A Randomized Double Blind Trial of Needle-free Injected Lidocaine Versus Topical Anesthesia for Infant Lumbar Puncture

Objectives: Lumbar punctures (LPs) are commonly performed in febrile infants to evaluate for meningitis, and local anesthesia increases the likelihood of LP success. Traditional methods of local anesthesia require injection that may be painful or topical application that is not effective immediately. Recent advances in needle-free jet injection may offer a rapid alternative to these modalities. We compared a needle-free jet-injection system (J-Tip) with 1% buffered lidocaine to topical anesthetic (TA) cream for local anesthesia in infant LPs.

Methods: This was a single-center randomized double-blind trial of J-Tip versus TA for infant LPs in an urban tertiary care children's hospital emergency department. A computer randomization model was used to allocate patients to either intervention. Patients aged 0 to 4 months were randomized to J-Tip syringe containing 1% lidocaine and a placebo TA cream or J-Tip syringe containing saline and TA. The primary outcome was the difference between the Neonatal Faces Coding Scale (NFCS) before the procedure and during LP needle insertion. Secondary outcomes included changes in heart rate (HR) and NFCS throughout the procedure, difficulty with LP, number of LP attempts, provider impression of pain control, additional use of lidocaine, skin changes at LP site, and LP success.

Results: We enrolled 66 subjects; 32 were randomized to J-Tip with lidocaine and 34 to EMLA. Six participants were excluded from the final analysis due to age greater than 4 months, and the remaining 58 were analyzed in their respective groups (32 J-Tip, 34 TA). There was no difference detected in NFCS between the two treatment groups before the procedure and during needle insertion for the LP (p = 0.58, p = 0.37). Neither HR nor NCFS differed among the groups throughout the procedure. Median perception of pain control by the provider and the need for additional lidocaine were comparable across groups. LPs performed with a J-Tip were twice as likely to be successful compared to those performed using TA (relative risk = 2.0; 95% confidence interval = 1.01-3.93; p = 0.04) with no difference in level of training or number of prior LPs performed by providers.

Conclusions: In a randomized controlled trial of two modalities for local anesthesia in infant LPs, J-Tip was not superior to TA cream as measured by pain control or physiologic changes. Infant LPs performed with J-Tip were twice as likely to be successful.