Mrs Dean is 27 years old and attends Accident and Emergency as she is struggling to breath and feels very unwell. She is known to have Asthma. She is clearly very distressed and struggling to breath, unable to complete sentences, has heart rate of 110, and a respiratory rate of 28, oxygen saturations are 93% and auscultation of her chest reveals widespread wheeze and crackles at the right base. She attempts but struggles to do a peak flow.
How would you grade the severity of her Asthma attack?