EUTECTIC MIXTURE OF LOCAL-ANESTHETICS IS NOT EFFECTIVE FOR EXTRACORPOREAL SHOCK-WAVE LITHOTRIPSY

Purpose: Eutectic mixture of local anaesthetics (EMLA(R)) produces cut aneous analgesia. This randomized, double blind, placebo controlled st udy evaluated the efficacy of EMLA cream during extracorporeal shock w ave lithotripsy (ESWL) using the Dornier(R) MFL 5000 lithotripter. Met hods: Patients scheduled to undergo lithotripsy of renal or pelviurete ric junction stones were randomized to receive either 30 g EMLA cream (E) or placebo (P) over the kidney area 60-90 min before the procedure . During lithotripsy all patients received alfentanil via a PCA machin e (dose 10 mu . kg(-1), lockout time - three minutes, no basal infusio n). Additional bolus doses of 5 mu g . kg(-1) alfentanil were administ ered by the anaesthetist if analgesia was inadequate. Visual analogue scores (VAS) for pain were documented prior to application of the crea m. On arrival in the post anaesthesia care unit VAS pain scores were d ocumented for maximum pain and average pain felt during the procedure as well as for satisfaction of the analgesic technique used. Total tim e spent in the PACU and the Aldrete scores on arrival were compared. R esults: Eighty-three patients completed the study. Demographic data we re similar between the tow groups. Also, VAS for maximal pain,average pain and satisfaction and the total number of shock waves were similar although the EMLA group received more shock waves at the lower energy level (kV) (P < 0.0001). Total dose of alfentanil, dose as boluses, r ate of alfentanil use, total number of PCA attempts and missed attempt s were similar. The incidence of adverse events such as bradypnoea, ai rway obstruction, transient hypoxaemia, pruritus and nausea were small and similar. There was a slightly higher incidence of inadequate anal gesia documented by the anaesthetist in the EMLA group. There was no d ifference between the groups with regards to duration of stay in the P ACU, incidence of nausea or Aldrete scores on admission to PACU. Concl usions: During lithotripsy EMLA cream does not modify the pain perceiv ed nor does it have any opioid sparing effect. It does not facilitate early discharge from the PACU.