INDWELLING URETHRAL CATHETER INSERTION484 Practical Procedures
7 Advance the needle through the skin, between the spinous processes aiming
towards the patient’s umbilicus.
(i) Stop if bone is contacted, withdraw and re-advance the needle.
(ii) Feel for increased resistance and then a ‘give’ as the needle passes
through the interspinous ligament then ligamentum flavum.
(iii) Withdraw the stylet and watch for a ‘flashback’ of CSF.
(iv) If there is none, replace the stylet and advance the needle another
few millimetres, checking for evidence of CSF return each time.
8 Once in the subarachnoid space and CSF is draining, remove the stylet fully
and attach the manometer.
(i) Measure the CSF pressure (normal opening pressure is 6–18 cm H 2 O).
9 Disconnect the manometer and catch CSF from the open end of the spinal
needle.
(i) Collect 10–20 drops into each of three specimen containers. Label
them 1, 2, and 3.
10 Send CSF to laboratory for cell count with differential, Gram stain plus
culture for bacteriology, sugar and protein content, polymerase chain
reaction (PCR) testing (meningitis/encephalitis), xanthochromia (subarach-
noid haemorrhage) and cytology (carcinoma suspected).
11 Re-insert the stylet to reduce post-LP headache risk, then slowly remove the
entire spinal needle.
(i) Place a small dressing or plaster over the puncture site.
12 Advise the patient to initially lie prone (on his or her stomach) to reduce CSF
leak by gravity.COMPLICATIONS
1 Post-LP headache (up to 20% or more).
2 Failure (may need CT or f luoroscopy guidance).
3 Bloody tap.
4 Epidura l haematoma, wit h signs of acute spina l cord compression.
5 Local skin haemorrhage, pain.
6 Infection (rare): meningitis, epidural abscess.INDWELLING URETHRAL CATHETER INSERTION
INDICATIONS
1 Continuous
(i) Acute or chronic urinary retention.