Epinephrine as an Adjunct to Plane Nerve Blocks 

Fascial plane nerve blocks, also referred to as plane nerve blocks, are regional anesthesia techniques in which local anesthetic is deposited between fascial layers, allowing it to spread across multiple adjacent nerves. Although the concept of fascial plane analgesia has existed for decades, its use has expanded, motivating continued research and innovation. Common examples include the transversus abdominis plane (TAP) block, erector spinae plane (ESP) block, quadratus lumborum block, and rectus sheath block. These techniques are particularly useful for truncal and abdominal surgery because they provide broad dermatomal coverage while avoiding some risks associated with neuraxial anesthesia, such as hypotension, urinary retention, and motor blockade (1). 

However, a significant limitation of these techniques is a rapid absorption into systemic circulation and a shorter duration of effect, as the target tissue plane is often highly vascular. To address these concerns, epinephrine is frequently used as an adjunct to local anesthetics in plane nerve blocks (2). 

Through alpha-adrenergic–mediated vasoconstriction, epinephrine reduces local blood flow and slows systemic absorption, which may prolong analgesia and improve safety. Additionally, epinephrine may help detect inadvertent intravascular injection, as systemic absorption can produce transient tachycardia or blood pressure changes that alert clinicians to vascular placement. These pharmacological properties make epinephrine particularly attractive in fascial plane blocks, where large-volume injections are commonly required (2). 

Importantly, the role of epinephrine in fascial plane blocks may differ from its function in traditional peripheral nerve blocks. Conventional nerve blocks involve deposition of local anesthetic near discrete nerves within relatively confined spaces, whereas fascial plane blocks rely on diffusion across broader tissue compartments. This introduces competing considerations, as vasoconstriction from epinephrine may reduce systemic absorption but could theoretically limit spread within fascial planes—so far, clinical data has not shown significant impairment of block efficacy (3).  

Clinical studies evaluating epinephrine in fascial plane nerve blocks have primarily focused on transversus abdominis plane blocks. Altermatt et al. demonstrated that the addition of epinephrine to levobupivacaine significantly reduced peak plasma concentrations and delayed systemic absorption following TAP block (4). Subsequent pharmacokinetic investigations confirmed that levobupivacaine combined with epinephrine resulted in lower systemic exposure and improved safety margins without compromising analgesic effectiveness (3). These findings are particularly relevant because truncal fascial plane blocks are frequently performed bilaterally, increasing cumulative local anesthetic exposure.  

Overall, current evidence suggests that epinephrine may provide meaningful pharmacokinetic advantages in fascial plane nerve blocks by reducing systemic absorption and improving safety when large-volume injections are required. However, further studies are needed to clarify optimal dosing strategies and clinical benefits across different block types. 

References 

1. Sharma R, Damiano J, Al-Saidi I, Dizdarevic A. Chest Wall and Abdominal Blocks for Thoracic and Abdominal Surgeries: A Review. Curr Pain Headache Rep. 2023;27(10):587-600. doi:10.1007/s11916-023-01158-7 

2. Rahiri J, Tuhoe J, Svirskis D, Lightfoot NJ, Lirk PB, Hill AG. Systematic review of the systemic concentrations of local anaesthetic after transversus abdominis plane block and rectus sheath block. Br J Anaesth. 2017;118(4):517-526. doi:10.1093/bja/aex005 

3. Miranda P, Corvetto MA, Altermatt FR, Araneda A, Echevarría GC, Cortínez LI. Levobupivacaine absorption pharmacokinetics with and without epinephrine during TAP block: analysis of doses based on the associated risk of local anaesthetic toxicity. Eur J Clin Pharmacol. 2016;72(10):1221-1227. doi:10.1007/s00228-016-2086-1 

4. Corvetto MA, Echevarría GC, De La Fuente N, Mosqueira L, Solari S, Altermatt FR. Comparison of plasma concentrations of levobupivacaine with and without epinephrine for transversus abdominis plane block. Reg Anesth Pain Med. 2012;37(6):633-637. doi:10.1097/AAP.0b013e31826c330a