In a patient of Bronchial Asthma, silent chest signifies?

Grave prognosis REF: Practitioner: Volume 230, Page 185, Allergy: principles & practice: Volume 1 page 517 "The silent chest, where air entry is so poor that few sounds are produced, is a grave prognostic sign" Cyanosis, an altered consciousness, gasping respirations, and a silent chest in a dyspneic patient all herald grave illness. These events occur in less than 1% of cases