Intrathecal morphine plus general anesthesia in cardiac surgery: effects on pulmonary function, postoperative analgesia, and plasma morphine concentration - Santos, Luciana Moraes dos; Santos, Verônica Cavani Jorge; Santos, Silvia Regina Cavani Jorge; Malbouisson, Luiz Marcelo Sá; Carmona, Maria José Carvalho (Clinics, 2009)