Table 2.
Signs and symptoms that may suggest a potentially fatal asthma attack
| Sign or symptom | Level of evidence |
|---|---|
| Signs | |
| Use of accessory muscles | III |
| Heart rate > 120/min or increasing2,6 | II-2 |
| Respiratory rate > 25–30/min | III |
| Difficulty speaking because of dyspnea or fatigue | III |
| Altered level of consciousness | III |
| Quiet chest in a patient who has dyspnea or reduced level of consciousness | III |
| Diaphoresis82 | II-2 |
| Inability to lie in the supine position because of breathing distress82 | II-2 |
| Peak expiratory flow < 30% of predicted or forced expiratory volume in 1 second < 25% of predicted 1–2 h after initial therapy83,84 | II-1 |
| Oxygen saturation < 90% | III |
| Cyanosis | III |
| Symptoms | |
| Sense of progressive breathlessness or air hunger | III |
| Sense of fear or impending doom | III |
| Progressive agitation or anxiety | III |