resistance/compliance from sedated animals

resistance/compliance from sedated animals

resistance/compliance from sedated animals

In anesthetized plethysmography, lung resistance and dynamic compliance are measured directly because the subject is anesthetized. emka TECHNOLOGIES provides setups for mice, rats and guinea pigs.

Depending on the level of sedation, the subject may be spontaneously breathing (SB configuration) or under mechanical ventilation (MV configuration).

A flow signal and a pressure signal are required to calculate compliance and resistance.

standard setup (no options)

• plethysmograph
• ventilation pump
• dpt differential pressure transducer (to obtain flow signal)
• other pressure transducer (the specific transducer used depends on the setup)
• amplifier
• interface box
• acquisition card
• iox2 software with the RC (respiratory compliance) analyzer
• homogenization tower (SB only)
• ventilator (MV only)

spontaneously breathing (SB) configuration: key features

• orotracheal cannula communicates with the atmosphere
• flow signal: a differential pressure transducer in the plethysmograph wall (signal reflects the expansion and contraction of the thorax during each breath)
• pressure signal: direct measurement of either esophageal pressure or pleural pressure (latter is more accurate but demands more technical expertise, especially in small subjects)
• better adapted to larger subjects
• no dead volume
• possible to perform repeated experiments in the same subject

mechanically ventilated subject (MV) configuration: key features

• subject is anesthetized and tracheostomized, and a cannula is inserted in the trachea. The cannula communicates with the ventilator
• flow signal: a differential pressure transducer in the plethysmograph wall is used to obtain the flow signal (signal reflects the expansion and contraction of the thorax during each ventilation cycle)
• pressure signal: tracheal pressure, pleural pressure (from which transpulmonary pressure is calculated), or esophageal pressure (an approximation of pleural pressure)
• the cannula eliminates the resistance due to upper respiratory airways
• possible to take bronchoalveolar lavage samples after lung function measurements

parameters

• inspiratory time (TI)
• expiratory time (TE)
• peak inspiratory flow (PIF)
• peak expiratory flow ( PEF)
• tidal volume (TV)
• expired volume (EV)
• relaxation time (RT) - time taken to expire a user-defined percentage of tidal volume
• minute volume (MV)
• breathing rate
• end-inspiratory pause (EIP)
• end-expiratory pause (EEP)
• pause and enhanced pause - indicators of bronchoconstriction
• end-expiratory work (EEW)
• lung resistance
• dynamic compliance
• developed pleural pressure
• mid-expiratory flow (EF50)

options

• aerosol generation & delivery
• vital signs monitoring

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