The Anesthetic and Recovery Profiles of Low-dose Hypobaric Mepivacaine
and Bupivacaine for Spinal Anesthesia in Total Hip and Knee Arthroplasty

There is increasing emphasis in modern orthopedic practice on same-day mobilization and
hospital discharge following total joint arthroplasty.
• PROBLEM: large doses of isobaric local anesthetic (LA) are often used to achieve adequate
block height ⇨ can cause unnecessarily prolonged sensory and motor blockade.
• PROPOSED SOLUTION: administration of hypobaric LA allows manipulation of intrathecal
distribution to achieve adequate block height independent of administered dose.

 

Unlike isobaric LA, hypobaric LA solutions have highly predictable distribution within the CSF
with appropriate positioning ⇨ enables use of lower doses and faster recovery without
sacrificing block onset and height.
• Both hypobaric solutions:
o Provide a rapid onset of block to T10 and L1 ⇨ shortens time to surgical readiness which
may enhance operating room efficiency;
o Provide satisfactory surgical anesthesia regardless of level of injection ⇨ useful when lower
interspaces like L5-S1 are the only accessible space;
o Have reliable onset and recovery profiles ⇨ can be ideal for fast-track pathways prioritizing
early mobilization or same-day discharge.