• Anesthesiology · Nov 2018

    Brain Dynamics and Temporal Summation of Pain Predicts Neuropathic Pain Relief from Ketamine Infusion.

    • Rachael L Bosma, Joshua C Cheng, Anton Rogachov, Junseok A Kim, Kasey S Hemington, Natalie R Osborne, Lakshmikumar Venkat Raghavan, Anuj Bhatia, and Karen D Davis.
    • From the Division of Brain, Imaging, and Behaviour - Systems Neuroscience, Krembil Brain Institute, Krembil Research Institute (R.L.B., J.C.C., A.R., J.A.K., K.S.H., N.R.O., A.B., K.D.D.) Department of Anesthesia and Pain Management (L.V.R., A.B.), Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada Institute of Medical Science (J.C.C., A.R., J.A.K., K.S.H., N.R.O., K.D.D.) Department of Anesthesia (L.V.R., A.B.) Institute of Health Policy Management and Evaluation (A.B.) Department of Surgery (K.D.D.), University of Toronto, Toronto, Ontario, Canada.
    • Anesthesiology. 2018 Nov 1; 129 (5): 1015-1024.

    What We Already Know About This TopicWHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Ketamine is an N-methyl-D-aspartate receptor antagonist that reduces temporal summation of pain and modulates antinociception. Ketamine infusions can produce significant relief of neuropathic pain, but the treatment is resource intensive and can be associated with adverse effects. Thus, it is crucial to select patients who might benefit from this treatment. The authors tested the hypothesis that patients with enhanced temporal summation of pain and the capacity to modulate pain via the descending antinociceptive brain pathway are predisposed to obtain pain relief from ketamine.MethodsPatients with refractory neuropathic pain (n = 30) and healthy controls underwent quantitative sensory testing and resting-state functional magnetic resonance imaging and then completed validated questionnaires. Patients then received outpatient intravenous ketamine (0.5 to 2 mg · kg · h; mean dose 1.1 mg · kg · h) for 6 h/day for 5 consecutive days. Pain was assessed 1 month later. Treatment response was defined as greater than or equal to 30% pain relief (i.e., reduction in pain scores). We determined the relationship between our primary outcome measure of pain relief with pretreatment temporal summation of pain and with brain imaging measures of dynamic functional connectivity between the default mode network and the descending antinociceptive brain pathway.ResultsApproximately 50% of patients achieved pain relief (mean ± SD; Responders, 61 ± 35%; Nonresponders, 7 ± 14%). Pretreatment temporal summation was associated with the effect of ketamine (ρ = -0.52, P = 0.003) and was significantly higher in Responders (median [25th, 75th] = 200 [100, 345]) compared with Nonresponders (44 [9, 92]; P = 0.001). Pretreatment dynamic connectivity was also associated with the clinical effect of ketamine (ρ = 0.51, P = 0.004) and was significantly higher in Responders (mean ± SD, 0.55 ± 0.05) compared with Nonresponders (0.51 ± 0.03; P = 0.006). Finally, the dynamic engagement of the descending antinociceptive system significantly mediated the relationship between pretreatment pain facilitation and pain relief (95% CI, 0.005 to 0.065).ConclusionsThese findings suggest that brain and behavioral measures have the potential to prognosticate and develop ketamine-based personalized pain therapy.

      Pubmed     Full text   Copy Citation  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…