INSTRUCTIONS, WARNINGS & MANUALS
Instructions for use
Lumbar Puncture Procedure
Wearing nonsterile gloves, locate the L3-L4 interspace by palpating the right and left posterior superior iliac crests and moving the fingers medially toward the spine. Palpate that interspace (L3-L4), the interspace above (L2-L3), and the interspace below (L4-L5) to find the widest space. Mark the entry site with a thumbnail or a marker. To help open the interlaminar spaces, ask the patient to practice pushing the entry site area out toward the practitioner.
Open the spinal tray, change to sterile gloves, and prepare the equipment. Open the numbered plastic tubes, and place them upright. Assemble the stopcock on the manometer, and draw the lidocaine into the 10-mL syringe.
Use the skin swabs and antiseptic solution to clean the skin in a circular fashion, starting at the L3-L4 interspace and moving outward to include at least 1 interspace above and 1 below. Just before applying the skin swabs, warn the patient that the solution is very cold; application of an unexpectedly cold solution can be unnerving for the patient.
Place a sterile drape below the patient and a fenestrated drape on the patient. Most spinal trays contain fenestrated drapes with an adhesive tape that keeps the drape in place.
Use the 10-mL syringe to administer a local anesthetic. Raise a skin wheal using the 25-gauge needle, then switch to the longer 20-gauge needle to anesthetize the deeper tissue. Insert the needle all the way to the hub, aspirate to confirm that the needle is not in a blood vessel, and then inject a small amount as the needle is withdrawn a few centimeters. Continue this process above, below, and to the sides very slightly (using the same puncture site).
This process anesthetizes the entire immediate area so that if redirection of the spinal needle is necessary, the area will still be anesthetized. For this reason, a 10-mL syringe may be more beneficial than the usual 3-mL syringe supplied with the standard lumbar puncture kit. The 20-gauge needle can also be used as a guide for the general direction of the spinal needle. In other words, the best direction in which to aim the spinal needle can be confirmed if the 20-gauge needle encounters bone in one direction but not in another.
Next, stabilize the 20- or 22-gauge needle with the index fingers, and advance it through the skin wheal using the thumbs. Orient the bevel parallel to the longitudinal dural fibers to increase the chances that the needle will separate the fibers rather than cut them; in the lateral recumbent position, the bevel should face up, and in the sitting position, it should face to one side or the other.
Insert the needle at a slightly cephalad angle, directing it toward the umbilicus. Advance the needle slowly but smoothly. Occasionally, a characteristic “pop” is felt when the needle penetrates the dura. Otherwise, the stylet should be withdrawn after approximately 4-5 cm and observed for fluid return. If no fluid is returned, replace the stylet, advance or withdraw the needle a few millimeters, and recheck for fluid return. Continue this process until fluid is successfully returned.
For measurement of the opening pressure, the patient must be in the lateral recumbent position. After fluid is returned from the needle, attach the manometer through the stopcock, and note the height of the fluid column. The patient’s legs should be straightened during the measurement of the open pressure, or a falsely elevated pressure will be obtained.
Collect at least 10 drops of cerebrospinal fluid (CSF) in each of the plastic tubes. If possible, the CSF that is in the manometer should be used for the first tube. If the CSF flow is too slow, ask the patient to cough or bear down (as in the Valsalva maneuver), or ask an assistant to press intermittently on the patient’s abdomen to increase the flow. Alternatively, the needle can be rotated 90° so that the bevel faces cephalad.
Replace the stylet, and remove the needle. Clean off the skin preparation solution. Apply a sterile dressing, and place the patient in the supine position.
- This information is provided for qualified healthcare professionals only.