Blood Pressure - Intravascular

Overview:

Blood pressure, which is regulated by the cardiovascular system, is a widely used parameter in cardiovascular assessment. It is defined as the amount of pressure exerted on the walls of blood vessels by the blood. Arterial blood pressure is recorded from a peripheral artery such as the carotid or femoral, and may be used to derive mean arterial pressure (MAP), systolic pressure, diastolic pressure, pulse pressure, etc. or monitor anesthesia. Left ventricular pressure is used to derive max and min pressures, maximum rates of ventricular contraction (dP/dt max) and relaxation (dP/dt min), and end diastolic pressure along with many other parameters in determining cardiac function.

Method:

Fluid Filled Transducer Technique
Invasive recording of arterial or venous blood pressure in animals is required in a wide range of research and teaching applications. A polyethylene catheter (PE-50 [1 mm O.D.] for rats; PE-10 [0.5 mm O.D.] for mice) is attached to a pressure transducer (both being prefilled with heparinised saline), inserted into the blood vessel of interest, and tied in place. Pressure fluctuations in the vessel are then transmitted along the catheter tubing to the transducer’s diaphragm, which moves very slightly in response. The diaphragm movements are converted into a varying electrical signal that is amplified through a Bridge Amplifier and recorded by the PowerLab.

Cannula Connection
Details of connection and filling methods differ greatly from laboratory to laboratory, and so only an outline is given here. The cannula (polyethylene tubing) is connected to one of the Luer fittings (‘cannula port’) on the transducer, with or without an intervening pressure line. Heparinised saline is then introduced through the other Luer fitting (‘filling port’) so as to fill the transducer and backfill the cannula, care being taken to avoid bubbles. Lastly a stopcock on the filling port is closed off, leaving the cannula as the only hydraulic connection from the transducer.

After the cannula has been tied into a blood vessel, it is necessary from time to time to inject small additional quantities of heparinised saline via the filling port, in order to prevent clotting of blood in the cannula.

Millar Mikro-Tip Pressure Catheters
Mikro-Tip Pressure Catheters are inserted directly into the blood vessel of interest, and tied in place. Pressure fluctuations are measured straight from the source through a high fidelity pressure transducer that is embedded at the tip of the catheter, which moves very slightly in response.

Mikro-Tip pressure catheters are resistant to movement artifact, provide an excellent frequency response up to 10 kHz, and do not attenuate the pressure signal.

Calibration
For information on Pressure Transducer Calibration, please consult Pressure Transducer Calibration (64 KB) technique note.

Recording Settings
For information on recommended blood pressure sampling rates and filtering options, please consult Signal Filtering (199 KB) technique note.

Related areas of interest include:

 

Software:

LabChart
LabChart software (for Windows and Macintosh) combines the familiar simplicity of a traditional strip chart recorder with the powerful analysis features of a digital acquisition system. LabChart software and a PowerLab data acquisition unit provide data integrity, easy selection of hardware settings, powerful online and offline analysis, procedure automation, seamless extraction of experimental data and flexible display options. Acquisition and analysis capabilities can be further increased with LabChart Extensions and LabChart Modules. LabChart Modules are available as part of LabChart Pro and LabChart Extensions are free for download from the website for existing LabChart users.

Blood Pressure Module (Windows)
The MLS370/7 Blood Pressure Module for Windows automatically detects, analyzes and reports cardiovascular parameters from arterial or ventricular pressure signals.


The settings dialog allows the user to select ventricular pressure for analysis and the Classifier View allows for easy selection of pressure waveforms for further analyses. Pressure cycles that are contaminated by artifact, have abnormal cycle heights or cycle durations (frequency) can be excluded from analysis using the classifier.

The Analysis View displays pressure cycles as beat-by-beat or as the average of a specified number of cycles. Ventricular parameters such as EDP, Max dP/dt, Min dP/dt, Min and Max Pressure are labeled. These measurements along with other calculated parameters are logged in the Table View for easy exporting.

Features and benefits include:

  • Suitable for analysis of pressure signals from humans as well as large and small animals
  • Pressure signals can be analyzed in real time during acquisition
  • The BP Classifier makes detection and exclusion of atypical waveforms easy
  • Parameters can be displayed as continuous data on separate channels
  • Values are logged to the Table View
  • Averages any number of pressure waveforms


Calculated arterial parameters include:

  • Systolic, Diastolic and Mean Pressure
  • Pulse Pressure
  • Dichrotic Notch Pressure
  • Ejection and Non-ejection duration
  • Cycle Duration
  • Heart Rate


Calculated ventricular parameters include:

  • Maximum Pressure
  • Maximum dP/dt
  • Isovolumic Relaxation
  • Minimum Pressure
  • Minimum dP/dt
  • Mean Pressure
  • End Diastolic Pressure (EDP)
  • Maximum-Minimum Pressure
  • Contractility Index


GLP and 21 CFR Part 11
For those researchers working within a laboratory requiring GLP and 21 CFR Part 11 compliance the GLP Client and GLP Server are available for use with LabChart (Windows only) and PowerLab data acquisition systems. For more information, visit the Good Laboratory Practice application page or contact your nearest ADInstruments representative.

Hardware:

Intravascular Blood Pressure Measurements in Animals
Mikro-Tip Blood Pressure System
ML870B35 Mikro-Tip BP Foundation System is a system for measuring blood or cardiac pressure in small animals (i.e. mouse) through to large animals (i.e. sheep) using Mikro-Tip Pressure Catheters.

Mikro-Tip Pressure Catheters
ADInstruments offers the full line of Millar Mikro-Tip Pressure Catheters ranging from 0.8F (for small animals) through to 7F (for large animals). These catheters are for use ONLY in animal research. Mikro-Tip Pressure Catheters may be interfaced to the PowerLab through ADInstruments Bridge Amplifiers (using either an AEC-10C (Viking) or AEC-10D (Low-profile) Catheter Interface Cable) or Millar Pressure Control Units. These include:


Mikro-Tip Implantable Pressure Catheters
For chronic studies, ADInstruments offers Millar Mikro-Tip Implantable Pressure Catheters ranging in size from 1.4 (for use with mice) through to 3.5F (for use in rabbits). The implantable Millar Mikro-Tip pressure sensor catheters provide the researcher with the ability to conduct studies which go beyond acute experimentation. Implantable pressure catheters require either an AEC-10C (Viking) or AEC-10D (Low-profile) Catheter Interface Cable for connection to any ADInstruments Bridge Amplifier.


Fluid-Filled Transducers
Intravascular blood pressure may be recorded using fluid-filled catheters (typically made from polyethylene tubing) attached to any of the following transducers:


Bridge Amplifiers
Mikro-Tip Pressure Catheters and fluid filled blood pressure transducers can connect to PowerLab data acquisition systems via our software-controlled bridge amplifiers including:


Bridge Amplifier Catheter Interface Cables


Pressure Control Units
Millar Mikro Tip Pressure Catheters may also be interfaced to the PowerLab through Millar Pressure Control Units, including:

  • TC-510 Pressure Control Unit: This is a passive interface between a Mikro-Tip Pressure Catheter and a strain gauge amplifier and therefore requires a Bridge Amp such as the ML221. The unit is supplied with a Monitor Cable to connect to any ADInstruments bridge amplifier. Catheter Interface Cables are required for connecting Millar pressure catheters. For pressure catheters with Viking connectors the TEC-10C is required, for Low-profile catheters the TEC-10D.
  • PCU-2000 Pressure Signal Conditioner: This is a two channel amplifier/interface unit for connecting one or two Millar Mikro-Tip catheters. The unit analog output signal level of 1V/100 mmHg is compatible with any PowerLab data acquisition system. To connect each of the pressure outputs to the PowerLab inputs, two MLAC12 BNC to Audio plug (6.5 mm (1/4"), 2m) need to be purchased separately. Millar pressure catheters require a PEC-10C (Viking connector) or PEC-10D (low-profile connector) Interface Cable for use with the PCU-2000.


Pressure Control Unit Catheter Interface Cables


Intravascular Blood Pressure Measurements in Humans

  • ML117 BP (Blood Pressure) Amp: Suitable for use with the MLT0670 Disposable BP Transducer. The ML117 BP Amp is an electrically isolated unit that is approved for invasive pressure recordings in humans when used with a suitable sterile transducer.
  • The MLT0670 Disposable BP Transducer (stopcock) may be used with the BP Amp and the MLAC05 Adapter Cable for invasive pressure recordings in humans provided that the transducer has been gas sterilized prior to use. Note: The MLT0670 is supplied in sterile packaging, however ADInstruments does not guarantee the integrity of the packaging or sterility. The MLT0670 will need to be gas sterilized prior to use with human subjects.


Calibration
The MLA1052 Pressure Gauge is used to calibrate both conventional fluid-filled pressure transducers and Millar Mikro-Tip pressure catheters.

Accessories

 

Effects of nitric oxide synthase inhibition on basal function and the force-frequency relationship in the normal and failing human heart in vivo
J M Cotton, M T Kearney, P A MacCarthy, R M Grocott-Mason, D R McClean, C Heymes, P J Richardson and A M Shah, Circulation, 2318-2323, 2001

Contrasting Inotropic Effects of Endogenous Endothelin in the Normal and Failing Human Heart : Studies With an Intracoronary ETA Receptor Antagonist
Philip A. MacCarthy, Richard Grocott-Mason, Bernard D. Prendergast and Ajay M. Shah, Circulation, 142-147, 2000

Citations Database


The material on this page is provided in good faith and believed accurate at the time of writing. No responsibility will be taken, or liability accepted, for damages arising from the use of information herein. Readers are urged to check with respective manufacturers the accuracy of all product related information.

Research Solutions
Education Solutions
Pharma Solutions
Citations Database
Top Solutions:
Site Feedback
X

Site Feedback

http://www.adinstruments.com/solutions/pharma/Blood-Pressure---Intravascular/

* Denotes a required field
* Name
* E-Mail
* Operating System
* Web Browser

* Comments