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A-163
2002
The Effect of Spinal Anesthesia on Aortic Pulse Wave Velocity: A Pilot Study
Gary M. Dobson, M.D., F.R.C.P.; John V. Tyberg, M.D., Ph.D.; Mustafa Karamanoglu, Ph.D.
Anesthesiology, Peter Lougheed Centre, Calgary, Alberta, Canada
Background:

Aortic pulse wave velocity (PWV) is a measure of aortic stiffness and has been shown to be a factor in determining left ventricular afterload. The effects of various dieases and medications on global aortic PWV have been well described. Spinal anesthesia, through its vasodilatory effect, would be expected to decrease PWV. To date, no report of the effect of spinal anesthesia on PWV has been published.

Methods:

6 males scheduled for elective TUPR with no underlying cardiac disease and requiring no vasoactive medications were enrolled. Non-invasive measurements of arterial pressure waveforms were recorded using arterial tonometers. Carotid and femoral artery waveforms were recorded simultaneously, followed by carotid and radial artery waveforms. These measurements were repeated 20 minutes after administration of a standardized spinal anesthetic (isobaric bupivacaine 15 mg). PWV in the aorta and the arm were calculated from the phase shift of their respective transfer functions. Data was compared using a paired t-test.

Results:

The mean age of the patients was 63 years (S.D. = 5). The mean volume of normal saline administered prior to the spinal was 883 ml. (S.D. = 130 ml.). The median sensory level post-spinal was T9-T10 (Range T5-T12). The following table summarizes the results:

Anesthesiology 2002; 96: A163
Spinal Anesthesia and Global Aortic PWV
Mean BP (mm hg)PWV Aorta (cm/s)PWV Arm (cm/s)
Pre-Spinal (S.E.)98 (8.1)849 (53)817 (202)
Post-Spinal (S.E.)96.5 (5.3)727 (55)718 (135)
p value0.700.045*0.75
*one-tailed t-test