Lidocaine for lumbar punctures. A help not a hindrance
C. Carraccio, P. Feinberg, L. S. Hart, M. Quinn, J. King and R. Lichenstein
Department of Pediatrics, University of Maryland School of Medicine, Baltimore, USA.
OBJECTIVE: To determine whether premedication for lumbar puncture (LP) with
lidocaine hinders collection of cerebrospinal fluid (CSF) through either
increased number of attempts or increased incidence of traumatic punctures.
DESIGN: A randomized controlled trial. SETTING: The pediatric emergency
department of an innercity teaching hospital. PATIENTS: A convenience
sample of 100 children, younger than 3 years, who required an LP as part of
their diagnostic workup. INTERVENTION: Patients were randomized to receive
either lidocaine or no local anesthetic before undergoing an LP. MAIN
OUTCOME MEASURES: Comparison of the number of attempts needed to obtain CSF
and the number of traumatic LPs between the lidocaine-treated and no local
anesthetic groups. RESULTS: The 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 differ with 59% of the patients in each group requiring 1
attempt. Defining a traumatic LP as more than 1000 x 10(6)/L red blood
cells in the CSF showed notably more traumatic LPs in the lidocaine-treated
group. Defining a traumatic LP as one with more than 10,000 x 10(6)/L red
blood cells in the CSF showed no significant difference in the number of
traumatic LPs whether or not the patient was premedicated with lidocaine.
The level of experience of the physician performing the LP did not affect
the outcome. CONCLUSIONS: Premedication with lidocaine for an LP does not
binder the ease of obtaining CSF. The clinical relevance of a greater
number of traumatic LPs in the lidocaine-treated group is questionable
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 results, we advocate
premedication with a local anesthetic when an LP is performed in the
pediatric emergency department.
