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Setup for Respiratory Studies of Resistance and Compliance with PULMODYN software on Rats and Guinea-Pigs

For measurement of bronchospasmolysis in anesthetized rodents Evaluation of typical parameters for respira-tory studies (flow, tidal volume, minute volume, respiratory rate, dynamic resistance and compliance, inspiratory and respiratory duration For acute experiments or on intubated animals Long term studies using Plethysmograph box Experimental triggering of a bronchospasm in the anesthetized guinea-pig (Urethane anaesthesia 1.5 g/kg i.p.). Administration of 0.9 µmol/kg i.v. acetylcholine.

Typical flow diagram acute experiment

Typical flow diagram using plethysmograph box

A respiratory mechanics measurement setup consits of a combination of transducers, amplifiers, a recorder and data acquisition. A large set of transducers for measurement of respiratory airflow (in mouse, rat, guinea pig...), oesophageal or intrapleural pressure or bioelectric signals (vagus nerve...) are available in different sizes to match all the animal species and sizes. The variety of amplifier modules for the PLUGSYS system allows to setup any combination of measurement modules according to your experiment. The signals can be recorded on polygraphs and/or analysed using a dedicated software HSE PULMODYN

In acute experiments, the anesthetized animal is placed on an operating table and tracheotomized or intubated. The respiratory flow is measured with a pneumotachometer Fleisch tube or PTM and a differential pressure transducer. In addition the oesophageal pressure is measured using an air or liquid filled tubing catheter and an adapted pressure transducer (MPX or P75). These two signals permit calculation of derived respiratory parameters such as:

• Maximal inspiratory and expiratory air flow
• Tidal volume and minute volume
• Respiration rate
• Lung resistance = pulmonary resistance = 75% airway resistance + 25% tissue resistance
• Conductance = 1 / Lung resistance
• Dynamic compliance = elasticity of the respiratory system
• Duration of Inspiration and duration of Expiration
• Apnea Time
• Time of brake and Time of pause
• Airflow at 0.5TV

For recording and evaluation the HSE PULMODYN software is used
The same measurement can also take place with an intubated animal placed in a plethysmograph box, type 853. This reduces the dead space in the respiratory path. The pneumotachometer is not needed and is replaced by the screens in the plethysmograph box. The box can be equipped with anesthesia equipment to allow Halotane or Eflurane anesthesia during the measurement, the animal recovers after that. This permits long term studies with the same animals (e.g. for toxicological studies). Possibility of aerosol application
Hemodynamic signals such as blood pressure, ECG, blood flow can also be recorded and analyzed by the software. The adapted transducer, amplifiers and software module must be added to the system.

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