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In this edition of Acute Medicine, Knight et al. demonstrate from SAMBA data that access to ultrasound machines and supervision is geographically heterogeneous.1 They raise concerns that this may lead to inequity of provision of Point of Care Ultrasound (POCUS) and the benefits it can provide for patients. This point is well made: Since the development of the Focused Acute Medicine Ultrasound (FAMUS) competencies in 20162 there has been a steady increase in the provision of supervisors to 803 and the number of individuals completing training has increased to 56. Whilst this is to be applauded, our experience concurs with this paper that much of the ultrasound training is concentrated in pockets of expertise in particular hospitals. As part of the AIM curriculum rewrite for 2022, the Special Advisory Group has proposed to the GMC that POCUS competencies become mandatory for all trainees in AIM. This will be supported by half a day of clinical time for training. This is a laudable aim but it is questionable whether, given the number of supervisors and their idiosyncratic distribution, the specialty of Acute Medicine would be able to support accreditation for all trainees. It is estimated that it takes 22 hours of supervision per supervised trainee.1 This is a significant commitment for jobbing consultants, especially with no supporting professional activity time in a job plan. The COVID19 pandemic has shown the value of POCUS lung ultrasound but has also highlighted further these training issues. A joint statement by the FAMUS and Focused Ultrasound in Intensive Care (FUSIC) committees has for the time being suggested that attendance at a course should no longer be a requirement for accreditation.4 This is an understandable attempt to try to keep training going but may have unintended consequences: It is often on courses that people are able to network and find solutions to mentoring and supervision in their areas and hospitals. The welcome support of the Royal College of Radiologists in their newsletter from Autumn 2019 may go some way to helping to fill the gap.5 The support of radiology and sonography departments will certainly lead to a greater number of training opportunities however there are concerns that many radiology departments remain sceptical about the role of POCUS and at an individual hospital level engagement is likely to be variable. As a solution to some of these problems at the Royal Berkshire hospital we have set up the AIM POCUS Academy with the goal of further embedding POCUS within the Acute Medicine department and the wider hospital.6 We are doing this by developing a multi-professional, multidisciplinary approach to POCUS through weekly teaching ‘Ultrarounds’. Links to the Sonography department, Cardiology, Respiratory Medicine, Emergency Medicine, Intensive Care, Vascular Access, Critical Care Outreach and Primary Care has led to a culture in which POCUS is considered a standard of care within the hospital and very much driven by the Acute Medicine department. This provides tremendous opportunities in all areas of the hospital for training and supervision but also the opportunities for different specialties to learn from each other. Individual Physiotherapists, Nurses and the Advanced Critical Care Practitioners in the hospital are either trained or are training up in lung ultrasound, ultrasound for vascular access or focused echocardiography and provide an excellent long term solution to the challenges of mentoring and supervision as they are more permanent members of staff. Where the sonography department and echocardiography department also provide mentorship for FAMUS and FUSIC, the exchange is both ways: Acute Medicine trainees have provided teaching around interpreting liver function testing which has led to rationalisation of inpatient abdominal ultrasounds and have taught sonographers how to interpret lung ultrasound; the echocardiography department are auditing the use of focused scans in specific conditions rather than a complete British Society of Echocardiography (BSE) full data sheet (so for instance in the context of an acute PE the echocardiographer will focus of right heart measures). This has helped to reduce waiting times within these departments. Technology has also helped to embed best practice and facilitate easier mentoring and supervision. Using the Butterfly IQ devices and a triple encrypted ‘cloud’ allows easy archiving of images and the possibility of remote reviewing which can even be in real time. This was invaluable during the COVID pandemic when GPs in our local ‘hot hub’ were trained up to use ultrasound to rule in and rule out COVID pneumonia allowing them to refer onto the ambulatory COVID pathway.6 They were able to share images via the cloud for review by experts in the hospital ensuring an extra degree of governance and oversight. We are trialing a similar system with our ‘Hospital at Home’ team with the hope it may save patients unnecessary visits to hospital for CXR and other imaging. If the specialty of Acute Medicine wants to take ownership of POCUS then we need to up our game and get serious about the supervision and mentoring of our trainees. Whilst the model of the AIM POCUS Academy may not be achievable everywhere, we believe initiatives like ours can act as the model for effective teaching and these centres could potentially provide a regional solution for POCUS training.

Background— Episodes of atrial fibrillation (AF) are known to cause both a rapid reduction in atrial refractoriness (atrial electrical remodeling) and a more delayed increase in AF stability thought to be due to a so-called “second factor.” The aim of this study was to quantify the effects and time course of such a factor on AF stability in the chronic goat model. Methods and Results— AF was maintained in 6 goats by burst atrial pacing for 3 consecutive 4-week periods separated a mean of 6±2.1 days of sinus rhythm. Six days of sinus rhythm was just sufficient for refractoriness changes to reverse fully in all goats. Atrial effective refractory period, AF inducibility, and duration of individual episodes of AF were assessed at regular intervals. There was a progressive reduction from month 1 to 2 to 3 in the mean duration of burst pacing required to induce individual episodes of AF of 60 seconds (178±251, 110±102, and 21±30 hours), 1 hour (229±224, 136±104, and 68±51 hours), and 24 hours (277±218, 192±190, and 102±75 hours; P P Conclusions— Sequential 4-week periods of atrial fibrillation result in a progressive increase in AF stability independent of baseline atrial refractory period. This finding suggests the presence of a second factor in the self-perpetuation of AF with a time course comparable to that of AF-induced ultrastructural changes in the atria.

Despite 50-60% of intensive care patients demonstrating evidence of pleural effusions, there has been little emphasis placed on the role of effusions in the aetiology of weaning failure. Critical illness and mechanical ventilation lead to multiple perturbations of the normal physiological processes regulating pleural fluid homeostasis, and consequently, failure of normal pleural function occurs. Effusions can lead to deleterious effects on respiratory mechanics and gas exchange, and when extensive, may lead to haemodynamic compromise. The widespread availability of bedside ultrasound has not only facilitated earlier detection of pleural effusions but also safer fluid sampling and drainage. In the majority of patients, pleural drainage leads to improvements in lung function, with data from spontaneously breathing individuals demonstrating a consistent symptomatic improvement, while a meta-analysis in critically ill patients shows an improvement in oxygenation. The effects on respiratory mechanics are less clear, possibly reflecting heterogeneity of underlying pathology. Limited data on clinical outcome from pleural fluid drainage exist; however, it appears to be a safe procedure with a low risk of major complications. The current level of evidence would support a clinical trial to determine whether the systematic detection and drainage of pleural effusions improve clinical outcomes.

No consensus exists as to the benefit of pleural drainage in mechanically ventilated patients with conflicting data concerning the effects on gas exchange. We determined the effects on gas exchange over a 48-hour period of draining, by thoracocentesis, large volume pleural effusions.A total of 15 thoracocenteses were performed in 10 mechanically ventilated patients with ultrasound evidence of pleural effusions predicted to be greater than 800 mL in volume. Gas exchange, mixed expired CO2, dynamic lung compliance, ventilator settings before procedure and at 30 min, 4, 8, 24 and 48 h were determined. Data were analysed using paired t-tests and repeated-measure anova.Following thoracocentesis there was a 40% increase in the PaO(2) from 82.0 +/- 10.6 mm Hg to 115.2 +/- 31.1 mm Hg (P0.05) with a 34% increase in the P:F ratio from 168.9 +/- 55.9 mm Hg to 237.8 +/- 72.6 mm Hg (P0.05). These effects were maintained for a period of 48 h. There was a correlation between the amount of fluid drained and the effects on oxygenation with an increase in the PaO(2) of 4 mm Hg for each 100 mL of pleural fluid drained. A-a gradients continued to improve over the course of the study together with a reduction in the dead space fraction and improved dynamic compliance.Drainage of large pleural effusions in mechanically ventilated patients leads to a significant improvement in gas exchange, and these effects are sustained for 48 h after the procedure supporting a role in the discontinuation of mechanical ventilation.