Old problems and new realities

Between the application of artificial intelligence to regional anaesthesia, the use of virtual reality in pain management and a modern interpretation of the iron lung for respiratory failure, the May issue of Anaesthesia examines some modern solutions to longstanding challenges.

Bowness, El-Boghdadly and Burckett-St Laurent discuss the role artificial intelligence for image interpretation in ultrasound-guided regional anaesthesia. The identification of anatomy under ultrasound is an essential step in the performance of regional blockade. Challenges with anatomical recognition and needle guidance limit the number of clinicians willing to learn or perform regional techniques. Might artificial intelligence become reliable to the point of recognising and highlighting different anatomical structures, whilst accounting for patient anatomical differences and proceduralist variability in image acquisition? Additionally, could this technology propose optimal needle trajectories to reduce the likelihood of nerve injury or intravascular injection of local anaesthetic?

Figure 1 Sono-anatomy of the adductor canal block. (a) Illustration showing a cross-section of the mid-thigh. (b) Enlarged illustration of the structures seen on ultrasound during performance adductor canal block. (c) Ultrasound view during adductor canal block. (d) Ultrasound view labelled by AnatomyGuide.

The application of virtual reality as a non-pharmacological pain therapy is reviewed by Chuan et al. in this issue. They discuss its potential role in acute and chronic pain scenarios, addressing the impact of their varied aetiological and biopsychosocial components on the efficacy of these programmes. In an accompanying editorial, Small and Laycock examine the broader application of virtual reality systems within healthcare along with the complexities involved in their evaluation in clinical trials

The familiarity of many clinicians with the ‘iron lung’ relates solely to their readings on polio epidemics. Improvements in positive-pressure ventilation technology in the mid-20th century resulted in a decline in the use of negative-pressure ventilation. But could the positive be turned into a negative once more with a comeback for the iron lung? This issue of the journal publishes an evaluation of the Exovent, a torso-only negative-pressure ventilatory support system, in volunteers. The device aims to generate continuous negative extra-thoracic pressure in order to increase functional residual capacity and avoid patient-ventilator dyssynchrony. The risk-benefit profile of the Exovent in clinical practice remains unknown at this time. 

Figure 2 Volunteer being ventilated in the Exovent in the semi‐recumbent position.

A new PROSPECT guideline on post-operative pain management for elective caesarean section features in the May issue of Anaesthesia. The guideline is based on analysis of 145 studies and addresses systemic non-opioid and opioid analgesics, neuraxial adjuvants, local and regional techniques, and surgical interventions. In an accompanying editorial, Landau and Richebé discuss procedure-specific and patient-specific approaches to pain management. They highlight procedure-related variations in caesarean delivery, such as parity, plurality and prior history. Patient-specific circumstances, such as substance abuse, mental health issues and patient expectations, also influence pain outcomes. The authors therefore advise caution against the indiscriminate application of such guidelines and encourage more comprehensive algorithmic approaches to address individual needs. 

Recent studies on peri-operative iron supplementation have raised as many questions as answers on this practice. This journal issue features two original research articles on the pre-operative use of intravenous iron in anaemic patients undergoing cardiac surgery. Both studies (one retrospective and one prospective observational) examine the impact of this intervention on haemoglobin level, transfusion rate and other complications. Meanwhile, Wittenmeier et al report the results of their prospective study on the detection of pre-operative anaemia in elective surgical patients using non-invasive haemoglobin measurement. The authors address the potential implications of these devices during pre-operative anaesthetic evaluation along with their limitations in determining when to administer a blood transfusion.

Meta-analyses and trial sequential analyses are only as good as their component trials enable them to be – working back to the methodological robustness of each study and individual patient enrolment. In this issue, an editorial by Kirkham and Taljaard discusses the role of trial sequential analysis in enabling us to draw firmer conclusions on existing literature and project future research needs. They use a recent meta-analysis and trial sequential analysis by Desai et al. on the role of epidural vs transverse abdominis plane block for abdominal surgery as a backdrop for their discussion. Ultimately, the conclusion of a meta-analysis traces its way back into the hands of every researcher involved in the included studies, each generating the bigger picture one paint stroke at a time.  

COVID-related research continues to feature prominently in Anaesthesia. Cook and Roberts model the impact of vaccination by priority group on UK deaths, hospital admissions and intensive care admissions from this illness. Meanwhile, Clinkard et al. evaluate the filtration efficacy of N95 respirators and modified snorkel masks in healthcare workers.

Chronic obstructive pulmonary disease is a co-morbidity frequently encountered by anaesthetists and an independent risk factor for peri-operative morbidity and mortality. In this issue, a review by Lee et al. provides advice on pre-operative optimisation of patients with this condition. Specific focus is afforded to pulmonary rehabilitation, smoking cessation, symptom and pharmacological optimization, nutrition and lung volume reduction procedures. The authors also discuss unmet research needs in this area and the potential role for a peri-operative disease pathway for the delivery of holistic care to patients with this potentially debilitating condition. 

In our Contemporary Classics series, commemorating 75 years of AnaesthesiaPearce, Duggan and El-Boghdadly ask whether Cormac and Lehane grading has stood the test of time. They examine the origins of this classification system, its subsequent modifications, and its role going forward, particularly as use of videolaryngoscopy increases.

Figure 3 Views obtained at laryngoscopy, assuming correct technique, as described by Cormack and Lehane [1]. (a) Grade-1 view; (b) grade-2 view; (c) grade-3 view; and (d) grade-4 view.

And… hot off the press! The May issue of Anaesthesia contains the malignant hyperthermia 2020 guideline from the Association of Anaesthetists. There have been a number of developments in the diagnosis and management of malignant hyperthermia since the last iteration of this guideline was published in 2011. Guidance is provided for anaesthetists beyond the acute period of the reaction, including critical care management, patient and family counselling, and referral for investigation. Patient populations at increased risk of developing malignant hyperthermia under anaesthesia are also discussed. You can listen to the podcast with Professor Phil Hopkins and patient, Connor Phillips, here!

All this, plus our popular correspondence section, is now available in the May issue of Anaesthesia. Please keep an eye on the journal’s twitter feed for live broadcasts, podcast releases and social media discussion surrounding our latest journal articles!

Craig Lyons and Andrew Klein 

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