Purpose: The aim of this study was to determine the outcome of lumbar punctures (LPs) in critically ill medical patients and how likely the results were to change case management.
Materials and methods: A retrospective review was conducted on the medical records of all 168 patients who underwent LP during their medical intensive care unit (MICU) admission at a university hospital during a 4.5-year period beginning in January 2000.
Results: Lumbar puncture was performed a mean of 2.8 days after MICU admission. The most common symptoms that prompted LP were changes in mental status and fever. Seventy-four percent of patients were on antibiotics at the time of LP, and 98% of patients had a computed tomography scan of the head performed before the procedure. Lumbar puncture confirmed meningitis in 47 (30%) patients and provided a specific bacteriologic diagnosis in 5 (3%) patients. The results of the procedure led to a change in management in 50 (30%) patients. The presence of meningeal signs and use of antibiotics at the time of the procedure were the factors that predicted change in management.
Conclusion: Although the likelihood that LP will yield a specific bacteriologic diagnosis in critically ill patients is low, the procedure frequently provides important information that can lead to a change in case management, most commonly de-escalation of antibiotic therapy.