Clinical Consequences

Each and every issue of Anaesthesia contains clinical messages that may change practice. Though there are a number of ways in which to measure academic impact, it is difficult to gauge the true clinical implications of published research. In the new, quarterly ‘Clinical Consequences’ series of articles, the implications of recently published research for clinically practicing anaesthetists will be discussed in depth. This first analysis focusses on the growing popularity of pre‐operative gastric ultrasound, and whether it should become part of routine clinical practice. Should we use an ultrasound probe to look inside Schrödinger’s gut? Be sure to read the full article for the answer!

Figure 1Figure 1 Sonographic image of (a) empty (b) fluid‐filled and (c) solid‐filled gastric antrum. L, liver; P, pancreas; Ao, aorta; A, antrum.

The battle against research misconduct has been well documented in Anaesthesia, with much focus on the detection of unreliable data and fraudulent authors. This new paper reports on the number of unretracted, retractable papers authored by Reuben, Boldt and Fujii, and the reasons given for this by journals, editors and publishers. It seems there is an urgent need to improve the way in which fraudulent or unethical articles are handled following publication. Why does retraction take so much longer than publication? Look no further than this excellent editorial from Loadsman, the Chief Editor of Anaesthesia and Intensive Care.

Pre-operative fasting guidance is changing to acknowledge the physiological and psychological risks associated with prolonged fasting. This new review article from Fawcett and Thomas synthesises clinical evidence and practice recommendations, and suggests we should now consider how best to manage fasting in patients with diabetes mellitus. We will soon be publishing our January 2019 supplement issue – ‘Patient optimisation before surgery’. Despite the fact that half the world’s population live in developing countries, this new review finds that such countries are poorly represented in systematically reviewed evidence on pre-operative optimisation.

Figure 2Figure 2 Cartograms showing (a) immediate and (b) extended pre‐operative interventions. The country polygon size is proportional to the cumulative sample size contribution to the literature.

Cricoid force is well and truly back on the agenda. This month, Gautier et al. report a new technique which may better prevent air entry into the gastric antrum during facemask ventilation – lower left paratracheal force. Perhaps, somewhere in a parallel universe, paratracheal force was described before cricoid force, with its use enshrined in clinical practice. What are the arguments for and against cricoid force? Naik and Frerk summarise several years of controversy in just a few lines, though whether or not the fact ‘they don’t use it in Europe’ continues to be relevant after Brexit will remain to be seen!

Figure 3Figure 3 For paratracheal compression applied manually, the thumb is positioned just cephalad to the clavicle between the trachea and the sternocleidomastoid muscle. A force of 30 N is applied to compress the oesophagus against the vertebral body.

These new Association of Anaesthetists guidelines on anaesthesia and peri‐operative care for Jehovah’s Witnesses and patients who refuse blood has already been extremely well received on Twitter, with an Altmetric score of 125! They are much more than a useful FRCA examination resource, they are a core document and essential reading for all anaesthetists, surgeons and clinical managers. On the subject of guidelines, should the next iteration of Association of Anaesthetists malignant hyperthermia guidelines address the use of activated charcoal filters? Yes, argue Bilmen and Hopkins, who also suggest they should be stored in all areas where volatile agents are used.

How best to accurately monitor the true injection pressure generated during performance of regional anaesthesia? This study from Saporito et al. suggests pressure measurement at the tip is more accurate as compared with measurement along the injection line. Barrington and Lirk argue there are more important factors to consider, such as education and core skills development, situational awareness, adequate organisation, preparation, non‐technical skills, standardised processes such as safety checklists, and routine patient follow‐up.

This prospective observational study in cardiac surgical patients suggests an association between impaired postoperative cerebrovascular autoregulation, as measured with cerebral oximetry, and delirium. You can still read this open access editorial from last year about cerebral oximetry which discusses all the controversies and much more. When marking the cricothyroid membrane (CTM) prior to surgery and anaesthesia, should the head and neck be in a neutral or extended position? This observational study suggests a skin mark made over the CTM in the neutral position cannot be relied upon when performing a surgical cricothyroidotomy in the extended position. Finally, this systematic review from Gerth et al. finds that patients surviving critical illness had a worse health-related quality of life when compared with population norms.

Elsewhere this month we have a study of the impact of emergency department patient‐controlled analgesia on the incidence of chronic pain following trauma and non‐traumatic abdominal pain, a narrative review of the association between attention deficit hyperactivity disorder and general anaesthesia, parental perception on the effects of early exposure to anaesthesia on neurodevelopment, and a prospective observational study of EEG density spectral array monitoring in children during sevoflurane anaesthesia.

January is a busy month for the journal, and we are very much looking forward to the Winter Scientific Meeting taking place 9th-11th January in London. This year, there will be two journal workshops taking place on Thursday. You can now register for ‘Social media for anaesthetic practice and education’ which takes place at 0900 and includes an introduction to Twitter with special guest Stuart Marshall (@hypoxicchicken). We will also be running our popular ‘How to publish a paper’ session in the afternoon.

We are very close to going live with our new journal, ‘Anaesthesia Reports’, an official journal of the Association of Anaesthetists which replaces what was known as ‘Anaesthesia Cases. It is international in scope and will publish original, peer-reviewed case reports, media content, and associated papers on all aspects of anaesthesia, peri-operative medicine, intensive care and pain therapy. We want you to send us your interesting cases, airway videos, blocks, and echo’s.

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See you in London!

Mike Charlesworth and Andrew Klein

The ORANGUTAN Score

What’s in a name? Researchers often want their studies to have catchy acronyms so they are easy to remember, advertise and tweet. This year’s special Christmas article assesses the prevalence of novel acronyms in the titles of anaesthetic and related studies, and the response of anaesthetists to them. Overall, acronyms were memorable at best but did not aid recall of the study topic and were generally unhelpful. It would be interesting to see the results of the ORANGUTAN score (Figure 1) as applied to studies from other specialties, but as Weale et al. quite rightly point out – we probably need to get out more.

Figure 1.jpgFigure 1 The ORANGUTAN scoring system for acronym accuracy and relevance.

An increasing number of patients are prescribed direct oral anticoagulants (DOACs) and there is a need for guidance on issues such as peri-operative cessation, reversal, and management of DOAC-associated bleeding. This month, we are delighted to publish the first multidisciplinary consensus statement on the management of DOACs for cardiac surgical patients. Though specific for cardiac surgery, there is also much useful advice for non-cardiac anaesthetists. In their accompanying editorial, Charlesworth and Arya argue peri-operative costs such as drug level assays and reversal agents should have perhaps been considered in already completed cost-effectiveness analyses.

On the topic of bleeding, what are the implications of activated partial thromboplastin time (APTT) for anaesthesia and surgery? We are perhaps less familiar with APTT as compared with other formal tests of coagulation, and this article will be of interest to all. It seems we should not ignore an isolated abnormal result, as causes may include a lack of coagulation factors VIII (Haemophilia A), IX (Haemophilia B), XI and XII; systemic anticoagulation from heparin; the presence of the lupus anticoagulant; and von Willebrand’s disease. Likewise, a positive bleeding history in a patient with a normal APTT should not be ignored. If in doubt, ask a haematologist!

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Figure 2 A suggested pathway for the management of deranged pre‐operative activated partial thromboplastin time (APTT).

“Yuk! That’s disgusting” – we have all heard those words from children when they try new food, drinks, and medicines. Salman et al. address an important clinical need in paediatric anaesthesia by evaluating the effect of a chocolate-based midazolam tablet in children aged 3-16 undergoing surgery. Though this new formulation underwent a higher first-pass metabolism, it was far more tolerable and remained efficacious when compared to i.v. midazolam solution given orally. In their editorial, Yuen and Bailey discuss the implications for other premedicants and drugs (e.g. antibiotics), the effects on the developing brain, and whether other flavours should also be developed.

Postoperative sore throat is an undesirable outcome for both patients and anaesthetists. From their meta-analysis, Kuriyama et al. conclude the topical application of corticosteroids to tracheal tubes significantly reduces the incidence of postoperative sore throat without any adverse effects and with a number needed to prevent of three. The quality of evidence was high and they even performed a trial sequential analysis to enhance the robustness of their findings. A potential practice changer? Let us know!

Traditional airway teachings are that plans ABC are attempted, sequentially, and failure should result in declaring a ‘cannot intubate, cannot oxygenate’ (CICO) situation. When faced with difficulty and in order to maximise ‘next-pass success’, is it possible to define final interventions before declaring CICO? Chrimes and Marshall discuss airway management at the opposite end of the alphabet: attempt XYZ. They call for a rapid, comprehensive and final single attempt at each of facemask ventilation, supraglottic airway insertion, and tracheal intubation that can be implemented independently of prior upper airway interventions (Table 1).

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Table 1 Attempt XYZ: suggested optimisations.

How best to monitor cardiac output during surgery? This study finds that when thermodilution is compared with arterial pressure-based measurements, accuracy may be affected by routinely encountered clinical factors. For example, thermodilution is affected by haemodynamic variability and arterial pressure measurements are affected by peripheral vascular physiology. Gillies and Edwards discuss the array of cardiac output monitoring technologies available and ask – does using them to guide therapy in the peri‐operative period actually improve patient outcomes? Though there is little evidence yet that this is the case, the conclusions from OPTIMISE-2 and FLO-ELA are eagerly awaited. Finally, this pragmatic randomised controlled trial was able to show that high-flow nasal oxygen (not THRIVE!) reduced the length of hospital stay in cardiac surgical patients at high risk for respiratory complications. Postoperative high-flow nasal oxygen is becoming more common and it is great to see useful evidence like this emerging to support these practices.

Elsewhere we have a study of body temperature, cutaneous heat loss and skin blood flow during epidural anaesthesia for emergency caesarean section; a comparison of two techniques for induction of anaesthesia with target‐controlled infusion of propofol; a retrospective study of peri-operative extracorporeal cardiopulmonary resuscitation; a pilot study of cardiopulmonary exercise testing and cardiac stress positron emission tomography before major non‐cardiac surgery; and this months ‘Statistically Speaking’.

How would you manage acute life-threatening massive haemoptysis in a patient with a predicted difficult airway and emphysematous lung disease? This great new case report published in Anaesthesia Cases generated a lot of attention and debate earlier this month and is well worth a read. The highest Altmetric scores this month came from this year’s supplement issue, ‘Complications’. We will shortly be publishing our 2019 supplement, ‘Pre-operative optimisation’, with topics including risk prediction, multimodal prehabilitation, shared decision making and a review of best practice for patients undergoing emergency laparotomy. We hope you are looking forward to it as much as we are!

It is also nearly time for the Winter Scientific Meeting in London, and this year we will be running a new workshop to complement our popular ‘How to publish a paper’ session. Make sure you register (limited places available) to find out how Twitter can help you stay up to date (with @hypoxicchicken), how to use and influence Altmetrics, and how to use freely available citation software such as Zotero and Mendeley.

 

Akshay Shah, Trainee Fellow

Mike Charlesworth, Social Media Editor

Andrew Klein, Editor-in-Chief

Patient Blood Management

Patient blood management is an international multidisciplinary initiative that aims to reduce the unnecessary transfusion of allogeneic blood components. Strategies include: the avoidance of oversampling; the use of appropriate transfusion triggers; the preoperative management of anaemia; and means of blood conservation, such as intra-operative cell salvage. One area that has perhaps been overlooked is the postoperative period, and this new international consensus statement on the management of postoperative anaemia after major surgical procedures aims to put this surprising lack of guidance right. Recommendations include screening those who have undergone major surgery for anaemia, monitoring the haemoglobin concentration until at least the third postoperative day, and the consideration of intravenous iron therapy or erythropoiesis stimulating agents. In their editorial, Hatton and Smith discuss several implications for clinical practice. An interesting consequence is the suggestion of increased cost-effectiveness, though there remain many unanswered questions about the role of iron therapy for certain patient populations, such as the elderly and frail.

The National Tracheostomy Patient Safety Project started as four intensive care doctors in Manchester wanting to improve the management of patients with tracheostomies. In 2012, we published their first multidisciplinary guideline on the management of tracheostomy and laryngectomy airway emergencies. Now, signs providing crucial information and algorithms can be found on the bedhead of every inpatient with a tracheostomy. This month, we are delighted to publish new guidelines for the management of paediatric tracheostomy emergencies. There are key differences when managing the routine and emergency care of children with tracheostomies and their reading is essential for all anaesthetists and intensivists working in a hospital that cares for children. Mackinnon and Volk discuss the need such guidelines, the use of simulation, their implementation and likely impact. They argue the guidelines will only work if shared and disseminated widely, and we call for all our readers and followers to do just that!

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Figure 1 National tracheostomy safety project emergency paediatric tracheostomy emergency management algorithm.

On the subject of paediatric airway management, this survey of paediatric and neonatal intensive care units has provoked much discussion on Twitter and was reported by BBC News. The authors found wide variations in practice with regards, for example, the availability of capnography, the existence of a difficult airway policy and the use of pre-intubation checklists. We expect there will be several letters from those working in such areas and we look forward to seeing the discussion continue.

There is a need to provide better training for junior medical staff who may care for patients in the perioperative period. This new mixed methods study evaluates the implantation of a new Foundation Programme in perioperative medicine for older people. The new programme proved popular and was able to deliver generic competencies alongside training in specialist topics, and the authors suggest such training may better meet the needs of an increasingly multimorbid surgical patient population. How best to optimise preoperative assessment for older people? This editorial has already been well received on Twitter and issues key clinical recommendation for such patients, including: the use of frailty scores and cognition checks; offering enhanced support where required; collaborating with geriatricians; shared decision making and admission planning.

Can a single, pre-operative dose of methylprednisolone reduce the severity of postoperative delirium? No, concludes this new randomised controlled trial, though it may reduce the prevalence of delirium and the severity of fatigue after hip fracture surgery in older patients, enabling remobilisation and recovery. Last month, we published an article on the characteristics of children aged less than 2 years undergoing anaesthesia in Danish hospitals between 2005-2015. This month, important information on children aged 2-17 undergoing anaesthesia during the same period is provided. Younger children were more frequently anaesthetised for non-surgical reasons and the use of inhalational agents was common. Reassuringly, complications were rare. The use of focussed cardiac ultrasound has many emerging uses and this paper demonstrates its utility for evaluating the haemodynamics of various positions in term pregnant women. It turns out that, in the ramped position, left lateral tilt may be unnecessary. Fascinating!

Elsewhere this month we have a study of cognitive recovery assessments in patients with low‐baseline cognition, an in‐vitro analysis of a novel ‘add‐on’ silicone cuff to improve sealing properties of tracheal tubes, a retrospective study of the association of time of emergency surgery with postoperative 30-day hospital mortality, and a study of the volume of 0.2% ropivacaine and common peroneal nerve block duration. Finally, in this month’s Snippet, we are reminded of the importance of ensuring not only monitoring wires but also oxygen tubing remains in sight at patient height during transfer.

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Figure 2 Sheared oxygen hose.

Over in Anaesthesia Cases we have a great new case report of anaphylaxis to all neuromuscular blocking agents, the first such case! Again, this has already attracted much attention on Twitter including a discussion of triggers to commence CPR in the context of perioperative anaphylaxis. Finally, as the end of the year draws closer, we begin to look forward to our Christmas article, which features in the December issue, and our January preoperative optimisation supplement, which will be published towards the end of December.

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Mike Charlesworth                   Andrew Klein

Social Media Editor                  Editor-in-Chief

Full time for sloppy terminology?

We have, very recently, published a number of papers on proximal approaches to intercostal nerve blockade (Figure 1). Do such blocks confer any advantages over and above direct injection of local anaesthetic into the paravertebral space? Probably not, as there are simply too many clinical unknowns with much of our knowledge derived from cadaveric studies (such as that presented by Yang et al. in this month’s issue). Furthermore, proximal intercostal nerve blocks may exert their effect by spread to the paravertebral space, and this month, Costache et al. call for a precise, unified definition for such blocks – paravertebral by proxy. Importantly, they provide clinical recommendations on which blocks should be selected for given patients in a range of circumstances.

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Figure 1 Schematic illustrating the location for the retrolaminar (RLB), intercostal/paraspinal, erector spinae plane (ESP) and midpoint transverse process to pleura (MTP) blocks.

The use of point of care ultrasound (POCUS) is, arguably, revolutionising the practice of modern obstetric anaesthesia. This new narrative review synthesises the current evidence and knowledge on its use to determine gastric contents, for safe airway management, and in order to quickly diagnose the cause(s) of breathlessness or acute circulatory collapse. It is, put simply, all you need to know about obstetric POCUS! When determining gastric contents, what exactly is a ‘full stomach’? Mike Kinsella argues there is no such phenomena, and more generally, that the use of confusing or imprecise language should be avoided. This underlines the belief that effective communication is arguably the key factor in providing safe medical practice.

How best to define ‘intra-operative hypotension’? We all know what it is, but the list of definitions is seemingly endless. This new study from Cleveland suggests intra-operative hypotension, defined as MAP < 65 mmHg, is strongly associated with postoperative acute kidney injury. Hypotension was somewhat more common prior to the first incision, and the authors call for anaesthetists to avoid hypotension immediately following induction of anaesthesia. Some have suggested a simpler message may be to avoid all hypotension, though defining how this sits in the era of bespoke anaesthesia presents more questions than answers. One possible way in which clinicians may negate intra-operative hypotension and postoperative acute kidney injury is though omission of ACE inhibitors/ARBs, but this collaborative study suggests otherwise. Both papers have been tweeted hundreds of times already and will be of interest to all readers!

How good are we at applying cricoid pressure, (or force, if you are so inclined)? This prospective study uses ultrasound to localise the cricoid cartilage as compared with a landmark method. The results are somewhat surprising, and bring into question previous studies of cricoid pressure efficacy. There are major clinical implications and we want to know if your practice will change?

Can this new device reduce the incidence of false passage formation, trauma, and failure as compared with the recommended technique for emergency front of neck access (eFONA) (Figure 2)? The results seem to be promising, at least in an obese porcine model, but how best to ethically study and use such devices in humans? As we have already seen, ‘The Airway App’ is a great way in which to collect data, collaborate, share practices, and learn from eFONA experiences. Are such methods better than large, whole-population database analyses? This new study from Denmark arguably provides important data on the characteristics of children less than two years of age undergoing anaesthesia. The accompanying editorial asks whether or not such databases are useful, and discusses the role of epidemiological surveys with reference to making sense of trends in clinical practice. Finally, this new observational study concludes middle finger length may be better associated with internal uncuffed endotracheal tube diameter in children than traditional formulae. Following on from the editorial by Craig Bailey, we are assured a similar study of cuffed tubes is on the way!

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Figure 2 Cricothyroidotomy introducer.

Elsewhere this month, there is a cohort study of the effect of lateral infraclavicular brachial plexus block on the axillary and suprascapular nerves as determined by electromyography, a randomised trial of serratus anterior plane block for analgesia after thoracoscopic surgery, and a meta‐analysis and trial sequential analysis of local vs. general anaesthesia for carotid endarterectomy. Over in Anaesthesia Cases, new reports include a description of spinal subdural haematoma pathophysiology and management following an epidural blood patch, and pharmacological cardioversion with nifekalant after release of the aortic cross-clamp during cardiac surgery.

This month’s blog immediately follows an incredible Annual Congress meeting in Dublin. Highlights included a keynote talk from Professor Rob Dyer (Cape Town, South Africa), a much-valued international advisory panel member for the journal. Professor Dyer also spoke on the peri-operative challenges of pre-eclampsia at the Anaesthesia journal session. Professor Mike Irwin delivered a fascinating talk on the advantages, disadvantages and clinical controversies associated with peri-operative remifentanil. Matt Wiles revealed the Top 10 Papers from 2017, with the award for best paper presented to John Carlisle for his ground-breaking analyses of randomised controlled trials from several major medical journals. John’s paper now has an Altmetric score of nearly 1000, making it the most shared and discussed paper we have ever published! It will most likely become our most cited paper too, replacing the classic paper by Cormack and Lehane. Our journal workshop, ‘How to publish a paper’, again proved popular among trainees and consultants alike, and we hope to see abstracts converted into papers over the next year.

Finally, congratulations to Akshay Shah from Oxford University who joins as trainee fellow. Kariem and Mike join the editorial board as Anaesthesia Cases Editor and Social Media Editor respectively.

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M_Charlesworth                  A_Klein

Mike Charlesworth          Andrew Klein

Social Media Editor         Editor-in-Chief

The Gold Standard?

Seven years ago, the results from the Fourth National Audit Project (NAP4)were published. A key conclusion was that awake fibreoptic intubation (AFOI) may have prevented several reported cases of airway-related morbidity and mortality, especially where difficulty was anticipated. The resultant recommendation was that all anaesthetic departments should provide a service where the skills and equipment are available to deliver AFOI when indicated. Though not explicitly stated, AFOI was seen thereafter, by many, as the ‘gold standard’ for difficult airway management.

Three years ago, Ahmad and Bailey suggested AFOI was becoming obsolete due to the emergence of other devices, such as the videolaryngoscope. Today, Alhomary et al. report the first systematic review and meta-analysis of videolaryngoscopy vs. fibreoptic bronchoscopy for awake tracheal intubation (ATI). They conclude intubation with videolaryngoscopy is quicker and has a similar success rate and safety profile as compared with AFOI. Their paper currently holds an Altmetric score of 226, which makes it the 8thmost shared and discussed paper from the journal, ever! In their editorial, Wilson and Smith discuss the clinical practice and study of ATI and how it presents significant problems to systematic reviewers. Their concluding argument is ATI with videolaryngoscopy should be a ‘core’ technique for all and a primary technique for novice anaesthetists. Will practice necessarily change in the future? The debate has been fascinating thus far and the arguments for and against will no doubt continue. A popular opinion seems to be that the real ‘skill’ is the technique of airway topicalisation, and Kariem El-Boghdadly has been kind enough to provide us with his recipe (Figure 1).

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Figure 1 A proposed recipe for oxygenation, topicalisation and sedation for ATI as provided by @elboghdadly.

Is there a gold standard for peri-operative neuromuscular blockade? Ask a surgeon and they may suggest it should be the provision of optimal operating conditions.This study from South Korea suggests deep neuromuscular blockade is indeed associated with better surgical conditions as compared with moderate blockade in patients undergoing laparoscopic surgery. Ask an Intensivist, however, and they might suggest neuromuscular blockade should be undertaken in a manner that reduces the incidence of postoperative pulmonary complications. This multifaceted quality improvement project from Massachusetts General Hospital was able to do just that through optimising the documentation of TOF monitoring and the dosing of neostigmine (Figure 1).

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Figure 2 Neuromuscular blocking agent dosing guide used at Massachusetts General Hospital as a cognitive aid in the quality improvement initiative. TOF, train‐of‐four.

In fact, their suggestion, that we should avoid the use of neostigmine when the degree of neuromuscular blockade has not been determined, may be supported by this next paper. Kent et al. present their results from a randomised controlled trial of neostigmine and glycopyrrolate given to healthy volunteers in the absence of neuromuscular blockade as compared with placebo. They conclude those given neostigmine and glycopyrrolate developed clinically significant muscle weakness which shared certain characteristics with a phase-1 depolarising block and may not be apparent with TOF monitoring. In their editorial, Naguib and Kopman argue these results have little or no clinical significance and anxiety around neostigmine-induced weakness is misplaced and unnecessary. Perhaps access to quantitative neuromuscular monitoring should be the real gold standard with regards the management of peri-operative neuromuscular blockade? If indeed it is, we still have a long way to go!

How best to manage, all at once, peri-operative neuromuscular blockade, depth of anaesthesia, coagulation, haemodynamics, mechanical ventilation and analgesia? In their editorial, Fawcett and Jones argue the technology exists to manage all these aspects of peri-operative care and more, but the anaesthetist should remain firmly at the controls. The general message seems to be that patients should be treated according to their individual needs rather than fixed formulas or algorithms, and practice does indeed seem to have evolved beyond the formulaic approach of the past. Does your hospital undertake surgery where blood loss is a recognised complication? If so, these new guidelines on the use of cell salvage for peri-operative blood conservation are essential reading. Again, this paper has already attracted much attention on social media and currently holds an Altmetric score of 113! Perhaps the most striking recommendation is that cell salvage should be universally available 24 hours a day in all hospitals performing major surgery. There is something here for everyone and we wholeheartedly recommend all members inspect these guidelines and discover how their future practice could be affected.

Many would agree the gold standard for generating clinical evidence is a randomised controlled trial, systematic review or meta-analysis. What if the aim is to prove a new, cost-effective intervention is no worse than (or non-inferior to) the current standard of care? So-called non-inferiority studies are increasingly common, yet their design, reporting, and interpretation can be extremely challenging. In this month’s Statistically Speaking, Charlesworth and Choi discuss non-inferiority studies with reference to a recent study from Nakanishi et al. Whether or not such studies should be seen as an inferior form of research methodology perhaps remains debatable, but the study by Nakanishi et al. demonstrates their value as an innovative way in which questions can be asked that cannot be answered by other means.

Point of care viscoelastic tests of coagulation such as ROTEM® are arguably becoming the gold standard for making transfusion decisions in the context of acute haemorrhage. This new study suggests a strong correlation between clot firmness at 5 (A5) and 10 (A10) minutes with maximum clot firmness (MCF). For coagulopathic trauma victims, do we really need to wait for the MCF or can we make early transfusion decisions using A5? Finally, what is the gold standard for critically injured burn patients? In the UK, they should be admitted to specialist burn units, and this new observational study finds that, on the whole, this seems to be the case. Furthermore, a generic risk prediction model outperforms two specialist models in such patients.

Elsewhere this month there is a retrospective study of pre‐operative anaemia, intra‐operative hepcidin concentration and acute kidney injury after cardiac surgery; a comparison of peripheral nerve blockade characteristics between non‐diabetic patients and patients suffering from diabetic neuropathy; a study of real‐time injection pressure monitoring system to discriminate between perineural and intraneural injection of the sciatic nerve in fresh cadavers; and the description of a new analgesic index using nasal photoplethysmography.

Over in Anaesthesia Cases there is an excellent case report of eFONA along with a discussion of how new guidelines and practices seem to be changing the skillset and role of the anaesthetist. Later this month, the Association of Anaesthetists will be holding their Annual Congress meeting in Dublin. The Anaesthesiajournal session takes place on Friday morning and first up will be Professor Mike Irwin discussing the advantages and disadvantages of remifentanil. This year, Matt Wiles hosts the ‘Anaesthesia article of the year’ and we look forward to finding out who made this year’s Top 10! Other highlights will include Professor Tim Cook discussing ‘Videolaryngoscopes for all?’ and we will, once again, be running our popular ‘How to publish a paper’ workshop. Finally, it’s all change at the association, and we are delighted to see our new design online for September. Printed journals should be landing from the 3rdof September onwards and you can read all about the new brand of the Association of Anaesthetists in your new-look Anaesthesia News.

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See you in Dublin!

 

 

Mike Charlesworth                                                             Andrew Klein

Trainee Fellow                                                                    Editor-in-Chief

Postoperative pulmonary complications

It was an absolute pleasure to attend the recent GAT Annual Scientific Meeting in Glasgow and our congratulations go to all who made it a success. At the ‘Research in Anaesthesia’ session, we discussed what makes a paper popular and the important role of social media in modern academic publishing. The attention a paper receives on social media is something we take very seriously, as it provides instant feedback on likely long-term impact and, more importantly, an opportunity to share and discuss. ‘Impact Factor’ is a more traditionally cited metric, and this month we are delighted to announce a healthy increase in ours to 5.431. Academic anaesthesia is alive and kicking!

Our first article this month is a prospective observational study in 177 patients comparing the diagnostic accuracy of postoperative CXR and lung ultrasound for the detection of pulmonary complications following cardiothoracic surgery. Touw et al. conclude lung ultrasound may detect more clinically-relevant postoperative pulmonary complications than CXR, and at an earlier time point, which may aid more effective clinical decision-making. Though some have called for all such patients to receive lung ultrasound prior to critical care discharge, others urge for caution. We look forward to receiving your lettersand seeing the debate continue.

In November of last year, Bagchi et al. published their retrospective study of 109,360 patients receiving either pressure- or volume-controlled ventilation during surgery. Their study, which reports in favour of VCV, has since attracted much attention. In their editorial, Charlesworth and Glossop argue why they believe the mode of mechanical ventilation is less important than other ventilatory and non‐ventilatory aspects of perioperative care. They also discuss the evidence around postoperative pulmonary complications and their management, and the merits or otherwise of retrospective database analyses (Table 1). Could a similar study in the UK yield the same number of patients and level of detail? Probably not, and so regardless of the inference, their data are of great value to us all.

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Table 1.Advantages and disadvantages of retrospective database analyses

 

The act of delivering a general anaesthetic to patients introduces a number of detrimental physiological processes that predispose to the development of lung damage. Neuromuscular blocking agents (NMBAs) have been suggested as a contributing factor in this regard. Is it possible, therefore, to avoid their use prior to tracheal intubation when using a MAC videolaryngoscope? This study suggests a NMBA free anaesthetic is ‘no worse’ than when such agents are used as regards postoperative laryngeal morbidity and intubating conditions. If you are wondering what is meant by ‘no worse’, make sure you look out for next month’s Statistically Speaking!

 

It is difficult to study and make sense of the evidence for postoperative pulmonary and other systemic complications due to the variable way in which they, and factors contributing to their development, are defined. In their editorial, Armstrong and Mouton discuss the need for universally agreed definitions for anaesthetic techniques and standardised reporting criteria. For example, how ‘awake’ are patients when they are deeply sedated? This may cause problems for systematic reviewers when retrieving and analysing studies pertinent to ‘awake’ tracheal intubation, but more on that next month.

Sodium-glucose co-transporter type 2 (SGLT2) inhibitors are increasingly prescribed as second line therapy for diabetes mellitus. Recently, there have been a number of published case reports of euglycaemic ketoacidosis related to SGLT2 therapy, and this new review of the peri-operative implications of SGLT2s is, in our opinion, essential reading for all anaesthetists. Though SGLT2s seem to be safe overall, their cessation prior to major surgery, during acute illness, or in a state of volume depletion is recommended. An agent with which we are more familiar is dexamethasone, but is a single anti-emetic dose immunosuppressive or immune-activating? Probably both, concludes this new study in ten healthy male volunteers. Keeping with the peri-operative theme, is it possible to assess physical fitness prior to major surgery in those unable to pedal? This study from Durrand et al. is a significant step forward towards validating arm-crank cardiopulmonary exercise testing as an alternative to pedalling in patients with an abdominal aortic aneurysm.

Acute kidney injury following cardiac surgery is common and associated with significant morbidity and mortality. Many studies have tried to identify protective agents, but this new study is the first network meta-analysis of RCTs comparing these reno-protective drugs in the setting of cardiothoracic surgery. They conclude atrial natriuretic peptide (ANP) and levosimendan are the most protective but advise for cautious interpretation of these findings. Thankfully, Irwin and Choi provide context to this conclusion in their editorial while discussing the wider implications of Bayesian network meta‐analyses in anaesthesia. Though such studies should, in general, be interpreted cautiously, they should also be seen as a powerful tool to ‘flag’ the possibility that certain interventions are more effective than others, as is the case for ANP.

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Figure 1 Indirect evidence for A vs. B can be collected if head to head trials exist for A vs. C and B vs. C.

 

August_Figure 2

Figure 2Network loops for different drugs. The solid lines show head to head trials, and the dotted lines show evidence which can be collected indirectly. The thickness of the solid lines indicates the number of trials in that comparison.

 

Elsewhere this month there is a meta-analysis of videolaryngoscopy versus Macintosh laryngoscopy for double-lumen tube intubation in thoracic surgery, a primer on the ethics of teaching and learning in airway management, a qualitative study of human factors enablers and barriers for successful airway management, an in-vitro study of the accuracy of near-patient versus inbuilt spirometry for monitoring tidal volumesand a discussion of NCEPOD at the age of 30.

 

Over in Anaesthesia Cases, recently published case reports include awake tracheal placement of the Tritube® under flexible bronchoscopic guidance, successful left-sided one-lung ventilation using two Arndt endobronchial blockers in a patient with right tracheal bronchusand sevoflurane for the treatment of refractory status epilepticus in the critical care unit. We want you to send us your interesting cases! Finally, this is the last issue in the current style. Next month, we will have new branding, a new logo and a completely new look journal. We look forward to receiving your feedback!

M_Charlesworth                          A_Klein

 

Mike Charlesworth                   Andrew Klein

Trainee Fellow                         Editor-in-Chief

Pragmatic peri-operative research

Two years ago, joint guidelines from the AAGBI and British Hypertension Society were published. They were the first to advise on the measurement, diagnosis and management of raised blood pressure prior to planned surgery and were warmly welcomed by all stakeholders. Despite this clarity, peri-operative research on the consequences of pre-operative hypertension is lacking. This month, Crowther et al. report their study on the association between pre-operative hypertension and intra-operative haemodynamic instability. Though they conclude pre-operative hypertension may be more common than we think (48% vs. 30%), they were nonetheless unable to establish a link between pre-operative hypertension and the incidence of intraoperative haemodynamic instability. A key recommendation from the authors is these data support the current AAGBI hypertension guideline.

 

In this month’s statistically speaking, Choi and Wong explore the methods used and the conclusions deduced by Crowther et al. They discuss the difficulties of research on the consequences of pre-operative hypertension, the pitfalls of prospective observation and the clinical context of the study. They argue the study is inherently limited due to a low signal-to-noise ratio, and larger studies with more precise recruitment strategies will be required to better study the association between pre-operative hypertension and peri-operative morbidity.

 

Next, this retrospective observational study from Palmer et al. aims to elucidate the association between anaesthetic technique, operating room-to-incision interval and neonatal outcome in emergency caesarean section. Unsurprisingly, general anaesthesia was the quickest (6 minutes) followed by spinal anaesthesia (11 minutes), epidural top-up (13 minutes) and combined spinal-epidural (24 minutes). Alarmingly, general anaesthesia was associated with fewer 5-minute Apgar scores ≥ 7. Despite this finding, some have already highlighted several study limitations and engaged with the authors on Twitter. We look forward to seeing this discussion develop and we invite all interested parties to send us their letters.

 

In another observational study of 164 patients aged at least 65-years presenting for unscheduled surgery, McGuckin et al. evaluate the association between frailty and common postoperative surgical outcomes. Though the duration of hospital stay was independently associated with ASA physical status, surgical severity and two commonly used scoring systems (E-POSSUM and SORT), frailty, as measured by the Clinical Frailty Score, was not independently associated with hospital stay, morbidity, mortality or readmission.

 

The limitations of observational studies are well understood yet their conclusions may affect the way we care for patients. Though large pragmatic randomised controlled trials in peri-operative decision-making are seen by many as the gold standard, is this really the case? Joshi et al. set out the fundamental issues with such trials that may explain why negative results are commonand argue clinical practice may be falsely influenced through a failure to recognise these limitations. On the other hand, Yeung et al. set out the arguments for conducting large randomised trials and clarify when and how they should be performed. They argue the need for such studies has never been greater, and their limitations can be negated through more thoughtful trial design. When the results of large scale randomised trials are unwelcome or unexpected, do we simply dispute their findings due to our own biases? The debate will no-doubt continue.

 

There are three RCTs this month and all have important clinical consequences. The first is an investigation of the effect of spinal hyperbaric bupivacaine–fentanyl or hyperbaric bupivacaine on uterine tone and foetal heart rate (FHR) in labouring women.They find that spinal hyperbaric bupivacaine offers similar pain relief yet with a lower incidence of FHR abnormalities as compared with a hyperbaric bupivacaine-fentanyl combination. The second is a comparison of bolus phenylephrine or ephedrine for the treatment of hypotension in women with pre‐eclampsia undergoing caesarean section(you can read the recent associated consensus statement here!). They conclude 50 mcg phenylephrine and 4 mg ephedrine, administered as intravenous bolus doses, resulted in similar foetal acid‐base status and effectiveness in treating hypotension in pre‐eclamptic patients undergoing caesarean section. Finally, Mendonca et al. report their RCT comparing the ‘sniffing’ and neutral position using channelled (KingVision®) and non‐channelled (C‐MAC®) videolaryngoscopes(Figure 1). They failed to demonstrate any difference in ease of intubation between the positions for both types of videolaryngoscope and argue that videolaryngoscopy, like direct laryngoscopy, should be regarded as a dynamic process in which a change in position should be considered when difficulty is encountered.

July_Figure 1

Figure 1 Channelled, non‐channelled videolaryngoscopes and bougie used in the study. (a) KingVision with tracheal tube loaded in the channel. (b) C‐MAC with D‐Blade and (c) Frova intubating catheter (bougie).

 

The mode of anaesthesia for patients with hip fracture has been discussed at length for many years. In 2012, the AAGBI published their guideline for the management of proximal femoral fracturesand in 2016, following a secondary analysis of ASAP2 data, White, Moppett and Griffiths called for standardisation of anaesthetic practices. This month, we are delighted to publish this consensus statement on the principles of anaesthesia for patients with hip fracture. We encourage all who care for such patients to study these principles and for hospitals to incorporate each into local protocols. The core principle is simply to do your best for every patient. Refreshingly, particular techniques, drugs or modes of anaesthesia are not definitively prescribed.

 

Elsewhere this month, there is a benchtop study of changes in hardness and resilience of i‐gelTMcuffs with temperature, a systematic review of topical benzydamine for prevention of postoperative sore throat in adults undergoing tracheal intubation, a meta-analysis of combined spinal‐epidural vs. spinal anaesthesia for caesarean sectionand an excellent discussion of the law around caring for obstetric patients with mental illness. Have you been involved with the management of an interesting case recently? Please consider writing it up for our sister journal, Anaesthesia Cases. Recent cases include acute postoperative compartment syndrome in a child receiving patient-controlled analgesia and peripheral nerve blockand Takotsubo cardiomyopathy secondary to needle phobia (this one received a lot of interest on social media!).

 

Finally, congratulations to our new fellow, Dr Akshay Shah, a talented NIHR Doctoral Research Fellow from Oxford. We look forward to Akshay joining the editorial team at the AAGBI Annual Congress in Dublin. The standard of applicants this year was exceptionally high, and our commiserations go to those who were unsuccessful. We have recently taken the decision to concentrate efforts on our Twitter accountinstead of our Facebook page. We do, however, have an Instagram accountwhere you can find out which paper is freely available each day and gain an insight into the day to day business of the journal. Finally, we will have a fresh new journal design from September onwards and we look forward to hearing what you think. Several articles in the new design are available now over on early view.

 

That’s all for now, but we hope to see you in a couple of weeks for the GAT annual scientific meeting in Glasgow!

 

M_Charlesworth                        A_Klein

Mike Charlesworth                   Andrew Klein

Trainee Fellow                         Editor-in-Chief