Description #
There are 2 components to knowing how to perform a procedure, cognitive and the psychomotor coordination or technical skill of performing the procedure itself
In this unit the cognitive understanding of the procedure includes: indications, contraindications, complications, steps of procedure, and technical skill will be performing the procedure itself.
Learning Objectives #
At the end of this unit, learners should be able to:
1. Know about the indication and contraindication of LP
2. perform Lumber puncture
#
Introduction #
Lumbar puncture
A lumbar puncture (colloquially known as a spinal tap) is a Diagnostic as well as therapeutic procedure that is performed in order to collect a sample of
Cerebrospinal fluid (CSF) for biochemical, microbiological and cytological
analysis, or very rarely as a treatment (“therapeutic lumbar puncture”) to relieve increased intracranial pressure.
Indications #
The most common purpose for a lumbar puncture is to collect cerebrospinal fluid in a case of suspected meningitis, since there is no other reliable tool with which meningitis, a life-threatening but highly treatable condition, could be excluded. Young infants commonly require lumbar puncture as a part of the routine workup for fever without a source, as they have a much higher risk of meningitis than older persons and do not reliably show signs of meningeal irritation (meningismus).
In any age group,
Subarachnoid hemorrhage, hydrocephalus, benign Increased Intracranial hypertension and many other diagnoses may be supported or excluded with this test.
Lumbar punctures may also be done to inject medications into the cerebrospinal fluid (intrathecally), particularly for Spinal anesthesia or chemotherapy.
It may also be used to detect the presence of malignant cells in the CSF, as in
Carcinomatous meningitis or medulloblastoma.
To summaries the indication are as follow:
Diagnostic:
· Infectious disease (e.g. Viral, bacterial or fungal meningitis or encephalitis)
· Inflammatory (e.g. GBS, MS)
· Oncologic (e.g. Leptomeningeal metastasis)
· Metabolic
Therapeutic:
· Lower body Analgesia/ Anesthesia
· Antibiotic Administration
· Interathecal chemotherapy (Lymphomas or Leukemia)
· Relieve chronically elevated ICP
Contraindications: #
Lumbar puncture should not be performed when idiopathic (unidentified cause)
Increased Intracranial pressure (ICP) is present. The exception is therapeutic use of lumbar puncture to relieve ICP. Whether or not CT brain scan should be performed prior to LP remains controversial. If the patient is over 65, has a reduced GCS, has seizure activity or focal neurological signs, consideration should be given to CT. Ophtalmoscopy for Papilledema should also be performed prior to any LP to check for raised ICP. Also, lumbar puncture should not be attempted when there is Coagulopathy, abnormal respiratory patterns, hypertension with bradycardia and deteriorating consciousness or when there are decreased levels of Platelets in the blood (less than 50 x 109/L). Lumbar puncture in cases of vertebral deformities (Scoliosis or Kyphophosis)
is also contraindicated in hands of an inexperienced physician or physician assistant.
To summaries the Contraindications are as follow:
· Cardiorespiratory compromise: The patient is placed in a position that confers a mechanical disadvantage for breathing.
· Coagulopathy: INR, PTT and platelate counts should be obtained. Bleeding diatheses should be reversed prior to procedure if possible.
· Infection: Active epidural infection or superficial cellulites.
· Increased intracranial pressure: The drop of within the dural space can precipitate uncal herniation if increased intracranial pressure already exists.
· A Ct scan of the head to rule out intracranial pathology is routinely ordered. Clinical features can be used to predict who is most likely to have an abnormal CT scan of the head.
· Age greater than 60
· Immunocompromised host
· History of central nervous system disease
· History of Seizure within one week before presentation
· Neurologic abnormalities: Altered level of consciousness, focal neurologic deficits, language abnormality, leg or arm drift.
Obtaining consent form: #
· Explain the procedure and what is being done for.
· List benefits and complication/risks (Headache (36%), infection, paresthesia, epidural bleeding/ hematoma (potential for cord/root compression), CSF leak.
· Lumbar punctures can be unpleasant for some people, due to increased sensitivity when the needle is inserted to collect the cerebrospinal fluid. Drinking plenty of fluids the night before can help relieve “spinal” headaches. Laying flat for at least 6 hours will improve flexibility and back pain, along with painkillers. The procedure can be done with thinner needles than generally used if the patient is lightweight. This is commonly used in children reviving IT chemotherapy for conditions like leukemia
Equipments: #
- Sterile drapes and cleaning sponges.
- Local anesthesia and needles.
- Spinal needle with stylet, Infants (1.5 inch/ 3.8cm), Child (2.5 inch/ 6.3 cm), and adults (3.5 inch/ 8.9 cm)
- 3 way stop cook
- Manometer to measure opening pressure
- Collecting tubes
Positioning: #
The patient can be positioned in one of the two positions based on his/her characteristics.
· Lateral recumbent position: Preferred as it allows for accurate assessment of opening pressure (OP), and decreases the risk of post puncture headache.
· Sitting position: Used for non-diagnostic taps, or difficult to perform taps where OP is not crucial.
· Instruct the patient to assume the fetal position or arch their back like a cat with the back flexed to widen the gap between the spinal processes. The lumber spine should be parallel to the table in the left lateral recumbent position.
Landmarks: #
A vertical line is drawn between the superior aspects of the Iliac crests on each side that intersects the L4 Spinous process. The needle should be inserted between L3 and L4 or L4 and L5.
Procedure:
1. After the patient is consented, appropriately positioned, the site is sterilized and draped, you can begin.
2. The anatomical landmark (L3/L4 or L4/ L5 intervertebral space at the level of iliac crest) is palpated and marked.
3. Local anesthetic is injected first at the bleb of the surface and then to the level of the dura mater.
4. The spinal needle at an angle of approximately 15 degree as if aiming the patients umbilical, is advanced slowly through the space. Either use a pencil tipped needle or ensure that the bevel of needle is cephalad and in a sagital plain in order to spread rather than cut the fibers of the Doral sac. A pop should be felt when the needle has transferred the dural sheath. If no pop is felt the stylet should be removed occasionally to see if one has reached the space.
5. When fluid starts flowing, attach monometer to the spinal needle and measure OP. OP is read when the Colum of fluid stopped rising. CSF should never be aspirated as this cause a negative pressure.
6. By using the three-way stopcock, the fluid in the manometer can be drained into the collection tubes. 1cc of fluid can be collected in each of the collection tubes.
7. After the pressure has been measured and fluid has been collected, the spinal needle can be removed, the site cleaned and bandage placed over the top of the puncture site.
8. The patient should be instructed to remain lying in the supine position for 1-2 hrs after the procedure.
Lumbar Puncture -CyberPatient