Objective: To assess the effects of procedural techniques, local anesthetic use, and postgraduate training level on lumbar puncture (LP) success rates.
Methods: In this prospective observational study, medical students and residents ("trainees") reported techniques used for infant LPs in an urban teaching emergency department. Data on postgraduate year, patient position, draping, total and trainee numbers of attempts, local anesthetic use, and timing of stylet removal were collected. Logistic regression analysis was used to identify predictors of successful LP, with success defined as the trainee obtaining cerebrospinal fluid with <1000 red blood cells per mm3.
Results: We collected data on 428 (72%) of 594 infant LPs performed during the study period. Of 377 performed by trainees, 279 (74%) were successful. Local anesthesia was used for 280 (74%), and 225 (60%) were performed with early stylet removal. Controlling for the total number of attempts, LPs were 3 times more likely to be successful among infants >12 weeks of age than among younger infants (odds ratio [OR]: 3.1; 95% confidence interval [CI]: 1.2-8.5). Controlling for attempts and age, LPs performed with local anesthetic were twice as likely to be successful (OR: 2.2; 95% CI: 1.04-4.6). For infants < or =12 weeks of age, early stylet removal improved success rates (OR: 2.4; 95% CI: 1.1-5.2). Position, drape use, and year of training were not significant predictors of success.
Conclusions: Patient age, use of local anesthetic, and trainee stylet techniques were associated with LP success rates. This offers an additional rationale for pain control. Predictors identified in this study should be considered in the training of physicians, to maximize their success with this important procedure.