Between evidence and aerosols

In the February issue, we are delighted to publish the articles by Brown et al., Dhillon et al. and the associated editorial by Nestor et al. Brown et al. report that both tracheal intubation and extubation sequences produce less aerosol than voluntary coughing (Fig. 1). On the other hand, Dhillon et al. find that tracheal intubation and extubation are aerosol generating procedures (Fig. 1) Who is right? The answer is probably that neither group is right or wrong, and differences in the experimental methods used might instead account for their different findings. This is all summed up nicely in the associated editorial and podcast.

**Figure 1** Simulation of aerosol measurement approach within operating theatre environment. The sampling funnel was positioned 0.5 m above the source of aerosol in the airway management zone allowing a sampling stream of air (1 l.min⁻¹*) to be routed to the optical particle sizer.*

When we use local anaesthetic agents in clinical practice, we usually go to great lengths to avoid local anaesthetic systemic toxicity, so injecting local anaesthetic agents intravenously might seem counterintuitive. That said, any anaesthetist who has used intravenous lidocaine as part of their peri-operative analgesic strategy will no doubt stand by the safety and efficacy of its use. This new guideline is the first of its kind, which is surprising as the use of intravenous lidocaine for analgesia seems to be widespread. It will hopefully provide a framework for hospitals and departments to write their own protocols, as well as standardising practices more generally. In the associated editorial, Pandit and McGuire discuss the evidence as well as the issues raised by using intravenous lidocaine as an unlicensed medication. They instead provide ‘a license to stop an infusion’ if a clinician encounters a patient in their care and they do not believe the drug to be efficacious. You can listen to both groups of authors debate the arguments for and against on the relevant podcast.

Which is best for patients with hip fracture, spinal or general anaesthesia? Thankfully, and although anaesthetists might always see this as an interesting talking point, guidance and expert opinion have moved beyond the debate of superiority of one mode of anaesthesia over another. Instead, and 11 years since the last iteration, this new guideline shifts focus onto areas such as anaemia, anticoagulation and getting patients to theatre in a timely manner. Direct oral anticoagulant agents seem to be the new major issue facing anaesthetists, and many will be pleased to see something on this topic written down. Again, the paper also has an excellent podcast where you can listen to Iain Moppett and Ciara O’Donnell take us through all the peri-operative considerations and controversies.

Constipation is common in critically unwell adults and this new study from Launey et al. suggests some associations and clinical implications. The associated editorial from Charlesworth and Ashworth discusses the many limitations of research in this area more generally and compares it with something more widely studied and understood – delirium. On the back of the recent regional anaesthesia supplement, Mariano, El-Boghdadly and Ilfeld present their thoughts this month in an editorial about postoperative pain trajectories and personalised pain medicine. They argue that If we knew the typical pain trajectories and patterns of postoperative pain regression and resolution for common surgical procedures, the data could guide our approaches to regional analgesia. Is it time to put the horse back in front of the cart? We think so! Few diseases in healthcare are as controversial and emotive as obesity. This new editorial from Selak and Selak has generated a lot of interest on social media as well as several items of correspondence. They argue that an empathetic approach to all patients, including those with obesity, may in fact be more patient‐centred and also protect against litigation.

Last but by no means least we have three excellent reviews this month which have all been extremely popular on Twitter. First, this airway management guidance document for the endemic phase of COVID-19 sensibly points out that current evidence does not support or necessitate dramatic changes to choices for anaesthetic airway management (Fig. 2). Second, this systematic review from Koyuncu et al. finds that trials on postoperative pain management after total hip and knee arthroplasty reported numerous outcome measures with heterogeneous timing of outcome assessment. Finally, Mallama et al. find that the peri‐operative route of paracetamol administration, intravenous vs. oral, did not affect pain or any other postoperative outcome. There was simply insufficient evidence to exclude important clinical effects and the quality of evidence overall was poor.

**Figure 2** Aerosol generation during supraglottic airway (SGA) use: risk‐factors and considerations. AGP, aerosol‐generating procedure.

To celebrate our 75^th anniversary each month there will be a brand-new article looking at a seminal paper from a different decade. This month it is the 1950s, and Aitkenhead and Irwin take on the topic of deaths associated with anaesthesia. A striking feature is the difference between anaesthetic practice during the study period and modern anaesthesia. More than 10% of the deaths were categorised as “circulatory failure immediately following intravenous barbiturate injection”. You can read the full paper for free, forever! Elsewhere we have: a study of ultrasound-activated needle tip tracker technology; a randomised controlled trial of intra-operative methadone vs. morphine on quality of recovery following laparoscopic gastroplasty; and a study looking at the effect of intra-operative intravenous lidocaine on opioid consumption after bariatric surgery. You can also check out what is new in Anaesthesia Reports, who recently advertised for a new Executive Editor, by going over to their homepage or Twitter account.

We have recently published five live broadcasts, with topics including COVID-19 vaccines, regional anaesthesia, obstetric anaesthesia and critical care outcomes. We plan to keep refining these events and if you have any feedback for us, please let us know! In total, these have now received nearly 30k views!