Final answer:
A client with a T4 spinal cord injury may experience respiratory depression due to autonomic dysreflexia, which involves involuntary blood vessel contractions leading to dangerous changes in blood pressure.
Step-by-step explanation:
The client is at risk for developing respiratory depression due to autonomic dysreflexia. A T4 spinal cord injury can disrupt the autonomic pathways that normally control blood vessel and muscle function in the chest and abdomen, potentially causing involuntary and excessive contractions of blood vessels, which in turn may lead to a sudden and dangerous spike in blood pressure. This condition, known as autonomic dysreflexia, can cause respiratory depression by impeding the client's ability to breathe properly. A client who is three days postoperative is still in the acute phase of recovery, during which monitoring for signs of respiratory depression is crucial to prevent serious complications.