To study the efficacy of ropivacaine (0.75%) with or without butorphanol as an adjuvant in single shot epidural anaesthesia in lower limb orthopedic surgeries. International Journal of Biomedical Research, [S. l.], v. 5, n. 12, p. 725–730, 2014. DOI: 10.7439/ijbr.v5i12.847. Disponível em: https://ssjournals.co.in/index.php/ijbr/article/view/1458.. Acesso em: 19 oct. 2024.