Thoracotomy for lung resection is deemed painful. Ketamine is now a renewed interest in preventing acute postoperative pain. A previous study performed in the service testing the association ketamine/morphine versus morphine PCA, postoperative, for patients who do not benefit from postoperative epidural thoracic surgery, has demonstrated a reduction of postoperative pain associated with a reduction of nocturnal arterial desaturation following surgery when ketamine was added to morphine.

In this prospective double blind randomized study, intravenous administration of an analgesic dose of ketamine was started since the induction of general anesthesia and continued during the first 48 postoperative hours in association with epidural analgesia.

Inclusion Criteria:

• Subject between 18 and 85 years
• subject of both sexes
• subject operated in the service of thoracic surgery of a lobectomy by thoracotomie lateral or postlaterale subject
• subject operated in settled surgery

Exclusion Criteria:

• Against indication in the epidural insanity,
• confusionnel, patient psychotic
• treatment in the long price by medicine which can interfere on the pain (morphine, antidepressants, psychotropic treatment)