Background
Methods
Model derivation
Local pressure–volume relationships
Parameter | Symbol | Value | Unit | Reference |
---|---|---|---|---|
Elastance |
\(E\)
| 0.23 | mL−1
| |
Exponential parameter |
\(p_{1}\)
| 4 | mmHg | [16]* |
Offset pressure |
\(p_{0}\)
| 3.2 | mmHg | [16]* |
Rate of CSF formation |
\(Q_{form}\)
| 0.35 | mL/min | [13] |
Total CSF outflow resistance |
\(R_{abs}^{tot}\)
| 20.6 | mmHg/(mL/min) | |
Relative spinal compliance |
\(k_{V}\)
| 0.35 | – | [17] |
Spinal venous pressure |
\(p_{v}^{s}\)
| 5.3 | mmHg | [4] |
Distance between spinal and cranial reference points |
\(l_{sc}\)
| 33.8 | cm | [4] |
Distance between jugular veins and cranial reference point |
\(l_{jug}\)
| 11.0 | cm | [4] |
Density of CSF |
\(\rho_{CSF}\)
| 1000 | kg/m3
| |
Density of blood |
\(\rho_{blood}\)
| 1060 | kg/m3
| |
Gravitational acceleration |
\(g\)
| 9.81 | m/s2
| |
Relative spinal outflow conduction |
\(k_{R}\)
| n/a#
| – |
Hydrostatic pressure gradients
Compliance
CSF formation and absorption
Model parameters
Sensitivity analysis
Cranial arterial volume
Evaluation
Sitting up
Upright equilibrium
Simulation of craniospinal flow rates
Results
Pressure–volume relationships
Compliance
Posture change
Posture condition | Horizontal | Upright | |
---|---|---|---|
– | Eq. 18
| Eq. 19
| |
\(p_{CSF}^{c}\) (mmHg) | 12.5 | −3.3 | −2.5 |
\(\Delta V^{tot}\) (mL) | 0.0 | 0 | 1.0 |
\(\Delta V^{c}\) (mL) | 0.0 | −1.8 | −0.9 |
\(\Delta V^{s}\) (mL) | 0.0 | 1.8 | 1.9 |
\(C^{tot}\) (mL/mmHg) | 1.1 | 1.5 | 1.1 |
\(C^{s} /C^{tot}\) (%) | 35 | 8 | 10 |
\(1 - (C^{s} /C^{tot} )/ k_{V}\) (%) | 0 | 77 | 71 |