| Age 12–24 months,median (IQ range) | Age 2–5 years,median (IQ range) | Age ⩾6 years,median (IQ range) | |
| Respiratory rate (breaths/min) | 46 (40–56) | 41 (36–50) | 32 (26–40) |
| Heart rate (beats/min) | 150 (133–165) | 142 (130–156) | 125 (110–140) |
| O2 saturation* (%) | 95 (93–96) | 94 (91–96) | 94 (91–96) |
| BTS/SIGN guidelines for acute severe asthma exacerbation7 | |||
| Respiratory rate (breaths/min) | – | >50 | >30 |
| Heart rate (beats/min) | – | >130 | >120 |
| O2 saturation* (%) | – | <92% | <92% |
*Oxygen saturation on admission measured in air.
BTS/SIGN, British Thoracic Society/Scottish Intercollegiate Guidelines Network; IQ, interquartile.