"What Constitutes the Typical Pressure Range for Cerebrospinal Fluid in Healthy People?"
Cerebrospinal Fluid Pressure and Its Measurement Methods
Normal Cerebrospinal Fluid Pressure
The normal cerebrospinal fluid (CSF) pressure for a healthy individual ranges from 80 to 180 mmH2O. Elevated intracranial pressure (ICP) can be observed in conditions such as intracranial hemorrhage, cerebral edema, cerebral hernia, traumatic brain injury, meningitis, and encephalitis. Conversely, low ICP is less common and typically seen in cases of cerebrospinal fluid aspiration or excessive dehydration. Elevated ICP is primarily a result of brain damage or disease, and its treatment should be tailored to the individual patient's underlying condition. Following cerebrospinal fluid aspiration, patients are advised to remain supine for 4 to 6 hours to minimize the risk of low ICP.
Methods for Measuring Cerebrospinal Fluid Pressure
The initial CSF pressure measurements vary according to the patient's age and position. For adults in the lateral recumbent position, the initial pressure ranges from 0.78-1.96 kPa (80-200 mmH2O), while for children, it is 0.39-0.98 kPa (40-100 mmH2O), and for newborns, it is 0.098-0.14 kPa (10-14 mmH2O). During these measurements, it is crucial to observe respiratory pulsations (0.098-0.197 kPa or 10-20 mmH2O) and pulse pulsations (0.02-0.039 kPa or 2-4 mmH2O) in the cerebrospinal fluid level. The absence of respiratory pulsations may indicate an obstruction or occipital hernia in the vertebral canal.
Jugular Vein Compression Test (Queckenstedt Test)
This test involves compressing both jugular veins to increase intracranial venous congestion and ICP. The resulting pressure rise is transmitted to the pressure manometer connected to the lumbar puncture needle. Upon releasing the compression, the fluid level rapidly decreases. In the case of a vertebral canal obstruction, the fluid level may rise and fall slowly or not rise at all. For a precise measurement, a blood pressure cuff is used, with incremental inflation up to 2.7-5.3-8 kPa (20-40-60 mmHg). The pressure is measured every 5 seconds for 30 seconds during compression and 30 seconds after relaxation, and the results are plotted on a graph. This test is contraindicated in patients with elevated ICP or suspected intracranial masses or hemorrhage.
Result Interpretation: In the absence of obstruction, the CSF pressure should rapidly rise to its peak within approximately 15 seconds after neck compression and rapidly return to the initial pressure level within 15 seconds after release. Alternatively, when compressed to 8 kPa (60 mmHg), the pressure should exceed 4.9 kPa (500 mmH2O). In cases of partial obstruction, the pressure rises and falls slowly or may not return to the initial level. In complete obstructions, there is minimal or no increase in CSF pressure measured through the needle after neck compression.
Abdominal Compression Test (Stookey Test)
This test involves pressing firmly on the patient's upper abdomen or instructing them to hold their breath, causing congestion in the inferior vena cava and epidural veins below the lower thoracic segment. This rapidly increases the CSF pressure below this level, allowing for the assessment of obstructions in the lower thoracic spinal canal, lumbosacral region, and the patency of the lumbar puncture needle and pressure manometer. A normal response is a twofold increase in pressure, which rapidly returns to the initial level after compression stops. A slow or absent pressure increase indicates a positive result, suggestive of an obstruction in the lower thoracic spinal canal.
Note: Obstructions in the lumbar puncture needle or pressure manometer can also yield a positive result, necessitating caution.
Double Needle Combined Puncture Test
This test involves performing punctures at suspected sites of obstruction within the vertebral canal, such as at the L2-3 and L5-S1 levels. By comparing the CSF pressure differences between these levels during the jugular vein compression test, a rough assessment of the presence of an obstruction between L2 and L5 can be made.
Unilateral Jugular Vein Compression Test (Tobey-Ayer Test)
This test involves compressing one jugular vein, which should
