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

Newborns can experience physiologic instability, or wide variations in measures of biologic function, when they are exposed to medical procedures or environmental factors. It has been suggested that some of the physiologic instability may result from pain associated with invasive procedures such as surgery, and can be reduced by pain-relieving drugs or anesthesia. Information about pain and its control in the newborn is limited. The effectiveness of local anesthesia in reducing physiologic instability associated with lumbar puncture was assessed in 77 newborns. Lumbar puncture involves inserting a needle into the lower back and into the space between membranes of the spinal cord to obtain fluid for diagnosis or to administer anesthetic agents. This procedure was performed after the administration of the local anesthetic lidocaine in 38 infants, and without lidocaine in the remaining infants. Lidocaine did not diminish physiologic instability associated with lumbar puncture in newborn or cause adverse effects, but prolonged the period of lumbar puncture. Physiologic instability developed during the preparation for lumbar puncture and was not worsened by administration or lidocaine or by the lumbar puncture itself. These findings suggest that local anesthesia does not improve physiologic instability associated with lumbar puncture. Furthermore, physiologic instability is greater during preparation for lumbar puncture than during administration of local anesthetic or during lumbar puncture. Efforts should focus on reducing the adverse effects of handling procedures on physiologic stability of the newborn. (Consumer Summary produced by Reliance Medical Information, Inc.)