Is there any need for expanding the perineural space before catheter placement in continuous femoral nerve blocks?
OBJECTIVE
There is debate regarding the benefit of perineural space expansion before catheter placement in continuous femoral nerve block. This question is addressed in this prospective, comparative, and randomized study.


METHODS
Sixty patients scheduled for total knee replacement were randomly assigned to receive continuous femoral nerve block with or without perineural space expansion using 10 mL dextrose 5% in water (D5W) flush before stimulation-guided catheter placement. Femoral block was initiated with a 5-mL bolus followed by an infusion of 5 mL/h ropivacaine 0.2% during the 2-hour surgery. The number of attempts before successful placement of the stimulating catheter and the resistance during its insertion were assessed. Patients also received obturator nerve blocks by using ropivacaine 0.75% (10 mL) and sciatic nerve blocks (20 mL). The number of boluses of ropivacaine 0.2% needed to achieve zero VAS scoring was recorded in the postanesthesia care unit during the 2-hour stay. Images of the contrast spread were also studied.


RESULTS
There were 30 patients in each group. The number of successful catheter placements at the first attempt was higher with expansion than without (22 vs. 8, P = .007). The resistance felt during insertion was lower with than without expansion (P = .01). More boluses of ropivacaine were required postoperatively without expansion (P = .03). No difference between groups was found regarding the images of the contrast spread.


CONCLUSIONS
Expansion of the perineural space with D5W is useful for catheter placement in continuous femoral nerve block.
Pham Dang
Charles
C
Pôle Anesthésie-Réanimations, CHU Nantes, France. charles.phamdang@chu-nantes.fr
Guilley
Jérôme
J
Dernis
Lyndia
L
Langlois
Cécile
C
Lambert
Chantal
C
Nguyên
Jean-Michel
JM
Pinaud
Michel
M
D000328:Adult; D000368:Aged; D002404:Catheterization; D005260:Female; D005267:Femoral Nerve; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D011446:Prospective Studies