GE Healthcare GE DINAMAP SuperSTAT Algorithm Brochure

GE Healthcare

GE DINAMAP SuperSTAT
Algorithm

Setting Target Inflation Pressure

By: Bruce Friedman, D.Eng.

Table of Contents

Introduction 3

Target Inflation Pressure 3

Changing Default Target
Inflation Pressures 4

Adaptive Inflate 4

Summary 5

References 5

Introduction

The GE DINAMAP® SuperSTAT™ Non-Invasive Blood Pressure
(NIBP) algorithm in the CARESCAPE™ Patient Data Module,
Dash® and CARESCAPE V100 monitors incorporates
patented curve fitting [1] and cuff pressure managment [2,3]
technologies which enable the use of lower target inflation
pressures. Setting a lower target inflation pressure improves
patient comfort and safety, can reduce determination times
and improves overall NIBP performance.

An additional feature of the CARESCAPE Patient Data Module
with the GE DINAMAP SuperSTAT NIBP algorithm is the ability
to work at lower signal levels while still maintaining accuracy.
This is accomplished through the use of various measures of
signal quality, which are used to reduce the impact of noise
[4,5,6].

Target inflation pressure

The factory default target inflation pressures currently
programmed into the Solar® 8000m/i monitor with V5.0D
software are for use with the CARESCAPE Patient Data
Module containing the GE DINAMAP SuperSTAT algorithm:

Cuff Pressure
(mmHg)

Cuff
Oscillations

Time (seconds)

Figure 1a – Extrapolation of Systolic Pressure with GE
DINAMAP SuperSTAT Algorithm

Figure 1b shows a recording of an NIBP determination
made with a computerized data collection system. The
target pressure was set to 135 mmHg and the GE DINAMAP
SuperSTAT algorithm correctly obtained the patient’s blood
pressure (145/89).

180

Pt = 135 mmHg

Adult cuff pressure 135 mmHg

Pediatric cuff pressure 125 mmHg

Neonatal cuff pressure 100 mmHg

These factory default target pressures are also in
the CARESCAPE V100 and Dash monitors with the GE
DINAMAP SuperSTAT algorithm.

As described in this whitepaper, there are advantages to
lowering the target pressure from the current defaults.

One feature of the GE DINAMAP SuperSTAT algorithm
is the ability to obtain an NIBP determination when the
target pressure (P
patient’s systolic pressure (P

) is equal to, or even slightly below, the

t

). As shown in Figure 1a, this

SYS

is accomplished through the use of the curve fit algorithm in
the GE DINAMAP SuperSTAT that enables the extrapolation of
systolic pressure of up to approximately 10 mmHg beyond
the target pressure.

120

60

Cuff Pressure (mmHg)

0 6020 40

Time (seconds)

Figure 1b – Extrapolation of Systolic Pressure (BP = 145/89)

In cases where the target pressure is more than 10 mmHg
below the patient’s systolic pressure, the ability of the GE
DINAMAP SuperSTAT algorithm to manage cuff pressure
allows it to search at higher cuff pressures to obtain the
patient’s blood pressure without significantly increasing
determination time.

3

In Figure 2, the target pressure is set to 120 mmHg, which is
significantly below the systolic pressure. After five deflation
steps, the algorithm repumps to a higher pressure (P

). By

r

combining the data from the initial inflation and the repump,
the GE DINAMAP SuperSTAT algorithm is able to obtain the
determination in slightly over 40 seconds.

180

120

60

Cuff Pressure (mmHg)

0 6020 40

Pt = 120 mmHg

Time (seconds)

= 168 mmHg

P

t

Figure 2 - Repump Sequence with GE DINAMAP SuperSTAT
Algorithm (BP = 147/87)

This behavior can be contrasted with the earlier Classic
algorithm, as shown in Figure 3. With P

= 120 mmHg, the

t

Classic algorithm requires more deflation steps before
starting a repump. In addition, the repump pressure is higher
(178 mmHg) and the algorithm completes a full determination
sequence before obtaining the blood pressure (141/82) in
60 seconds. Unlike the GE DINAMAP SuperSTAT algorithm,
the Classic algorithm does not use the data from the initial
inflation sequence. The Classic algorithm in the Tram® also
requires a higher target inflation pressure (160 mmHg).

Changing default target
inflation pressures

The default target inflation pressures for adult, pediatric and
neonatal cuff types in the Solar monitor can be accessed
from the host MAIN MENU by selecting MORE MENUS >

MONITOR SETUP > MONITOR DEFAULTS > SETUP DEFAULT
DISPLAY and scrolling down the list of defaults. This will reset

the default target pressure for all subsequent admissions.
For more complete information, please refer to the Solar
monitor’s operators manual.

The target inflation pressure for an individual patient can be
changed upon admission by selecting INITIAL INFLATION
PRESSURE from the NIBP menu. This opens a popup
window, which allows selection of target pressure in 5 mmHg
increments. For adult and pediatric cuff sizes, the range
of pressures is 100 mmHg to 250 mmHg. The cuff will be
inflated to the value indicated by the INITIAL INFLATION
PRESSURE softkey only when a previous systolic value is not
known or could not be obtained. (See Adaptive Inflate.) Upon
admission of a new patient, the target pressure will revert to
the default.

Higher defaults used with acquisition products containing
the Classic algorithm should not be carried forward when
upgrading host software for use with products containing the
GE DINAMAP SuperSTAT algorithm.

For changing target inflation pressures in the Dash or
CARESCAPE V100 monitors, refer to the appropriate
operators manual.

180

P

= 120 mmHg

120

60

Cuff Pressure (mmHg)

0 6020 40

t

Time (seconds)

Pt = 178 mmHg

Figure 3 - Repump Sequence with Classic Algorithm
(BP= 141/82)

Adaptive inflate

In AUTO MODE, the target inflation pressure is determined
from the previous systolic value. In the GE DINAMAP
SuperSTAT algorithm, the adaptive inflate is 10 mmHg above
the previous systolic value. This allows the CARESCAPE
Patient Data Module to adjust the inflation pressure as the
patient’s condition changes. If the patient’s blood pressure
changes rapidly, for example, a hypertensive patient whose
blood pressure drops suddenly after intubation, returning to
the set target pressure can improve performance. This can
be accomplished by selecting CLEAR NBP READING from the
NBP menu.

4

Summary

References

The GE DINAMAP SuperSTAT algorithm is designed to work
at lower target inflation pressures. In hospital units that
frequently see hypotensive patients (systolic ≤ 100 mmHg),
NIBP performance can be optimized by reducing the Adult
default target from 135 mmHg to 110 mmHg when using the
CARESCAPE Patient Data Module or Dash monitor. The final
selection of target inflation pressure should be done with
reference to the clinical characteristics of the patients in each
hospital unit.

Higher target pressures, while appropriate for hypertensive
patients, can result in prolonged determination times and
determination timeouts in hypotensive patients.

1. Hersh L.T., Friedman B. and Medero R., “Method for
oscillometric blood pressure determination employing
curve fitting,” U.S. patent 5, 704, 362

2. Medero R., “Oscillometric blood pressure monitor with
enhanced cuff pressure control,” U.S. patent 5, 579, 776

3. Kolluri S., Hersh L.T. and Medero R., “Physiological-signal­analysis device for measuring a blood pressure and
method,” U.S. patent 6, 746, 403

4. Medero R., Hersh L.T., Kolluri S. and Friedman R., “Artifact
rejection using pulse quality values,”

U.S. patent 7, 070, 566

5. Friedman B., Hersh L.T. and Medero R., “Calculation of
quality and its use in determination of indirect noninvasive
blood pressure,” U.S. patent 6, 358, 213

6. Kolluri S., Hersh L.T. and Medero R., “Oscillometric
determination of blood pressure,” U.S. patent 6, 893, 403

5

©2009 General Electric Company – All rights reserved.
GE, GE Monogram, DINAMAP, SuperSTAT, Dash,
CARESCAPE, Solar and Tram are trademarks of
GE Healthcare.

General Electric Company reserves the right to make
changes in specification and features shown herein, or
discontinue the product described at any time without
notice or obligation. Contact your GE representative for
the most current information

GE Healthcare, a division of General Electric Company

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