A 27-year-old woman presented with a 4-hour history of severe shortness of breath and was found to have features of acute asthma. She had a past history of repeated attendances for acute exacerbations of asthma.
What finding would indicate that this exacerbation of her asthma should be regarded as life-threatening?
A: PaCO2 of 5.5 kPa
B: PaO2 of 8.4 kPa
C: peak flow 35% predicted
D: pulse 114 beats per minute
E: respiratory rate 30 breaths per minute
Correct answer: A Explanation Patients with severe asthma get tired and start hypoventilating. As a result, the CO2 starts going up. Therefore, even though it is in the normal range, this is the most worrying result. The others are also features of severe asthma