Measuring and managing neuromuscular blockade

It is not clear yet why facemask ventilation becomes easier following neuromuscular blockade. This new prospective observational study from Lee et al. evaluates changes in tidal volume after administration of neuromuscular blockade and assesses the correlation of this with changes in the vocal cord angle. They found that tidal volume and vocal cord angle during induction of anaesthesia increased after neuromuscular blockade in patients with normal airways. In addition, both insufficiency of ventilation before neuromuscular blockade and improvement after neuromuscular blockade were correlated with vocal cord angle (Fig. 1). They suggest a new role for considering ‘vocal cord status’ to optimise facemask ventilation using neuromuscular blocking drugs. In the associated editorial, Chau and El-Boghdadly discuss the age-old question of whether adequate facemask ventilation should be confirmed before administering a neuromuscular blocking drug. They argue that drug administration is not just about a point of no return but about making the onward journey easier.

Figure 1 Increase in mean tidal volume before (black bars) and after (white bars) neuromuscular blockade. The bars indicate the mean and SD values. *p < 0.001 vs. before neuromuscular blockade.

In ICU patients, there is a risk of unintended residual neuromuscular blockade and associated complications. This new prospective study from Ross et al. aims to determine the incidence and identify associated factors. They found that it occurred in at least one-third of patients with no difference between postoperative and non-postoperative patients. Worryingly, 63% of New Zealand ICUs rarely test neuromuscular function before tracheal extubation, and 37% never do. In the associated editorial, Bailey simply states that if we cannot measure it, we cannot manage it. Afterall, as far as the administration of neuromuscular blockade is concerned, the ICU environment should be considered the same as the operating theatre.

Figure 2 Model inputs and output, with observed occurrence of residual neuromuscular blockade (RNMB): sex and postoperative status; predicted probability of RNMB; and whether RNMB was observed. Male (black); female (grey); non-postoperative (triangle); postoperative (circle); RNMB not observed (empty); RNMB observed (filled). (a) Rocuronium; (b) atracurium; (c) vecuronium; (d) pancuronium.

In the early COVID-19 pandemic, clinical guidelines in all areas of practices were changed beyond recognition in a matter of weeks and months. This new mixed methods study of UK anaesthetists from Shrimpton et al. looks at current practice and perceptions of so called ‘aerosol generating procedures’. The paper is rich with data and insight as well as lessons for the future. For example, some anaesthetists preferred using high level personal protective equipment during pre-operative patient assessment, despite this being at odds with national guidance. Overall, there was a call for more involvement of professional representative bodies, should practice change rapidly in this manner again. Severe maternal morbidity is of interest given that it is expected that historical reductions in maternal mortality might be reversed by increasing risk factors in the general population, such as obesity. This new cohort study from Masterson et al. found that severe maternal morbidity was recorded for about 1% of pregnant women in Scotland. Morbidity was independently associated with: maternal age; BMI; pre-existing morbidity; previous smoking; previous caesarean section; multiple pregnancy; and maternal birth in Africa or the Middle East. Morbidity was associated with delayed hospital discharge, stillbirths and maternal deaths. This paper was featured in the mainstream media with focussed placed on obesity as a significant risk factor. 

There is a need to prioritise equity, diversity and inclusion (EDI) within anaesthesia and medicine as a whole. This position statement outlines the Anaesthesia Editors’ current policies and practices aiming to achieve equity, represent the diversity of our specialty and actively include people engaged with this journal and beyond. We hope this will be an effective starting point towards embedding EDI into everything that the journal does and influences in clinical practice and academia. You can listen to a discussion of the statement, chaired by Association of Anaesthetists CEO Nicky de Beer, here. We all know that desflurane and nitrous oxide are bad for the environment, but how well can their avoidance and other strategies be implemented into clinical practice? This new guidance document from Devlin-Hegedus et al. provides recommendations for all clinicians that can be implemented right now. Will you start doing something different today? 

Another paper featured in major news outlets recently was this narrative review by Pandit et al. on the effect of overlapping surgical scheduling on operating theatre productivity. This might be a strategy that promises much in terms of reducing the waiting list backlog, but this must be balanced against the risk of adverse patient outcomes, safety, training and patient autonomy. You can read the associated press coverage here. Elsewhere we have: a feasibility trial of angiotensin-2 in cardiac surgerya pooled cross-sectional analysis of trends in country and gender representation on editorial boards in anaesthesia journalsa discussion of SARS-CoV-2 and airway reactivity in children; and a narrative review of the consequences of COVID-19 for chronic pain patients and services.

Finally, this month’s ‘Reviewer Recommendations’ tackles scientific dissemination, with the aim to get research to the people that need it. The authors argue that scientific dissemination is not an optional extra, and there is much work to be done to optimise dissemination tools in academic anaesthesia and peri-operative medicine. 

We have two big papers coming soon from important collaborative groups – PUMA and NAP! Look out for details of publication dates and live broadcasts, with PUMA set to launch their avoidance of oesophageal intubation guideline on Wednesday evening! We will see you for the broadcast on Thursday at 2000 BST. 

Mike Charlesworth and Andrew Klein