LIDOCAINE FOR LUMBAR PUNCTURES - A HELP NOT A HINDRANCE

Objective: To determine whether premedication for lumbar puncture (LP) with lidocaine hinders collection of cerebrospinal fluid (CSF) throug h either increased number of attempts or increased incidence of trauma tic punctures. Design: A randomized controlled trial. Setting: The ped iatric emergency department of an inner-city teaching hospital. Patien ts: A convenience sample of 100 children, younger than 3 years, who re quired an LP as part of their diagnostic workup. Intervention: Patient s were randomized to receive either lidocaine or no local anesthetic b efore undergoing an LP. Main Outcome Measures: Comparison of the numbe r of attempts needed to obtain CSF and the number of traumatic LPs bet ween the lidocaine-treated and no local anesthetic groups. Results: Th e 51 patients randomized to receive lidocaine did not differ markedly in age from the 49 patients randomized to receive no local anesthetic. Ease of obtaining CSF, as measured by number of attempts, did not dif fer with 59% of the patients in each group requiring 1 attempt. Defini ng a traumatic LP as more than 1000 x 10(6)/L red blood cells in the C SF showed notably more traumatic LPs in the lidocaine-treated group. D efining a traumatic LP as one with more than 10 000 X 10(6)/L red bloo d cells in the CSF showed no significant difference in the number of t raumatic LPs whether or not the patient was premedicated with lidocain e. The level of experience of the physician performing the LP did not affect the outcome. Conclusions: Premedication with lidocaine for an L P does not hinder the ease of obtaining CSF. The clinical relevance of a greater number of traumatic LPs in the lidocaine-treated group is q uestionable because this finding is negated when traumatic is defined as more than 10 000 X 10(6)/L CSF red blood cells. Based on these resu lts, we advocate premedication with a local anesthetic when an LP is p erformed in the pediatric emergency department.