Point-of-care lung ultrasound during and after the COVID-19 pandemic.

Abstract

Wars, pandemics and disasters advance medical science and care. Oxygen saturationmonitors were initially only used in anaesthesia and intensive care but are now available from supermarkets and are used for home monitoring of COVID-19. Ultrasound is following a similar path from a specialist investigation to common use in acute care. In the next 10 years, a handheld ultrasound device could be in every medical practitioner’s pocket. Previously, point-of-care lung ultrasound (LUS) was used in acute care for diagnosing causes of hypoxia and so when COVID-19 developed into a global pandemic there was great interest in LUS for this disease. Initial case series from China detailed the LUS findings in COVID-19 with bilateral patchy B-lines, peripheral consolidations and a lack of large effusions. Further studies into diagnostic accuracy and prognostic ability of LUS for COVID-19 were ongoing or awaiting publication. Despite the lack of firm data, it still was useful during the first wave in the UK due to limitations in other diagnostic tests. There was very limited availability of rapid molecular tests and delays of several days for reverse transcriptase polymerase chain reaction (RTPCR). Other imaging methods were limited by poor specificity for disease (chest radiograph) or practical limitations in moving highly infectious patients within the hospital (computed tomography). LUS had a unique advantage, as it could be performed at the bedside giving results within minutes allowing rapid triage and treatment. During the second wave, rapid molecular testing was available in many centres and the turn-around time for RTPCR was significantly reduced. LUS also played a role in the diagnosis of patients with negative molecular tests and high clinical suspicion, particularly as nasopharyngeal RTPCR is only about 70% sensitive. In addition, LUS was used to rule out other causes of hypoxia such as pleural effusion and cardiac failure which can present in tandem with COVID-19. LUS findings consistent with COVID-19 should be treated with caution in times with low prevalence, as false positive rates will be higher. As the pandemic subsides, LUS will still play a key role in diagnosing other causes of hypoxia. The experience learnt in COVID-19 will lead to more practitioners being familiar with LUS and in particular with sonographic findings of a viral pneumonitis. It is unknown whether LUS will be useful in management of long COVID and its advantages over CT imaging of instant results at the bedside are far less important in chronic disease. A lack of equipment and suitably skilled practitioners restrict the availability of point-of-care LUS in the UK. The Society for Acute Medicine and Intensive Care Society are working hard to address this through their established LUS training pathways, while handheld devices provide a cost-effective alternative to cart-based machines. LUS can provide rapid diagnosis of COVID-19 at the bedside and there is now clear evidence to support its use.