Which of the following is a treatment for syncope?

Placing the patient in a sub-supine position is an effective treatment for syncope, which is a temporary loss of consciousness typically caused by a drop in blood flow to the brain. By positioning the patient in a sub-supine position, with their legs elevated above their heart, you facilitate improved blood flow to the brain. This can help restore consciousness more rapidly and minimize the risk of injury upon fainting.

In cases of syncope, the goal is to ensure adequate blood flow while minimizing stress and discomfort for the patient. Elevating the legs allows gravity to assist in returning blood flow to the brain, significantly aiding the recovery process. This method is both practical and effective in clinical situations where a patient may faint or feel faint, which is why it is commonly recommended as a first response.