Which one of the following values is not a feature of Acute Severe Asthma?

b. PEF of 60 to 70% of expected(Ref: Nelson's 20/e p 1095-1115, Ghai 8/e p 382-392)Note: 1kPa=7.5mmHg; So 8kPa=60mmHgGrading of severity of Asthma exacerbationCharacteristicsMildModerateSevereHeart rate<100100-120>120PEF (Peak expiratory flow)>=70% or response <40%40-69%<40%Pulsus paradoxusAbsentMay be presentOften presentPaO2 Normal>=60mmHg (8KPa)<60mmHg (8KPa)