Methods, apparatus and articles-of-manufacture for noninvasive measurement and monitoring of ...

82 Pages·2013·4.77 MB·English

US 20030135124A1
(19) United States
(12) Patent Application Publication (10) Pub. No.: US 2003/0135124 A1
Russell (43) Pub. Date: Jul. 17, 2003
(54) METHODS, APPARATUS AND (57) ABSTRACT
ARTICLES-OF-MANUFACTURE FOR
NONINVASIVE MEASUREMENT AND The invention relates to methods, apparatus, articles-of
MONITORING OF PERIPHERAL BLOOD manufacture, and coded data signals for measuring cardiac
FLOW, PERFUSION, CARDIAC OUTPUT output, limb blood ?oW, perfusion, blood pressure, artery
BIOPHYSIC STRESS AND elasticity, and cardiovascular deterioration and disease,
CARDIOVASCULAR CONDITION including performing these measurements on a continuous
heart beat-by-beat basis, for humans and animals. Unlike
(76) Inventor: Ted W. Russell, Madison, CT (US) empirical methods of other noninvasive blood pressure
concepts, the invention is grounded on scienti?cally appro
Correspondence Address: priate hemodynamic principles that studies have validated as
David Garrod, Ph.D., Esq. accurate, and is practical for Wide clinical use. Devices
180 Candlewood Lake Rd. N. constructed in accordance With the invention can be com
New Milford, CT 06776 (US) fortably employed for numerous applications, including
hospital monitoring, physician’s office cardiovascular dis
(21) Appl. No.: 10/222,564 ease management and drug therapy monitoring, home moni
toring, and athletic applications.
(22) Filed: Aug. 16, 2002
The invention may be implemented in a variety of single or
Related US. Application Data multi-sensor embodiments, such as: invasive pressure can
nula sensor systems; non invasive pressure transducer arrays
(60) Provisional application No. 60/313,292, ?led on Aug. and pieZo or other strain sensing materials that are placed
17, 2001. against the skin above arteries; “upstream” pulsing-sensors
(that apply single or multi-frequency vibrations that are
Publication Classi?cation measured “downstream” from the ?rst placement location);
other types of plethysmographic sensors; sonic/ultrasonic/
(51) Int. Cl? ..................................................... ..A61B 5/02 Doppler sensors; MRI blood spin magnetiZer/sensors; oXy
(52) US. Cl. .. ..... .. 600/500 gen sensors; and electrocardiographic sensors, etc.
_____________________________________ .,
Af?x cul‘fto patient‘s upper arm as in FIG. 1a.
200
Pressurizc cuff to occlude blood ?ow, while
monitoring air volume added to the cuff.
300
Monitor pressure and volume in the cuff.
400
Bleed cuff, incrementally reducing
pressure, while monitoring non~pulsatile
pressure and volume of air exhausted.
Pulses detected? N
Y
500
Phase-[ OCD Calibration
600
Servo cuff to low monitoring pressure.
700
PhaSCeIl Static Elasticity Calibration
800 l 100
Blood Pressure Monitoring
Shadow
900 \ Monitoring.
Hemodynamic Monitoring
3 Apply eumpuIedpresSure-?vw phase’.
1000 \ Cardiac Output Monitoring
and
Oxygen Perfusion Monitoring
Patent Application Publication Jul. 17, 2003 Sheet 1 0f 42 US 2003/0135124 A1
100 N
200
300
400
500
600
700
800 1 100
Shadow
900 Monitoring.
Patent Application Publication Jul. 17, 2003 Sheet 2 0f 42 US 2003/0135124 A1
Cbnvre'nti‘onalk ~ ‘
pressure buff
Non co pliant air tubin
to pres re sensors
and com uting system
Patent Application Publication Jul. 17, 2003 Sheet 3 0f 42 US 2003/0135124 A1
E6525
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EBm?EEm:.wSm S
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Patent Application Publication Jul. 17, 2003 Sheet 4 0f 42 US 2003/0135124 A1
‘‘ntetnlrasma nd
mWwhCmmmmah a CYcudeif0 hs mm.0am2bao?am p
am4p.wD.nC.?l lm.
dha_Pimw ,umeen l‘fu.m?lw $ewmWmbD mw1..s,n (H rt 651 6S 0h mnmmmin0.Wmvu5 r& M
mwSMmhem3dn ? C 6%Sd ne?DuEa.fO Cs mur rCisomt8L u.% 1.D:.g 0Ihi:D. b.. :MPm m0nummcP 6e r d0lm murm0rd ? sekPmC0rE 3 a1 .. 11m5 m8..l[lmOn ySU. uW|X t . uY.ly. m.ole d gb0e ui D . wmsalv(dv?tdc l,rlu Coo h HwaHmay“mog na m0 dmw ? nppg em6pCnmr rmd l Idd mOQ mrs6C?M. Vm 19vC5 .6 tg0an0enl
VmaaCteu eSt ..nC 1 g.ln.t . u1Da€€ D.S». r)t‘Z n F
nu/Or\a(
.mh/m mm
Dpie STIm.dlS t ee . lC.l
eprte
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e
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as
10
cuff), relative to pre-determined engineering lookup table data.
Organize the pressure samples into waveforms, such
that each waveform contains a plurality of samples
representing a single heart-beat cycle.
Detect and store the maximum (peak) and minimum
(trough) pressures during each waveform.
For each heartbeat i, determine a volume displacement
amplitude (vda) from the peak and trough pressures
during the cycle. the temperature of air in the cuff, and
the 2-second moving average of p(t) pressure and cv(t)
volume during (and preceding) the cycle, as follows:
1
vda, : p sec, ' CVQseC, ' [pm 7M
a1
continued on FIG. 3
Patent Application Publication Jul. 17, 2003 Sheet 5 of 42 US 2003/0135124 A1
continued from FIG. 2
l
508
Form a vda envelope (i. e., a plot of vda vs. cuff pressure shown f
in FIG. 21) with vda samples collected during cuff de?ation.
i
Using the vda envelope, determine a calibration-pass f 509
mean arterial pressure (MAPCaI) as the cuff pressure
at which the maximum vda occurs.
Using the vda envelope. determine calibration-pass systolic, Sm‘, f 510
and diastolic, Deal, pressures from the cuff pressure(s) at which the
vda envelope transgresses preselected fraction(s) of its peak value.
i i
l 500,
As shown in FIG. 22 by evaluating successive peak-to-peak slopes, / 511 1
cont.
determine an initial-?ow cuff pressure. F , by determining the point at
which blood begins to flow through the previously-occluded artery.
7
Using the vda envelope. determine a zero-stress cuff pressure, C, by 512
determining the point at which the vda envelope ?rst exhibits a /
substantial decrease in slope with decreasing cuff pressure, and a
zero-stress amplitude, vdazs, as the vda at Zero-stress cuff pressure.
513
Determine relative wall thickness, ;1/,, , using: /
V
Determine the ratio of the unoccluded radius, R“, to the
partially occluded, Zero-stress radius, l'pz, using the formula‘
- 514
it (Fe or“ $275,‘ f
u * I'p: where M, e x ‘A:
Where AZ is a pre-computed conversion factor from FIG 23.
Patent Application Publication Jul. 17, 2003 Sheet 6 0f 42 US 2003/0135124 A1
I
Phase-II Calibration II
I
l
I
I
I
l
At the end of an initial 2-4 beat sequence at monitoring I
I
I
pressure, average cuff pressure ACPcal and cuff volume 701 I
|
I
CVcal are determined when the cuff and transducer f l
I
I
system are isolated from atmospheric, and K is computed I
I
I
as: lI
K: AC'DCAL ' CVCAL I
I
I
I
I
l
l
‘ I
I
I
Artery volumetric displacement samples are computed using I
I
l
measured pressure transducer samples p(t) (individual l
I
waveform sampling starts after identifying trough vda of prior lI
I
beat, proceeding to the next waveform trough) such that: f 702 II
I
l
I
l
I
l
where the discrete-time waveform, vdal(t), is valid for II
I
sampled values (e.g., [ = ), SR represents the lI
l
system sampling rate, and p(t) represents the real-time cuff I
I
|
pressure during the i‘h beat cycle. l
l
l
l
I
i
From sample-by-sample volume displacement data,
calculate the displacement amplitude of the waveform 703
vda(t), for each of the i heart beat cycles during a f
preselected Phase-ll period of six beats, using the formula:
vda,:K -T,
l
After the initial six Phase-ll i waveforms in a initial
monitoring period, calculate an average external
radius, Ra‘, using the formula:
f 704
R” : (’ Vml (acpl - ACRnI) + R]?
' ZIZ'LL acp,
where acpl represents the average cuff pressure
during the ill] beat cycle.
l
. continued on FIG. 5 . 4
Patent Application Publication Jul. 17, 2003 Sheet 7 0f 42 US 2003/0135124 A1
continued from FIG. 4
l
I
Calculate a beat-by-beat radial displacement
ampli. tude Al, for each of preselected i beat cycles f 70S
of Phase-ll cal, using:
vda‘ l
A = x
l
Mean radial displacement is computed from the contour-area 706
weighted average of the sampled radial displacement waveform f
I area, using :
I HR 60 SR/HR
Amiga”, : 60 SR 0
E V
707
Calculate an average radial displacement, A a! , and mean radial / 700,
displacement, _\ an“ , for the waveforms of Cthe preselected period. cont.
we
7
Compute OCD calibration pulse pressure, Fm, , f 708 a
in accordance with the following formula: 5
pm, 2 S — D5,,
l
Calculate a static Young’s elasticity, Ey, over the preselected
period, in accordance with the formula:
y - _
Am! " AA_ca/ y"
/ 709
where the pressure-?ow phase lag correction factor, AA (0,,
is estimated as: , x , _
,/_I_\ \ my - 2 ' :5 Vt",
which becomes I A‘b during ?ow monitoring, as
Computed with process 926, and depicted in FIG. 24.
|
|
l
| (NOTE: all E moduli units are in dynes/cm2 x 106)
|
|
l
Il &
l
I
|I continued on FIG. 6
|
l
Patent Application Publication Jul. 17, 2003 Sheet 8 0f 42 US 2003/0135124 A1
(pa
WPm
Cb
,S6
r t e
16 .]. myFwlr 7 H
m200 .
maEEEm wwwm11. Mm5fw _m W eP yo 0 A .A5 M m%a 5m S a_ .u_c ww0 00fgmm ) ) m0pw bM O5O/8 5k m+sCD OFFL Wmb<PyP) . |wi6 8 .0mmmm .gm m
cAa‘ma,m . a:ia3 d: ? Or.l8£l _D1_00:. 1 lWmmW2 AAm, adwam 2pmH>ma.7 p 00 Wcmmm
A24
0M
7 0 O,
Using the 0p value determined above, increase or decrease the
Ora shift factor (in the approximate equations below) until the
curve crosses the intersection of PAcal and R“. (see FIG. 26)
0 .713, A 21450 Q
’ ?o_r PAcal > 200 mmHg / 712
195
For 60 < PAcal s 200 mmHg
PA‘ ,4 r i 601805 4 - [939 "Fr 3M5“? n For PACa, 5 60 mmHg
Final Curve Tilt (“PCT”) Factors: Calculate and apply, if
necessary, FCT factors to adjust the above-noted elasticity
referencing relationship from pressures of Du, to Seal.
Patent Application Publication Jul. 17, 2003 Sheet 9 of 42 US 2003/0135124 A1
Continuous Blood Pressure Monitoring
Continue real-time sampling of cuff pressure, p(t), pursuant to /
obtaining volumetric displacement waveform samples, vda(t)
for heart beat cycle i, with:
vdat'f) = K/pm
heart beat cycle i, using the formula:
VdHIIK'
Calculate an average external radius, R , for each beat
cycle i, in accordance with the formulaz‘
CI/r'nl (acpl — ACPrnI)
2/z'LUacp,
where acpI is average cuffpressure during the i‘“ heart beat.
i
Calculate relative wall thickness that corresponds to
radius for heart
2
beat1,us1ng ,V a. _— 1_'\/1'/.!. 1(2"/a, n)Rn2 ,R a
Calculate radial displacement waveform
amplitudes for each heart
vda
beat i_ with the formula:
A, : R '
continued on FIG. 8