NIRO Data Guide Book Vol 1 Oct 2012

Contents Introduction...

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Near infrared spectroscopy...

4

Measurement parameters by NIRO...

5

MBL method...

6

SRS method...

7

Cerebral circulation and NIRO parameters...

8

Interpretation for the NIRO measurement parameters...

9

Examples of the changes of NIRO parameters... 10 The importance of ΔHb... 11 The difference between the MBL and SRS methods... 12 Examples of clinical applications 1 Changes of NIRO parameters in open heart surgeries in normal and troubled cases

Normal case of open heart surgery (without blood transfusion)... 14 Blood transfusion (priming)... 15 Spell spasm... 16 Trouble in the insertion of cannule for blood drainage... 17 Poor blood drainage during the extracorporeal circulation... 18 Blood transfusion... 19 Examples of clinical applications 2 Changes of NIRO parameters under selective perfusion of brain

Circulatory arrest... 21 Retrograded perfusion in the brain... 22 Forward perfusion in the brain... 23

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Introduction A highly functional tissue oxygenation monitor to meet a variety of needs.

series are the monitors for measuring the oxygenation inside the brain or muscle by utilizing near infrared light spectroscopy easy to be penetrated into human body. This handbook is for the purpose of explaining the way of reading clinical data measured by NIRO and simultaneously helping you understand the mechanism of near infrared spectroscopy.

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Near infrared spectroscopy Measures based on the near infrared spectroscopy Near infrared spectroscopy is an analyzing method to collect the information about body tissue or solution by the use of not-visible "near infrared light" We currently have 4 methods for the near infrared spectroscopy.

Modified beer-lambert Phase resolved spectroscopy

Time resolved spectroscopy Spatial resolved spectroscopy

d are Infr copy r a Ne ctros Spe

NIRO applies MBL and SRS methods, excellent for the practical usage, among these rules.

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Measurement parameters by NIRO We have the following 5 measurement parameters for NIRO. The degree of light absorption by Hemoglobin inside the blood changes based on the condition of Hemoglobin. NIRO uses this characteristic of Hemoglobin for the measurement of each parameter.

Measurement parameters by NIRO symbol [unit]

contents of measurement

Δ02Hb [μmol/l]

The change of the concentration for oxidized Hemoglobin The change of the concentration for de-oxydized Hemoglobin The change of concentration for total Hemoglobin The ratio of O2Hb to cHb in the tissue Relative concentration for total Hemoglobin

ΔHHb [μmol/l] ΔcHb [μmol/l] TOI [%] nTHI [a.u.]

principle of measurement

MBL method

SRS method a.u = aribitrary unit

Tissue Artery

NIRO reflects the oxygenation of all Hemoglobin in the artery, vein, and capillary vessels; mainly reflects that of capillary vessels, easy for the light to be penetrated inside. Based on this characteristics, NIRO can measure the oxygen metabolism.

vein

Capillary vessel

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MBL method Measurement principle Incident light

Incident light Oxygenated Hemoglobin (HHb)

De-oxygenated Hemoglobin (O2Hb)

Tissue

Increase of the amount of Hemoglobin

Decrease of the detected light

The method based on the changes of the amount of detected light by the concentration change Measurement parameters: ΔO2Hb

ΔHHb

ΔcHb

Characteristics Reflects even the small change of Hemoglobin In need of only 1 point for the detection, makes it possible to miniature the size of probe.

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SRS method Measurement principle Slope for the intensity of detected light

Detection probe Area under detection

Increase of the amount of Hemoglobin

The method based on the difference of intensity between the 2 detection points in different distance Measurement terms: TO I

nTHI

Characteristics Possible to measure the relative concentration, not just the changes = calculated as the value of TOI and nTHI Tend not to be affected by the blood flow in the surface layer (The changes of blood flow in the skin bring only small effect to the slope of the amount for the detected light)

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Cerebral circulation and NIRO parameters

Normal brain circulation

Oxygenated Hemoglobin De-oxygenated Hemoglobin

Brain ischemia

Brain hypoxia

In case of the decrease in artery blood flow

In case of the decrease in the oxygenated Hemoglobin inside artery

O2Hb decrease HHb increase cHb decrease

Increase of cerebral blood flow

O2Hb decrease HHb increase cHb stays constant

Vein congestion In case of the phlebemphraxis

In case of the increase for the blood flow inside brain

O2Hb increase HHb stays constant cHb increase

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O2Hb increase HHb increase cHb increase

Interpretation for the NIRO measurement parameters Starting point for measurement (t=0)

O2Hb decrease, HHb increase (t=T) * under the case of DO2Hb=DHHb

Blood and tissues except Hb

Blood and tissues except Hb

O2Hb O2Hb HHb HHb

TOI =

O2Hb [%] HHb + O2Hb

ΔO2Hb = O2Hb(T) - O2Hb(0) ΔHHb = HHb(T) - HHb(0) ΔcHb = ΔO2Hb + ΔHHb

THI = O2Hb + HHb

The amount of changes based on assigning the starting point as zero.

Screen on the NIRO

Screen on the NIRO

TO I

ΔO2HB ΔHHb ΔcHb

nTHI

The change of the concentration for Hb

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Examples of the changes of NIRO parameters Brain ischemia TO I nTHI

ΔO2HB ΔHHb ΔcHb

Brain hypoxia

Vein congestion

Increase of cerebral blood flow

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The importance of ΔHb Taking look at the changes of oxygenated and de-oxygenated hemoglobin given as sub-data for total change of oxygen saturation, will make you understand much more clearly about the tissue condition. (Example) Comparison of TOI data for forearm muscle under the artery occlusion and vein occlusion

Changes of TOI

Artery occlusion

Vein occlusion

As it seems the same change for TOI of both cases, you can realize the different explanation for each of them. Additionally taking look at the change of oxygenated and de-oxygenated hemoglobin, can make you understand much more clearly about the tissue condition.

ΔHb parameter

Artery occlusion

Vein occlusion

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The difference between the MBL and SRS methods

MBL law Explanation for the measured value

Influence of surface layer

Oxygenated Hemoglobin De-oxygenated Hemoglobin

O2Hb

Reflects also the oxygenation of the surface layer

HHb

ΔcHb

Measurement based on the amount for changes

SRS method Explanation for the measured value

Influence of surface layer

Oxygenated Hemoglobin De-oxygenated Hemoglobin

Detection at two points TOI

nTHI 1

12

Little reflect the oxygenation of the surface layer

0.88

Measurement based on the relative values

Examples of clinical applications 1 Changes of NIRO parameters in open heart surgeries in normal and troubled cases

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Normal case of open heart surgery (without blood transfusion) Case: Ventricular Septal Defect (VSD) Age: 10 months

sex: female others: finished the surgery without blood transfusion

①② ③

④

⑤

ΔcHb ΔHHb ΔO2HB TO I

Case example

1 Starting a heart-lung machine

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As the extracorporeal circulation starts, blood gets diluted and a decrease of the amount for cHb is observed.

2 Brain cooling and the aorta occlusion As the aorta occluded, blood get diluted by the cardioplegia and a decrease of the amount for cHb is observed.

3 Start warming As it gets warmed, increase of the amount for HHb is observed.

4 Release aorta occlusion As the aorta released from occlusion, distribution of blood flow changes and perfusion pressure declines, which causes TOI to decrease a little.

5 Finishing a heart-lung machine To get ready for the end of extracorporeal circulation, blood gets concentrated and a increase of cHb is observed. Even after the end of extracorporeal circulation, blood collected from the route of heart-lung machine is returned to the patient, and a increase of cHb is observed.

Blood transfusion (priming) ① ②

ΔcHb

①

②

ΔHHb ΔO2HB

ΔcHb ΔHHb ΔO2HB TO I

Priming without blood transfusion

TO I

Priming with blood transfusion

Case example

1 Starting a heart-lung machine 2 Occlusion of the aorta During the priming, blood has chance of getting diluted which can be shown as the decrease of cHb but no decrease of TOI.

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Spell spasm

② ③

ΔcHb

①

ΔHHb ΔO2HB TO I

NIRO

Case example

Collation of both data

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Metavision

・ETCO2 ・SpO2 ・BP(mean)

④

(made by Fukuda electrical Co.)

1 Decrease of O2 Hb 2 Increase of HHb 3 Almost no change of cHb Cardiac output gets no changes, but it seems as less oxidized blood circulated through the brain.

4 Condition of blood flow:

Decrease of blood flow in the lung which causes decrease of oxidation.

Trouble in the insertion of cannule for blood drainage ΔcHb ΔHHb

①

②

ΔO2HB

Case example

TO I

1 After the insertion of cannule for blood drainage into upper vena cava,

cHb and HHb increases, and TOI decreases Upper vena cava is thought to be closed by the insertion of cannule for blood drainage. Increase of cHb and HHb suggests the blood congestion inside the brain.

2 The decrease of TOI brought immediate start of extracorporeal

circulation, and as a result, cHb and HHb decrease with the increase of TOI, which is thought to improve the trouble. 17

Poor blood drainage during the extracorporeal circulation ΔcHb

① ②

ΔHHb ΔO2HB

Case example

TO I

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1 cHb, and HHb increases, and TOI decreases Condition of blood drainage gets worse for upper vena cava. Worse condition of blood drainage brought the cerebral blood congestion.

2 Improvement of blood drainage brought decrease of cHb and HHb,

which can be understood as the recovery of cerebral blood congestion.

Blood transfusion ΔcHb ΔHHb

①

②

ΔO2HB

Case example

TO I

1 Under the extracorporeal circulation without blood transfusion,

an increase of body temperature with decrease of TOI was observed. 2 cHb increases and TOI improves with the start of blood transfusion. Function of transporting oxygen to the brain seems to be improved.

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Examples of clinical applications 2 Changes of NIRO parameters under selective perfusion of brain

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