Which sign indicates that the spontaneous breathing trial has failed?

• A. Tachycardia
• B. Desaturation
• C. Abnormal BP
• D. Tachypnea

Answer: (D)

During a spontaneous breathing trial, the patient should be able to breathe without heavy support and without signs of distress. If the rhythm of breathing becomes very fast, it shows the patient is doing a lot of work to ventilate and is unlikely to sustain this effort after extubation. Tachypnea signals increased work of breathing and potential fatigue, meaning the patient isn’t ready to breathe independently. This makes it the best indicator that the spontaneous breathing trial has failed. Desaturation or abnormal blood pressure can occur as well, but a persistently rapid respiratory rate directly reflects the inability to maintain adequate ventilation on their own.