Spinal anaesthesia for ambulatory arthroscopic surgery of the knee: a comparison of low-dose prilocaine and fentanyl with bupivacaine and fentanyl.
BACKGROUND
Prospective data on the use of prilocaine for ambulatory spinal anaesthesia remain limited. We compared the behaviour and characteristics of subarachnoid block using prilocaine and fentanyl with that of bupivacaine and fentanyl.


METHODS
In a prospective, double-blind, randomized controlled trial, 50 patients undergoing elective ambulatory arthroscopic knee surgery received subarachnoid anaesthesia, with either prilocaine 20 mg and fentanyl 20 µg (Group P) or plain bupivacaine 7.5 mg and fentanyl 20 µg (Group B). Primary endpoints included times for onset of maximum sensory block level and regression of sensory block to L4, and also motor block at 1 and 2 h, and levels of haemodynamic stability. Comparisons between the groups were made by χ² test for proportions and the Mann-Whitney test for ordinal data. Time-to-event data were analysed by the Mann-Whitney test for uncensored data or the logrank test for censored data.


RESULTS
At 2 h, motor block in Group P had fully resolved in 86% of patients, compared with 27% in Group B (P<0.001). Median time to regression of sensory block to L4 was significantly shorter in Group P (97 min) than in Group B (280 min) (P<0.001). A clinically significant decrease in arterial pressure was more common in Group B (73%) than in Group P (32%) (P=0.004). Two patients in Group P required conversion to general anaesthesia, but for reasons unrelated to prilocaine itself.


CONCLUSIONS
The combination of prilocaine and fentanyl is a better alternative to that of low-dose bupivacaine and fentanyl, for spinal anaesthesia in ambulatory arthroscopic knee surgery.
Department of Anaesthesia and Pain Medicine, Flinders Medical Centre, Bedford Park, SA 5042, Australia. Adam.Black@health.sa.gov.au
A S
AS
Black
G N
GN
Newcombe
J L
JL
Plummer
D H
DH
McLeod
D K
DK
Martin
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000556:Ambulatory Surgical Procedures / Q000379:methods; D000775:Anesthesia, Spinal / Q000379:methods*; D019162:Anesthetics, Combined / Q000008:administration & dosage; D001182:Arthroscopy / Q000379:methods; D002045:Bupivacaine / Q000008:administration & dosage; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005283:Fentanyl / Q000008:administration & dosage; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008875:Middle Aged; D009068:Movement / Q000187:drug effects; D017060:Patient Satisfaction; D011184:Postoperative Period; D011318:Prilocaine / Q000008:administration & dosage; D011446:Prospective Studies; D013697:Thermosensing / Q000187:drug effects; D014554:Urination / Q000187:drug effects; D055815:Young Adult
D019162:Anesthetics, Combined; D011318:Prilocaine; D005283:Fentanyl; D002045:Bupivacaine