Article Figures & Data
Figures
- Fig 1.
Schematic of Valsalva device used for experiments. Participants were directed to exhale into the plastic tubing with sufficient force to hold the end of the bellows at the 40-cm H2O mark on the clear plastic cylinder. This provided a consistent and reproducible Valsalva-generated pressure.
- Fig 2.
Sagittal and coronal T2-weighted images show PBI excitation cylinder extending from above the level of the foramen magnum to the C2–3 disk level.
- Fig 3.
Cardiac cycle–dependent CSF flow before, during, and after a Valsalva maneuver in 1 participant by using fast cine-PC imaging. Flow in milliliters per second is shown as a function of time, normalized to the cardiac cycle. During Valsalva, V̄CSF and App decreased compared with resting. After Valsalva, both V̄CSF and App increased compared with during the maneuver, rebounding to values larger than resting.
- Fig 4.
Figure shows invasive pressure measurements vs time. Trace 4 shows heartbeat-by-heartbeat changes in lumbar minus ventricular pressure (craniospinal pressure differential) with Valsalva. Note the similarities between trace 4 and CSF flow waveforms (panel 2) in the On-line figure. Note further that PBI captured many dynamic CSF flow features including transients precisely synchronized with timing of Valsalva similar to that seen here. Reproduced from Williams B. Simultaneous cerebral and spinal fluid pressure recordings. I. Technique, physiology, and normal results. Acta Neurochir (Wein) 1981;58:167–85 with kind permission from Springer Science and Business Media.
Tables
- Table 1:
CSF flow displacement volume per cardiac cycle, peak-to-peak amplitude, and heart rate at rest, during, and post-Valsalva maneuver, from fast cine-PC measurements
R VAL P-VAL Comparison (P Value) R vs VAL VAL vs P-VAL R vs P-VAL Mean CSF V̄CSF (mL) per cardiac cycle 0.57 ± 0.24 0.37 ± 0.17 0.68 ± 0.19 <.001 <.001 <.05 App (mL/s) 4.51 ± 1.61 3.52 ± 1.59 5.28 ± 1.49 <.007 <.001 ≤.01 Heart rate (beats/min) 67.1 ± 10.4 78.5 ± 9.9 64.22 ± 6.6 <.002 <.001 NS NS indicates not significant; P-VAL, post-Valsalva; R, resting; VAL, Valsalva.
Note:— All values are expressed as mean ± SD.
Table 2:Effects of Valsalva maneuver on intrathoracic pressure, cardiovascular system, intracranial and spinal pressures, and CSF flow
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