Articles: analgesia.
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The major goal of translational research is to evaluate the efficacy and effectiveness of treatments and interventions that have emerged from exhaustive preclinical evidence. In 2007, a major clinical trial was started to investigate the impact of paravertebral analgesia on breast cancer recurrence. The trial was based on preclinical evidence demonstrating that spinal anesthesia suppressed metastatic dissemination by inhibiting surgical stress, boosting the immunological response, avoiding volatile anesthetics, and reducing opioid use. ⋯ An obvious question is why there was an almost complete disconnect between the copious preclinical investigations suggesting benefit and robust clinical trials showing no benefit? The answer is complex but may result from preclinical research being mechanistically driven and based on reductionist models. Both basic scientists and clinical investigators underestimated the limitations of various preclinical models, leading to the apparently incorrect hypothesis that regional anesthesia reduces cancer recurrence. This article reviews factors that contributed to the discordance between the laboratory science, suggesting that regional analgesia might reduce cancer recurrence and clinical trials showing that it does not-and what can be learned from the disconnect.
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Randomized Controlled Trial
Epidural Labor Analgesia-Fentanyl Dose and Breastfeeding Success: A Randomized Clinical Trial.
Epidural fentanyl at concentrations up to 2 mcg/mL does not effect breastfeeding rates in women who have previously successfully breastfed.
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Meta Analysis
Application of Dexmedetomidine as an Opioid Substitute in Opioid-Free Anesthesia: A Systematic Review and Meta-analysis.
Opioid-based general anesthesia was previously used to alleviate perioperative pain; however, several complications associated with using anesthesia have raised several concerns. Various studies have investigated the application prospect of using opioid-free general anesthesia, such as dexmedetomidine, as an opioid substitute. ⋯ These findings indicate that opioid-free general anesthesia based on dexmedetomidine could be effective; however, prolonged extubation time and cardiovascular complications are a few risks associated with dexmedetomidine.
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Randomized Controlled Trial
Ketamine infusion for 96 hr after thoracotomy: Effects on acute and persistent pain.
Why is this significant?
This is the first randomised controlled trial looking at the impact of perioperative ketamine on persistent post-surgical (PPS) pain 1 year after thoracic surgery. Thoracotomy is associated with both severe and a high incidence (up to 50% at 6 months) chronic pain.
Ketamine has important analgesic properties through NMDA blockade, and has been long thought (hoped) that via this it may modify chronic post-surgical pain. Nonetheless, many studies have been unable to show a benefit for ketamine in reducing PPS pain.
What did they show?
Chumbley et al. ran ketamine infusions at 0.1 mg/kg/hour for 96 hours in patients undergoing thoracotomy, starting with a 0.1 mg/kg bolus 10 minutes before surgery. Patients also received either an epidural or paravertebral infusion for post-operative analgesia.
Although there were small differences in acute pain (notably the ketamine group used less PCA morphine) there was no difference in persistent post-surgical pain at 12 months.
Bottom-line
The evidence continues to mount against perioperative ketamine, suggesting it does not reduce persistent post-surgical pain, not-withstanding its acute analgesia benefits. Await results of the ROCKet trial (Reduction Of Chronic Post-surgical Pain with Ketamine) to provide greater clarity...
An afterthought
Notably, the researchers did demonstrate a dramatically lower incidence of PPS pain than for similar studies (27%, 18%, 13% at 3, 6, 12 months) across both the ketamine and placebo group. This suggests that either the study participants were not representative of the typical thoracotomy patient (unlikely), or other care associated with the study had a beneficial effect on reducing PPS – perhaps even via a Hawthorne-like effect.
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Randomized Controlled Trial
A Randomized Controlled Trial Using Epidural Analgesia for Pain Relief After Lumbar Interlaminar Decompressive Spine Surgery: The RAPID trial.
Prospective, double-blind randomized controlled trial. ⋯ This randomized controlled trial shows that administrating a bolus of intraoperative epidural bupivacaine is a safe and effective method for reducing early postoperative pain following lumbar decompression surgery.