Lumbar Puncture

Consent: Prior to performing the procedure, consent must be obtained from either the patient or a surrogate decision maker, and the proper consent form must be signed. Review the procedure, potential benefits, potential risks, and complications.

Position: Raise the patient’s bed to an appropriate height to avoid hunching over during the procedure. Put the bed rail down at the side from which you will be performing the procedure. The patient should be lying in a lateral recumbent position with their spine flexed in a fetal position to widen the gap between the spinous processes. The lateral recumbent position is preferred and is the only position you can obtain an accurate opening pressure. If unable to lie flat, you can also position the patient upright sitting at the edge of the bed with their spine flexed. The patient may hold a pillow to aid in spinal flexion.

Landmarks: There are two techniques used to find an appropriate site for puncture

1. Classic Intercristal Line technique - The top of the posterior iliac crests align at the level of L4. Palpate the superior border of the posterior iliac crest and slide your hands medially towards the L4 spinous process. You will insert your needle either above or below the L4 spinous process either between L3-L4 or L4-L5.

2. SAIL (Sacral anatomical interspace landmark) technique - Palpate the top of the sacrum and move up to 2 interspaces towards the patients head which will bring you to L4-L5

Mark: Mark the site of the palpated interspinous space using a 5 cc syringe by using pressure against the blunt end of the syringe to the skin. Draw back on the syringe, hold for a few seconds, and then remove. Once the site is marked, re-confirm the position through palpation.

Gown Up: Wash your hands. Place your bouffant cap on. Put on your sterile gown and then gloves (see sterile approach tab for more detailed information).

Sterilize: Open the chloraprep antiseptic swabstick included in the lumbar puncture kit. Sterilize the insertion site you located previously starting at the insertion site and moving outwards in a circular manner for at least 2 min. Allow it to completely dry before starting the procedure.

Drape: The drape is included within the lumbar kit. Remove the sticker lining. Align the opening of the drape at the cannulation site and stick the drape onto the site.

Time Out: Physician and RN will perform time out together in front of the patient. You will confirm the 3 P’s - proper patient, procedure, and location. Review allergies and confirm that informed consent was obtained.

Anesthetize: Patient’s may need IV sedation in addition to local anesthetics prior to the procedure if the patient is altered and agitated, as it is dangerous for the patient to move during the procedure. You will also locally anesthetize the site using lidocaine. Open the lidocaine, swab the top of the vial with an alcohol pad, and attach the blunt needle to the syringe. The blunt needle allows you to draw the lidocaine into the syringe as it has a bigger diameter, however, you cannot inject the patient using this needle. Once lidocaine is drawn into the syringe, change the blunt needle tip to the 22 or 25 gauge anesthetizing needle. Create a wheal at the site of insertion, however, aspirate prior to pushing lidocaine to ensure you are not in a vessel. Once a wheal is created, you will anesthetize deeper along the tract of needle insertion. Insert your needle vertically into the insertion site, aspirate to ensure no blood return, push medication, advance needle and repeat (Advance, Aspirate, Push Medication). Withdraw the needle.

Insertion: Palpate the interspinous space (between the two spinous processes L3-L4 or L4-L5). Ensure the bevel of the needle is pointing towards the head of the patient. You will insert the needle right above the superior border of the bottom spinous process, at a 15 degree angle pointing upward, as if you are aiming for the patient’s umbilicus. As the needle passes through the ligamentum flavum, you will feel a popping sensation. At this point, withdraw the stylet to assess for CSF flow. If without flow, return the stylet within the needle, advance the needle 2 mm, and withdraw the stylet again to assess for flow. Repeat this in 2 mm increments until you see flow. CSF will flow once you enter the subarachnoid space. Tip: If you encounter bone, withdraw the needle to the subcutaneous without exiting the skin and redirect the needle. If the tap is traumatic, the CSF may be blood tinged, but should clear as additional CSF is collected.

Opening pressure: You can also assess the opening pressure in patients in the lateral recumbent position. Remove the stylet. Attach the 3 way stop cock to the hub of th needle. Attach the manometer to the second port of the 3 way stop cock. Turn the stop cock away from the patient so that the manometer fills with fluid. Measure the pressure after the column of fluid stops rising. Note: It is normal to see pulsations from cardiorespiratory motion. If the opening pressure is > 25 mmHg, assess for etiology if increased intracranial pressure and monitor patient closely post procedure as high risk for herniation

Collection: Use the vials in the lumbar puncture kit to collect samples. Keep track of the order of vial collection and label them post procedure from vial #1 to vial#4. If you are using the manometer, collect fluid after measuring the opening pressure. Then, turn the stop cock towards the patient, and allow the fluid to drain into the collection tubes from the manometer. If you are not using the manometer, once you remove the stylet, let the CSF drip into the collection tubes and collect 3-4 cc per vial as you want to limit the amount of fluid collected to the smallest volume necessary. If cytology is indicated, fill up the cytology vial.

Remove needle: Replace the stylet and then remove the needle.

Dressing: Apply pressure against the site with gauze, and then apply a bandaid.