Emergency department physicians with no prior specialised ultrasound training can be taught to reliably identify bronchiolitis, pleural effusions, pneumothorax and pneumonia, in children presenting with cough, shortness of breath and hypoxia through the use of lung ultrasound after a brief training. In this study, we are assessing the effectiveness of trainees performing a lung ultrasound examination of children, capturing their images and recording their findings. No clinical decisions will be made based on these findings without consultation with the consultant on duty. We will consider to what extent the teaching was successful and try to determine whether the teaching resulted in a objectively verifiable benefit to the emergency department. We anticipate a reduction in the amount of time the child spends in the department. It is also anticipated that there will be decline in x-rays relative to the number of presenting patients.