Acute Pain
Conditions
Keywords
tDCS, Opioid, Pain, Pain threshold
Brief summary
The purpose of this study is to evaluate the potential additive effect of tDCS compared to placebo-sham in opioid analgesia on pain thresholds in nociceptive experimental model in healthy volunteers .
Detailed description
Pain is a prevalent symptom in medicine and the role of various opioids is valuable in the treatment of moderate to severe pain. Several technologies of brain stimulation , including transcranial direct current stimulation ( tDCS) are emerging as therapeutic options for many pain conditions. The effect of tDCS was demonstrated in sensory perception , decreasing the threshold for acute pain in healthy volunteers and in various chronic pain conditions . There is evidence about the use of tDCS with the participation through many mechanisms in cortical modulation , including the regulation of neurotransmitters, including opioids. In the context of neurostimulation, opioidergic system and cortical pain modulation, emerge the hypothesis of a possible potentiating effect of tDCS on clinical application of opioid analgesia.
Interventions
DRUGRemifentanil
Remifentanil (IV infusion): 0,06mcg.kg.min. The infusion starts 10min before tDCSThe infusion will be stopped in the event of: a decrease in respiratory rate below 7 breaths / min, a peripheral oxygen saturation below 85%, a lower heart rate of 40 beats per minute, a lower mean arterial pressure of 60 mmHg, sedation causing inadequate management switch stimuli tests and occurrence of vomiting.
DEVICEActive tDCS
The stimulation will be administered with a pair of surface electrodes, sponge coated, soaked in saline. A battery-powered constant current stimulator will be used for this purpose (tDCS device). The stimulation is performed by placing the anodal electrode in the primary motor cortex (M1) and the cathodal one in the contralateral supraorbital area and it will use a 2 mA (milliampere) current.
DEVICESham tDCS
The sham tDCS consists in the same montage of the active tDCS, but the device is turned off 30 seconds after starting stimulation (without letting the patient notice it). The rest of the montage is kept identical to the active one during the 20 minutes session.
DRUGPlacebo
Saline infusion - Infusion 10min before the tDCS session, during the tDCS session and after the tDCS session, until the end of pain tests.
Sponsors
Hospital de Clinicas de Porto Alegre
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* Male * Healthy * Without medication * Sign the informed consent
Exclusion criteria
* Patients who did not understand the Portuguese * Acute or chronic pain conditions * Medical or psychiatric disorders * History of sleep disorders (apnea, hypersomnia, somnambulism…) * History of alcohol or substance abuse * Neurological disorder * Use of anti-inflammatory drugs, steroids and non-steroids, opioid and non-opioid analgesics, psychiatric medications, anticonvulsants, alpha and beta blockers * Traumatic brain injury * Neurosurgery * Metallic implant in the brain
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Thresholds of pain to the cold pressor test (CPT) | 20min |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Intensity of electrical brain activity in the bi-spectral index (BIS) | 60min | — |
| Sedation level in the visual analogue scale (VAS) | 60min | — |
| Temperature of tolerance to the thermal stimulus (TTTS) | 20min | — |
| Serum levels of BDNF | 20min | — |
| Threshold of pain to the thermal stimulus (TT) | 20min | — |
| Hemodynamic changes of brain using fNIRSNear-infrared spectroscopy (NIRS) | 60 | The vascular response will be assessed using functional near infrared spectroscopy (fNIRS). Emerging technique that allows the functional mapping of the brain, with a better understanding of the neuro-vascular coupling, the neurophysiological fluctuations and cerebral hemodynamics. |
| Conditioned pain modulation (CPM) | 20min | A nociceptive tonic conditioning stimulus - immersion of the non-dominant hand in cold water (0°C for 1 minute) - will be applied concomitant to the progressive thermal stimulus in the dominant forearm as applied in the QST pattern until it reaches the 6/10 pain temperature previously determined by the participant. |
Countries
Brazil
Contacts
Primary ContactGilberto Braulio, MD
Backup ContactWolnei Caumo, MD, P.h.D
Outcome results
None listed