[Intra-operative ketamine administration reduced the level of post-thoracotomy pain].
BACKGROUND
Two different types of post-operative pain (such as acute pain and chronic pain) occur in patients undergoing thoracotomy. It has been suggested that the acute post-thoracotomy pain consists of inflammatory pain and chronic post-thoracotomy pain caused by intercostal neuralgia. In the present study, we examined the effect of intra-operative administration of ketamine, an NMDA receptor antagonist, on the acute and chronic post-thoracotomy pain.


METHODS
Sixteen patients were assigned to one of two groups (ketamine or control). The ketamine group received a ketamine bolus (1 mg x kg(-1)) just before the skin incision, followed by continuous infusion of ketamine (1 mg x kg(-1) x hr(-1)) during surgery.


RESULTS
Verbal rating scores (VRSs) at rest and on cough were significantly lower in the ketamine group on day 1 and VRS of chronic pain was also significantly lower in the ketamine group 4 weeks after the surgery.


CONCLUSIONS
These data suggest that post-thoracotomy pain might be mediated by NMDA receptor dependent central sensitization and that the intra-operative administration of ketamine might block the development of the NMDA receptor dependent central sensitization.
Sano
Makoto
M
Department of Anesthesiology, Graduate School of Medicine, Chiba University, Chiba 260-8677.
Inaba
Susumu
S
Yamamoto
Tatsuo
T
Nishino
Takashi
T
D000368:Aged; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage* / Q000494:pharmacology; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007430:Intraoperative Care; D007649:Ketamine / Q000008:administration & dosage* / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000209:etiology / Q000517:prevention & control*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology; D013908:Thoracotomy; D016896:Treatment Outcome
D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D007649:Ketamine