Lund, Sweden

Lumbar Puncture

Clarity in Emergency Medicine



  • Suspected meningoencephalitis

  • Suspected subarachnoid hemorrhage despite negative CT



Risk for cerebral herniation:

  • Altered mentation

  • Focal neurologic signs

  • Papilledema

  • Seizure within the previous week

  • Impaired cellular immunity


  • Infected skin over the needle entry site

  • Coagulopathy (e.g. anticoagulant or antiplatelet use, renal failure) is a relative contraindication


  1. Prior

Prepare the Patient

  • Inform the patient about the procedure

  • Position the patient in the lateral recumbant or sitting position with the hips, knees and chin flexed towards the chest

  • Identify the L3-L4 interspace which is at the level of the posterior superior iliac crests. Identify the L2-L3 interspace and the L4-L5 interspace. Mark the interspace which is widest.

Prepare the Equipment

  • Mentally rehearse the procedure steps and assemble the necessary equipment

  1. Procedure

Sterilize and Drape

  • Don sterile gloves

  • Clean the skin over the L2-L4 area using antiseptic solution

  • Place sterile drapes around the work area


  • Administer local anesthetic under the surface of the skin at the target site +/- anesthetize the deeper tissue

Needle Insertion

  • Insert the spinal needle, with the bevel parallel to the spine, at a slightly cephalad angle, aiming towards the umbilicus, and advance the needle approximately 3-4 cm.

  • Remove the stylet and check for fluid return; if no fluid i obstained, replace the stylet, advance a few millimeters and repeat the process until CSF is obtained.

  • Attach the manometer and note the height of the fluid column. The patient’s legs should be straightened during pressure measurement.

  • Collect cerebrospinal fluid in each of 4-5 tubes (10 drops – 1 ml in each tube)

  • Replace the stylet and remove the needle

  • Apply a sterile dressing

  1. Post

  • Cerebrospinal Fluid Analysis depending on the context:

  • Cell count and differential (first and the last tube)

  • Glucose and protein levels

  • Direct microscopy, Gram stain, bacterial cultures, PCR for HSV etc.

  • Spectrophotometry if the setting of suspected subarachnoid hemorrhage