Airway management research – what next?

This month, we are delighted to publish the first systematic bibliometric review of airway management research. This stemmed from a series of exchanges on the benefits, risks, and ethics of conducting airway research in manikins vs. patients. Ahmad et al. included 1505 studies published between 2006 and 2017, of which 1082 (71.9%) were patient studies and 322 (21.4%) were manikin studies (Figure 1). They observed an increase in the annual number of airway management studies over time. Patient studies mostly included elective ASA 1-2 patients and reported on tracheal intubation. A total of 77 primary outcomes were measured with success rate (27.4%) and procedure time (22.7%) the most common. Only seven trials used patient-centered primary outcomes and the authors highlight the need for a core outcome set. McGrenaghan and Smith agree with these sentiments and discuss how airway research may be conducted in the future.

figure 1Figure 1 Flow diagram demonstrating study subjects, study design and type of patient airway involved in experimental patient studies. Grey circles are for all studies, blue circles are for patient studies, green circles are for manikin studies and yellow circles are for all other subject types.

Supraglottic airway devices (SAD) play an important role in difficult airway management. In this retrospective registry study, Thomsen et al. describe the use of SADs in cases of difficult airway management. The Danish database is a unique repository and receives information from over 75% of Danish hospitals – their work is always of interest. From a cohort of 658,104 patients, difficult intubation occurred in 4898 (0.74%) cases. The most striking and perhaps worrying finding was that only 18.9% received a SAD in the course of their management. When SADs were used as rescue devices, they were successful two-thirds of the time. In their accompanying editorial, Ahmad and El-Boghdadly discuss possible reasons as to why SADs were so underutilised, and provide a framework for difficult airway management research (Figure 2). How does fibreoptic-guided tracheal intubation through a SAD compare between an I-gel® with the LMA® Protector™? Mendonca et al. observed no differences in mean intubation time, success rate, glottic view and ease of tracheal intubation.

figure 2Figure 2 Proposed framework for developing a difficult airway management research strategy.

The Global Capnography Project is arguably one of the most important projects in anaesthesia safety in the last decade. The results from their new study in Malawi support the development of an international project to help make global capnography provision a reality, so that like pulse oximetry, it can be included in the WHO surgical safety checklist and improve patient safety worldwide. In their accompanying editorial, Lipnick et al. call upon the global anaesthesia community (i.e. providers, researchers, national societies, manufacturers and donors) to accelerate research, education and development, manufacture, and distribution to make capnography accessible to anaesthesia providers in all practice settings.

Kwikiriza et al. report their RCT of intrathecal morphine versus ultra-sounded guided transverse abdominis plane block after caesarean section at a Ugandan regional referral hospital. Overall, the authors found both approaches were clinically effective in terms of providing adequate pain relief. The authors should be commended on this well-conducted study and for demonstrating the potential of using ultrasound in a low-resource setting. In the accompanying editorial, Bashford and Vercueil, provide suggestions on supporting and conducting such research and what role journals can play in developing and promoting authors from low‐ and middle‐income countries.

This case series on anaphylaxis to intravenous gelatin‐based solutions from Farooque et al. attracted plenty of attention during a TweetChat in December. Twelve patients were identified over a five-year period, 11 of which had severe or life-threatening reactions with three progressing to cardiac arrest. Unlike the classic presentation of anaphylaxis, which occurs within five minutes, the majority of patients developed signs/symptoms 10-70 minutes after administration. The commonest clinical features were cutaneous signs and hypotension. In view of the risk of severe allergy, along with the lack of any other clear benefits, is this the final nail in the coffin for the use of gelatins? Catch up with all the discussion on Twitter by searching for #Gelophylaxis.

The guidelines for the safe practice of total intravenous anaesthesia (TIVA) are a core document and essential reading for all anaesthetists (Figure 4). They have been extremely well received on social media with an Altmetric score of >300. Irwin and Wong argue that more work needs to be done on the practical education of TIVA and processed EEG monitoring so that more patients can benefit from this technique.

figure 4 - tiva guidelineFigure 4 Key recommendations from the TIVA guidelines.

Elsewhere, Morrison et al. suggest that fibrinogen concentrate may be used as an alternative to fresh frozen plasma to treat hypofibrinogenemia and coagulopathy during thoraco-abdominal aortic aneurysm repair. Tabl et al. were unable to demonstrate non-inferiority in uterine tone induced at elective caesarean delivery by carbetocin 20 mg to that induced by carbetocin 100 mg. Wittenmeier et al. report that point of care and non-invasive haemoglobin measurement devices are still not reliable enough to replace the laboratory measurement in term and pre-term infants. Lastly, Ferguson & Dennis review the literature regarding various definitions of anaemia in pregnant women (Figure 5) and provide a framework for patient blood management in obstetrics.

table 1Table 1 Definitions of anaemia in pregnancy in guidelines.

This blog follows an excellent Winter Scientific Meeting. Highlights from the journal session included Dr Kariem El-Boghdadly announcing the imminent arrival of Anaesthesia Reports (@Anaes_Reports), Professor Bruce Biccard’s talk on delivering pragmatic clinical trials in low resource settings, and Professor Peter Marfoher’s update in regional anaesthesia for shoulder surgery. Our journal workshop on ‘How to publish a paper’ also proved popular.

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Dr Akshay Shah and Professor Andrew Klein

Patient optimisation before surgery

Imagine a future where complete patient data are precisely recorded and seamlessly transferred between clinicians; where patients are presented with plain, accurate facts; where decision-making is shared; where patients experience less post-operative complications and shorter hospital stays; and where patients rapidly return to their functional and cognitive baseline. In their editorial, Levy et al. argue all this and much more is achievable, now. This year’s supplement contains 14 evidence-based free to access review articles and is a user-friendly, complete, and practical manual for all healthcare workers, patients, and relatives/carers. This month’s blog aims to pick out the key clinical messages.

Much time and effort seem to be spent developing models to predict postoperative morbidity and mortality, and we all use them to inform discussions with patients. John Carlisle asks, are they fit for purpose? Far from it, he argues, and we should instead focus on selecting who to operate on and how. This is a must-read for all anaesthetists as it challenges the fundamentals of how we think about peri-operative risk, communication of risk, care of the dying (and living!), patient selection, and healthcare priorities.

We all know what we mean by ‘shared decision-making’, but how does it differ from informed consent (which has its own problems), risk assessment, and decision aids? This review from Sturgess et al. discusses the relevant legal background; the barriers to peri-operative shared decision-making; the need for patient-focused processes; and how shared decision-making might be implemented. Perhaps a good place to start is with the SHARE approach (Table 1) and MAGIC questions (Table 2).

Table 1Table 1 The SHARE approach to shared decision-making: five essential steps for clinicians

Table 2Table 2 MAGIC questions for patients to ask their healthcare professionals

Multi-modal prehabilitation may reduce post-operative complications by 30% and shorten hospital stay after major surgery. This review from Sheede-Bergdahl et al. addresses the ‘why, when, what, how and where next?’. It seems nutritional and psychological optimisation are just as important as physical activity and exercise, and the pre-operative period should be fully utilised in order to promote more effective care (Figure 1). Gillis and Wischmeyer set out the case for pre-operative nutrition screening for the diagnosis, treatment, and prevention of peri-operative malnutrition, which may prevent complications and shorten hospital length of stay. Likewise, Levett and Grimmett present strategies for psychological prehabilitation and describe the limitations of the relevant evidence. Perhaps this should be a high priority area for future research?

Figure 1Figure 1 An overview of a multi-modal prehabilitation programme and related goals. SF-36, 36-Item Short Form Health Survey; HADS, Hospital Anxiety and Depression Scale.

The prevalence of asthma is increasing and now stands at 10-15% in developed countries. The incidence of peri-operative bronchospasm in those with asthma is ~1.7%, and Andrew Lumb argues pre-operative optimisation of respiratory disease such as asthma together with smoking cessation (which alone may reduce complications by as much as 41% if stopped four weeks prior to surgery) are high-impact evidence-based interventions. The evidence for exercise training for the prevention of postoperative pulmonary complications is mixed, but it does remain an important strategy. Around 40% of patients presenting for major surgery are anaemic and peri-operative anaemia is associated with poor postoperative outcomes. Munting and Klein provide an evidence-based treatment algorithm that should be used by everyone encountering patients scheduled for surgery. Print it out and put it on the wall!

Figure 2Figure 2 Treatment algorithm for preoperative anaemia.

Optimisation of diabetes prior to major surgery can take as long as three months. Gathering information and making a referral at an early stage is vital. Levy and Dhatariya argue the identification of poorly controlled or undiagnosed diabetes just prior to elective surgery is no longer acceptable. They propose criteria for diabetes screening prior to the initial referral for surgery (Table 3).

Table 3Table 3 Proposal for who should be screened for diabetes before referral for surgery.

Two hundred million major operations are performed worldwide every year with 10% of patients suffering postoperative complications. Though death due to surgery and/or anaesthesia is rare, 40% of peri-operative deaths may be attributed to a cardiac complication. Lee et al. discuss how assessment and management of cardiac conditions in the peri-operative period can significantly improve outcomes, especially for high-risk patients. Topics include hypertension; chronic heart failure; cardiac murmurs; and implantable devices. These should all be seen as modifiable risk factors that require attention well in advance of surgery. The proportion of the population aged over 65 years in the UK is expected to increase from 16.9% to 24.7% between 2006 and 2046. More than 40% of patients aged over 80 years are considered to be frail, with frailty more common in women. Chan et al. discuss the principles of peri-operative optimisation as applied to elderly and frail patients, and call for tailored pathways incorporating social issues; shared decision-making for patients and families; multidisciplinary care; personal values; and quality of life.

As depicted by the title picture for this blog, our traditional working environment is still seen by many as the operating theatre. Grocott et al. argue there is a need for us to adapt to the changing nature of our work and align our interests with those of patients. Their proposed ‘re-engineered’ pre-operative pathway hints at what the future of peri-operative medicine could look like (Figure 3 and 4).

Figure 3Figure 3 Traditional pre-operative pathway. MDT, multidisciplinary team.

Figure 4Figure 4 Proposed ‘re-engineered’ pre-operative pathway.

So far there has been much discussion about elective surgery. Poulton and Murray argue the principles of optimisation should also be applied to patients undergoing emergency laparotomy. Strategies include the timely administration of antibiotics; rational fluid resuscitation and electrolyte balance; omitting and optimising medications; nutrition; glycaemic control; pre-operative physiotherapy; damage control surgery; reducing delays; timely access to CT scans and other investigations; standardisation and surgical pathways; recognising high-risk cases; consultant-lead care; and shared decision-making. The time available to address each of these components should be traded against the need for timely surgery, particularly in the context of sepsis or circulatory shock.

Finally, we have included two reviews from the January issue, which were extremely well received last month. The review of pre-operative fasting in adults and children from Fawcett and Thomas currently has an Altmetric score of 156! The paper from du Toit et al. reminds us that half the world’s population live in low and middle Human Developmental Index (HDI) countries, and patients from these countries are poorly represented in systematically reviewed evidence on pre-operative optimisation.

We hope you enjoy this year’s supplement, which is the most complete, accurate and up to date synthesis of evidence, consensus and expert opinion relevant to patient optimisation before surgery. More importantly, we hope it contributes to further incremental improvements in the quality of care for patients in the peri-operative period.

See you next week for #WSMLondon19!

Dr Mike Charlesworth and Professor Andrew Klein