How to avoid
“Scary Movies” during the
night shift …
Practical Aspects for the Clinical use of PulmoVista 500
Table of contents
1 The electrode belt ─ Size selection and application
2 Positioning the electrode belt
3 System setup ─ Filter settings
4 Defining the Regions of Interest
5 Effect of alternating pressure air mattresses on EELI
Practical aspects for the clinical use of PulmoVista 500 2 | 41
1. The electrode belt ─ Size selection and application
Practical aspects for the clinical use of PulmoVista 500 3 | 41
Lift the patient
Roll the patient
2. How to apply?
Use the measuring tape
Measure from mid axilla to mid axilla
In the transition zones go for the bigger
belt size
1. Which belt size?
Practical aspects for the clinical use of PulmoVista 500 4 | 41
- Firstly, put the bed to a 45° - 80° position
- Lift the patient’s head and put the mid
position of the belt to the cervical spine
- Then, lift the upper body a bit to move
the belt downwards to ICS 5
- Ensure, that the mid position is located
on the spine
- Close the belt
How to apply? Procedure 1
1. The electrode belt ─ Size selection and application
Practical aspects for the clinical use of PulmoVista 500 5 | 41
- Lift the upper part of the patient with two
persons
- Pass the belt under the patient
- Ensure, that the mid position is located
on the spine
- Close the belt
How to apply? Procedure 2
1. The electrode belt ─ Size selection and application
Practical aspects for the clinical use of PulmoVista 500 6 | 41
- Turn the patient onto his side
- Put one half of the belt into proper
position (i.e., where the belt is supposed
to be located on the patient)
- Put the other half cranial into a central
position
- Roll the patient on the other side
- Grab the half in central position and
arrange the belt accordingly
- Turn the patient back into supine position
and close the belt
How to apply? Procedure 3
1. The electrode belt ─ Size selection and application
1. The electrode belt ─ Size selection and application
Practical aspects for the clinical use of PulmoVista 500 7 | 41
Skin develops humidity and generates good
skin ─ electrode contact typically over the
first 5 minutes
Use water or ECG gel to establish a proper
contact right away
How to generate good skin-electrode contact ?
Perfect closing position would be closure
position no. 3
Do not close the belt too tight - just tight
enough to establish a sufficient contact
between the electrodes and the skin
Regularly observe skin condition
How tight?
1. The electrode belt ─ Size selection and application
8 | 41
Place it ideally on the upper abdomen
ECG electrodes from different manufacturers
work better or worse ─ check the contact on
the Signal check page
If contact is insufficient, put electrode gel or
water on the center of the contact
5. Where to place the reference electrode?
Practical aspects for the clinical use of PulmoVista 500
1. The electrode belt ─ Size selection and application
Typical pattern of initial electrode resistance (without ECG gel)
9 | 41
Practical aspects for the clinical use of PulmoVista 500
1. The electrode belt ─ Size selection and application
Typical pattern of electrode resistance after five minutes
10 | 41
Practical aspects for the clinical use of PulmoVista 500
1. The electrode belt ─ Size selection and application
Steady state electrode resistance after ten minutes
11 | 41
Practical aspects for the clinical use of PulmoVista 500
Practical example 1 – Live measurement
12 | 41 Practical aspects for the clinical use of PulmoVista 500
1. Select proper belt size
2. Attach the belt to the volunteer leaning on the backrest
3. Attach the ECG reference electrode
4. Check the electrode resistance
According to the Instructions for Use: ICS 4–6 (mid-clavicular line)
2. Positioning the electrode belt
13 | 41
3D EIT ─ AP projection
L
Apical part of the lung
cannot be captured by EIT
ICS 4
ICS 6
Practical aspects for the clinical use of PulmoVista 500
In contrast to CT scan, EIT captures a lense-
shaped volume
2. Positioning the electrode belt
14 | 41
which represents a large part of the chest
whose impedance changes contribute to
the generation of EIT images
Practical aspects for the clinical use of PulmoVista 500
Why is relevant to have the electrode belt
placed in the right position?
15 | 41
If the belt is placed very high (directly under the armpits):
The mediastinum might not be located within the
electrode plane
You might not be able to clearly distinguish between left
and right lung
Basal lung regions mostly affected by recruitment/
de-recruitment might not be located within the electrode
plane
If the belt is placed “too low” (in a male, about 2 cm, or
more below the nipples, and in some females, below the
breasts):
Tidal images might display a mixture of diaphragmatic
movement and ventilation (making it impossible to
interpret the images)
During PEEP changes, the effects caused by diaphrag-
matic movement are getting stronger at lower PEEP
levels, making it hard to compare different PEEP levels
with the trend pages
Practical aspects for the clinical use of PulmoVista 500
Anatomy is not familiar with “standards” …
16 | 41
ICS 6
Practical aspects for the clinical use of PulmoVista 500
2. Positioning the electrode belt
17 | 41
When positioning the belt, consider conditions
that may cause an elevated diaphragmatic
position:
Obesity
Intubated patients with low PEEP settings
Diaphragmatic paralysis (e.g., in sedated
patients)
Abdominal sepsis (high IAP)
Other conditions causing expansion of the
abdomen (e.g. tumor)
In such cases, it is recommended to place the belt at ICS 5 rather than ICS 6.
In female patients, put the belt on the breast rather than directly under the breast.
Practical aspects for the clinical use of PulmoVista 500
TV/VT ratio: 5.37 Pos. 10: ICS 4 TV 3785; VT 705
2. Positioning the electrode belt
Effect of belt position on Tidal images: ICS 4
18 | 41 Practical aspects for the clinical use of PulmoVista 500
TV/VT ratio: 5.45 Pos. 11: ICS 5 TV 3625; VT 665
2. Positioning the electrode belt
Effect of belt position on Tidal images: ICS 5
19 | 41 Practical aspects for the clinical use of PulmoVista 500
TV/VT ratio: 3.19 Pos. 12: ICS 6 TV 2285; VT 716
2. Positioning the electrode belt
Effect of belt position on Tidal images: ICS 6
20 | 41 Practical aspects for the clinical use of PulmoVista 500
TV/VT ratio: 2.19
2. Positioning the electrode belt
Effect of diaphragmatic position on Tidal images
21 | 41
Diaphragmatic position TV 1642; VT 750
Practical aspects for the clinical use of PulmoVista 500
TV/VT ratio: 1.36
2. Positioning the electrode belt
Effect of abdominal position on Tidal images
22 | 41
Abdominal position TV 1001; VT 735
Practical aspects for the clinical use of PulmoVista 500
Effects of the belt position
23 | 41
Practical aspects for the clinical use of PulmoVista 500
L01
L17
Verifying the right belt position on the Main view
The new button “Enhance contrast”…
24 | 41 Practical aspects for the clinical use of PulmoVista 500
While keeping this button pressed, both positive and
negative (= phase-inverted) impedance changes are
enhanced, which makes it easier to detect
• diaphragmatic artefacts due to wrong belt position
• cardiac artefacts at the position of the heart
• aortic artefacts at the aorta (can be observed
occasionally)
• artefacts caused by fluid accumulations
(e.g., pleural effusion, lung empyema, hemothorax)
Normal color scaling Enhanced color scaling
PulmoVista 500 SW 1.20
Origin of phase-inverted impedance changes
PulmoVista 500 SW 1.20 | Product Training | September 2017 25 | 51
Pleural effusion
Heart/Mediastinum Aorta (?)
Diaphragma (= Belt too low)
Practical example 2 – Live measurement
26 | 41 Practical aspects for the clinical use of PulmoVista 500
1. But the belt down in steps of 2 cm, check for diaphragmatic artefacts
using the “Enhance contrast” button
2. Determine the position, where diaphragmatic movement becomes
obvious in the Tidal images
3. System setup ─ Filter settings
27 | 41
You get
what you set
Practical aspects for the clinical use of PulmoVista 500
Resp. Rate
Heart Rate
3. System setup ─ Filter settings
Filtering “off”
28 | 41
Practical aspects for the clinical use of PulmoVista 500
3. System setup ─ Filter settings
Filtering “low pass (35)”
29 | 41
Practical aspects for the clinical use of PulmoVista 500
3. System setup ─ Filter settings
Filtering “band pass (70–150)”
30 | 41
Practical aspects for the clinical use of PulmoVista 500
3. System setup ─ Filter settings
Filtering “band pass (70–150)”
31 | 41
Load 01HealthyLung.eit
Filter settings off first
Practical aspects for the clinical use of PulmoVista 500
6. Impact of cardiac pacing on EIT
Minor artifacts, no low-pass filtering
32 | 41
Practical aspects for the clinical use of PulmoVista 500
6. Impact of cardiac pacing on EIT
Minor artifacts, with low-pass filtering (60 1/min.)
33 | 41
Practical aspects for the clinical use of PulmoVista 500
6. Impact of cardiac pacing on EIT
Major artifacts, no low-pass filtering
34 | 41 Practical aspects for the clinical use of PulmoVista 500
Baseline is set to an artefact (as default definition sets baseline to minimum value…)
6. Impact of cardiac pacing on EIT
Major artifacts, with low-pass filtering (50 [1/min] )
35 | 41 Practical aspects for the clinical use of PulmoVista 500
Baseline is set to an artefact (as baseline is always defined for unfiltered data)
6. Impact of cardiac pacing on EIT
Major artifacts, with artefact filter turned on, no low-pass filter!
36 | 41 Practical aspects for the clinical use of PulmoVista 500
Artefact completely eliminates short-term artefacts (Baseline is always correctly defined at the end of expiration
7. Impact of cardiac pacing on EIT
New artefact filter (SW 1.12) eliminates short term spikes
37 | 41 Practical aspects for the clinical use of PulmoVista 500
Practical example 3 – Live measurement
38 | 41 Practical aspects for the clinical use of PulmoVista 500
1. View the unfiltered data
2. Turn on BandPass filter and determine the heart rate
3. Turn on LowPass filter and set it above the heart rate
4. Set the LowPass filter below the heart rate
5. Load the simulation file “Pacemaker”, (Artefact filter turned off),
observe the artefacts… Turn on the Artefact filter
Right Left
4. Defining the Regions of Interest
Distribution of ventilation in the healthy lung of a slim subject
39 | 41
ROIs set to quadrants (to assess unilateral effects):
Slightly more ventilation occurs in the right lung (ROI 1 and 3).
Expect about 50–55% in the right, 45–50% in the left lung
The upper (ROI 1 and 2) to lower lung ratio is about
50–50%, depending on the anatomy, the body position and the
belt position
Each quadrant has typically 25 ±5%
ROIs set to layers (to assess gravity dependent effects):
Mid-ventral/mid-dorsal is usually greater than ventral/
dorsal
Expect about 10 to 15% in ventral/dorsal regions
Note: In contrast to ROI arrangement as Quadrants, the height
of the ROI as Layers always affects the distribution of ventilation
Upper lung
Lower lung
1 2
3 4
Ventral
Mid-ventral
Mid-dorsal
Dorsal
Practical aspects for the clinical use of PulmoVista 500
4. Defining the Regions of Interest
In subjects with lung pathologies in dorsal regions
40 | 41
The issue: In contrast to CT scans, the location of the
ribcage is not displayed in EIT images:
Use the simplified assumption, that the distance of the
body surface to the ribcage is equal in the ventral and
dorsal part:
– Then, the ventral borderline can be used as a guide
to adjust the size of the ROIs
– Verify by Tidal images and ventilator settings, that
the lungs are not subject to overdistension
– If the size of the ROIs is reduced, check if the
sum of the 4 regional TVs is close to 100 %
Practical aspects for the clinical use of PulmoVista 500
Practical example 4 – Adjusting Regions of Interest (ROIs)
41 | 41 Practical aspects for the clinical use of PulmoVista 500
1. Load the simulation file “Healthy_Lung_obese”, with standard
ROI settings
2. Start measurements
3. Set ROI to Quadrants and assess ventilation distribution
4. Set ROI to Layers and assess ventilation distribution
5. Adjust size of ROIs to achieve normal ventilation distribution
5. The “Mattress-Effect”
42 | 41
This leads periodically to an improved skin-
electrode contact and lower resistances
between skin and dorsal electrodes
Self inflating and deflating air mattresses create specific artetacts in EIT data.
The periodical inflating and deflating increases and decreases the pressure on the electrodes in the
dorsal regions and changes the electrode position.
Pressure
Practical aspects for the clinical use of PulmoVista 500
5. The “Mattress-Effect”
43 | 41
Practical aspects for the clinical use of PulmoVista 500
5. The “Mattress-Effect”
44 | 41
Practical aspects for the clinical use of PulmoVista 500
5. The “Mattress-Effect”
45 | 41
Offline analysis revealed the
characteristic pattern of the
inflatable mattresses
Effects can only be observed in
the dorsal/mid-dorsal areas
Practical aspects for the clinical use of PulmoVista 500
5. The “Mattress-Effect”
46 | 41
Conclusions
Be aware of such effects when using
inflatable air mattresses
By knowing the effect the use of the dEELI-
trend is not feasible due to the strong effects
on the EELI
The distribution of ventilation can still be
evaluated
If dEELI is of importance, the inflation/
deflation function should be switched off
during the period of EIT monitoring
Practical aspects for the clinical use of PulmoVista 500
Practical example 5 – Assessing EIT data in the presence
of mattress artefacts…
47 | 41 Practical aspects for the clinical use of PulmoVista 500
1. Load the simulation files of the folder “21 Mattress effect” Start
measurements
2. Go to the End-insp. trend view to assess ventilation distribution
3. Go to the dEELI trend view to assess changes in end-expiratory
lung impedance
Thank you for
your attention.