Acute Pain, Analgesia, Upper Extremity Injury
Conditions
Keywords
Dexamethasone, Nerve Block, Adjuvant, Pharmacokinetic Analysis
Brief summary
The investigators will conduct a prospective, randomized, double-blinded study using an axillary brachial plexus block in patients undergoing elective surgery of the distal forearm and hand to characterize and describe the pharmacokinetics of bupivacaine associated with perineural dexamethasone. The pharmacokinetic analysis will be performed by measuring bupivacaine plasma levels at different time intervals after the blockade (15, 30, 45, 60, and 90 minutes), allowing comparison between 2 different groups: Bupivacaine (B) and Bupivacaine-dexamethasone (BD). Thus, the hypothesis is that plasma levels of bupivacaine during the first 90 minutes after a blockade are lower in the presence of perineural dexamethasone, suggesting a decrease, at least initially, in systemic absorption from the injection site.
Interventions
DRUGBupivacaine Hydrochloride
Patients will receive a total volume of 30 ml of bupivacaine 0.5% in an axillary block with a double puncture.
DRUGBupivacaine Hydrochloride with Dexamethasone
Patients will receive a total volume of 30 ml of bupivacaine 0.5% with Dexamethasone 4 mg in an axillary block with a double puncture.
Sponsors
University of Chile
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Caregiver, Outcomes Assessor)
Masking description
A research assistant (licensed anesthesiologist) will prepare the local anesthetic solutions and will add the study drug following the randomization order. The operator, patient and investigator assessing the block will be blinded to group allocation.
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* American Society of Anesthesiologists classification 1-2 * Real weight between 80 and 100 kg * Body mass index between 20 and 30
Exclusion criteria
* Adults who are not capable of giving their own consent * Medical history or physical findings of pre-existing neuropathy * Coagulopathy (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. platelets ≤ 100, International Normalized Ratio ≥ 1.4 or prothrombin time ≥ 50) * Renal failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. creatinine ≥ 100) * Hepatic failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. transaminases ≥ 100) * Allergy to local anesthetics (LAs) * Pregnancy * Previous surgery in the axillary region of the surgical side
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Maximum plasma concentration (Cmax) of bupivacaine | 0 to 90 minutes after the ending time of local anesthetic injection | Maximum plasmatic level of bupivacaine |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Plasmatic concentration of bupivacaine at 30 minutes | 30 minutes after the ending time of local anesthetic injection | Plasmatic level of bupivacaine 30 minutes after local anesthetic injection (ng/ml) |
| Plasmatic concentration of bupivacaine at 45 minutes | 45 minutes after the ending time of local anesthetic injection | Plasmatic level of bupivacaine 45 minutes after local anesthetic injection (ng/ml) |
| Plasmatic concentration of bupivacaine at 60 minutes | 60 minutes after the ending time of local anesthetic injection | Plasmatic level of bupivacaine 60 minutes after local anesthetic injection (ng/ml) |
| Plasmatic concentration of bupivacaine at 90 minutes | 90 minutes after the ending time of local anesthetic injection | Plasmatic level of bupivacaine 90 minutes after local anesthetic injection (ng/ml) |
| Time to obtain the maximum plasma concentration of bupivacaine (Tmax) | 0 to 90 minutes after the ending time of local anesthetic injection | Time in minutes in which the maximum plasmatic level of bupivacaine is reached |
| Area under the curve of plasma concentration versus time at 90 minutes (AUC90) | 0 to 90 minutes after the ending time of local anesthetic injection | Area under the curve at 90 minutes |
| Sensory and motor block score | 30 minutes after the ending time of local anesthetic injection | The sensorimotor block will be assessed every 5 minutes until 30 minutes after the end of local anesthetic injection using a 16-point composite score evaluating sensory and motor block of musculocutaneous, medium, radial, and ulnar nerves. Sensation will be assessed with ice in each nerve territory with a 0 to 2 point scale. 0= no block, patients can feel cold; 1= analgesic block, the patient can feel touch but not cold; 2= anesthetic block, the patient cannot feel cold or touch. The motor function will be assessed for each nerve with a 0 to 2 points scale where 0= no motor block; 1= paresis; 2= paralysis. Successful blocks at 30 minutes correlate with a final score ( sum of all individual sensory and motor scores) of at least 14 points out of 16. |
| Block onset time | 30 minutes after the ending time of local anesthetic injection | Time required to reach a minimal sensorimotor composite score of 14 points out of a maximum of 16 points. The sensorimotor score is described in outcome 9. |
| Plasmatic concentration of bupivacaine at 15 minutes | 15 minutes after the ending time of local anesthetic injection | Plasmatic level of bupivacaine 15 minutes after local anesthetic injection (ng/ml) |
| Motor block duration | 48 hours after the ending time of local anesthetic injection | The elapsed period in minutes between the ending time of the local anesthetic injection and the time of return of hand and fingers movement. |
| Sensory block duration | 48 hours after the ending time of local anesthetic injection | The elapsed period in minutes between the ending time of the local anesthetic injection and the time of the return of hand and fingers sensation |
| Analgesic block duration | 48 hours after the ending time of local anesthetic injection | The elapsed period in minutes between the ending time of the local anesthetic injection and the time of the first sensation of pain in the surgical area |
| Intensity of pain during block procedure | During the execution of the nerve blockade | Evaluated with the Numeric Rating Scale for Pain. This scale is graduated from 0 to 10 points. A 0-point score represents the absence of pain, and a 10-points score represents the worst imaginable pain. Patients will be asked to rate their pain verbally with this scale. The blinded assessor will register the score reported. |
| Block performance time | From the skin anesthesia to the end of local anesthetic injection | Sum of: 1- the acquisition time of the ultrasonographic image. and 2- the time to perform the block itself (from the skin anesthesia to the end of local anesthetic injection) |
| Incidence of nerve block side effects | From the skin anesthesia to the end of local anesthetic injection | Determined by the presence of paresthesia, local anesthetic systemic toxicity, vascular puncture after the block. |
| Persistent neurologic deficit | 7 days after surgery | Presence of persistent sensory or motor postoperative deficit. |
| Incidence of successful block | 30 minutes after the ending time of local anesthetic injection | Percentage of blocks with a minimal sensorimotor composite score of 14 points out of a maximum of 16 points at 30 minutes after the injection |
Countries
Chile
Outcome results
None listed