A controlled clinical trial of local anesthesia for lumbar punctures in newborns

To evaluate the efficacy of subcutaneous administration of lidocaine for reducing physiologic instability in acutely ill newborns during clinically required procedures, 81 neonates who required lumbar punctures within the first month of life were stratified by birth weight and respiratory support and randomly assigned to an experimental or a control group. The experimental group received an injection of 0.1 mL/kg of 1% lidocaine prior to the lumbar puncture. The control group received a nonanesthetized lumbar puncture without placebo. Changes in heart rate, respiratory rate, transcutaneous oxygen and carbon dioxide tensions, and heart rate variability from baseline, preparatory (positioning/handling), lumbar puncture, and recovery periods were measured. The administration of lidocaine did not minimize physiologic instability in response to the lumbar puncture nor was it associated with any detectable adverse effects other than prolonging the duration of the lumbar puncture. Although significant physiologic changes were observed in response to preparatory procedures, few additional changes beyond those occurred in response to lumbar punctures in either the experimental or control group. It is concluded that local anesthesia failed to influence manifestations of physiologic instability during neonatal lumbar punctures and that preparatory procedures were more destabilizing than either the administration of lidocaine or the lumbar puncture itself. The results suggest that the management of newborns requires emphasis on minimizing the destabilizing effects of required and frequent handling procedures.