Needle-free jet injection of lidocaine for local anesthesia during lumbar puncture: a randomized controlled trial

Lumbar puncture (LP) is an essential procedure in the emergency department (ED) for the evaluation of meningitis. Subcutaneous injection of lidocaine before LP for local anesthesia is not a pain-free procedure. The J-Tip device allows an intradermal needle-free jet injection of 1% buffered lidocaine. This study compares needle-free jet injection of lidocaine to saline in reducing pain before LP in infants.

This is a randomized, double-blinded, placebo-controlled trial involving infants, younger than 3 months, presenting to the ED meeting clinical criteria for LP. All patients were administered the J-Tip and randomized to either treatment with 1% buffered lidocaine or an equivalent amount of sterile normal saline before LP. Vital signs were recorded during the procedure. Facial expressions as well as crying times were video recorded from start to finish. Independent reviewers assigned pain scores based on the validated Neonatal Facial Coding System with possible scores ranging from 0 to 5.

A total of 55 patients were enrolled. Mean (SD) pain scores at the time of needle insertion were 4.1 (1.3) for the lidocaine group and 4.8 (0.5) for the saline group (P = 0.01). Length of cry was also shorter for those in the lidocaine group, 38.5 versus 48.8 seconds (P = 0.04). Overall, κ was 0.76 between 2 independent reviewers.

Needle-free injection of 1% buffered lidocaine administered before needle insertion for LP in infants reduces pain and length of cry, compared with normal saline.