Further information
(internal access only)
Secretariat
Max-Delbrück-Center for Molecular Medicine
Preclinical Research Center (PRC)
Robert-Rössle-Str. 10
13125 Berlin
phone: +49 30 9406 3521
Since the mid-20th century, pulmonologists have used the linear relationship between the pressure and volume of gaseous phases (the law of Boyle-Mariotte) to assess lung functions.
A specialized apparatus, the whole-body plethysmograph, permits measurements of essential ventilatory parameters leading to an evaluation of pulmonary function. Basically, this method consists of measuring the course of pressure inside the plethysmograph over time which results from the respiration of the subject. Then these pressure values can be related to distinct volumes of the respiratory cycle using the law of Boyle-Mariotte.
For pre-clinical purposes we provide a dual-chamber system of plethysmography consisting of a body and a head part, separated by a gas-tight seal. This setup (EMKA Technologies) allows us to measure the thoracial as well as the nasal respiratory flow of up to eight animals simultaneously. This permits measurements of ventilatory parameters including breathing rate, inspiratory/expiratory time, flow, volume, and further values of pulmonary function. For example, measurements of the specific airway resistance and conductance depend on the discrete assessment of both the nasal and thoracial respiratory flow. Ultimately, these values are necessary to evaluate most relevant diseases of the lung, such as chronic obstructive pulmonary disease (COPD) or asthmatic diseases.
In addition, the use of a head-chamber in this plethysmography system allows an optional, systematic administration of aerosolic substances like metacholine via a nebulizer unit. In this way respiratory stress models or inducible bronchodilative effects can be studied.
Whole-Body Plethysmography is non-invasive and does not rely on anesthesia. It permits measuring respiratory function in mice and rats of several sizes.
Parameter | Description | Unit |
---|---|---|
Ti | inspiration time | ms |
Te | exspiration time | ms |
RT | relaxation time | ms |
PIF | maximum inspiration stream | ml/s |
PEF | maximum exspiration stream | ml/s |
TV | tidal volume | ml |
EV | exspiration volume | ml |
MV | volume per minute | ml |
f | breathing frequency | bpm |
EIP | pause at end of inspiration | ms |
EEP | pause at end of exspiration | ms |
dT | nasal-thoracic lag | ms |
Sraw | specific respiratory resistance | cmH2O*s |
Sgaw | specific respiratory conductance | 1/cmH2O*s |
EF50 | end-diastolic pressure-volume ratio | ml/s |
As one of our special facility services, we provide comprehensive data analysis of recorded respiratory parameters. The raw data will be pre-screened in terms of signal acquisiton by technical experts and the summarized data will be sent to the customer in a neatly arranged data-sheet. At this point, the customer is free - if desired - to manually select single subjects to exclude from the study.
After selecting all subjects for analysis, the final group comparison is generated automatically. In a second sheet, all parameters are averaged per group (two groups in the standard version - ask for customized solutions!) and the final group values are displayed in a comparative view as shown in the example below. As a basic statistical analysis of group data, a T-Test based on the group-variances (type-2 or type-3) will be already included.