Procedures
Patients assigned to epidural analgesia and usual care received thoracic epidural analgesia as soon as possible after randomization. An epidural catheter was placed in an intervertebral space between the sixth and ninth thoracic vertebra by a certified anesthesiologist-intensivist or a resident in anesthesiology and intensive care, under the supervision of a certified anesthesiologist-intensivist. A mixed solution of ropivacaine (2 mg/mL) and sufentanil (0.5 μg/mL) was administered for at least 72 h using a patient-controlled epidural analgesia system with continuous infusion rates set between 5 and 15 mL/h and boli of 3 to 10 mL every 10 min at maximum. Nurses were encouraged to administer boli to achieve analgesia goals when the patient was not able to self-administer. Supplemental iterative epidural administrations of clonidine (1 μg/kg) were allowed to achieve analgesia goals. The duration and weaning of epidural analgesia, as well as removal of the epidural catheter, were conducted according to routine protocols from each participating center.Patients assigned to usual care alone did not receive epidural analgesia. Usual care was based on current consensual guidelines [