To compare the sedation effects of propol and remifentanil during breast biopsy under monitored anesthesia care(MAC).

Forty patients undergoing single-lateral breast biopsy were randomly assigned to propofol group and remifentanil group, with 20 patients in each group. In propofol group, and infusion was initiated 2 mg·kg^-1·h^-1, then decreased to 1 mg·kg^-1·h^-1 5 minutes later before operation, and maintained 2 mg·kg^-1·h^-1 during operation. In remifentanil group, and infusion was initiated 0.1 μg·kg^-1·min, then decreased to 0.05μg·kg^-1·min^-1 until end of procedure. The pain was evaluated with a ten-point visual analogue scale(VAS) and the sedation was evaluated with OAA/S scale during local anesthetic infiltration and deep tissue dissection. The awake time after operation(OAA/S score was 5), the pain scores 30min after operation and any postoperative complications were recorded.

The pain scores and sedation scores were similar between two groups. Seven patients in remifentanil group and one patient in propofol group experienced a decline in respiratory rate lower than 8 bpm(P<0.05), but correction was rapid following verbal instruction.

Both propofol and remifentanil provide good sedation druing breast biopsy under monitored anesthesia care, but remifentanil decrease respiratory rate significantly.