Such interventions would have the potential to reduce the prevalence of chronic pain in the population .
Although certain risk factors can identify individuals who are most likely to develop chronic pain , few interventions to prevent chronic pain have been identified .
To facilitate the identification of preventive interventions , an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain .
We present general design considerations for prevention trials in population s that are at relatively high risk for developing chronic pain .
Low-dose Intravenous Ketamine Potentiates Epidural Analgesia after Thoracotomy
Background : Ketamine potentiates intravenous or epidural morphine analgesia . The authors hypothesized that very-low-dose ketamine infusion reduces acute and long-term postthoracotomy pain . Methods : Forty-nine patients scheduled to undergo open thoracotomy were r and omly assigned to receive one of two anesthesia regimens : continuous epidural infusion of ropivacaine and morphine , along with intravenous infusion of ketamine ( 0.05 mg · kg−1 · h−1 [ approximately 3 mg/h ] , ketamine group , n = 24 ) or placebo ( saline , control group , n = 25 ) . Epidural analgesia was continued for 2 days after surgery , and infusion of ketamine or placebo was continued for 3 days . Pain was assessed at 6 , 12 , 24 , and 48 h after surgery . Patients were asked about their pain , abnormal sensation on the wound , and inconvenience in daily life at 7 days and 1 , 3 , and 6 months after surgery . Results : The visual analog scale scores for pain at rest and on coughing 24 and 48 h after thoracotomy were lower in the ketamine group than in the control group ( pain at rest , 9 ± 11 vs. 25 ± 20 and 9 ± 11 vs. 18 ± 13 ; pain on coughing , 26 ± 16 vs. 50 ± 17 and 30 ± 18 vs. 43 ± 18 , mean ± SD ; P = 0.002 and P = 0.01 , P < 0.0001 and P = 0.02 , respectively ) . The numerical rating scale scores for baseline pain 1 and 3 months after thoracotomy were significantly lower in the ketamine group ( 0.5 [ 0–4 ] vs. 2 [ 0–5 ] and 0 [ 0–5 ] vs. 1.5 [ 0–6 ] , median [ range ] , respectively ; P = 0.02 ) . Three months after surgery , a higher number of control patients were taking pain medication ( 2 vs. 9 ; P = 0.03 ) . Conclusions : Very-low-dose ketamine ( 0.05 mg · kg−1 · h−1 ) potentiated morphine-ropivacaine analgesia and reduced postthoracotomy pain
Such interventions would have the potential to reduce the prevalence of chronic pain in the population .
Although certain risk factors can identify individuals who are most likely to develop chronic pain , few interventions to prevent chronic pain have been identified .
To facilitate the identification of preventive interventions , an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain .
We present general design considerations for prevention trials in population s that are at relatively high risk for developing chronic pain .