non invasive cardiac output monitoring (nicom)

NON INVASIVE CARDIAC OUTPUT MONITORING (NICOM)
Pierre SQUARA, Dominique DENJEAN, Philippe ESTAGNASIE, Alain BRUSSET, Jean-Claude DIB, Claude DUBOIS
Clinique Ambroise Paré. 27, boulevard Victor Hugo, 92200 Neuilly-sur-Seine, FRANCE
ABSTRACT
Our objective was to evaluate the clinical utility of the NICOM, a new tool
for automatic continuous cardiac output (CO) monitoring based on chest
bio-reactance, using continuous thermo dilution as reference (PAC-CCO).
Method. We included 110 consecutive adult patients after cardiac surgery
in a prospective, single centre study taking place the intensive care unit.
CO measurements obtained from NICOM and PAC-CCO were simultaneously recorded minute-by-minute. We evaluated the accuracy, precision,
responsiveness, and reliability of NICOM for detecting CO changes. Tolerance for each of these parameters was specified prospectively.
Results. 65888 pairs of cardiac output measurements were collected.
Mean reference values for PAC-CCO ranged from 2.79 to 9.27 L/min.
During periods of stable PAC-CCO (slope <±10%, 2SD/mean <20%), the
correlation between NICOM and PAC-CCO was R=0.82; bias was +0.16
±0.52 L/min (+4.0±11.3%), and relative error was 9.1%±7.8%. In 85% of
patients the relative error was <20%. During periods of increasing CO,
slopes were similar with the two methods in 96% of patients and intraclass
correlation was positive in 96%. Corresponding values during periods of
decreasing CO were 90% and 84%, respectively. Precision was always
better with NICOM than with PAC-CCO. During hemodynamic challenges,
changes were 3.1±3.8 min. faster with NICOM (p<0.01) and amplitude of
changes were not different (NS). Finally, sensitivity for detecting significant
directional changes was 93% and specificity was 93%.
Conclusion: CO measured by NICOM had most often acceptable
accuracy, precision, and responsiveness in a wide range of circulatory
situations.
RESULTS: Data base
• 119 consecutive ICU Patients, Age 68± 11
• 41% CB, 47% valve replacement
• 9 removed : 3 internal Pace Makers
2 early disconnections
2 major Tricuspid Regurgitation
2 major agitations
• 81540 minutes = n of comparisons
• 66060 with acceptable quality (81%), 599
min ± 341 per patient
• Cardiac Output range : 2.79 - 9.27 L/min
RESULTS: Precision = 2SD/mean
*p< 0.08, **p< 0.001
NICOM
PAC
mean ±SD
mean ±SD
Slope =
0 ± 6%
-1 ± 9%
Precision around slope 12 ± 7% * 14 ± 4%
Slope +
18 ± 13% **26 ± 14%
Precision around slope 16 ± 10% **23 ± 9%
Slope —
-18 ± 19% **-25 ± 12%
Precision around slope 16 ± 10% ** 20 ± 7%
RESULTS: Accuracy of NICOM. Min-by-min measurements during periods of stable CO: 9004 points
R = 0.64, slope = 0.71 (95%CI = 0.70-0.72)
Bias +0.06 L/min (98.6% of point inside the 2SD LOA)
10
4
8
2
6
The NICOM system
uses the changes in
chest bioimpedance
components
(frequency+ phase)
=
Chest bioreactance
0
4
nicom
-2
2
CHEST
-4
0
0
This completely original signal analysis improves the
Signal /Noise ratio by 100.
4
6
8
0
10
2
4
6
R = 0.82, slope = 0.82 (95%CI = 0.64-1.01, NS from identity line)
• Setting: Post operative period of cardiac surgery.
• Inclusion criteria: Preoperative insertion of PAC
• Exclusion criteria: none
• Design: Comparing NICOM vs. PAC-CCO each
minute of time during the entire post operative period.
METHOD: Qualitative criteria and tolerance,
prospectively specified
Bias +0.16 L/min (95% of point inside the 2SD LOA)
8
2
6
1
4
0
2
-1
0
-2
0
2
4
6
8
0
2
4
6
Tolerance
< ±20% error (bias)
var. around mean < ±20%
< 5 min
= 0, for change >±20%
PAC-CCO trend line segmentation was necessary
according to the trend line slope (example below)
RESULTS: CO challenges, one example
9.0
8.0
7.0
6.0
5.0
SWAN
NICOM
SvO2
4.0
SvO2
1.0
0.0
1
31
61
6.0
c
0,6
5.0
+ Challenge 23 patients
Δ CO (L/min)
0.8±0.5
0.9±0.6
Delay (min.)
4.0±2.2 ** 6.8±3.2
91
121
151
181
211
241
Time Point [1xMin]
0,7
7.0
NICOM
PAC
mean ±SD mean ±SD
- Challenge 18 patients
Δ CO (L/min)
-0.9 ± 0.5 -0.9 ± 0.6
Delay (min.)
3.4 ± 1.3 ** 6.7 ± 3.1
3.0
2.0
CO (L/min.)
RESULTS: CO challenges n = 46,
**p< 0.001
CO [Ltr/Min] & SvO2/10
Accuracy
Precision
Responsiveness
Directional changes
RESULTS: Reliability to detect significant changes in CO (> ±20%):
Sensitivity = 93% Specificity = 93%
CONCLUSION
0,5
4.0
60
120
180
240
300
Time Points (Min)
Blue = SvO2, red = NICOM, black = PAC-CCO.
PAC slope is first increasing (+25%), then unchanged (-2%).
Between min 235 to 250 a PEEP test was performed, resulting
in a sudden fall in CO (negative challenge), then stopped
(positive challenge). After min. 235, slopes are not represented
for better readability
8
RESULTS: Accuracy of NICOM. Averaged value during periods of stable CO: 40 Patients
DESIGN: NICOM clinical validation in ICU
Quality
2
NICOM: A totally Non Invasive Continuous Cardiac Output Monitoring for the ICU environment
NICOM: A new novel approach of Signal Analysis and Signal/Noise ratio enhancement.
The actual acceptability reaches 85-100% according to different criteria.
• Bias: <4% , <20% in 85% of cases,
• Precision: higher than PAC, NICOM outliers < PAC blanks
• Responsiveness: NICOM 4 min faster than PAC
• Sensitivity and Specificity for detecting significant changes: 93%
8

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