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

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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

Lies, damned lies, and statistics

If you missed the media storm that descended upon us on the 5th of June, where were you hiding? Anaesthesia published what is surely going to be one of the landmark papers not just in our beloved specialty, but across all academic medicine. Our very own John Carlisle, one of the editors of this journal, has spent years designing a statistical technique to analyse the baseline patient characteristics of randomised controlled trials, and applied this to more than 5000 published studies over a 15-year period across six of the largest anaesthetic journals, as well as the New England Journal of Medicine and the Journal of the American Medical Association. By comparing the reported to the expected distribution of variables such as age, gender, height or weight, the Carlisle Method gives the probability of these characteristics coming from a truly randomised population sample. He showed that 1.6% of published RCTs use data that is either erroneous or fabricated. The Carlisle Method demonstrated a higher frequency of non-random sampling in retracted studies, but found no differences between the anaesthetic and general medical literature. There are numerous reasons for the data to be erroneous, including simple mistakes by both authors and journals, as well as data reporting and analysis, and the publication and method used will now be subject to further scrutiny.

Loadsman and McCulloch contextualise Carlisle’s paper, both applauding and expressing reservations. Perhaps one of the more interesting takes on the issue is that fraudsters may adapt to find newer ways of overcoming the Carlisle Method. They take the example of software that is currently being used to overcome the issue of plagiarism in literature, and state that there are now accessible methods to circumvent the software. Whilst a massive undertaking is called for to clean up the potential mess that John Carlisle has picked up, the authors are not clear how and when this methodology will become the industry standard.

Of course, followers of this blog and of Anaesthesia will be familiar with the Carlisle Method, as it has been used to pick up non-random sampling in 31 trials published by Yujhi Saitoh after previous investigative successes with Yoshitaka Fujii. Anaesthesia has since decided to apply the Carlisle Method do all submitted RCTs to the journal with the aim of increasing the quality of published studies, and combat scientific misconduct.

In the June edition of the Journal, another high-impact paper was published looking at the impact of  implementing the Lifebox pulse oximeter in Malawi. These simple yet game-changing devices are not broadly available in low- and middle-income countries. Introducing them initially requires staff training before the monitors could be demonstrated to improve safety. That is precisely what Albert et al assessed, and found that understanding and knowledge retention of pulse oximetry increased. Perhaps more importantly, they also found a 36% reduction in oxygen desaturation episodes after training staff with the device.

 

Scott and McDougall’s accompanying editorial suggests that the data is a testament to dealing with a real-life practical problem. Looking beyond pulse oximeters, the authors remind us that 77,000 operating theatres did not have one, but the simple introduction of the WHO Surgical Safety Checklist led to tangible outcome improvements. The key, argue Scott and McDougall, is an effective education programme that aids in attainment and retention of knowledge, which is what was beautifully demonstrated in Alberts study. It is not enough to merely donate equipment, but training in its use is just as important.

Moving back from a global stage to the UK, exciting trainee research networks are beginning to produce high-quality and practice-changing data. The PAINT Study is one such paper, which looked at how often physicians document (if it isn’t documented, it didn’t happen!) assessing pain in critical care patients. In a 24-h snapshot study, they assessed documentation from all adult critical care patients across 45 centres in London and the South-East of England. They found that 21.2% of the 750 patients had no documented pain assessment by anyone, 28.6% had no documented pain assessment by a nurse, and 64.5% had no documentation of pain being assessed by a physician. This included many patients that were receiving opioid infusions, and even patients where changes in analgesic regimen were concurrently implemented. This is certainly an area that all clinicians, not just critical care physicians, must work hard to improve. I know I’ve changed my practice since this paper!

At an institutional level, El-Boghdadly et al prospectively assessed awake fibreoptic intubation (AFOI) practice at their tertiary centre. They reported that the most common indication for AFOI was limited mouth opening, and less than 1 in 100 were truly ‘awake’ intubations (I know I would rather have some sedation if I needed AFOI!). Interestingly, three-quarters of AFOIs were done by trainees, and the success rate was independent of training grade, but dependant on practice. Only 1% of AFOIs were not successful, but there were no episodes of severe complications, CICV or hypoxia. They have progressively taken up high-flow, heated, humidified nasal oxygenation (remember the big hitter of 2015: THRIVE!) during AFOI.

Murphy and Howes critically appraised this study in an interesting accompanying editorial. They question the generalisability of data from a single-institution study, particularly as the training opportunities afforded in that institution seem higher than most, alluding to a previous editorial suggesting an increasing role for videolaryngoscopy rather than AFOI. Additionally, the editorial points to the increased use of THRIVE did not reduce the rate of complications, and if anything increased the incidence of over-sedation. Are we now over-relying on THRIVE without the evidence to support it? Lots of interesting questions asked here, and it is worth considering where AFOI sits in current practice.

 

The June edition of the Journal was exciting and varied. We published interesting ultrasound data demonstrating delayed gastric emptying in patients with renal failure, a brilliant bench study revealing that different spinal needles have variable flow characteristics, a game-changing Cochrane review demonstrating the superiority of suxamethonium over rocuronium for RSI, and a terrifying case report of airway ignition with THRIVE. If you pick it up this month, you won’t be able to put it down.

 

Kariem El-Boghdadly

Trainee Fellow, Anaesthesia

Andrew Klein

Editor-in-Chief

A new year, another investigation

The January edition of the journal is out today, which feels strange considering Christmas hasn’t even happened yet (but is definitely coming). In an era of evidence-based medicine, scientific misconduct remains a real threat to medical research. John Carlisle, one of the editors of this journal, has developed an analytical method in order to determine whether baseline data is truly random in what is now known as the Carlisle Method. The new year brings another potential case of data fabrication. This was triggered by the submission of a suspect article to another journal, and when the data from this and other manuscripts by the same author were examined closely, there was evidence of non-random sampling. In other words, that the data was not random in its distribution in 31 trials published by Yujhi Saitoh. The majority of these papers were about neuromuscular monitoring, and they were broadly spread around the anaesthetic journals worldwide. Seven of these were published in the Canadian Journal of Anesthesia, six in the British Journal of Anaesthesia, four in the European Journal of Anaesthesiology, three in Anesthesia and Analgesia, three in Anaesthesia, three in the Journal of Anesthesia, two in Acta Anaesthesiologica Scandinavica, two in the Journal of Clinical Anaesthesia, and one in the Fukushima Journal of Medical Sciences.

This is clearly very concerning, and we await the findings from the investigation that is ongoing by the Japanese Society of Anaesthesia. However, we can’t only look backwards at studies that are already published – we also need to look very closely at what is submitted to journals in all different specialties in the future. To that end, at Anaesthesia, we have decided to screen all randomised controlled trials submitted to the journal from 2016 using the Carlisle Method. We believe we are the first journal to do this. Any that fall foul due to suspicious data that are not consistent with random sampling will be rejected and the authors informed of the reason for rejection. We hope to persuade all the other anaesthetic journals to follow suit soon, and will look to involve other specialties and organisations over the coming years.

We are seeing more and more ‘disposable’ single-use devices in our practice. These include laryngoscopes, bougies, and now even fibreoptic scopes. While there are clear advantages in terms of infection control, there remains concern about comparable efficacy, design, cost and the ‘green’ effect of throwing away so much plastic and other materials. With this in mind, it is very tempting to re-use these single-use devices in the same patient repeatedly, both on the same day and perhaps even on subsequent days, especially in the case of fibreoptic scopes. Surely if they are going back into the same patient then that can’t do any harm? Wrong – a study published in this month’s edition of the journal showed that 16 out of 20 bronchoscopes cleaned then kept after use were contaminated after 48 hours. There is a very clear clinical lesson here – single-use means exactly that, and you can’t re-use them later even in the same patient. This will have significant implications for many hospitals I suspect.

This is a welcome update on consent for anaesthesia in this month’s journal, and this a ‘must read’ for every anaesthetist. The twelve key tenets include intuitive as well extremely thoughtful recommendations. Full consent should be obtained as early in the patient pathway as possible (not in the anaesthetic room), and the information provided should be tailored to each patient, with adequate time allowed for patient questions. Documentation should be made of the consent obtained although specific consent forms are not required. The fluid nature of consent means it is an ongoing process and should be confirmed at each interventional stage. If a patient lacks capacity, the reasons should be documented, efforts should be made to reverse or reduce temporary incapacity, and if this is unachievable we should always act in the patient’s best interest. Seeking a lasting power of attorney (LPA), valid advanced decisions, a validly appointed health and welfare LPA or a court-appointed deputy are legally binding. A knowledge of the existing frameworks regarding consent in patients aged 17 or younger is recommended. Finally, when training in practical procedures is undertaken, maximising benefit whilst minimising risk to the patient is important and alternative means of training, such as virtual models or manikins should be considered. These guidelines are clear and thorough and will be the mainstay of clinical practice for years to come.

Finally for now, we have published a comparison of the adjustable pressure-limiting valves in two well-known anaesthetic machines. The manufacturer of the APL that was shown to be ‘unusual’ in its performance has also commented on the study, and an accompanying editorial has put this into perspective. The clinical lesson here is know the machine you are using and read the instructions for use. Admittedly, so many of us don’t, and if you read this article you will see how important it is to know the difference between different designs of APLs and how they function in practice, especially for paediatric use. My final comment is, why are different APLs produced and why aren’t clinicians telling manufacturers what they want and being involved in the design of new equipment? It seems nonsensical to me that there should be such a difference, with such important implications, in APLs on different common anaesthetic machines. Should we accept this from a safety perspective?

Andrew Klein

Editor-in-Chief

Understanding Uncertainty

How good are you at understanding chance, risk, uncertainty and probability? The UK referendum on whether to leave or remain in the European Union has brought statistics, risk and uncertainty back into our everyday language. We have (re) learnt that statistics without context can be misleading, tolerance of an acceptable risk is opinion–based, and that both financial markets and individuals struggle to deal with uncertainty. This is emphasised in an excellent article, which makes the point that 50% of anaesthetists are actually worse than average at understanding risk. Anaesthesia has made a point of providing easy-to-understand, concise, educational articles in the last year, our statistically speaking series, and this will continue into next year. We plan to publish a series called ‘methodological madness’, in which we invite readers to write in and ask our statistical guru (Dr Choi from Hong Kong email: msmethodmatters@gmail.com) about what authors have got up to when designing their methods for studies. The main message is, we all need to understand more about statistics, probabilities and risks.

Airway management is the prime professional skill of the anaesthetist; research into this topic is widespread, and Anaesthesia receives many such submissions. In a study from Switzerland, Kleine-Brueggeney and colleagues compared the performance of the Bonfils™ and SensaScope™ rigid fibreoptic scopes in 200 patients with a simulated difficult airway. They note in their introduction that rigid scopes such as the two studied are relatively underused in anaesthesia despite being favoured in otolaryngology and respiratory medicine.  The authors simulated a difficult airway by applying a cervical collar to each patient such that mouth opening was limited to a mean of 23 mm. The patients were randomly allocated into two groups; the primary outcome of the study was overall success of intubation. In this, the overall success rates were high for both devices (88% for the Bonfils and 89% for the SensaScope (p = 0.83), although median intubation times were a little shorter with the SensaScope (34 vs. 45  seconds).

In an accompanying editorial, Ward and Irwin explore the ethical implications of airway research where the normal airways of routine patients are rendered ‘difficult’ for the purpose of evaluating the performance of new devices (or those using them). Notwithstanding the fact that there are many reasons for an airway being ‘difficult’, and the difficulty created by the methods commonly used in the research context may not reproduce all of them, there are also important questions to consider about the nature of risk and benefit in such studies.

As Ward and Irwin note, patients taking part in such studies do not themselves benefit from such participation; instead, the data may contribute to the common good of future patients in general. In this context, the possible harms implied by the intervention are thrown into sharper focus. The members of research ethics committees may lack the specialist knowledge of anaesthesia devices to allow them to make a fully informed judgement about the balance of benefits and harms. Here, the anaesthetist’s first duty is the responsibility of a physician to a patient, not a researcher to data. An innovative Consensus on Airway Research Ethics is proposed, and I have also added a note advising anyone conducting airway device evaluation studies that manuscripts will need to comply with the recommendations in the Consensus if they wish to be considered for publication in Anaesthesia.

Also on the theme of airway management, this report from the Netherlands details the development of an audit tool to identify prospectively all peri-operative adverse events during airway management over an 8 week period. Data were collected daily by  questionnaires from, and interviews with, anaesthesia trainees and anaesthetic department staff members. A total of 168 airway-related events were reported out of 2803 patients undergoing general anaesthesia. The incidence of severe airway management-related events was 24/2803 (0.86%). There were 12 (0.42%) unanticipated ICU admissions and two patients (0.07%) required a surgical airway. There was one (0.04%) death, one ‘cannot intubate cannot oxygenate’ (0.04%), one pulmonary aspiration of gastric contents (0.04%) and eight (0.29%) severe desaturations (defined as an oxygen saturation less than 50%). Whilst this survey is restricted to one hospital, the authors suggest that the methodology they used could easily be followed by others within their own departments of anaesthesia.

Finally, this being December and Christmas being just around the corner, we have published our first-ever Christmas special in the journal, CRAC-ON, as in why don’t you just CRAC ON and give the anaesthetic! CRAC ON stands for complete relinquishing of anaesthetic conscientiousness, optimisation and nuance. This special article is meant to be light-hearted and satirical, and I really enjoyed reading it. It is included as an extra article, and the rest of the journal contains as many serious articles as normal. I hope you enjoy it too, and would be interested in receiving your feedback. CRAC ON and have a good Christmas!

Andrew Klein

Editor-in-Chief

Just breathe!

Breathing seems to be a major theme in the literature (and at meetings) at the moment, and there are a number of articles in this month’s edition of the journal that are relevant.

Apnoeic oxygenation and nasal oxygen administration are two concepts that are hardly new in anaesthesia, but are rapidly taking centre-stage for management in a wide variety of situations. Dr’s Patel and Nouraei coined the term THRIVE – Transnasal Humidified Rapid-Insufflation Ventilatory Exchange – and described a case series in Anaesthesia in 2015. This paper has just received the award for ‘Best paper in Anaesthesia of 2015’ at the AAGBI Annual Scientific Meeting in Birmingham.

The situation of rapid sequence induction of general anaesthesia is one in which we are poor at predicting airway management difficulty (see e.g. Norskov et al. Anaesthesia 2015; 70: 272 – number 2 ranked of the 2015 Anaesthesia articles), yet we produce an unstable situation of complete muscle paralysis before the definitive tracheal intubation procedure. In this edition of the journal, Pillai et al. using the Nottingham Physiology Simulator have  shown that, under ideal conditions, oxygen delivery during apnoea might increase the time to desaturation of a pregnant subject from 4.5 min to 58 min. This is incredible if true, and will be of great interest to all obstetric anaesthetists, but needs to be further investigated in pregnant patients – I believe such trials are ongoing.

There are likely to be more papers on this subject in Anaesthesia in the near future – watch this space for progress that may dramatically change how we do things in one of the high-risk areas of our practice.

This edition of the journal also includes a paper describing the current state of airway training in UK anaesthetic departments. The Fourth National Audit Project (NAP4) recommended routine and regular airway training for trainee and trained anaesthetists. However, in this survey from 206 hospitals (62%) covering all regions of the UK, 16% of hospitals did not provide airway workshops for staff at all, and 51% only for trainees. Of those providing workshops, more than half were being run less than annually. The authors concluded that workshop-based airway training is variable in provision, frequency and content, and is often not prioritised by departments or individual trainers. I agree that the provision of appropriate training identified in NAP4 is sadly lacking in many hospitals, and the reasons for this are many, but surely include resources as well as motivation. Getting Consultants out of the operating theatre into an hour or two-long airway workshop is what is needed, and regularly, but this isn’t easy, especially when getting any time out of theatre (or ICU) is getting harder and harder in the current climate. Should this be made part of mandatory training? And are workshops really the answer?

Finally, what about trainees challenging consultants? There is a perception that trainees should challenge their ‘seniors’ more frequently, especially when they are obviously wrong. This is borne out by this simulation study which explores the concept of ‘barriers to challenging seniors’ for anaesthetic trainees. The authors concluded that more senior trainees challenged their consultant supervisor quicker, allowed fewer intubation attempts, established quicker adequate rescue oxygenation and ventilation and less simulated patient desaturation was observed. This is not really surprising as experience and maturity should improve performance, especially in this sort of scenario, but the authors make some interesting observations about improving training to give trainees the confidence to challenge more effectively and with less hesitation. Take a deep breath and go for it!

 

Andrew Klein

Editor-in-Chief

Occam’s razor

Occam’s razor (or the law of parsimony) is a problem-solving principle attributed to William of Ockham (c. 1287–1347), who was an English Franciscan friar, scholastic philosopher and theologian. The principle states: ‘other things being equal, simpler explanations are generally better than more complex ones’. This month’s blog looks at simple interventions and principles, and whether Occam’s razor hold true in our practice.

Paracetamol – great drug, right? I swear by it, and dispense it liberally, both at home and in the operating theatre and the intensive care unit. A simple study with a very simple hypothesis is published in October’s edition of the journal, comparing oral (enteral) with intravenous (parenteral) paracetamol in ICU patients. Patients who received the intravenous formulation were much more likely to suffer hypotension and require vasoconstrictors to ameliorate this. Wow – so paracetamol is not as harmless as we all think? If one off doses can cause hypotension like this should we still be giving it at all in our ICU patients, or should we only be giving it enterally (presumably via the NG tube – hypotension still occurred but less commonly)? Maybe this simple, effective drug is not the panacea? A very interesting study I am sure you will agree.

What about teaching tracheal intubation to novices? We have traditionally taught the use of the Macintosh laryngoscope first, but will they learn it and remember it better if they are taught with a videolaryngoscope? Actually, perhaps not – this excellent study studied a group of medical students and looked at skill retention. This study showed that the students learnt how to use the Macintosh, A.P. Advance™, C-MAC® and Airtraq® laryngoscopes equally well at first, but one month later, they seemed to have retained the skill-set required for laryngoscopy significantly better with the Macintosh and Airtraq laryngoscopes. In this instance, simpler seems to be easier to pick up again and get to grips with more quickly, a salutary lesson.

This month, we also publish an interesting systematic review of the effect of propofol compared with inhalational anaesthesia on postoperative outcomes including pain. This well-conducted rigorous review found that patients who received total intravenous anaesthesia with propofol did indeed have reduced pain scores 24 hours after surgery, although the effect size was quite small. But, it also confirmed that postoperative nausea and vomiting was markedly less common. Is this enough to make you switch your technique to TIVA? Maybe not, after all these are not really important outcomes like mortality, but will we ever recruit enough patients to see a difference in mortality if there was one – I doubt it. So what are we waiting for, or do we just not believe there is actually a difference? Perhaps it is simpler to believe the opposite, that inhalational and propofol are much of a muchness for maintenance of anaesthesia and we are not convinced either way yet.

Finally, our statistics article explains why odds and risks (and other numbers) often confuse things, both for researchers and for readers (consumers). Why do we like to use complicated statistics to describe things, when simpler explanations are often possible if not preferable? If you, like me, don’t know the difference between the odds of something and the risk of the same thing, then read it and learn – I did, and I am off to put a bet on the 2-30 at Newmarket…

 

Andrew Klein

Editor-in-Chief

The Olympics for anaesthetists

Well, that’s it for another four years. Months and years of preparations, and in the end it came down to five days of non-stop action and one night of celebration, then everyone goes home. This is the week that was the World Congress of Anaesthesiologists in Hong Kong, and what a good one it has been. I am going to give you a bit of a flavour of the event and how this journal fared at the pinnacle of our professional calendar of conferences.

The whole event was organised by Mike Irwin, Professor at Hong Kong University and one of the editors of Anaesthesia. Siu Wai Choi, the statistical advisor to this journal was also ever-present, coaching us to rise above any mathematical missed passes. However, John Carlisle, another editor of the journal, was the real star turn when he shared the podium with Steve Shafer (ex Editor-in-Chief of Anesthesia and Analgesia @stevenlshafer) and Nathan Pace (from the University of Utah and Senior Statistical Advisor at Cochrane). John presented his initial analysis of Fujii that led to the retraction of 183 publications and his undisputed Number 1 position on the Retraction Watch Hall of Shame (@RetractionWatch). He then presented the rationale for Monte Carlo simulation and his updated analysis – the Carlisle Method – which he announced he has now applied to all randomised controlled trials published over the last 15 years in this and seven other journals. Interestingly, another author has come to light after the application of the Carlisle Method following the submission of a suspicious manuscript to another journal, and this further analysis previewed at the World Congress will be published shortly in Anaesthesia.

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One of my own personal highlights was the sight of the delegates queuing patiently to get hold of souvenir USB sticks containing the China Special Edition and World Special Edition of Anaesthesia produced especially for the Congress, and you can see these special editions yourself on our website by clicking on the links above. I also particularly enjoyed crossing the city to Hong Kong University to present a workshop to upcoming biomedical researchers on what and how to publish. The researchers packed the room and posed many questions about publication, research and the world of journal intrigue and peer review.

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There was great interest at the Congress in several recently published articles. A Korean group presented their findings about complications during subclavian central venous catheterisation, and their conclusion that a wire-through-needle technique is safer than a catheter-over-needle technique should finally put to bed the longstanding debate about the two techniques. There were several fiery debates and discussions about routine or otherwise use of dexamethasone, with the presentation of data about the inescapable rise in glucose concentration associated with its use in diabetics and non-diabetics. Finally, novel regional blocks were much in evidence, and particularly the serratus anterior plane block, which was dissected in detail.

To finish up, a bit about the final night of celebration. A crowd of us were shown the sights of the harbor from the top deck of a boat, followed by a seafood dinner and even one or two local beverages. I understand that a number then went on to do a crawl around the top 10 rooftop bars of the city, but myself, I was tucked up in bed ready for the Closing Ceremony. I am sure everyone is looking forward to the next Olympics in Prague in 2020 – I certainly am.

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Andrew Klein

Editor-in-Chief