Comparison of local anesthetic effect of lidocaine by jet injection vs needle infiltration in lumbar puncture.

Background: Usual routes of drug administration are often painful and invasive. Nowadays, using jet injection has been introduced successfully, as a noninvasive and painless method of anesthetic delivery in performing different procedures.

Objective: The objective of the study is to compare the local anesthetic effect of lidocaine by jet injection vs needle infiltration in performing lumbar puncture in the emergency department (ED).

Methods: A randomized single-blind controlled study was performed in 65 patients needing lumbar puncture recruited from the ED from July to November 2014. We enrolled 44 patients and excluded 21 patients by the exclusion criteria. Local lidocaine was delivered in 1 group by jet injector (group B), whereas in the other group conventional method, needle infiltration was used (group A). In both groups, intravenous midazolam 1 mg was administered as an anxiolytic drug before the procedure. Patients' pain score (visual analog scale [VAS]) from 0 to 10 was recorded both during drug delivery and performing the procedure itself. The observer who collected patients' data and fulfill the questionnaire was blinded to the study.

Results: During lidocaine injection, the mean ± SD VAS score was 5.27 ± 1.77 in group A and 2.95 ± 1.81 in group B (mean difference, 2.31; 95% confidence interval, 1.22-3.41) (P= .000). During performing the procedure, the mean ± SD VAS score in groups A and B was 3.77 ± 1.77 vs 2.18 ± 1.50 (mean difference, 1.59; 95% confidence interval, 0.59-2.58) (P= .003).

Conclusions: Injecting lidocaine by jet injector is less painful than infiltrating it by needle and syringe.