A nurse is collecting data on a client following administration of an opioid narcotic. Which of the following findings indicates a decrease in the client's pain?

The correct answer is B: The client is asleep. When a client is asleep after receiving an opioid narcotic, it indicates a decrease in pain as opioids can induce sedation. This is because opioids work by binding to opioid receptors in the brain and spinal cord, which can reduce the perception of pain. Elevated blood pressure (A), increased respiratory rate (C), and diaphoresis (D) are not direct indicators of a decrease in pain following opioid administration. Elevated blood pressure may be a response to pain, increased respiratory rate may indicate respiratory distress, and diaphoresis may be a side effect of opioids rather than a direct indicator of decreased pain.