Clinical Research
Clinical Research Papers
A New Non-Invasive Method
for Obtaining Arterial Pressure Waveforms: Assessment of Vascular
Compliance and Validation with Catheter Data
Brinton TJ, Cotter B, Brown DL, Baddour
P, Vuong A, Chio S-S, Calisi C, DeMaria AN; UCSD, La Jolla, CA.
We
evaluated a novel automated non-invasive technique (NI) developed
to record waveforms (WAVE) of actual arterial pressure (AP)
throughout the cardiac cycle. The algorithm derives pressures
every 20 msec by an oscillometric cuff WAVE pattern recognition
method. WAVE are derived assuming a T tube aorta, a straight tube
artery, and that systolic and diastolic phases of the
supra-systolic and sub-diastolic cuff waves best approximate the
respective pressures. AP by NI were compared to those from the
aorta (INV) in 26 catheterized pts. Systolic (146±3 vs 147±6)
diastolic (75±2 vs 80±5) and mean (98±2 vs 100±4) pressures
by INV and NI were similar (r=.94, .89, and .94). NI and INV WAVE
were analyzed for peak positive (+) and negative (-)
dp/dt(mmHg/sec), peak positive to negative time (sec), and the
slope of pressure decay (mmHg/sec). NI local compliance was
computed as 4Π 2r2(L+2r)/[(dp/dt)ppTpp]
where r=radius, L=cuff length, and pp=distance between peak + and
- values, and compared to INV systemic compliance (ml/mmHg).
Results (mean±SD):
| |
dp/dt |
-dp/dt |
Slope |
Tpp |
COMPLIANCE |
| NI |
600±154 |
-466±135 |
-74±24 |
0.25±.04 |
0.37±.14 |
| INV |
508±138 |
-377±89 |
-74±22 |
0.25±.04 |
1.23±44 |
| r |
0.87 |
0.68 |
0.96 |
0.85 |
0.73 |
Thus, measures of absolute pressures, their rate of change,
and vascular compliance by a new non-invasive method show a good
correlation with cath and should be of value in assessing cardiac
and vascular properties.
*Presented at the American Heart
Association 67th Scientific Sessions, 1994 (see Circulation 1994
Vol 90), No. 4, Part 2, pg. 1445).
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