Reduction of topical anesthetic onset time using ultrasound: a randomized controlled trial prior to venipuncture in young children.
BACKGROUND
Ultrasound treatment prior to topical anesthetic application has been shown to speed anesthesia onset by enhancing anesthetic penetration into the skin.


OBJECTIVE
To evaluate a low-frequency ultrasound device to facilitate absorption of topical anesthetic in young children who require venipuncture.


METHODS
This was a prospective controlled comparison of analgesic effect of a 5-minute application of liposomal lidocaine cream after ultrasound treatment, with a 30-minute application of liposomal lidocaine cream, in children aged 3 to 7 years undergoing venipuncture. Children rated the pain of the venipuncture using the Wong-Baker FACES Pain Rating Scale (FACES) (0 = no pain, 10 = maximal pain), and parents rated their child's pain using a 100-mm (0 = no pain, 100 = maximal pain) visual analogue scale (VAS). Venipuncture skin sites were evaluated for effect immediately posttreatment, and at 24 to 72 hours post phlebotomy.


RESULTS
Seventy subjects were enrolled: the first 10 patients comprised a pilot series, receiving the ultrasonic treatment and liposomal lidocaine cream; the next 60 subjects were randomized, including 29 allocated to the ultrasound treatment group, and 31 randomized to the 30-minute control treatment with liposomal lidocaine cream. Demographics were similar between the two groups. Mean child's FACES scale results were similar: Ultrasound group 4.78 (95% CI; 3.06, 6.52), CONTROL group 4.32 (95% CI; 2.82, 5.82) (P = 0.72); and mean parent VAS scores were also the same: Ultrasound: 19.1 (95% CI; 10.3, 27.8), CONTROL: 23.2 (95% CI; 14.7, 31.7) (P = 0.87). Skin effects immediately after ultrasound were limited to minor redness in 9/39 children and significant redness in 2/29 patients.


CONCLUSIONS
Ultrasound treatment speeds time of onset of liposomal lidocaine cream anesthesia in young children undergoing venipuncture. Side effects were mild in our population.
Zempsky
William T
WT
Pain Relief Program, Department of Pediatrics, University of Connecticut School of Medicine, Hartford, Connecticut, USA. wzempsk@ccmckids.org
Robbins
Bertha
B
McKay
Kathleen
K
D000287:Administration, Topical; D000779:Anesthetics, Local / Q000008:administration & dosage; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D010146:Pain / Q000175:diagnosis / Q000209:etiology* / Q000517:prevention & control*; D010147:Pain Measurement / Q000187:drug effects; D018962:Phlebotomy / Q000009:adverse effects* / Q000379:methods*; D013010:Sonication; D013997:Time Factors; D016896:Treatment Outcome; D014464:Ultrasonic Therapy / Q000379:methods*
D000779:Anesthetics, Local; D008012:Lidocaine