NEJM - Lumbar Puncture

Summary

This video from the New England Journal of Medicine demonstrates how to perform a lumbar puncture safely. It's used for diagnostic tests like identifying meningitis or therapeutic applications like administering antibiotics. The video covers contraindications, patient positioning, needle insertion technique, and potential complications. It emphasizes the importance of proper patient assessment and informed consent.

Takeaways

• 🩺 **Lumbar Puncture Indications**: Performed for both diagnostic (e.g., meningitis, multiple sclerosis, leukemia) and therapeutic purposes (e.g., administering chemotherapeutic agents and antibiotics).
• 🚫 **Contraindications**: Should be avoided in patients with cardiorespiratory compromise, signs of cerebral herniation, increased intracranial pressure, or those receiving anticoagulant therapy.
• 💉 **Equipment Needed**: A spinal needle with a stylet, skin preparation equipment, drapes, collection tubes, and sometimes a manometer are required.
• 🧍 **Patient Positioning**: The lateral recumbent position is preferred for accurate pressure measurement and to reduce the risk of post-puncture headache.
• 🔍 **Landmark Identification**: Key landmarks include the L3-L4 or L5 interspace, which is below the termination of the spinal cord.
• 🩹 **Skin Preparation**: Involves cleaning with a disinfectant and draping the area to maintain sterility.
• 💊 **Local Anesthesia**: Essential due to the painful nature of the procedure; sedation may also be required.
• 💉 **Needle Insertion**: Insert the needle at an angle aiming towards the umbilicus to minimize leakage of cerebrospinal fluid (CSF).
• 📈 **CSF Pressure Measurement**: Performed with the patient in the lateral recumbent position using a manometer.
• 🧪 **CSF Collection**: Fluid should drip into collection tubes without applying negative pressure to avoid complications.
• 🛑 **Post-Procedure Advice**: Traditional advice to lie flat for several hours post-puncture has no evidence supporting its necessity to prevent complications.

Q & A

What are the main indications for performing a lumbar puncture?

Lumbar puncture is indicated for both diagnostic and therapeutic purposes. Diagnostically, it helps in analyzing cerebrospinal fluid to diagnose infections such as meningitis, inflammatory diseases like multiple sclerosis, cancers such as leukemia, and metabolic disorders. Therapeutically, it allows for the intrathecal administration of chemotherapeutic agents and antibiotics.

What are some contraindications for performing a lumbar puncture?

Contraindications include patients with cardio-respiratory compromise, signs of cerebral herniation, incipient herniation, increased intracranial pressure, or focal neurologic signs. In such cases, a cranial CT should be performed before a lumbar puncture. There is also an increased risk of spinal hematoma in patients with coagulopathy or those receiving anticoagulant therapy.

What types of needles are typically used in a lumbar puncture procedure?

Typically, a 20- to 22-gauge needle is used, with lengths ranging from 1.5 inches (3.8 cm) for infants, 2.5 inches (6.3 cm) for children, and 3.5 inches (8.9 cm) for adults.

What are the preferred patient positions during lumbar puncture?

The patient can be positioned in either the lateral recumbent or sitting position. The lateral recumbent position is preferred for obtaining accurate opening pressure and reducing the risk of post-puncture headache.

How do you locate the needle insertion point for lumbar puncture?

A line is drawn between the superior aspects of the iliac crest, which intersects the midline of the L4 spinous process. The needle is inserted between the L3 and L4 or L4 and L5 interspaces, which is below the termination of the spinal cord.

Why is it important to use a stylet when inserting the lumbar puncture needle?

Using a stylet prevents the introduction of a skin plug into the subarachnoid space, which could lead to complications like the formation of a subarachnoid epidermal cyst.

What should be done if the lumbar puncture needle encounters bone during insertion?

If bone is encountered, the needle should be withdrawn to the level of subcutaneous tissue without exiting the skin, and the needle should be redirected to find the subarachnoid space.

How is cerebrospinal fluid pressure measured during lumbar puncture?

Cerebrospinal fluid pressure is measured using a manometer attached to the hub of the spinal needle. The patient must be in the lateral recumbent position for accurate pressure measurement.

What are some common complications associated with lumbar puncture?

Common complications include cerebellar herniation, referred pain, headache, bleeding, infection, formation of a subarachnoid epidermal cyst, and leakage of spinal fluid. Careful patient assessment before the procedure can help avoid many of these complications.

How can complications from cerebrospinal fluid leakage be minimized after lumbar puncture?

To minimize complications from cerebrospinal fluid leakage, a smaller bore needle should be used whenever possible. If leakage persists, an anesthesiologist may be consulted to perform a blood patch to occlude the leak.