section name header

Introduction ⬇

The CSF pressure is directly related to pressure in the jugular and vertebral veins that connect with the intracranial dural sinuses and the spinal dura. In conditions such as heart failure or obstruction of the superior vena cava, CSF pressure is increased, whereas in circulatory collapse, CSF pressure is decreased.

Pressure measurement is done to detect impairment of CSF flow or to lower the CSF pressure by removing a small volume of CSF fluid. Provided that initial pressure is not elevated and there is no marked fall in the pressure as fluid is removed, 10–20 mL of CSF may be removed without danger to the patient. Elevation of the opening CSF pressure may be the only abnormality found in patients with cryptococcal meningitis and pseudotumor cerebri. Repeated lumbar punctures are performed for ICP elevation in cryptococcal meningitis to decrease the CSF pressure.

Normal Findings ⬆ ⬇

Adult: 90–180 mm H2O (or 9–18 cm H2O) in the lateral recumbent position. (This value is position dependent and will change with a horizontal or sitting position.)

Child (younger than 8 years): 80–100 mm H2O (or 8–10 cm H2O)

Procedure ⬆ ⬇

  1. A lumbar puncture is performed (see Lumbar Puncture [Spinal Tap]).

  2. Measure the CSF pressure before any fluid is withdrawn.

  3. Obtain up to four samples of 2–3 mL each, place in separate sterile screw-top tubes, and label with the patient’s name, date and time of collection, and test(s) ordered. Label the tubes sequentially: tube 1 is used for chemistry and serology, tube 2 is used for microbiology studies, tube 3 is used for hematology cell counts, and tube 4 is used for special studies.

Clinical Implications ⬆ ⬇

  1. Increases in CSF pressure can be a significant finding in the following conditions:

    1. Intracranial tumors; abscess; lesions

    2. Meningitis (bacterial, fungal, viral, or syphilitic)

    3. Hypoosmolality as a result of hemodialysis

    4. Heart failure

    5. Superior vena cava syndrome

    6. Subarachnoid hemorrhage

    7. Cerebral edema

    8. Thrombosis of venous sinuses

    9. Conditions inhibiting CSF absorption

  2. Decreases in pressure can be a significant finding in the following conditions:

    1. Circulatory collapse

    2. Severe dehydration

    3. Hyperosmolality

    4. Leakage of spinal fluid

    5. Spinal subarachnoid block

  3. Significant variations between opening and closing CSF pressure can be found in the following conditions:

    1. Tumors or spinal blockage above the puncture site when there is a large pressure drop (no further fluid should be withdrawn)

    2. Hydrocephalus when there is a small pressure drop that is indicative of a large CSF pool

Interventions ⬆ ⬇

Pretest Patient Care

  1. Follow pretest patient care for lumbar puncture (see Lumbar Puncture [Spinal Tap]).

  2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Care

  1. Review abnormal pressure levels; report and record findings. Modify the nursing care plan as needed to prevent complications.

  2. Follow posttest patient care for lumbar puncture (see Lumbar Puncture [Spinal Tap]).

  3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Interfering Factors ⬆

Slight elevations of CSF pressure may occur in an anxious patient who holds their breath or tenses their muscles.

If the patient’s knees are flexed too firmly against the abdomen, venous compression will cause an elevation in CSF pressure.