Which ED procedure involves puncture of the lower back to collect cerebrospinal fluid?

• A. Lumbar Puncture
• B. Central Line
• C. Slit Lamp Exam
• D. ET Intubation

Answer: (A)

Lumbar puncture is the ED procedure used to puncture the lower back to access the cerebrospinal fluid in the lumbar cistern. The needle is inserted between the L3-L4 or L4-L5 interspaces, well below the end of the spinal cord, to safely reach the subarachnoid space. This allows opening pressure to be measured and CSF to be collected for analysis (cell counts, protein, glucose, Gram stain, cultures, and PCR if needed), helping diagnose meningitis, subarachnoid hemorrhage, or other CNS conditions. The procedure is done with sterile technique, after local anesthesia, and patient positioning can be seated or lying on the side. Common complications include post-dural puncture headache, back pain, infection, or bleeding; in rare cases, there’s a risk of brain herniation if there’s very high ICP with a mass effect. Central line, slit lamp exam, and ET intubation serve different purposes (vascular access, eye examination, and airway management, respectively) and are not involved in CSF collection.