Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Sep 2013
Randomized Controlled TrialEffect of Chronic β-Blockade on the Utility of an Epinephrine-Containing Test Dose to Detect Intravascular Injection in Nonsedated Patients.
A test dose containing epinephrine is routinely used during epidural blockade to detect accidental intravenous needle or catheter placement before the administration of local anesthetics to avert local anesthetic systemic toxicity. β-Blocker therapy may interfere with the expected hemodynamic response from an intravascular injection. This study describes a cohort of 24 patients and their response to an epinephrine test dose (ie, if expected increased heart rates during test-dose administration are valid in this population.) ⋯ Epinephrine test-dose administration in nonsedated, chronically β-blocked patients cannot distinguish intravenous injection at the classic threshold increase of 20 bpm. The response in individuals is varied, and thresholds for a positive test need revising for this population of patients on therapeutic β-blockers.