 This study will assess the efficacy of TUS in identifying extravascular lung water EVLW through the presence or absence of B-lines also known as comet tails on ultrasound; whilst also determining whether TUS can distinguish between other pulmonary pathologies that may cause both a similar ultrasonographic appearance and respiratory compromise. A TUS protocol will be tested and validated in a stable patient population, concurrently assessing patient and operator satisfaction with the tool. It is intended that the results of this study will inform a larger second-phase study of a modified TUS protocol in the acute clinical setting medical admissions unit - emergency department. 