Lower-Dose Mepivacaine Plus Fentanyl May Improve Spinal Anesthesia for Knee Arthroscopy

Abstract

Background: Previous work indicates that 30 mg isobaric mepivacaine 1.5% plus 10 μg fentanyl produces reliable anesthesia for knee arthroscopy with a more rapid recovery profile than 45 mg mepivacaine. Questions/Purposes: This randomized controlled trial compared plain mepivacaine to three reduced doses of mepivacaine with 10 μg fentanyl for spinal anesthesia. Methods: Following written informed consent, subjects undergoing outpatient knee arthroscopy were prospectively randomized into one of four groups: mepivacaine 37.5 mg (M37.5); mepivacaine 30 mg plus fentanyl 10 μg (M30/ F10); mepivacaine 27 mg plus fentanyl 10 μg (M27/F10); and mepivacaine 24 mg plus fentanyl 10 μg (M24/F10). The spinal was evaluated by the blinded anesthetist and surgeon. In the post-anesthesia care unit, sensory and motor block resolution was assessed. Subjects rated their satisfaction with the overall experience. Results: Group M30/F10 (n=6) had two Bfair^anesthetics, and group M27/F10 (n=10) had one Bfair^and one Binadequate^anesthetic. Both groups were eliminated from further enrollment per study protocol. The recovery profiles showed little difference between groups M37.5 and M30/F10, except for motor block resolution (median (25th percentile, 75th percentile): 171 (135, 195) and 128 (120, 135), respectively). Groups M27/ F10 and M24/F10 demonstrated recovery profiles that were faster than group M37.5. Patient satisfaction was 10/10 for all groups. Conclusions: Adding fentanyl 10 μg to a lower dose of mepivacaine 1.5% can lead to quicker recovery profiles. However, this advantage of a quicker recovery must be weighed against the likelihood of an incomplete anesthetic.

Time of return of neurologic function after spinal anesthesia for total knee arthroplasty: mepivacaine vs bupivacaine in a randomized controlled trial

“…Previously known as “transient neurologic toxicity” when initially described with lidocaine in 1993, it has also gone by the name of “transient radicular irritation” and presents with pain that can be light to severe with onset that occurs within 24 hours of injection [15] . TNS is used to currently describe such pain, lasting no more than a few days, originating in the gluteal region radiating to both lower extremities after a single injection of any spinal anesthetic [16] , [17] . Mepivacaine is an intermediate-acting local anesthetic with a reported duration of action of 90-150 minutes, which may offer a favorable pharmacokinetic profile for ambulatory arthroplasty without the historic TNS drawback.…”

“…Mepivacaine is an intermediate-acting local anesthetic with a reported duration of action of 90-150 minutes, which may offer a favorable pharmacokinetic profile for ambulatory arthroplasty without the historic TNS drawback. Several modern studies regarding other procedures have shown that mepivacaine has a faster recovery from induction, decreased urinary retention, and increased patient and surgeon satisfaction [16] , [17] , [18] , [19] , [20] . Until recently, mepivacaine had only been described for knee arthroscopy and anterior cruciate ligament reconstruction [16] , [17] .…”

“…Several modern studies regarding other procedures have shown that mepivacaine has a faster recovery from induction, decreased urinary retention, and increased patient and surgeon satisfaction [16] , [17] , [18] , [19] , [20] . Until recently, mepivacaine had only been described for knee arthroscopy and anterior cruciate ligament reconstruction [16] , [17] . Both of these randomized studies found benefit to a lower mepivacaine dose with differing amounts of added fentanyl to prolong and titrate its duration.…”

Spinal sensory and motor blockade by intrathecal doxylamine and triprolidine in rats

“…In other words, the lower dose of intrathecal doxylamine than subcutaneous doxylamine to achieve the local anaesthetic effects. Additionally, mepivacaine (1.41%; 7.76 μmol/kg) produced completely spinal motor and sensory blockades, while the dose is in accordance with clinical dosage of spinal anaesthesia with mepivacaine (30 mg, 1.5%) …”

“…Additionally, mepivacaine (1.41%; 7.76 lmol/kg) produced completely spinal motor and sensory blockades, while the dose is in accordance with clinical dosage of spinal anaesthesia with mepivacaine (30 mg, 1.5%). [36,37] Local anaesthetics inhibit nerve conduction through blocking voltage-gated Na + channels in the nerves. [38] Although pharmacological actions of doxylamine or triprolidine (i.e.…”