary complications and there is therefore scope for us all to improve patient outcomes. Cardiac complications following major non-cardiac surgery are common and Sellers et al. argue patients should be better triaged to more advanced postoperative care environments based on their preoperative risk. Myocardial injury after non-cardiac surgery is a spectrum (Figure 3) and the use of postoperative troponin assays merits attention through further research. Overall therefore, there seems to be more questions than answers, but there are several measures we can take to prevent respiratory and cardiovascular complications.

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Figure 3 The spectrum of myocardial injury and troponin rise after non-cardiac surgery

 

There are a range of different topics covered in this issue such as, for example, spinal cord and peripheral nerve injury following anaesthesia, peri-operative neurological complications associated with cardiac surgery and adverse drug reactions. Obstetric anaesthesia is an area with high patient expectation in combination with the need for time-critical high stakes anaesthetic intervention. It is of little surprise there are several commonly occurring obstetric complications together with a small number of rare yet potentially catastrophic complications. The narrative review from Maronge and Bogod discusses their pathophysiology, prevention and management in detail and is therefore a ‘must read’ for all those practicing obstetric anaesthesia. They argue women should be believed when describing symptoms consistent with an iatrogenic injury and that steps should be taken to ensure complications are identified early and treated appropriately.

Though the pathophysiology of perioperative acute kidney injury (AKI) is complex, the article from McKinlay et al. offers an excellent summary of the relationship between contributory surgical, anaesthetic and haemodynamic factors (Figure 4). It is somewhat alarming that, despite easily identifiable risk factors, perioperative AKI accounts for 30-40% of all in-hospital AKI cases and is associated with significant morbidity and mortality, even for seemingly trivial postoperative creatinine rises. Detailed recommendations are provided for preoperative, intraoperative and postoperative strategies to prevent renal complications and the authors call for more consistency in the diagnosis and reporting of postoperative AKI.

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Figure 4 Schematic representation of the potential pathophysiology of perioperative AKI.

 

Finally, what should we do when complications occur? There are obvious consequences for patients but the impact on healthcare workers must also be considered. Cruikshanks and Bryden argue it is important to put matters right (if possible), apologise and explain the implications of complications when events don’t take their intended course. They list recommendations from the Francis report into the Mid-Staffordshire NHS Trust and argue poor handling of complications will likely lead to complaints and litigation through attempts by patients to receive explanations and support which should have been provided initially.

That’s all for now, but planning for the 2019 supplement ‘Pre-operative optimisation of the surgical patient’ is already well underway. We do hope you enjoy the 2018 complications supplement and that it provides ample education and stimulation whilst retaining clinical relevance to all. Please discuss and engage with the articles either through twitter or formally through our correspondence site as we are always interested to hear what you think. See you in London next week!

 

Mike Charlesworth                                                               Andrew Klein

Editor Fellow                                                                          Editor-in-Chief

Consensus, consent and consciousness

Hypotension following spinal anaesthesia for caesarean section is common with significant maternal and foetal consequences. Despite this, practices vary markedly and there has, thus far, been a lack of formal guidance. This month in Anaesthesia sees the publication of an international consensus statement on the management of hypotension with vasopressors during caesarean section under spinal anaesthesia. (Developing a consensus statement is a complex process, as there are few simple black and white recommendations that can be supported with robust scientific evidence.) Ten key recommendations for best practice are provided including, for example, a phenylephrine infusion starting at 25-50 mcg.min-1 and titrated to systolic blood pressure (≥ 90% baseline), left lateral uterine displacement and the consideration of colloid or crystalloid pre-loading. Jeremy Campbell and Gary Stocks argue this puts right a surprising lack of guidance for an important group of patients, and its introduction will no-doubt improve foetal outcomes and the birthing experience of all mothers undergoing caesarean section under spinal anaesthesia. Although we may have not, just yet, discovered the Holy Grail of obstetric anaesthesia (and some have highlighted the limitations of a consensus approach), this guidance certainly provides clear, sensible and practical advice to all.

 

The consensus statement and editorial are accompanied by two similarly themed original research articles. The first, by Zieleskiwicz et al., investigates the association between maternal hypotension following spinal anaesthesia and point-of-care ultrasound derived subaortic ΔVTI before and after performance of a passive leg raise manoeuvre prior to spinal anaesthesia for caesarean section. They found a subaortic ΔVTI of ≤ 8% and ≥ 21% to be predictive of absence or occurrence of hypotension respectively. Secondly, Dyer et al. report their RCT of maternal cardiac output response to colloid preload and vasopressor therapy during spinal anaesthesia for caesarean section in patients with severe pre-eclampsia. They found cardiac output increased following spinal anaesthesia in women with severe early onset pre-eclampsia, and a small dose of phenylephrine reversed this haemodynamic change more effectively than ephedrine. Lower doses of phenylephrine are therefore recommended for such patients, where required.

 

How well do you understand and practice consent for anaesthesia? Nicholas Chrimes and Stu Marshall discuss the barriers to informed consent in anaesthesia and argue certain practical challenges may deny patients their legal right to make decisions about their care. They call for better alignment between the principles of consent and the realities of clinical practice in light of recently published guidelines. (The 2017 AAGBI consent for anaesthesia guideline is a ‘must read’ for every anaesthetist!) For example, if patients are to be informed of and give permission for every individual element contributing to their anaesthetic, together with every possible complication, they argue obtaining informed consent for anaesthesia may be at best extremely challenging and at worst, impossible.

 

Does loss or responsiveness (LOR) and recovery of responsiveness (ROR) occur at the same concentration of anaesthetic agent? Not according to the study by Sepúlveda et al. where propofol was administered to 19 healthy volunteers using a Schnider effect site target controlled infusion (Figure 1). They found LOR ensued at a higher propofol concentration than ROR and conclude this may suggest evidence of neuronal inertia in transitioning between LOR and ROR. In the accompanying editorial, Frank Engbers asks, is unconsciousness simply the reverse of consciousness? He argues ROR is likely dependent upon external and internal stimuli as well as the anaesthetic drug concentration. An observed hysteresis between LOC and ROC, although not illogical, may therefore be explained by many factors other than brain inertia.

 

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Figure 1 Observed numbers of unresponsive subjects during induction (red line) and recovery (blue line) periods as a function of Schnider model predicted effect-site concentration (a) and measured plasma concentration (b).

 

We are delighted to have published two narrative reviews this month and each provides a summary of recent evidence for core anaesthetic topics. They are, therefore, essential reading for all. Firstly, Tim Cook emphasises the critical importance of communication, decision-making and non-technical practice with regards the avoidance of major airway complications. (He describes this as everything he has ever said on twitter in one long article!) Highlights include a description of themes emergent from fatal case reviews (Figure 2) and a novel cognitive aid for dealing with an evolving airway crisis, the Vortex approach© (Figure 3). The second review from Tasbihgou et al. presents a synthesis of recent evidence with regards accidental awareness under general anaesthesia (AAGA). They argue AAGA is both common and preventable yet associated with severe psychological consequences in some. They therefore call for anaesthetic departments to implement and maintain strategies to limit its occurrence.

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Figure 2 Recognisable events and pitfalls of fatal airway complications.

 

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Figure 3 The Vortex approach© to airway management (vortexapproach.org; reproduced with the permission of Nicholas Chrimes.

 

If a patient develops intra-operative anaphylaxis and is successfully resuscitated, should planned surgical procedures continue? Sadleir et al. argue it seems reasonable to do so following grade 1, 2 and 3 immediate hypersensitivity reactions (Figure 4) based on their retrospective analysis of 223 patients over nine years in Western Australia. This, however, is as long as the continuing management of acute hypersensitivity does not prevent successful completion of surgery, or proceeding with surgery does not prevent resuscitative efforts, should they be required. Elsewhere this month Henningsen et al. report a qualitative study of patient experiences with regards peripheral nerve blockade for ankle fracture surgery, Tallent et al. evaluate the ‘ISO-Gard’ oxygen/scavenging mask as a means to reduce the level of exhaled sevoflurane/desflurane below recommended exposure limits and László et al. describe a method of teaching flexible fibreoptic tracheal intubation in cadavers preserved using Thiel’s method as compared with manikins.

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Figure 4 Classification of severity of acute hypersensitivity reactions.

 

Finally, preparations are well underway for the AAGBI Winter Scientific Meeting in London (10th-12th January). Congratulations to all those with an accepted abstract! Our ‘How to publish a paper’ workshop (11th January, 2-4pm) is once again free to all attendees. Matt Wiles chairs the Friday morning Anaesthesia session with topics for discussion including respiratory, cardiovascular and blood transfusion associated complications. Our stand will be open throughout and we very much hope to see you there!

Mike Charlesworth, Editor Fellow

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Andrew Klein, Editor-in-Chief

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Lights, camera, action!

Is videolaryngoscopy (and by that we don’t mean uploading your intubation/airway videos to YouTube/Twitter) superior to direct laryngoscopy? Though this may oversimplify an area of great controversy and complexity, the evidence keeps coming and the debate rages on. Just in the last year we have seen studies of different glottic view scoring systems, different tracheal tube types, videolaryngoscopy (VL) vs. direct laryngoscopy (DL) in patients with a simulated difficult airway, awake VL-assisted intubation in patients with a periglottic tumour and awake intubation of bariatric patients with a difficult airway.

This month in Anaesthesia sees a welcome addition to the above in the form of a systematic review and meta-analysis of VL vs. DL use by experienced anaesthetists in patients with a known difficult airway. The authors retrieved 9 articles with a total of 1329 patients and concluded VL to be associated with greater success at the first attempt, even with an experienced DL operator (OR 0.34 [95% CI 0.18-0.66]). In addition, VL yielded fewer Cormack and Lehane grade 3 and 4 views (OR 0.04 [95% CI 0.01-0.15]) and less mucosal trauma (OR 0.16 [95% CI 0.04-0.75]). The question remains however, should VL become the standard of care for the initial approach to intubation in the context of a known difficult airway? We would very much like to hear your opinions on this one! Get in touch with us through Twitter or Facebook.

Keeping with the VL theme, Abrons et al. report an RCT of asleep VL-assisted nasotracheal intubation using either a bougie (Figure 1) or non-bougie technique. They found a significant reduction in the incidence/severity of bleeding and trauma to the nasopharynx with the bougie technique, though with no difference in first attempt and overall success rates. For those who regularly perform nasotracheal intubations, will this study change your practice? Let us know!

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Figure 1 The tracheal tube (red arrow) is seen advancing over the bougie.

 

Uncontrolled haemorrhage in trauma is a major problem, as mortality in such circumstances approaches 50%. In their editorial, Nevin and Brohi describe the evidence for and the clinical applications of permissive hypotension for active haemorrhage in trauma. It is difficult to conduct primary studies to support such practice and the evidence base is necessarily sparse and of low quality. In general, whilst permissive hypotension may be physiologically undesirable in the short-term, they argue its use has almost certainly contributed to improved long-term outcomes for such patients.

When uncontrolled haemorrhage presents in addition to a traumatic brain injury however, the evidence for permissive hypotension is more so limited. In his accompanying editorial, Matt Wiles argues that hypotension should be a trigger for aggressive management in the trauma patient with a suspected head injury and only permitted for as short a time as possible. Rather than liberal crystalloid resuscitation, he argues management should consist of normalisation of coagulation with haemostatic resuscitative measures, avoiding hypothermia and acidaemia, and rapid transfer for definitive management. Additionally, an individualised cerebral perfusion pressure target should be achieved with small volume fluid boluses and vasopressors. There are no easy answers here and we require more evidence, difficult though it may be to generate.

 

From VL vs. DL to permissive hypotension in traumatic haemorrhage, this month’s edition is packed full of controversial topics! Continuing the theme, Lei et al. report their RCT of cerebral oximetry and postoperative delirium in 249 cardiac surgical patients. All patients received rScO2 monitoring, but half were randomised to algorithmic treatment for rScO2 below 75% of the baseline value for 1 minute or longer. For the control group, the rScO2 monitoring screen was electronically blinded. Although postoperative delirium was reported to be associated with baseline saturations ≤ 50% (p = 0.0001) there was no difference between intervention and control (OR 0.98 [95% CI 0.55-1.76]). In their accompanying editorial, Kunst and Milan argue whilst there is observational evidence to support the predictive power of cerebral oximetry together with its intraoperative algorithmic optimisation, there is little evidence yet that such measures affect clinical outcomes in cardiac surgery. Rather than a ‘deadly blow’ to non-invasive cerebral monitoring, they argue the equipoise demonstrated by Lei et al. is complicated by several limitations. When you consider the lack of evidence for the use of pulse oximetry with regards clinical outcomes (and we certainly couldn’t do without that!) it begs the question, will we ever be able to prove the utility of cerebral oximetry through traditional research methods?

Keeping with the cardiac theme, there are several scores available to predict mortality in such patients (though scoring systems and risk estimation have well described weaknesses). If the long-term postoperative risk prediction is greater than preoperative estimates, is this indicative of an adverse intraoperative event such as a stroke, AKI, sepsis or a gastrointestinal complication? Currently, there is no method to capture adverse intraoperative events and/or determine their effect on long-term survival. Coulson et al. term this the ‘acute risk change’ (ARC) and derive its value from the difference between the preoperative AusScore (analogous to EuroSCORE-2) and the postoperative APACHE-3 score. They found the ARC to be associated with long-term survival at 1 and 5 years but argue this could be a function of noise, adverse perioperative events and/or unmeasured patient risk.

In his accompanying editorial, John Carlisle asks whose fault are wrong predictions: the clinician, the patient or the pigeon? (Though rather than the pigeon, mortality after cardiac surgery is primarily determined by the patient and to some extent, the surgeon.) In addition to offering an alternative statistical interpretation of Coulson’s results, he argues our understanding of perioperative mortality would be greatly improved by developing a single model common to all patients and all operations with the ability to accommodate additional information as the patient progresses through their perioperative care.

Elsewhere this month there is a retrospective study of ketamine administration and the development of acute or post-traumatic stress disorder in 274 war-wounded soldiers, a study of neuromuscular blockade and the efficiency of facemask ventilation in patients difficult to facemask ventilate (another controversial topic!), a study of the association between pre-operative variables and complications after oesophagectomy and Miss Method Matters explains how to compare times in clinical studies with a finite ending.

Finally, this being our Christmas edition (apologies it is the middle of November!) we are delighted to publish our second annual Christmas article, the FARCE study! You may remember CRAC-ON, our first Christmas article as published last year. This year however the question is, what is the association between critical care nursing staff emotions and their surrounding environment as assessed using the ancient system of feng shui? Although feng shui as applied to critical care bed spaces appears to have no effect on the feelings and inner harmony of nursing staff, one conclusion is that simple measures such as an impromptu cake or a simple friendly hello can increase a person’s chi score. We are therefore going to spend the rest of the day doing just that!

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Andrew Klein, Editor-in-Chief

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Mike Charlesworth

Editor Fellow

Major trauma, marginal gains

There is little doubt that major trauma care has significantly improved over the last three decades. This is likely due to the cumulative effect of a number of practice changes such as, but not limited to, regional trauma networks, education (though ATLS and its limitations have been discussed at length) and the implementation of systems and procedures from the military setting. In this month’s Anaesthesia, Stein et al. report retrospective observational data from University Hospital, Zürich before (2005-07) and after (2012-14) establishing several quality improvement bundles, including the implementation of a goal-directed transfusion and coagulation algorithm. They found significant reductions in the incidence of massive transfusion, administration of blood products, mortality and ICU stay (Table 1).

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Table 1 Raw and adjusted differences in transfusion of allogeneic blood products and outcome between the two cohorts (2005–2007 and 2012–2014). Values are number (proportion), mean (SD) and odds ratio (95%CI)

 

Smith and Choi urge for cautions interpretation of these results. The main issue seems to be the retrospective manner of data collection and the resultant difficulty in determining the exact size of the effect. This begs the question, why do we persist with retrospective studies when they have clear limitations? One suggestion is that, through versatility and pragmatism, retrospective observation can force rapid advances in patient care by allowing us to form testable hypotheses, establish trends and make sense of clinical practice. As we have seen with ERAS+, comparing outcomes before and after a series of quality improvement interventions can provide powerful evidence for these practice changes. There are several retrospective observational studies this month and we will no doubt see many more in the future.

 

We are seeing more older adults with injuries sustained through major trauma and the results from Stein et al. support this perception. In the UK, over half of all those entered onto a recent national trauma database were over 60 years old. Griffiths and Kumar discuss the implications of this changing demographic and ask whether systems for the management of major trauma are fit for the needs of older adults? The recent ‘Trauma Audit and Research Network (TARN)’ report suggests that many improvements are required, starting with more effective ways of injury prevention in the home. The one bit of good news (and there isn’t much) is that many older patients do well and return home following a full recovery. The report and editorial are essential reading for anyone with an interest in trauma management.

 

Green et al. report an analysis of CLWRota data from 2.5 million anaesthetic sessions during 2015. Their aim was to look at the number of supervised sessions trainees undertook as compared with the three per week RCoA standard. The results show the majority of trainees did not achieve this, more so with increasing seniority (Figure 1). It is suggested, amongst other measures, that logbook inspection should be more frequent so that training can be tailored to individual trainee requirements.

Figure 1 Nov Blog

Figure 1 Number of supervised sessions worked by trainees per week in 89 Trusts, for individual training grades (the dotted horizontal line indicating the three sessions per week RCoA recommendation). Horizontal line, median; box, IQR; whiskers, 1.5 × IQR; crosses, outliers.

 

Penfold and Carey, the Joint Chairs of the Training Committee of the RCoA, write in their accompanying editorial that although trainees may not be meeting RCoA supervision standards, the overall impact of this may be difficult to quantify. Moreover, there are many barriers for Schools in their quest to meet these standards. Keeping with the training theme, England and Jenkins argue that clinical time is the most important aspect of a training programme and that it should be protected. They call for efficiency in the delivery of training outside the clinical environment and for trainers to provide this without reducing clinical time. What do you think about supervision and training time? Send us a letter through our correspondence website, or tweet us!

 

We continue to invite authors to submit narrative as well as systematic reviews to Anaesthesia, as we believe both evidence and opinion have their place in modern science and medicine. This month, Trend et al. present a narrative review of aerosolised drug therapy in children receiving respiratory support. It seems that we know less about the use of such drugs in these circumstances, and this review provides guidance as to when and how the inhaled route may be of value for such patients (Table 2).

Table 2 Nov Blog

Table 2 The clinical use of inhaled medications in children within specific therapeutic contexts.

Elsewhere, Bagchi et al. examine the association between the mode of perioperative ventilation and postoperative pulmonary complications (POPCs) in 109,360 patients (this has already generated a lot of interest on Twitter!). They found pressure-controlled ventilation to be associated with more POPCs, possibly due to higher driving pressures, higher tidal volumes and low or no PEEP. Heesen et al. report their results from a systematic review of epidural volume extension (EVE) by saline injection, and its effect on the efficacy and safety of intrathecal local anaesthetics. They found inadequate evidence in general, although a shorter motor block recovery time may result. Onodi et al. examine the difference between arterial and end-tidal carbon dioxide in 799 children undergoing mechanical ventilation during general anaesthesia. They conclude end-tidal monitoring of carbon dioxide may lead to an unrecognised hypocarbia.

 

There is much more in this month’s edition including a case series of apnoeic oxygenation for laryngeal surgery, an evaluation of various epidural drug mixes for labour analgesia and a comparison of gastric emptying for soluble solid meals and clear fluids matched for volume and energy content.

 

Finally, we were delighted to reveal the Top 10 Papers of 2016 at the recent Annual Congress meeting in Liverpool. You can find all these high-impact articles online in one convenient location. Our ‘How to publish a paper’ workshop continues to be well attended (Figure 2), and we look forward to seeing the abundance of ideas, enthusiasm and creativity transform into an article or two. Will they make the Top 10 Papers of 2017, or possibly even win? We certainly hope so!

Figure 2 Nov Blog

Figure 2 ‘How to publish a paper’ Workshop at AAGBI Annual Congress 2017, Liverpool. Copyright AAGBI.

M_Charlesworth                        A_Klein

Mike Charlesworth                 Andrew Klein

Editor Fellow                          Editor-in-Chief

Neostigmine is dead, long live neostigmine!

This month in Anaesthesia sees yet another possible victory for sugammadex as compared with neostigmine for the reversal of rocuronium-induced neuromuscular blockade. Laryngeal microsurgery is an example of a short surgical procedure where surgeons request deep neuromuscular block yet complete reversal prior to emergence and extubation. (Of course, trans-nasal rapid insufflation ventilatory exchange [THRIVE] is an exciting alternative these days – but that debate is for another time.) This presents an obvious dilemma for the anaesthetist, as intubating, operating and extubating conditions are traded off against emergence and recovery time. Choi et al. randomly allocated 44 patients to receive either high-dose rocuronium (0.9 mg.kg-1) with sugammadex reversal (4 mg.kg-1) or low-dose rocuronium (0.45 mg.kg-1) with neostigmine reversal (50 μg.kg-1 with 10 μg.kg-1‑ glycopyrrolate) for patients having laryngeal microsurgery. Unsurprisingly, onset time, level of block, operating conditions and recovery time (2.1 vs 9.9 minutes) were all superior in the sugammadex group. The clinical efficacy and versatility of sugammadex is substantial yet its financial cost remains a major barrier preventing widespread use. The insightful accompanying editorial by Bailey asks when it is appropriate to use sugammadex and whether we should be using it more. The general message seems to be that there are certain circumstances where it is most definitely appropriate, but neostigmine is by no means dead……just yet.

The ethics of airway research have been extensively debated in recent issues. This month, Cook et al. provide discourse in relation to ‘consensus on airway research ethics’ (CARE)  published in Anaesthesia. The issue seems to be whether or not the consensus guideline is necessary at all and how such research can reflect an increasingly complex workload that includes more ASA 3+ patients with difficult airways. The ultimate question Cook et al. ask is: how generalisable is manikin-based airway research? The authors of the guideline provide a counter opinion in the correspondence section and argue that rather than an all-encompassing mandatory protocol, the CARE guidelines were designed to provide guidance and to promote informed discussion in the field of airway research. What do you think? Send us a letter through our correspondence website!

There are three further airway papers of interest this month, all in relation to paediatric anaesthesia. Firstly, Mihara et al. performed a network meta-analysis* of various types of supraglottic airway device in children (Figure 1).

Octoberblog_Figure 1.png

Figure 1. Network graph for insertion failure at first attempt. The size of the blue node represents the number of patients included in studies featuring that device. The thickness of the lines connecting the nodes is proportional to the number of head-to-head randomised controlled trials in each comparison. The numbers next to the connecting line indicate the number of randomised controlled trials. Where a number is absent, there is only one trial reporting that comparison. airQ-SP, self-pressurised air- Q; Ambu-AG, Ambu AuraGain; Ambu-i, Ambu Aura-i; Ambu-o, Ambu AuraOnce; c-LMA, laryngeal mask airway Classic; Cobra, Cobra perilaryngeal airway; f-LMA, flexible laryngeal mask airway; LT, Laryngeal Tube; p-LMA, Proseal laryngeal mask airway; s-LMA, Supreme laryngeal mask airway; SLIPA, Streamlined Liner of the Pharynx Airway; u-LMA, laryngeal mask airway-Unique

 

They identified 65 trials with 5823 patients assessing 16 different supraglottic airway devices to determine oropharyngeal leak pressures, first attempt success, blood-staining risk and device failure. They reported that LMA®-Proseal and i-gel™ have high oropharyngeal leak pressures and a low risk of insertion trauma, as previously suggested, however the risk of device failure with i-gel™ is somewhat higher. Nevertheless, before translating this study into clinical practice it may be worthwhile reading the accompanying editorial by Nørskov et al. Scientific evidence, important though it is, forms only one piece of the puzzle when choosing whether to adopt a new airway device into clinical practice.

How does the UK fare in terms of anaesthetic research output as compared to other G-20 countries over the last 15 years? As revealed by Ausserer et al., although the absolute number of anaesthesia articles (2564 from the UK in 2011-2015, if you’re wondering) is steadily increasing, there has been a considerable lack of relative growth from many developed countries against a backdrop of an 11 and 9-fold increase for China and India respectively (Figure 2).

Octoberblod_Figure 2.png

Figure 2. Percentage distribution of selected G-20 countries regarding published articles. Others not shown (ARG, AUS, BRA, CAN, FRA, IDN, ITA, KOR, MEX, RUS, SAU, TUR, ZAF) changed only by 1% or less. EU* excludes the EU countries otherwise shown in this figure

 

Of course, our Canadian cousins published the most articles per million inhabitants, which is testament to their research systems. But is this a cause of concern for the UK, or is it that output, as measured by the quantity of publications, only tells part of the story?

The early withdrawal of treatment for out of hospital cardiac arrest (OOHCA) victims and those with a devastating brain injury is never straightforward as we cannot predict the probability of survival with absolute precision. Yet there is evidence and even an expert consensus-based pathway for OOHCA victims that advises against prognostication during the first 72 hours after return of spontaneous circulation. Manara and Menon present a compelling argument for translating these practices to the care of those patients who have suffered a devastating brain injury. This would offer a number of benefits including the survival of a small number of retrievable patients, permitting families time to come to terms with a catastrophic event, allowing informed withdrawal after an appropriate interval, offering families the opportunity for carefully considered organ donation, and supporting development of the evidence base for clearer prognostication and decision making in the management of patients. As we have seen before, perhaps we need to stop the concept of therapeutic nihilism?

Elsewhere in the October edition there is an interesting  comparison of oral chloral hydrate and intranasal dexmedetomidine to facilitate CT scanning in children, an evaluation of the Minto TCI model during cardiopulmonary bypass, an RCT comparing different analgesic approaches for postoperative pain following caesarean section, and the description of a novel approach to thoracic paravertebral block (Figure 3).

Octoberblog_Figure 3.png

Figure 3. (a) Ultrasound transducer position and needle insertion site for mid‐point transverse process to pleura (MTP) block technique. (b) Ultrasound image and schematic demonstrating the injection point for the MTP technique. SCTL, superior costotransverse ligament; PVS, paravertebral space; i/c muscle, intercostal muscle; m, muscle; TP, transverse process.

 

All this and much more in a bumper edition of Anaesthesia to keep you feeling bright as Autumn draws in and the nights get longer. Enjoy!

 

*A network meta-analysis is a systematic review where several interventions are directly and indirectly compared in terms of their efficacy.

 

Mike Charlesworth

Trainee Fellow, Anaesthesia (17-18)

Kariem El-Boghdadly

Trainee Fellow, Anaesthesia (16-17)

Andrew Klein

Editor-in-Chief

 

Post art: Kariem El-Boghdadly

Rest when you’re dead?

“Resting is fitness training”

–Jenson Button

 

The well-documented struggles trainees have suffered recently are compounded by training requirements and clinical workload. So how do the pressures of modern day training affect physical, psychological and social well-being? McClelland et al.  looked to answer this question by conducting a national survey of trainees and assessing the impact of night shifts on fatigue. Over half of all trainee anaesthetists responded, with an even spread of training grades. After finishing a night shift, nearly half of the respondents needed to drive on the motorway to get home, and nearly a fifth travelled for more than 60 minutes. This is compounded by the fact that 84.2% of respondents claimed to be too tired to drive home after a night shift, and more than half having experienced either an accident or a near miss (including falling asleep at the wheel) on their post-nights homeward journey. Less than a third of trainees were aware of rest facilities following night shifts, and if they were available, they could cost up to £65 a shift. Night shifts commonly led to sleep disturbance and the use of substances such as caffeine to mitigate the adverse effects of their fatigue. Finally, the study authors found that personal relationships, physical health, psychological well-being, the ability to do the job and the ability to manage exam revision and projects were all negatively affected by fatigue in more than half of respondents. All in all, McClelland et al.  have reported highly concerning adverse effects of the working patterns of anaesthesia trainees.

Michael Farquhar has followed this up with a telling editorial, questioning the ‘hero attitude’ that trainees have been encouraged to develop, and describing the measures his institution and specialty have taken to mitigate the worrying results reported by McClelland et al. These include breaks that are not voluntary, mandatory training in sleep hygiene, and changing culture to accept that self-care is not ‘an optional luxury.’ We should no longer believe that we as doctors can fool physiology, particularly at a time when morale is plummeting, and burnout is on the rise.

In a very different study, Suehana Rahman et al.  present a much-needed review of the literature pertaining to patient medical alert identification (ID) tools, something that seems to have slipped under the regulation radar thus far. Medical ID tools can be in the form of jewellery, body art such as tattoos, personal devices, medical ID cards, or other forms such as key rings or bag tags (Fig. 1).

 

Figure 1.png

Figure 1. (a) MedicAlert wristband and (b) bracelet worn over the traditional ‘pulsepoint’ location

 

They could present a range of material, including allergy status, information of medical conditions the ID carrier suffers from, pharmacotherapy, and contact details of next of kin. The authors conducted a systematic review of medical databases as well as a Google search, and found four reports of adverse events due to medical alert jewellery, and 32 online vendors of medical alert jewellery, with no evidence of any standards and minimal involvement of physicians. There was no evidence reported that medical IDs ‘work’ or are even safe. With little guidance available, the authors proposed four principles:

  1. Medical IDs should be substantiated by messages conveyed by patients
  2. In unconscious patients, healthcare workers should not conduct ‘disproportionate searches’ for medical IDs
  3. If medical IDs are discovered in unconscious patients, staff should interpret the information rationally and proportionately
  4. Conscious patients should convey all relevant information directly and not rely on the information in IDs alone

Could these proposals be the start of a new era of international standardisation of medical alert IDs?

Contrary to this scarcely-researched question, Stens et al. reported another interesting study, fuelling the ongoing debate regarding the value of intra-operative cardiac output monitoring on perioperative outcomes. They assessed the addition of pulse pressure variation and cardiac index to arterial blood pressure monitoring via the non-invasive ccNexfin device in patients undergoing general surgery. This multicentre, double-blinded trial randomised 244 patients to either be monitored with just continuous arterial pressure, or adding pulse pressure variation and cardiac index monitoring to standard arterial pressure monitoring and managing fluid therapy according to a specified algorithm. They found that there was no difference in 30-day complications, total fluid and blood products infused, fluid loss and blood loss, or return to mobility. Notably, fewer patients in the control group needed vasopressors. So, does this add further fuel to the fire against goal-directed therapy with cardiac output monitoring? Or does this simply suggest that the Nexfin device does not reliably contribute to improved patient outcomes? Only time will tell.

Another question of time relates to pre-operative fasting guidelines. We mandate a six-hour fast for solids and two hours for clear fluids, but what is really going on in the stomach in emergency patients after this duration of time? Dupont et al.  performed gastric ultrasound assessment, determining the volume of the gastric antrum, in 263 patients who were starved for > 6 h and having emergency surgery (Fig. 2).

Figure 2

Figure 2. The distribution of gastric volume estimated for 263 participants before unplanned surgery, after at least six hours of fasting

 

They found that more than a third of patients had volumes consistent with unstarved stomachs, and the size of the antrum was associated with BMI and the pre-operative consumption of morphine. Moreover, one patient in their cohort suffered from pulmonary aspiration, yet this patient did not have a gastric antrum that suggested a full stomach. The data presented by Dupont et al.  suggests that the duration of pre-operative starvation may not be related to gastric antral area, and thus volume, in emergency surgery – so what does this mean for aspiration risk without rapid sequence induction in all emergency surgery patients?

On the subject of food, there is plenty of food for thought from novel, thought-provoking and practice-changing papers published in the September edition of Anaesthesia. The dynamic research group working with the NIAA and The James Lind Alliance Priority Setting Partnership explored the difference in anaesthesia and critical care research priorities between clinicians, carers and patients. Despite all groups prioritising patient safety, they found a discrepancy between patients and clinicians – the former favouring patient experience while the latter favouring clinical effectiveness. A surprising result? Perhaps not. However, in another paper published this month, Berning et al.  surveyed nearly 500 patients to compare the effect of quality of recovery from surgery on patient satisfaction and they found little correlation. So how is patient satisfaction, experience, quality of recovery and clinical effectiveness all linked, and what is most important? Expect a flurry of research trying to answer this question in the coming years!

Also in the September edition, Chen et al. reported an increased success rate of double-lumen endobronchial intubation using a novel wireless videostylet, the Disposascope® versus conventional intubation (Fig. 3), Shah et al.  found that psoas muscle mass is associated with mortality following elective AAA repair, and Pillai et al. discovered that Luer and non-Luer spinal needles are equally as strong! All this and much more in one of the most diverse editions of Anaesthesia this year – eat, drink and sleep well!

Figure 3.png

Figure 3. The Disposascope® in a pre-shaped double-lumen tube with the wireless monitor

 

Kariem El-Boghdadly

Trainee Fellow, Anaesthesia

Andrew Klein

Editor-in-Chief

 

Post art: Kariem El-Boghdadly

 

Pain(ful) management?

Other than the ground-breaking results of John Carlisle that we have recently discussed, this latest issue of the Journal gives us food for thought in our management of acute pain. Pritchard et al present a unique cost-effectiveness analysis of using patient-controlled analgesia (PCA) vs standard care in patients admitted from the emergency department for the management of acute traumatic or non-traumatic abdominal pain. They assessed hourly visual analogue scale (VAS) pain scores for 12 hours in 20 patients meeting inclusion criteria, and determined the hourly rates patients were in moderate to severe pain (VAS ≥45). Cost-effectiveness was quantified by determining the additional cost per hour that moderate to severe pain was avoided with PCA rather than standard practice. As expected, overall costs were higher in the PCA groups but did this translate in to additional cost-effectiveness benefits? It turns out, an additional £24.77 and £15.17 per hour were incurred to avoid moderate to severe pain in the PCA group in traumatic and non-traumatic abdominal pain groups respectively. This was spent on a range of additional tasks and equipment that was not seen in the standard care group (Figure 1).Figure 1. PCA Costs

Figure 1. Time and staff costs for patient-controlled analgesia and standard care groups per participant during the 12-h study period. Values are mean (SD)

The question of whether these costs represent value for money, and a more philosophical approach to this evaluation was published in an accompanying editorial by Doleman and Smith. They argue that choosing a cut off VAS of ≥45 arbitrarily puts patients with a VAS of 44 and 46 in separate severity of pain categories, which might invalidate the economic evaluation. Additionally, they followed up on the baseline data reported by Pritchard et al and found that the usual care group had higher pain scores than the PCA group. Moreover, Doleman and Smith ask an invaluable question: is the choice of outcome measure (VAS) looked at really that important? If not, which outcomes are actually important? Despite some interesting criticism of the study, I think it is safe to say that the unique methodology taken by Pritchard et al is worthy of reviewing and applying in similar studies in the future.

 

Speaking of novel pain management research, Lyngeraa et al report a randomised, double-blind pilot study of a novel ‘suture-method’ peripheral nerve catheter. It consists of a curved suture needle, a needle hub, and a catheter that can be placed under ultrasound-guidance in close proximity to a target nerve, with the distal end of the catheter emerging at a distal site (Figure 2). Figure 2..png

Figure 2. The suture-method catheter. Left: The suture-catheter device. N, needle; H, hub; and C, catheter. Right: The suture-method catheter during insertion. The needle has been inserted past the nerve to exit the skin on the other side of the nerve

 

The idea behind this technique is that catheters might be easier to insert in the appropriate position and should displace less than traditionally sited catheters. Sixteen volunteers had bilateral ultrasound-guided sciatic nerve catheters placed with the suture-method catheter system, and were randomised to receive either local anaesthetic or saline in each leg. They reported a 94% success rate in the initial catheter placement, but only three-quarters were still effective after vigorous physical exercise. The study authors argue that the novel suture-needle design is as effective as other techniques, and speculate that it might be more secure due to the double skin penetration anchoring, whilst reducing local anaesthetic leakage as the catheter is the same diameter as the placement needle. They also suggest that it might be easier to insert and see on ultrasound than traditional catheter techniques.

 

Of course, they have little data to truly support their claims of superiority of the suture-needle catheter, argues Fredrickson. This design necessitates a more invasive insertion, catheter placement tangential to nerves, extra steps to catheter insertion, and technical challenges to inserting a curved needle, all of which are significant drawbacks of this design. Additionally, Fredrickson’s group often insert ambulatory catheters that patients can remove themselves at home, a strategy that would be impossible to achieve with the suture-needle system as it needs medical expertise to remove. Traditional catheter techniques, argues Fredrickson, are currently superior and should be increasingly used in clinical practice. Of course, some experts believe that there is no role for catheters at all in management of perioperative pain – but that is a discussion for a different day.

 

Our next pain study in this issue of the Journal comes from Holmberg et al, who compared the effectiveness of a pre-operative vs post-operative analgesic infraclavicular brachial plexus block in 52 patients having radial fracture fixation surgery. Patients were randomised, and the time to first rescue analgesia after emergence from general anaesthesia, as well as pain scores, rescue analgesia, and plasma stress markers. Surprisingly, patients who had the pre-operative blocks requested rescue analgesia on average more than three-hours later than those who had the post-operative blocks, and their absence of sensory and motor function lasted an hour longer (Figure 3).

Figure 3..png

Figure 3. Kaplan-Meier curve showing the proportion of patients in each group not requiring opioid rescue analgesia. Red line, pre-operative block group; blue line, postoperative block group

Moreover, they had lower pain scores up to four hours after surgery, and lower analgesic consumption in the first post-operative week. However, there was no difference in ‘strong pain’ after block resolution, stress markers, and chronic pain between pre-operative and post-operative block groups. Overall, Holmberg et al have elegantly demonstrated the potential for pre-emptive regional analgesia to attenuate short-term pain.

 

Our final pain study was an interesting Cochrane systematic review assessing the analgesic efficacy of remifentanil patient-controlled analgesia (PCA) vs other parenteral analgesic strategies in labour. Jelting et al sought relevant randomised, controlled, and cluster-randomised trials reporting patient satisfaction with pain relief and adverse events. Twenty studies informed their analysis, although the outcomes they sought were poorly reported. When compared to other parenteral opioids, remifentanil PCA demonstrated superior satisfaction, but inferior patient satisfaction to epidural analgesia. There was not much to show for the difference in respiratory depression, nor low Apgar scores between remifentanil PCA and epidural analgesia. However, the authors attributed low or very low quality of evidence to most of the reported results. Does this tell us that we just don’t know yet?

 

The August issue of the Journal also sports some remarkable other studies. Did you know that we might be over-estimating the size of the cricothyroid membrane for emergency front of neck access? A size 6.0mm tube could just be too big – as we discovered in our recent TweetChat on the subject. We might also be over-nihilistic when considering surgery for patients with fractured necks of femur – are survival rates better than we think? What do you know about ventilation for lung transplant, or 3D-printed bronchoscopy simulators? These and more can be found in our August issue – I couldn’t put it down!

 

Kariem El-Boghdadly

Anaesthesia Fellow

Andrew Klein

Anaesthesia Editor-in-Chief

New Blood, Old Money

“Blood alone moves the wheels of history” — Benito Mussolini

 

We often assume what we were always taught must always be true. But what if it’s not? What if we make efforts to go beyond dogma and do things differently; understand things differently? July’s issue of Anaesthesia might just encourage readers to do that by publishing work on anaemia, laryngoscopy grading, and more.

 

Haemoglobin is the vehicle that helps to keep us alive, and surgery is an insult that may remove that vehicle. But do we know enough about pre-operative anaemia and iron deficiency to optimise the vehicle? In this month’s issue of Anaesthesia, Muñoz and colleagues presented a retrospective cohort study of five centres in Spain addressing precisely this question. They assessed data from more than 3000 patients undergoing a range of surgical procedures in which the underlying pathology predisposes to anaemia, has an expected risk of > 500 ml blood loss, and/or has a > 10% transfusion risk. They found that one third of patients were anaemic (Hb < 130 g.l-1), of which two-thirds had either iron deficiency or iron sequestration, and, perhaps unsurprisingly, two thirds of anaemic patients were women. Notably, 62% of anaemic patients had absolute iron deficiency, but half of non-anaemic patients were iron deficient or had low iron stores. They took this information and incorporated the recently published game-changing international consensus statement on anaemia management to suggest management for different scenarios pertaining to iron deficiency (Fig. 1).

July_fig1.png

 

Figure 1. Patients’ classification, according to pre-operative haemoglobin levels and iron status, and *suggested actions to be taken, as per a recent international consensus statement. Absolute iron deficiency defined by ferritin < 30 μm.l−1 or ferritin 30–100 μm.l−1, plus transferrin saturation < 20% and/or C-reactive protein > 5 mg.l−1; iron sequestration defined by ferritin > 100 μm.l−1, plus transferrin saturation < 20% and/or C-reactive protein > 5 mg.l−1; low iron stores defined by ferritin 30–100 μm.l−1, plus transferrin saturation > 20%.

 

This data was accompanied by a thought-provoking editorial by Butcher et al, who looked at the findings from a different perspective. Butcher et al. suggest that, as women generally have smaller circulating blood volumes than men, the same peri-operative blood loss would have a significantly larger effect on the former than the latter. Compounding this, we have long accepted that anaemia in women is defined by a lower Hb than that for men, and therefore females are more likely to require transfusion. This is a curious paradox, one which has received little consideration in the past. However, Butcher and colleagues point to Muñoz’s data as a demonstration that, if target Hb concentrations are the same between men and women, the latter are far more likely to be anaemic. It is imperative, therefore, that we readjust our age-old targets, and consider changing the arbitrary cut-offs of to 130 g.l-1, irrespective of sex. This novel thinking is likely to drive a significant amount of research in the future, and could perhaps increase the safety of patient management, no matter the gender.

 

O’Loughlin et al have assessed a question that many haven’t asked: what scoring system should to describe glottic visualisation at videolaryngoscopy? The authors compared the age-old Cormack and Lehane score (published in Anaesthesia just 35 years ago), the percentage of glottic opening (POGO) score, and the authors’ very own Fremantle score. As a quick reminder, the POGO score is an estimate of the percentage of the glottic inlet that is seen on laryngoscopy, and the Freemantle score is the three-component composite describing the view, the ease of intubation and the device use for intubation. The authors showed 20 videolaryngoscopic intubation videos to 74 critical care physicians, and compared accuracy with an expert panel assessment, as well as assessing intra- and inter-rater reliability. They found that the POGO and Fremantle score are superior to the Cormack and Lehane score in the outcomes assessed. However, O’Loughlin et al go one step further and suggest that, because their Freemantle score provides additional information about the ease of intubation, this should be the go-to scoring system. Of course, few anaesthetists in the UK apply this scoring system, and ultimately the reason to describe the view at laryngoscopy is for communication. The next question should be: does the Fremantle score improve communication enough to drop the tried and tested Cormak and Lehane score?

 

This issue of the Journal next takes us to a simple, yet novel method for determining the location of epidural needle placement using continues pressure wave-form monitoring. By attaching extension tubing attached to a pressure transducer to epidural needles, pulsatile waveforms synchronised with heart rate represent epidural placement (fig. 2). 93% of patients who had effective epidural block also had a clear epidural pressure waveform on transduction. This technique thus provides, in the authors words, a ‘simple adjunct to loss-of-resistance for identification of needle placement.’ Of course, can you imagine the challenge in routinely locating a transducer set, appropriate monitor, whilst meeting 30 minute to attendance for epidural placement limit that many departments work towards? Neither can McKendry and Muchatuta, who question the necessity for this technique in the obstetric environment, and suggest that not only should other techniques be explored, but one should always consider that problems with regional anaesthesia techniques might be addressed by ‘looking for the cause on the proximal end of the needle.’ So let’s work out how best to improve our technique!

 

July_Fig2

Figure 2. An example of a typical pulsatile waveform, synchronous with the arterial pressure trace, recorded from a correctly located epidural needle. Top trace–intra-arterial pressure; middle trace (labelled CVP)–epidural space pressure; bottom trace–pulse oximeter waveform.

 

Novelty is abound, and Leong et al have presented a vital signs-controlled remifentanil PCA technique.  By programming a PCA device to act based on feedback from vital signs, the authors demonstrated a reduction in adverse events. Scholten et al published an exciting systematic review of novel techniques to assist with needle tip identification during ultrasound-guided procedures. They summarise the data on needle guides (including lasers!), needle tip design, 3D and 4D ultrasound, magnetism, robots and more. The challenges of regional anaesthesia might be overcome by the plethora of technological advances. Feng, Liao and Huang demonstrated that internal iliac artery balloon catheters might not be as effective for placenta accreta than we once thought; Flubacher et al demonstrated what we probably know about the efficacy of ondansetron as an anti-emetic; and Brix and colleagues found that day surgery does not always mean single day care episodes.

 

That was our whistlestop tour of the July issue of the Journal, but much more can be found between the covers that is sure to excite, entice and enlighten all who read it!

 

Kariem El-Boghdadly

Trainee Fellow, Anaesthesia

Andrew Klein

Editor-in-Chief

 

Post art: Kariem El-Boghdadly