LUMBAR PUNCTURE

LUMBAR PUNCTURE – Purpose, Indications, Contraindications, General Instructions, CSF Analysis, Preliminary Assessment, Preparation of the Patient and Environment, Equipment, Procedure, Post-Procedure Care and Complications

Lumbar puncture is the insertion of a needle into the subarachnoid space of the spinal canal to withdraw cerebrospinal fluid.

Lumbar puncture or spinal tap or spinal puncture is the insertion of a needle into the lumbar region of the spine for removal of cerebrospinal fluid.

Lumbar puncture is an aspiration of cerebrospinal fluid (CSF) from the subarachnoid space (lumbar cistern) by puncturing the space between the spinous process of L3/L4 or L4/L5.

PURPOSE

• To test the pressure of CSF
• To relieve pressure by removing CSF
• To remove fluids such as CSF, blood, pus, etc. containing in the subarachnoid space, thereby reduce the intracranial pressure
• To remove a sample of CSF for laboratory examination in order to diagnose disease
• To inject a spinal anesthetic, dye or air into the spinal cord
• To detect spinal subarachnoid block
• To introduce medication into the spinal fluid in treating neurological illness, e.g. meningitis

INDICATIONS

• Diagnostic: to obtain pressure, suspected intracranial infections, suspected subarachnoid hemorrhage, peripheral none diseases (Guillain-Barre Syndrome) and peripheral vascular diseases
• Therapeutic: intrathecal drug administration – Inj. Hydrocortisone 50-100 mg in spinal arachnoiditis, tuberculosis meningitis to prevent late fibrotic strictures. Inj. Crystalline penicillin in pyogenic meningitis. Inj. Methotrexate in acute lymphatic leukemic (NS) prophylaxis
• Anesthetic: Inj. Lignocaine 50 mg and inj. Bupivacaine 1% in spinal anesthesia.
• Radiological: to do a myelogram/myelography/myodil dye injection

CONTRAINDICATIONS

• Gross spinal tension with obvious neurological damage because of danger of complete transverse lesion
• Sepsis in skin at or near the proposed puncture site or osteomyelitis
• Papilledema or other signs of raised intracranial pressure or focal neurological signs, until intracranial mass is ruled out
• Bleeding diathesis or anticoagulant therapy

GENERAL INSTRUCTIONS

• Site used for lumbar puncture is between third and fourth or between fourth and fifth lumbar vertebrae in adults and still lower in children
• Strict aseptic techniques are to be followed. Since any infection introduced into the spinal cavity would be fatal for the patient
• The position used is side-lying position with the knees drawn to the chin or a sitting position with the head and neck flexed is maintained during the procedure
• The patient should be placed near the edge of the bed or table for the convenience of the doctor
• The lumbar puncture needles should be sharp, small in size and not curved
• The pressure reading of the CSF is taken with the patient is relaxed and the fluid level remains fairly constant in the manometer
• The flow of CSF varies in different conditions, when the intracranial pressure is high, the fluid may spurt out in jets, when the tension is low as in case of dehydration
• The patient’s vital sign should be checked frequently during and after the procedure to detect the early signs of complications
• Drug to be injected must be warmed to body temperature and it should be injected very slowly
• The amount of CSF withdrawn is equal to the volume of fluid to be introduced or is sufficient for the laboratory investigations planned
• If a ‘Queckenstedt’s test’ is to be carried out during the procedure. The nurse is asked to compress the jugular vein first on one side, then on the other side and finally on both sides at the same time.
• When the ‘Queckenstedt’s test’ is normal, there is a sharp rise in the pressure followed by a full as the compression is released. If the test is negative, one must conclude, that a block exists between the ventricles of the brain and the spinal canal which might be caused by spinal tumor, dislocation or fracture of the vertebrae, etc
• Queckenstedt’s test is control indicated in the presence of intracranial diseases particularly in the presence of intracranial pressure and intracranial hemorrhage
• At the end of the procedure, the puncture site is sealed to prevent leakage of fluid from the spinal cavity and infection, entering into the spinal cavity
• After the lumbar puncture, the patient should lie flat on the bed

CSF ANALYSIS

CSF analysis is done to detect the followings:

• Physical findings: color and appearance – normally, the CSF is crystal clear. Turbulence indicate infection, blood indicates hemorrhage
• Cell count: normally there is no RBC found in CSF. Presence of RBC indicates hemorrhage in the CNS. Increased number of WBC indicates infection somewhere in the CNS
• Sugar count: bacterial infections, such as tuberculosis meningitis often lower the sugar content from the normal level of 40-60 mg per 100 ml
• Chloride level: bacterial infection also reduces the chloride level from the normal 720-750 mg per 100 ml
• Protein level: in the presence of degenerative diseases and brain tumors, the protein content is increased from the normal level of 30-50 mg per 100 ml
• Serological test: serological test for syphilis may be positive in the CSF even when the blood serology is negative

PRELIMINARY ASSESSMENT

• The doctor’s order for specific instructions
• General condition and diagnosis of the patient
• Self-care ability of the patient
• Mental status to follow directions or instructions
• Specimen bottles available to collect sample
• Equipment available in the unit

PREPARATION OF THE PATIENT AND ENVIRONMENT

• Explain the sequences of the procedure
• Provide privacy
• Warn the patient that any movement
• Monitor the vital signs before the procedure starts
• Prepare the skin as for as a surgical procedure
• Arrange the articles that are necessary for lumbar puncture at the bedside
• Protect the bed with Mackintosh and towel
• The nurse should stand near the patient throughout the procedure observing the general condition and helping him to maintain the desired position
• Provide a stool for the doctor to sit comfortably during the procedure

EQUIPMENT

An unsterile tray containing:

• Mackintosh drapes and towel
• Cleaning articles, tincture, iodine, spirit
• Local anesthetic 2% Xylocaine
• Tincture benzoin
• Mask apron
• Kidney tray or plastic bag
• Manometers, specimen container, laboratory requisition forms

A sterile tray containing:

• LP needles – 2 sizes with their stilette
• Sponge holding forceps
• Syringe (5ml) with needles to give local anesthesia
• Small bowl to take cleaning lotion
• Specimen bottles
• Cotton balls, gauze pieces and cotton pads
• Gloves, gown and masks
• Dressing towels or slit
• The 3-way adapter, manometer, and tubing to measure the pressure of CSF

PROCEDURE

Positioning —- landmark LP site —- marking LP site —- tray opening and set-up —- prep and drape —- cutaneous anesthesia —- deep anesthesia —- lumbar puncture —– attach manometer and obtain opening pressure —– collect CSF —- finishing up

• Position patient on left side with pillow under head and between legs
• Make the patient to lie on firm surface with spine parallel to edge of bed
• Place the patient in fetal position to that chin touches knee and assist patient to maintain this posture throughout procedure
• Cover the patient with top sheet and expose back
• Wash hands thoroughly
• Provide sterile gloves to doctor
• Open a LP set and assists in preparing site
• Open 5 ml, Ro 2 ml syringe, 20 or 22 G needles and place one by one into sterile tray
• After showing label to doctor, clean top of local anesthetic bottle and assist to withdraw medication
• Specimen is collected in respective container and pressure reading is obtained
• After collecting specimens, needle is withdrawn. Assist physician to seal site with tincture swab

POST-PROCEDURE CARE

• Instruct patient to lie in supine position for 6 – 24 hours
• Maintain every half hourly pulse and respiration for 4 to 5 hours till stable
• Encourage liberal fluid intake
• Label specimens and send to lab with investigation slip
• Wash hands
• Replace the articles after cleaning
• Record the procedure in the nurse’s record sheet
• Observe for any complication
• Check the puncture site frequently for CSF leak

COMPLICATIONS

• Injury to the spinal cord and spinal nerves
• Infection introduced into  the spinal cavity which may rise to meningitis
• Leakage of CSF through the puncture site and lowering the intracranial pressure and cause post puncture headaches
• Damage to intervertebral discs
• Pain radiating to the things due to tumor of the spinal nerves
• Herniation of the brain structures into the foramen magnum due to sudden reduction in the intracranial pressure (transtentorial herniation)
• Temperature elevation
• Local pain, edema, and hematoma at the puncture site
• Sixth cranial nerve palsy caused by removal of large volume of CSF with traction on the sixth nerve