Major peri-operative complications

Major airway complications are rare and the best evidence on which we base current practice comes from NAP4, which was published in 2011. This new contribution from Cumberworth et al. used similar methods within six hospitals to see what has changed and highlight key areas for further training and development. They found an overall incidence of 1 in 3600 general anaesthetics, which is over six time that cited in NAP4. Even when certain cases were excluded that would have similarly been excluded in NAP4, the incidence remained higher. A key finding is that in those with a predicted easy airway, a standard approach of ‘anaesthesia induction followed by SAD/tracheal intubation’ very rarely results in serious airway complications. However, in those with a predicted difficult airway, this standard approach results in serious airway complication 45 times more frequently (Fig. 1). In the accompanying editorial, Armstrong and Cook list reasons as to why this new contribution is difficult to compare with NAP4. Importantly, it does not tell us the extent to which NAP4 recommendations were implemented. There still seems to be much to be done. Elsewhere, a more specialist paper from Peterson et al. reports complications associated with paediatric airway management during the COVID-19 pandemic. Their results, including that children with COVID-19 were 2.7 times more likely to experience hypoxaemia during tracheal intubation and extubation, challenge the belief that the implications of COVID-19 in children are insignificant. Clinicians should consider this when general anaesthesia is required.

**Figure 1** Sequential management of the 17 cases of airway complication. ATI, awake tracheal intubation; DL, direct laryngoscopy; FONA, front of neck access; ICU, intensive care unit; PACU, post-anaesthesia care unit (recovery); SAD, supraglottic airway device; TT, tracheal tube.

There has long been concern about patients undergoing major surgery with pre- or undiagnosed diabetes. This large prospective cohort study reveals a causal relationship between prevalent diabetes and adverse postoperative outcomes, which supports previous work. Going one step further though, the strength of the relationship between HbA_1C and postoperative risk was lessened following adjustment for comorbid disease (Fig. 2). This begs the question, should we be targeting comorbidities, rather than short term glycaemic control? In the accompanying editorial, Polderman and Sieglaar argue the time has now come to find a place for pre-operative HbA_1C screening, but how to optimise glycaemic control before surgery to improve outcomes remains a question with no answers.

**Figure 2** Directed acyclic graph representing the casual relationship between HbA_1c and postoperative complications. HbA_1c, glycated haemoglobin; MI, myocardial infarction; CCF, congestive cardiac disease; PVD, peripheral vascular disease; and Composite, 30-day major postoperative complication and 90-day all-cause mortality. The green line from HbA_1cto the composite outcome represents the direct casual pathway of HbA_1c (direct effect). The blue risk factors represent mediators through which HbA_1c also acts. If, after adjustment of mediators, an association is found between HbA_1c and the composite outcome, this would suggest that HbA_1c is not dependent on the mediators, that is, has a direct effect on the composite outcome. A direct effect would support optimisation of HbA_1c before surgery. No direct effect would support optimisation of the mediators before surgery.

There has been increasing concern about an increase in stress and mental illness including alcohol and substance use disorder in the medical workplace. There has also been more recent evidence suggesting a risk of suicide/accidental overdose among anaesthetists. This new Association of Anaesthetists guideline provides several recommendations in an area where there are insufficient resources available for anaesthetists, colleagues and medical managers. The good news is that over 75% of anaesthetists return to full practice if they co-operate fully with the required treatment and supervision. This new randomised controlled trial from Friedman et al. attracted a lot of attention recently on social media. They deliberate deceived trainee simulation participants by being told that the consultant was a subject in the study. Learners then participated in a simulated crisis that presented them with situational opportunities to challenge the consultant regarding clearly wrong decisions. They found that anaesthesia trainees were more effective at challenging a consultant’s clearly wrong clinical decision when they thought he was acting and a part of the simulation scenario.

Has the shift to digital prehabilitation been forced by the COVID-19 pandemic? Durrand et al. remind us that patients are facing extended waits for surgery and we need to help patients wait better. Although digital solutions have advantages, one size can never fit all (Fig. 3). A co-ordinated national response comprising innovative solutions is required urgently to address this problem.