Intranasal or Oral midazolam 20 min prior to procedure
Blood clots obstructing flow?
Try corrective maneuvers
- Clinical need for lumbar puncture
- Clinically unstable patient
- Patients at risk of decreased venous return to heart from LP positioning
- Soft tissue infection over puncture site
- Anatomical issues (obesity, orthopedic issues, etc.) making LP very difficult
CSF flowing?
Insert stylet, remove needle and attempt at different site
Consider delaying LP or consulting interventional radiology for fluoroscopic guidance
Patient positioning
Lateral recumbent
- Opening pressure needs to be measured
Sitting
- May improve CSF flow in patients < 2 weeks
- May be better for patients at risk of respiratory compromise from neck flexion
- Patients in respiratory distress
Risk of increased intracranial pressure?
Potential thrombocytopenia or coagulation factor deficiency?
Able to correct obvious cause?
Consult hematologist
< 3 months?
Contraindications to topical anesthetics?
Place topical anesthetic
Need to measure opening pressure?
Patient to require sedation?
Patient to require anxiolysis?
Contraindications to nitrous oxide?
Contraindications to midazolam?
Puncture the skin and remove the stylet
Attach manometer via 3-way stopcock and read opening pressure (normal 50 -200 mmH20 in relaxed patient, 100 to 280 mm H2O with the neck and legs flexed)
Oral sucrose
Sterilize working field and puncture site with providone-iodine or chlorhexidine. Place sterile drapes around field
Bony resistance?
Withdraw needle to subcutaneous tissues, check rotation and puncture site, position patient for optimal flexion, redirect to a more cephalad angle and reintroduce into the interspinous space
Contraindications to midazolam
- History of adverse event
- Current disease process causing myocardial depression
- Patients at risk for hypoventilation
Corrective measures
- Advance slowly until you meet resistance
- Rotate needle (90 - 180 degrees)
- Pull back and redirect needle
- Remove needle and attempt with a new needle at a different site
- Remove needle and attempt a different positioning
Contraindications to topical anesthetics?
- Urgent need for IV access
- Allergy or hypersensitivity
- Wound or lack of intact skin over anatomic site
- Medication specific contraindications
- EMLA: risk for methemoglobinemia
Determine optimal patient positioning
Obtain head imaging (CT or MRI) to ensure safety to continue LP
Topical anesthetics & peak effect
- EMLA
- 60 min
- Liposomal lidocaine (ELA-max)
- 30 min
- Self heating patch (Synera)
- 20 min
Needle size
- Infant 1.5 inch (3.8 cm)
- Child 2.5 inch (6.3 cm)
- Adult 3.5 inch (8.9 cm)
Determine optimal puncture site (L3/4 or L4/5), consider using ultrasound guidance
Anesthetize skin over puncture site with 1% lidocaine
Needle angle
- Less than 12 months old: 45 degrees from perpendicular
- Greater than 12 months old: 30 degrees from perpendicular
Ensure that the spinal needle (highest gauge possible) has a stylet firmly in place. Align the spinal needle midline in the back and turn the bevel parallel to the fibers of the ligamentum flavum (upwards in the lateral decubitus - sideways for sitting)
Aim the needle cephalad toward the umbilicus and advance through spinous ligaments and dura
Collect CSF in sterile tubes (1 ml per tube) or infuse desired medication, return stylet prior to removal of needle
Contraindications to nitrous oxide
- History of adverse event
- Vomiting
- Pregnancy
- Gas within body cavities (SBO, Pneumothorax, Otitis Media, etc)
