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).
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).
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).
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
#TheAnaesthesiaBlog 