The fourth session in our "PV Loops to Measure Cardiac Function" Webinar Series touched on what is essential for the researcher to be aware of in order to collect valid Pressure-Volume Loop data that can be used with confidence in the ensuing analysis stage of their research project. Dr. Filip Konecny and Peter Plouf present and offer discussion on best practices for obtaining quality and consistent Pressure-Volume loop data. The presentation is a distillation of more than 10 years of working with the PV Loop research community to develop better results, and insights from Dr. Konecny’s body of knowledge from collecting and publishing PV Loop study data across a wide spectrum of species and research models. This presentation touches on what is essential for researchers to be aware of in order to collect valid PV Loop data that can be used with confidence in the ensuing analysis stage of their research project. Key Topics: - surgical considerations for improved data stability and consistency between animals - procedure checklists -- essential steps before, during, and post surgery - how to properly check data integrity at the bench-top - understanding conductance and admittance methodologies for deriving volume

1. Best-Practices to
Achieve Quality
Pressure-Volume
Loop Data

2. Best-Practices to Achieve Quality PV Loop Data
1. Equipment Requirements, Operation, & Sanity Checks (Peter Plouf)
2. Volume Calibration Considerations (Peter Plouf)
3. Surgical Considerations – Rodent non-survival applications (Filip Konecny)
• Anesthesia, Analgesia, Ventilation
• Monitoring Physiology (HR, BT, RR, and ECG)
4. Optimizing Pressure-Volume Signals (Filip Konecny)
• Catheter Placement
• Validating good “baseline data”
5. Q&A Session (Peter Plouf & Filip Konecny)

3. InsideScientific is an online educational environment
designed for life science researchers. Our goal is to aid in
the sharing and distribution of scientific information
regarding innovative technologies, protocols, research
tools and laboratory services.

4. Pressure-Volume Equipment,
Operation, and Considerations
for Volume Calibration
Peter Plouf
Director of R&D –
Scisense Products
Transonic
Copyright 2015 InsideScientific & Transonic. All Rights Reserved.

5. “Be confident in the data you
collect when you collect it.”
THE PURPOSE OF THIS SECTION IS TO PRESENT A SERIES OF “BEST
PRACTICES” THAT WILL EVOKE CONFIDENCE IN YOUR PV LOOP DATA
WHILE YOU ARE COLLECTING IT.
WHEN FOLLOWED, THE SANITY CHECKS PRESENTED WILL PREVENT
THE RESEARCHER FROM COLLECTING INNACURATE DATA

6. Tools & Equipment List
1. PV System, Data Acquisition System, & PV Catheter
Tip: Read the manuals. Call us for help if needed…
Click for Equipment
Information

7. Tools & Equipment List
2. Ventilator
Tip: use them! But remember, one size does not fit all…

8. Tools & Equipment List
3. Vaporizer & Appropriate
Anesthesia Kit
Tip: consistent delivery
and control of
anaesthesia is just as
important as the type of
anesthesia being used

9. Tools & Equipment List
4. Surgical Tools
Tip: when using catheters
smaller than 2F, handle
them with padded forceps.
Or, regular forceps covered
with PE tubing

10. Tools & Equipment List
5. Microscope for mouse
& other small rodents
Tip: use a microscope for
better view of the insertion
point, and to have better
confidence when working
with small catheters

11. Before Starting: System Check
• Data collection relies on a properly set up
system consisting of the ADV500, and A/D
device and a Data collection software program
• Assuming your system is assembled to the
computer and you are familiar with your
acquisition system, it is important to make sure
your entire system is working and calibrated
• The ADV500 displays high and low calibration
values that are used to calibrate the acquisition
system
Before starting an experiment, output these values and make sure that the values match

12. • No matter what data
acquisition system and
software you are using,
the process is the same
• Ensure the low and high
values (mmHg, uL, etc.)
that correspond with the
values provided by the PV
System manufacturer
• Pay close attention to the
units, and subtle
differences between
similar animal models
(ie. Mouse and Rat)
Emka IOX2
iWorx
LabScribe2
ADI
LabChart
Notocord
Heme

13. Catheter Selection
• A PV catheter has 4
electrodes and it is
important that all 4
be inside of the
ventricle
• Single segment
catheters are available
with segment lengths
from 3.5mm (small
mouse) all the way to
100mm (large animal)
Tip: If in doubt, err
on the side of too
short.

14. Catheter Selection
• Variable Segment
Length (VSL)
catheters, offering 4
different sensing
lengths per catheter,
are available to
accommodate
studies where
ventricle size varies
• Available in 1.9F –
7.0F sizes (rat to
larger animal)

15. Rodent Catheter Selection
Segment spacing Species
Shaft OD
(F)
Recommended
Long Axis (mm)
Total Shaft
Length (in)
Maximum
Volume (µL)
3.5mm Mouse 1.2 5.2 - 5.7 18 150
4.0mm Mouse 1.2 5.7 - 6.2 18 150
4.5mm Mouse 1.2 6.2 - 6.75 18 150
6.0mm Rat 1.9 7.8 - 9.8 18 1000
8.0mm Rat 1.9 9.8 - 11.8 18 1000
10.0mm Rat 1.9 11.8 - 13.8 18 1000
VSL (6, 8, 10, 12 mm) Rat 1.9 8.3 - 15.0 18 1000
VSL (8, 10, 12, 14 mm) Rat 1.9 10.3 - 17.0 18 1500
VSL (8, 11, 14, 17 mm) Rat 1.9 10.3 - 20.0 18 2000
When in doubt, contact us for help!

16. Balancing
Pressure sensor
• Start hydration of the
catheter (20 min) prior
• Use a 10 ml syringe
with room-temperature
saline or PBS
• Use balance controls to
reference pressure to
zero, while lifting
catheter pressure
sensor under the
meniscus of saline
solution
Tip: Correct pressure sensor
balancing is key for accurate
EDP and ESP measurement

17. Data Accuracy Comes From Calibration
• PV systems track SV, EF and Contractility.
• Absolute Volume is a mathematically calculated value.
• The calculation is based on three calibration values that
the researcher needs to be aware of:
1. Stroke Volume Calibration Factor
2. Blood Resistivity (Rho)
3. Heart Type (Muscle Electrical Property)

18. 1. Stroke Volume Calibration Factor
Echo Flow Probe Swan Ganz Literature
Reference
The type of catheter connected to the ADV500 will populate a default value
(ex. 20uL for mouse); however, use one of the following options to determine
the most accurate reference as possible…

19. 2. Blood Resistivity (Rho)
Resistivity (or conductivity) is a
property of the blood being measured.
Default values are provided in the ADV500
that represent healthy non-modified
mammalian blood at 37C. If your
experiments involve changing blood
properties (ie. hemorragic shock models),
make measurements manually and address
both pre and post blood change states.
Manual Sample

20. 3. Heart Type (Muscle Electrical Property)
• The ADV 500 uses the term “Muscle Properties” to describe the ability of
the myocardium to conduct a constant AC current signal.
• It is important to acknowledge this calibration parameter since it will
impact how much tissue contribution is removed from the measured
admittance signal. The ADV500 offers 3 default options for Heart Type:
Healthy , Infarcted or Hypertrophied
• A fourth option is to select “Custom” and use the supplied probe to obtain
a value by placing it on the LV surface of a beating heart

22. Surgical Considerations &
Best-Practices for Successful
PV Data Collection
Filip Konecny, DVM PhD
Applications Scientist &
Surgical Trainer
Transonic
Copyright 2015 InsideScientific & Transonic. All Rights Reserved.

23. Overview
1. Surgical Considerations – Rodent non-survival applications
• Anesthesia, Analgesia, Ventilation
• Monitoring Physiology (HR, BT, RR, and ECG)
2. Optimizing Pressure-Volume Signals
• Catheter Placement
• Performing a baseline scan
• Validating your “baseline data”
• 3 steps to good PV data

24. Anesthesia, Analgesia, Ventilation
DO…
• weigh each subject to calculate proper anesthetic dose
• adhere to suggested delivery and
administration guidelines for selected anesthetic
request a copy of our Rodent PV Workbook
DO NOT…
• use expired pharmaceutical grade injectable compounds
• use expired anesthetic/sedative antagonists
• use an expired vaporizer
• use a non-compatible VAPORIZER for your chosen
anesthesia
Tip: learn about
anesthetics and their
effects on hemodynamics

25. Anesthesia, Analgesia, Ventilation
DO…
• administer analgesics to control pain
• optimize analgesia delivery with anesthesia –
animals that receive pre-operative analgesia often require
less anesthetic to reach a surgical plane
• work in pairs or teams if possible – animal physiology and
vitals can be better monitored by one partner while the
other focuses on surgery and PV measurements
• monitor anesthetic depth using the following techniques:
Toe pinch, Palpebral reflex, Corneal reflex
• continually monitor vital signs and animal physiology to
maintain a stable prep
Tip: Select Anesthesia that you
can readily reverse that has
predictable effect on heart

26. Monitoring Physiology (HR, BT, RR, and ECG)
DO…
• have suitable equipment to control body
temperature
• have suitable equipment to monitor Heart Rate,
Body Temperature, Respiration Rate, and ECG
• consider taking blood gas measurements or
measuring *SpO2 –(noninvasive, fast, continuous)
• monitor continuously and save data throughout
your experiment – consider integration with PV
data into one acquisition file
Tip: vital signs monitoring is
crucial for PV repeatability

27. Monitoring Physiology (HR, BT, RR, and ECG)
Mouse Rat
Temperature
35.8 - 37.4 °C
96.6 - 99.7 F
35.9 - 37.5 °C
96.6 - 99.5 F
Respiration Rate
90 – 220
breaths per min
66 – 144
breaths per min
HR 450 – 780 BPM 250 – 500 BPM

28. Additional Thoughts on Heating

29. Special Consideration – Maintaining Blood Volume
• loss of 10 % total blood volume is tolerable (for PV)
• loss of 20-25% will lead to shock (Final data not physiological)
• good PV vascular prep. technique will minimize blood loss
Species Blood Volume Blood loss (10%) Blood loss (20%)
Mouse 20g 1.5 ml 0.15 ml 0.3 ml
Rat 250g 15-18ml (17) 1.7ml 3.4ml

30. Special Consideration – Maintaining Blood Volume
• Rodents (particularly mice) have a high body surface-area to blood volume ratio,
high metabolic rate, and limited fat storage  RESULT: greater risk of dehydration
• Therefore, it is better to compensate and plan for blood loss by having a consistent
and standard pre-operative injection plan (IP route is most common)
Species SC or IP fluids IV fluids PO fluids intake
Mouse 20g 0.15 ml 2ml/100g/hr 1.2ml/24h
Rat 250g 1.7ml 2ml/100g/hr 17ml/24h

31. Surgical Documentation & Study Approach
DO…
• Document ALL Settings: equipment, surgical
methodology, and operation details
download our PV Loop Surgery Documentation Sheet
• work through cohorts: if different animal groups in
your study have different volume calibration factors
(SV correction factor) or require PV catheters with
different electrode spacing (rat dilated cardiomyopathy)
• utilize “marks” and “comment” functions in your data
acquisition software –input details specific to the
animal being studied (volume calibration factors), and
make note of unique occurrences during the work

32. 3 Steps To Good PV Data
• Turn on system and
start catheter hydration
• Enter values for Admittance
cal. factors:
1. Stroke volume
2. Blood resistivity
3. Heart type
• Balance pressure sensor
Step 1
• Place catheter into ventricle
• Position catheter in center of
ventricle by viewing Pressure
vs. Magnitude loops and phase
signal
• Once optimal signals are
achieved, press “Enter” during
acquisition to perform a
baseline scan
• Accept the reported
scan numbers, or rescan
if needed
Step 2
• Switch to Pressure vs.
Volume loops view
• Continue with protocol
steps (injections,
occlusions, etc.)
• Use software analysis
features to study
hemodynamic results
Step 3

33. Transition Guided by Pressure Note the drop of
the pressure at the
end diastole when
entering into LV
chamber through
RCA (right carotid
artery)
Use the pressure
signal to confirm
that the catheter has
entered the ventricle

34. Understanding “Magnitude”
• Sinusoidal pattern
of the wave
• Concentrate on
Magnitude
Amplitude and
Range at the same
time
See table for specific
ranges and values by
animal model

35. Understanding “Phase”
• Sinusoidal pattern
of the wave
• Concentrate on
Phase amplitude
and range at the
same time
See table for specific
ranges and values by
animal model

36. Typical Values in Healthy Subjects
Animal
Phase
Range
Phase
Amplitude
Magnitude
Range
Magnitude
Amplitude
Rat 2-6  2.0  1400-2600 µS 600-1000 µS
Rabbit 2-6  2.0  8-14 mS 2-3 mS
Small Dog 1-5  1.5  10-16 mS 2-3 mS
Large Dog (>15kg) 1-5  1.5  12-18 mS 2-4 mS
Small Swine 1-3  1.5  12-18 mS 2.5-4 mS
Large Swine (>65kg) 1-3  1.5  15-30 mS 4-6 mS
Sheep 1-3  1.5  14-22 mS 4-5 mS
Cow 2-5  2.0  20-40 mS 10-15 mS

37. Signs of a Good Baseline Scan
• Once phase and
magnitude “look
good”, perform a
baseline scan
• Observe a short break
in data recording
(shown here)
• The result should be
stable, accurate
volume… if not,
adjust catheter,
repeat scan

38. • Pressure –
Magnitude loop
Looks good
• However, phase
range is too high
for mouse
(~8-10 deg.)
• Catheter needs
repositioning
Catheter Positioning

39. Catheter Positioning • Pressure-Volume: same
data set from previous
slide, but now we are
viewing Pressure vs.
Volume
• Note – Volume is not
calculating correctly…
this is because the
catheter is not in the
center of the ventricle
• Phase angle can be
used as a guidance of
the catheter position in
the chamber

40. Catheter Positioning
• Catheter position is
adjusted followed
by baseline scans
• Volume is now
accurate and the
user can move
forward with their
protocol

41. 3 Steps To Good PV Data
• Turn on system and
start catheter hydration
• Enter values for Admittance
cal. factors:
1. Stroke volume
2. Blood resistivity
3. Heart type
• Balance pressure sensor
Step 1
• Place catheter into ventricle
• Position catheter in center of
ventricle by viewing Pressure
vs. Magnitude loops and phase
signal
• Once optimal signals are
achieved, press “Enter” during
acquisition to perform a
baseline scan
• Accept the reported
scan numbers, or rescan
if needed
Step 2
• Switch to Pressure vs.
Volume loops view
• Continue with protocol
steps (injections,
occlusions, etc.)
• Use software analysis
features to study
hemodynamic results
Step 3

42. Thank You!
For additional information on Pressure-Volume
Loop best-practices and solutions for studying
hemodynamics please visit:
http://www.transonic.com

43. NEXT WEBINAR: Dr. James Clark of King’s College London will present
surgical monitoring best-practices, and demonstrate how to improve study
and animal outcomes in CV related research studies using integrated
surgical monitoring combined with hemodynamic measurements.
WORKSHOP: