Perineural administration, compared with intravenous administration, of dexamethasone prolongs analgesia of brachial plexus blocks, according to a study presented here at the 2018 Annual Meeting of the Canadian Anesthesiologists Society (CAS).
“When we do surgeries that involve the upper arm, we freeze the arm with regional anaesthesia,” explained Billy Sun, BHSc, University of Calgary, Calgary, Alberta, on June 17. “Sometimes, the duration of pain control is not adequate, the block will wear off, and the patient will have pain. The issue is how we prolong the duration of pain control.”
Clinicians often attempt to add a steroid to the injection for shoulder or forearm surgery, with the goal of extending the impact of the block.
“There is evidence that using the steroid works, that it helps to prolong the block,” said Sun. “The question is which one helps more—injecting into the vein or injecting with the block. We want to know how to use dexamethasone to maximise its usage.”
The researchers included 8 studies that involved 702 patients in their meta-analysis. They found that patients who were exposed to perineural dexamethasone benefitted from a longer duration of analgesia than patients who received intravenous dexamethasone (mean difference, 2.57 h; P = .004). In regard to the survival analysis, investigators noted that patients exposed to intravenous dexamethasone were more likely to experience a loss of analgesia than patients who received perineural dexamethasone (P < .00001).
At 12 and 24 hours, perineural dexamethasone produced pain scores superior to those with intravenous dexamethasone (P = .01 and .007, respectively). In addition, a more significant effect size that favoured perineural administration was observed in a subset of patients.
Investigators did not find a difference in analgesic consumption or adverse effects associated with the route of administration of dexamethasone.
One of the possible concerns around perineural dexamethasone is safety, which may be why some clinicians hesitate to administer it in this manner, suggested Sun.
“We know that intravenous dexamethasone is safe to administer, whereas injecting a steroid directly on a nerve may cause damage,” said Sun, adding that there may be general hesitation in adopting new practices.
One of the strengths of this meta-analysis is that it was confined to brachial plexus blocks.
The next step would be to conduct a randomised, controlled trial in Calgary to determine whether results support the finding of this meta-analysis, concluded Sun.
[Presentation title: Analgesic Efficacy of Perineural and IV Dexamethasone in Brachial Plexus Block: Systematic Review & Meta-Analysis. Abstract 428943]