A 32-year-old client with a history of asthma presents to the emergency department in severe respiratory distress. The client is using accessory muscles, is unable to speak in complete sentences, and has an SpO2 of 88% on room air. Peak flow measurement is 25% of predicted. Despite three consecutive nebulizer treatments with albuterol, the client shows minimal improvement. Which finding indicates the client is progressing to status asthmaticus requiring immediate escalation of care?