IPL-4 Core Isolated Perfused Lung System for Rabbit to Fetal Pig

IPL-4 is an isolated organ perfusion system is specially designed for rabbit or fetal pig lung for measurement of key parameters associated with ex vivo lung perfusion (EVLPP) studies.

The IPL-4 core system plus the selection of an appropriate ventilation option contains all the equipment required to perform basic perfusion and ventilation experiments. Many options are available for the IPL-4 system to further extend its capabilities.

Advanced System Design
Features & Benefits
Applications
Measured Signals & Calculated Parameters
Included items
Additional Requirements for a Functional Unit
Other Components
Specialized Applications & Options

Advanced System Design

The IPL-4 system's unique in-situ cannulation system allows the researcher to align the cannulation head with the operating table while simultaneously retracting the lung chamber. No parts of the system need to be removed during cannulation. 

The lung is perfused via the pulmonary artery by a roller pump. The perfusate is stored in a water-jacketed container to maintain constant temperature. Aeration is provided to keep the pH constant. A heat exchanger and a bubble trap are placed next to the pulmonary artery connection for exact adjustment of the perfusate temperature just before the thorax chamber and to prevent air bubbles entering the lung.

Positive and Sub-Atmospheric (Negative) Pressure Ventilation with the VCM-4 Module

During the surgery the lung is ventilated under positive pressure using a special ventilation head driven by the VCM-4 module. The artificial thoracic chamber includes an integrated Venturi jet that in combination with the airflow from the VCM module creates a vacuum within the chamber. The the lung can then be ventilated physiologically by sub-atmospheric pressure ventilation. The ventilation head is removed and replaced by the pneumotachometer for measurement of respiratory airflow. The ventilation medium (air or a gas mixture) is constantly flowing past the distal end of the pneumotachometer directly via the tracheal cannula into the lungs. The breathing frequency can be varied between 30 and 60 breaths/min. In addition, the inspiration/ expiration ratio as a percentage of each breath can be set between 10 and 90% in 10% steps. The end-inspiratory, end-expiratory, and deep breath (sigh or hyperinflation) negative pressure can be set individually. A deep breath (sigh) is usually induced every 5 to 20 minutes.

Constant Flow or Constant Pressure Perfusion

The lung can be perfused at constant flow or constant pressure. A switch on the SCP module allows you to quickly switch perfusion modes so that the lung can be perfused either at a constant flow rate or at constant pressure, with no change in system dead-space volume. In constant pressure mode, the SCP uses the measured perfusion pressure as a control input and through feedback circuitry adjusts the pump speed to maintain the user-specified perfusion pressure.

Lung Mechanics

The pressure inside the thoracic chamber is measured with a MPX pressure transducer. Air flow is determined with the pneumotachometer connected to a DLP2.5 differential pressure transducer. The tidal volume is derived from the pulmonary air flow by integration. The calculation of pulmonary compliance and resistance needs a computer-controlled data acquisition system (HSE-HA PULMODYN). The IPL-4 core system contains virually everything you need to accomplish the basic perfusion and ventilation experiments, requiring only the addition of core options for ventillation. Application-specific upgrades and options are also available.

PULMODYN Data Acquisition Software can calculate respiration rate, peak inspiratory and expiratory airflow, tidal volume, minute volume, vascular resistance, end-inspiratory and end-expiratory pressures, dynamic airway resistance and dynamic lung compliance, inspiratory time and expiratory time from these raw signals in real time.

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Features & Benefits

• Optimized temperature conditions for the isolated lung; unique jacketed thoracic chamber
• Operating table for non-damaging in situ preparation
• Sub-atmospheric pressure ventilation similar to in-vivo condition or positive-pressure ventilation
• Low flow resistance and dead space volume, minimize perfusion artifacts
• Drug injection pathway built directly into pulmonary perfusate stream
• Unique compensation system for vascular transmural pressure changes during sub-atmospheric pressure ventilation
• Optimized in-situ preparation
• Sub-atmospheric pressure ventilation to mimic closely the in-vivo situation
• Regular induction of hyperinflation of the lung (sigh)
• Perfusion under constant flow or constant pressure condition using buffer solution or blood
• Continuous measurement of respiratory mechanics (respiration rate, inspiratory and expiratory air flow, tidal volume, minute volume, dynamic airway resistance, dynamic compliance) and perfusion characteristics (pulmonary artery pressure, left atrium pressure, lung vascular resistance, pO2, pH
• More measurement parameters than any other system

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Applications

• Investigation of ventilation and perfusion in the isolated rabbit or fetal pig lung
• Drug testing on respiration and vascular parameters
• Toxicology tests on respiration and vascular parameters
• Aerosol tests, surfactant studies, etc.
• Continuous measurement of lung weight changes (edema)

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Measured Signals and Calculated Parameters

Signals recorded as raw data:

• Respiratory Flow
• Intrapleural (artificial thorax) Pressure orTracheal Pressure
• Pulmonary Artery (Perfusion) Pressure
• Perfusion Flow

Parameters calculated from raw data*:

• Respiration Rate
• Peak Inspiratory and Expiratory Airflow
• Tidal Volume, Minute Volume
• Vascular Resistance
• End Inspiratory and Expiratory Pressure
• Dynamic Airway Resistance & Compliance
• Inspiratory Time & Expiratory Time

* Calculations are automatic when PULMODYN data acquisition software is used.

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Included Items

Included items are representative of a typical IPL-4 Core System.  Individual components can be customized to your needs.

The Base Unit (73-4138) includes: 

Temperature-controlled negative pressure lung chamber (artificial thorax) with cover including venturi jet, positive pressure ventilation head, air humidifier, pneumotachometer, operating table, connectors to interface with the perfusion system, pressure equilibration vessel for venous flow and all necessary accessories (tracheal cannulae, pulmonary artery cannulae, left atrium cannulae).

Pulmonary Artery, Left Atrium and Tracheal Cannulae (included with Base Unit):

•  Pulmonary Artery Cannula for Rabbit with Basket, OD 4.6 mm (73-4161)

•  Left Atrium Cannula for Rabbit with Basket, OD 5.9 mm (73-4162)

•  Tracheal Cannula for Rabbit, OD 5.0 mm (73-4163)

If additional or replacement tubing is needed, order pump tubing 73-1863 and 73-1864. Complete IPL-4 tube sets are available on request for the thermostatic circuit (22051), for ventilation (22052) and for the perfusion  circuit (22054). Please inquire.

Operating Table  (included with Base Unit):

The operating table (73-2487) is specially designed for a stable and easy in situ preparation under most physiological conditions (e.g. stable perfusion pressure). It is attached to the Perspex stand and allows an exploration of the lung without interruption of ventilation and perfusion.

Surgery takes place at a hydrostatically neutral elevation, minimizing physiological hydrostatic pressure perturbations. An included plastic trough collects waste. The table is easily removed for cleaning after the lung is placed in the chamber. The operating table is 300 mm x 195 mm in size and includes ball joint, plastic trough, parts for mounting the table to the acrylate stand, four paw clamps, two thorax retractors, and a holder to support tracheal cannula and positive pressure ventilation head during surgery.

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Additional Requirements for a Functional Unit

For a functional unit the core system requires a suitable ventilation system. For only positive ventilation the Small Animal Ventilator, Type 683 with a 30 ml cylinder can be used. If positive and sub-atmospheric ventilation is wanted,a special Ventilation Control Module (VCM-4R) is required.

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Other Components

PULMODYN Data Acquisition Software

Online evaluation of a wide range of signals and classical respiration parameters.

Note: Ponemah Data Acquisition & Analysis Software from DSI,  a Harvard Bioscience Company is also suitable.

Small Animal Ventilator, Type 683

The Model 683 Small Animal Ventilator comes standard with two piston and cylinder assemblies. For the IPL-4, the large piston must be installed. This allows tidal volumes to be set from 3.0 to 30 cc in 0.3 cc increments. By setting the cylinder stroke between gradations it is possible to achieve finer resolution in tidal volume settings. Respiratory rate can be set from 18 to 150 strokes per minute. Volume and rate settings can be adjusted while the ventilator is running

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Specialized Applications & Options

Real-Time Flow Measurement

Direct real-time flow measurement with functional IPL-4 systems. 

Venous Pressure Measurement

Venous pressure transducer and amplifier for venous pressure measurement in an isolated perfused lung system.

Perfusate Deoxygenation

For deoxygenation of blood or buffers containing proteins (e.g. albumin) or erythrocytes.

Perfusion Solution Monitoring 

Permits precise continuous or discontinuous measurement in liquid media or perfusate of these three key parameters: pO₂, pH and pCO₂.

Temperature Measurement

Measure perfusate temperature in any isolated perfused organ system.

Perfusate Filtration

For filtration of recirculated perfusate.

Aerosol Application

Nebulizer setup for delivery of aerosols to the isolated lung.

Drug Addition

For accurate drug addition using a syringe pump. Additional option for flow controlled drug addition, where flow is measured (or calculated) and a drug must be added in a certain ratio. 

Lung Weight Measurement (Edema Balance)

Weight measurement-edema balance option for IPL-4 core system for rat or guinea pig lungs.

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