Linear Inflation Technology Non-invasive Blood Pressure Measurement

iNIBP Case Report – Experiences in OR

C ONTENTS
Introduction……………………………………………………………………………… 2
Technological Description of iNIBP
iNIBP advantages………………………………………………………………………… 2iNIBP technology adapts to each patient situation and condition ………………… 4[Case 1] Laparoscopic assisted distal gastrectomy……………… 5[Case 2] Pelvic lymphadenectomy,
para-aortic lymphadenectomy …………………………… 6[Case 3] Laparoscopic resection of descending colon……………… 7[Case 4] Radical prostatectomy …………………………………………… 8[Case 5] Laparoscopic uterine myomectomy………………………… 9Discussion …………………………………………………………………………… 10

iNIBP Case Report – Experiences in OR

Introduction
iNIBP is Nihon Kohden's new non-invasive blood pressure measurement algorithm using linear inflation technology. Thiscase report, which describes the perioperative use of iNIBP, is designed to help clinicians and healthcare professionals
understand and appreciate the performance characteristics of iNIBP, including the advantages and limitations of themeasurement.

Technology Description of iNIBP
iNIBP advantages
Non-invasive blood pressure (NIBP) is commonly used as an importantvital sign to evaluate patients' hemodynamic status. In the traditional
oscillometric NIBP measurement using the conventional step-deflation
method, a cuff placed on the patients' limb is rapidly inflated to atarget pressure greater than systolic, and then deflates step-wise
while sensing the oscillations of the arterial wall created by pulsatileblood flow through the ar ter y. On the other hand, iNIBP inflationmethod completes the measurement while inflating a cuff. Therefore,
when compared to the conventional method, the iNIBP measurement
time is shor ter (Figure 2) and target inflation pressure is lower 1,
ma ximizing patient comfor t while preser ving the accuracy of thisimportant parameter.
The conventional step-deflation method sets the target inflation
pre s su re ba se d o n th e prev iou s systo lic b lo od pre s su re (SYS).
When the patient's blood pressure increases compared to previous
measurements, the target inflation pressure may be set to a level
which is insufficient for the measurement. In these cases, anotherinflation-deflation cycle is required, and may be repeated, increasing
both the measurement time and potential for patient discomfor t(Figure 3.a). When the patient's blood pressure has dropped since theprevious measurement, the target inflation pressure is set significantly
above the previous systolic pressure, which again leads to longer
measurement time and excessive pressure applied to the patient(Figure 3.b). With iNIBP technology from Nihon Kohden, the algorithm
ef fects a slow inf lation of a cuf f while simultaneously detecting
oscillations, then deflates the cuff as soon as SYS is determined.
The advantages of iNIBP are best demonstrated when patient's bloodpressure is varying, for example during surgery. As iNIBP inflates whilesensing blood pressure variation, it can complete the measurement ina shorter amount of time without applying excessive and unnecessarypressure to the patient.

SYSDIA

Cuff pressure
oscillation

SYS

DIA

Cuff pressure
oscillation
Figure 1

Comparison of the iNIBP inflation method to theconventional deflation method(Upper) The conventional step-deflation method: A cuff is
rapidly inflated to a target inflation pressure, and thendeflated step-wise while sensing oscillations.
(Lower) iNIBP inflation method: A cuff is slowly inflated toa lower inflation pressure while simultaneously sensing
oscillations.

250
20 sec shorteriNIBP

Deflation method

Frequency (Number)

200
150

iNIBP
13.0±2.3 sec (avg)

Deflation method32.7±13.6 sec (avg)

100
50

05

10

15

202530

35

40

45

50

5560

65

70 Measurement time(sec)

Onodera J. et al. Validation of inflationary non-invasive blood pressure monitoring in adult surgical patients. J Anesth. 2011 Feb;25(1):127-30.

Figure 2 Histogram of measurement time of iNIBP inflation method and deflation method
323 measurement data collected in 64 cases in operating room were used to compare measurement time of iNIBP inflation method
and conventional deflation method.

2Cuff300
pressure(mmHg)
250

SYS elevated to200 mmHg

iNIBP can complete the measurement in ashorter amount of time as it inflates thecuff while sensing blood pressure variationand detecting oscillations, whereas thedeflation method needs to repeat theinflation-deflation cycle when the target
inflation pressure, based on previous
systolic pressure measurements arecomparatively low.

iNIBPDeflation method

250mmHg
Pressure still too low

210mmHg

SYS

200150Pressure too low

Deflationmeasurement
completes

iNIBP

140mmHg

Measurement
completes assoon as SYS
is determined

10050

Shorter measurementtime0102030

4050

Figure 3.a. iNIBP in blood pressure elevation

9:30

10:30

11:30

12:30

60
Time (sec)

13:30

BP
200

100
SYS
DIA

Cuff
300
pressure(mmHg)
250

iNIBP

240mmHg

Measurement
completes assoon as SYS
is determined

200 Lower pressure
150130mmHg

50

Shorter measurement
time
1020Figure 3.b. iNIBP in blood pressure dropFigure 3 iNIBP in elevation and drop in blood pressure

3SYS

Deflationmeasurement
completes

1000

SYS dropped to100 mmHg

iNIBP
Deflation method

30405060
Time (sec)iNIBP inflates the cuff to only slightly
above the SYS while detecting oscillations
and completes the measurement in ashorter amount of time, in comparison
with the deflation method, which inflates acuff based on a pre-determined target
pressure that often significantly exceeds
actual SYS, leading to longer
measurement times with the increased
potential for patient discomfort.

iNIBP Case Report – Experiences in OR

iNIBP technology adapts to each patient situation and condition
iNIBP automatically switches its measurement mode to step-deflation in situations where it cannot determine an accurate
blood pressure value with inflation method because of factors related to measurement environment and patient's physiology.
Also, iNIBP automatically employs the deflation method when signal reliability of the blood pressure reading, based on theblood pressure determined while inflating, is poor (Figure 4). Examples of these situations and conditions are shown below.
When these conditions improve, iNIBP will change the mode to the inflation measurement method. Based on the analysis ofactual clinical data, about 80% of measurements in the Operating Room (OR) and 70% of measurement in the Emergency
Room (ER) were performed with the inflation measurement method2.

Factor related to measurement environment
Cuff and/or tube are not secure and stable because of body motion or contact with the cuff/tube
Cuff is either too tight or too loose
Non-recommended cuff or an older cuff with worn Velcro® is used
Improperly sized cuff for the patient
Cuff placed over thick clothing

Factor related to patient’s physiology
Frequent arrhythmia
Patient has weak pulsation due to shock or has extremely low blood pressure(SYS lower than 60 mmHg or DIA lower than 30 mmHg)
Patient has pulse waves with low amplitude (small pulse wave)
Slow pulse rate

Inflation measurement

Inflationmeasurement

ON

Deflationmeasurement

OFF

Inflate a cuff

Inflate a cuff until reachinga target cuff pressure

Detect oscillationsDeflate step-wise

Calculate SYS, DIA, and MAP

Unable tocalculate

Detect oscillations

Determine the reliability

Low reliability

Calculate SYS, DIA, and MAP

Unable tocalculate

Determine the reliability

Low reliability

Display SYS, DIA and MAP

Display SYS, DIA and MAP

Measurement
completes

Measurement
completes

No NIBPreading provided

Figure 4 Measurement flow of linear inflation technology non-invasive blood pressure measurement – iNIBP4

[Case 1] Laparoscopic assisted distal gastrectomy
Disease : Stomach cancer
Anesthesia : General anesthesia with epidural block (volatile anesthetic)
Patient : 68 years old male, height 170 cm, weight 81 kg. Cuff on left arm
Anesthesia time : 8:55 – 15:50
Surgical time : 9:37 – 15:25

9:00
Pulse
rate

BP

140

140

10:00

100

12:00

13:00

14:00

15:00

16:00

B

120
100

11:00

CA

80

PR
SYS

60

60

DIA

40
20

Deflationmeasurement

20

Inflationmeasurement

Measurement
time (sec)80
60

Anesthesia
starts40

Anesthesia
ends

20

Surgery
starts0Surgery
ends

Measurement time (sec)

Number ofmeasurement

Average

Minimum

Maximum

Inflation

1314.7

13.9

16.9

Deflation

0---In this case, a minimally-invasive procedure was performed. Blood pressure increased approximately 30 mmHg between
the second ( A ) and third ( B ) NIBP measurement, then decreased 25 mmHg between the third ( B ) and fourth ( C )measurement. In cases such as this where blood pressure varies significantly, the conventional deflation method is more
likely to repeat the inflation-deflation cycle or set the target inflation pressure too high, leading to longer measurement
times. This case shows that iNIBP successfully completed all measurements with the inflation measurement method evenin a patient with significant blood pressure variation within a short measurement time.

[Feedback from anesthesiologist]"I'm curious if NIBP will perform in patients with arrhythmia (e.g. AF, bigeminy or trigeminy). The iNIBP measurement time
appears to be shorter compared to the conventional method when used in patients with normal sinus rhythm."

5

iNIBP Case Report – Experiences in OR[Case 2] Pelvic lymphadenectomy, para-aortic lymphadenectomy
Disease : Ovary cancer
Anesthesia : General anesthesia with epidural block (volatile anesthetic)
Patient : 47 years old female, height 161 cm, weight 56 kg. Cuff on left arm
Anesthesia time : 10:55 – 17:06
Surgical time : 11:21 – 16:39

10:00
Pulse
rate

BP

140

140

11:00

12:00

13:00

14:00

15:00

16:00

17:00

E

120
100

100

B

A

C

80

DPR
SYS

60

60

DIA

40
20

Deflationmeasurement

20

Inflationmeasurement

Measurement
time (sec)80
60

Anesthesia
starts40

Anesthesia
ends

20

Surgery
starts0Surgery
ends

Measurement time (sec)

Number ofmeasurement

Average

Minimum

Maximum

Inflation

1012.2

11.0

14.2

Deflation

451.5

44.6

57.3

In the first half of the surgery (beginning of surgery until approximately 14:30), the cuff frequently detected noise caused
by touching the cuff, so the iNIBP algorithm did not determine blood pressure while inflating the cuff and switched its
measurement mode to the deflation method ( A B C and D ). As shown in this case, iNIBP automatically changes its
measurement mode depending on the situation in order to provide reliable readings.
This case also shows that iNIBP can complete the measurement with the inflation method in a shorter period of time in caseswhen the patient's blood pressure increases to 43 mmHg ( E ) , where the conventional method will require repetitive inflationdeflation cycles.

[Feedback from anesthesiologist]“The measurement time of iNIBP did not appear to be significantly shorter compared to the conventional method.”6

[Case 3] Laparoscopic resection of descending colon
Disease : Descending colon cancer
Anesthesia : General anesthesia with epidural block (volatile anesthetic)
Patient : 72 years female, height 151 cm, weight 74.5 kg. Cuff on left arm
Anesthesia time : 9:05 – 15:49
Surgical time : 10:00 – 15:03

9:00
PulserateBP

160

160

10:00

11:00

12:00

13:00

14:00

15:00

16:00

140
120

120
100
PR

80

80

SYS
DIA

60

Measurement
time (sec)40

40

Deflationmeasurement

20

Inflationmeasurement

80

Anesthesia
starts60

Anesthesia
ends

40

Surgery
starts20

Surgery
ends

0Measurement time (sec)

Number ofmeasurement

Average

Minimum

Maximum

Inflation

1314.2

10.8

29.7

Deflation

1158.649.0

80.5

The patient had low amplitude pulse wave and her blood pressure was relatively low (SYS 60-90/DIA 30-50 mmHg) during
surgery. When the amplitude of oscillations is lower than a threshold, where it cannot determine an accurate blood pressure
value with inflation mode, iNIBP determines NIBP value with the deflation measurement mode instead of the inflation mode. In
this case, the amplitude of patient's pulse wave frequently ranged about the threshold, so iNIBP provided half of the readings
with the deflation method. However, iNIBP completed the measurement in a shorter period of time with the inflation method
even when blood pressure dropped immediately after the anesthesia induction and when blood pressure elevated after theend of surgery and at awakening of the patient.

[Feedback from anesthesiologist]“It appears that the iNIBP measurement time was half the conventional NIBP measurement time.”

7

iNIBP Case Report – Experiences in OR[Case 4] Radical prostatectomy
Disease : Prostate cancer
Anesthesia : General anesthesia with epidural block (volatile anesthetic)
Patient : 65 years old male, height 168 cm, weight 68 kg. Cuff on left arm
Anesthesia time : 11:50 – 17:25
Surgical time : 12:14 – 16:52

11:00
PulserateBP140

140

12:00

13:00

14:00

15:00

16:00

17:00

120
100

100
80

PR
SYS

60

60

DIA

40
20

Deflationmeasurement

20Inflation
measurement

Measurement
time (sec)80
60

Anesthesia
starts40

Anesthesia
ends

20

Surgery
starts0Surgery
ends

Measurement time (sec)

Number ofmeasurement

Average

Minimum

Maximum

Inflation

13

13.3

12.0

16.2

Deflation

0---

In this case, all measurements throughout the surgery, from the anesthesia induction through patient awakening, wereperformed with the inflation measurement mode under the condition of varying blood pressure.

[Feedback from anesthesiologist]“I was impressed by the speed of the measurement. iNIBP can be convenient because of the shorter measurement time,
which may not be essential.”

8

[Case 5] Laparoscopic uterine myomectomy
Disease : Uterine myoma
Anesthesia : General anesthesia (volatile anesthetic)
Patient : 37 years old female, height 151 cm, weight 53 kg. Cuff on left arm
Anesthesia time : 8:38 – 12:43
Surgical time : 9:08 – 12:25

8:00
Pulserate

BP

140

140

9:00

10:00

12:00

13:00

B

120
100

11:00

A

100
80

PR
SYS

60

60

DIA

40
20

Deflationmeasurement

20Inflation
measurement

Measurement
time (sec)8060

Anesthesia
starts40

Anesthesia
ends

20

Surgery
starts0Surgery
ends

Measurement time (sec)

Number ofmeasurement

Average

Minimum

Maximum

Inflation

7

13.9

12.8

14.6

Deflation

239.4

39.2

39.6

After the start of the surgery, the deflation method was used for the third ( A ) and fourth ( B ) measurement because of noisecaused by patient's body motion. Subsequently, iNIBP completed all measurements with the inflation measurement
method throughout the surgery. This case demonstrates that iNIBP automatically switches its measurement mode to thestep-deflation method in a situation where it cannot determine an accurate blood pressure value with the inflation method
due to factors that can affect measurement.

[Feedback from anesthesiologist]“iNIBP's advantage of being able to measure while inflating allows for shorter measurement time, which can make themeasurement more comfortable for patients.”

9

iNIBP Case Report – Experiences in ORDiscussion
Nihon Kohden's Linear Inflation Technology, Non-invasive Blood Pressure Measurement,“iNIBP”, determines blood pressure bydetecting oscillations during the initial inflation of the cuff. Compared to the conventional method, iNIBP can provide accurate
blood pressure readings in less time without applying excessive pressure to the patient, leading to maximized comfort forpatients. iNIBP allows clinicians to accurately measure blood pressure immediately and when this critical vital sign is needed
the most, especially during dynamic blood pressure changes during surgery.
Nihon Kohden is hopeful that you find this report useful to understand the performance of iNIBP. Please contact us with yourideas and suggestions on how this technology might benefit you and your patients.

Reference1 Jun Onodera, Yoshifumi Kotake et al. Validation of inflationary non-invasive blood pressure monitoring in adult surgicalpatients. J Anesth, 2011;25:127-130.
2 Junichi Sasaki, Shingo Hori. Validation of inflationary non-invasive blood pressure monitoring in emergency room patients.
Poster presentation at the 34th International Symposium on Intensive Care and Emergency Medicine.

The data shown in this Case Report was provided by Department of Anesthesiology, Toho University Ohashi Medical Center.

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iNIBP Case Report – Experiences in OR

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