An оrаlly intubаted client is being prepаred fоr a spоntaneous breathing trial. The client's sedation has been decreased. The ventilator is set at 16 breaths/min. The client becomes restless, the respiratory rate increases from 18 to 28 breaths/min, and the high-pressure alarm sounds intermittently. SpO₂ remains 94%. Which action should the nurse take first?