Continuous peripheral nerve blocks with stimulating catheters.
OBJECTIVE
This study evaluated the efficacy of stimulating catheters used for continuous peripheral nerve blocks as a means of immediate verification and confirmation of correct catheter position.


METHODS
This observational study presents our experience with 130 stimulating catheters used in 40 intersternocleidomastoid, 24 axillary, 47 femoral, and 19 lateral midfemoral sciatic nerve blocks. Placement characteristics (amperage, depth of introducer needle or catheter insertion, elicited motor responses), subsequent postoperative analgesia, and catheter position evaluated with the radiopaque dye analysis were all studied.


RESULTS
Except in femoral blocks, characteristics of motor responses elicited (1 Hz, 0,1 ms) by the introducer assembly and catheter differed. The amperage required to elicit motor responses typically was higher with the catheter than with the introducer needle (1.6 [0.2 to 4 mA] v 0.5 [0.4 to 1 mA] P <.0001). The ability to elicit a motor response with the stimulating catheter correlated with successful clinical anesthesia in 124 cases. Opacified radiography showed no aberrant position in these cases. Three catheters for upper limb block failed to stimulate, provided poor anesthesia, and had radiologic evidence of aberrant position. Even though they failed to stimulate, 3 catheters for sciatic block functioned well, and the opacified radiography showed correct position.


CONCLUSIONS
The ability to electrostimulate nerves using an in situ catheter increases success rate in catheter placement for continuous peripheral nerve blocks. Further controlled investigations are necessary to compare this technique with more conventional methods in terms of cost and utility for various peripheral nerve blocks.
Pham-Dang
Charles
C
Anesthésie - Réanimations, Chirurgie Orthopédique, Hôtel-Dieu, University Hospital, Nantes, France. charles.phamdang@chu-nantes.fr
Kick
Ottmar
O
Collet
Thurial
T
Gouin
François
F
Pinaud
Michel
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000577:Amides / Q000008:administration & dosage / Q000627:therapeutic use; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000627:therapeutic use; D001365:Axilla; D002404:Catheterization / Q000295:instrumentation / Q000379:methods*; D004558:Electric Stimulation; D005260:Female; D005269:Femur; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D009339:Needles; D009407:Nerve Block / Q000295:instrumentation / Q000379:methods*; D010149:Postoperative Pain / Q000628:therapy; D010525:Peripheral Nerves; D000077212:Ropivacaine; D012584:Sciatic Nerve
D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine