DYNAMIC AND STATIC COMPLIANCES – WHAT DO THEY TELL US?

At each breath, the respiratory system must overcome two opposing forces to be able to move air in and out of the lungs: the resistance to airflow and the distensibility (or compliance) of the respiratory system. Physiological and/or pathological factors may alter these mechanical characteristics and induce significant changes in the effort required to breathe or tolerance to exercise.

During flexiVent experiments, it is possible to measure the mechanical properties of the respiratory system and to evaluate the impact a given change will have on specific parameters. While a measure of resistance can only be performed in presence of airflow (or under dynamic conditions), measurements of compliance can be obtained under dynamic or static conditions. Assessing compliance in presence or absence of airflow, can allow for an exhaustive evaluation of the respiratory system or of its response under particular physiologic or pathophysiologic states.

Dynamic Compliance

A measure of the dynamic compliance of the respiratory system (also often simply called compliance) is obtained with the SnapShot perturbation, which studies the lung under conditions of tidal breathing.

Since this measure is typically performed under closed chest conditions, the compliance obtained generally reflects the overall stiffness the entire respiratory system has to overcome on a breath-by-breath basis and will include the compliance of the lungs, the chest walls, as well as that of the airways.

Static compliance

A measure of the static compliance (Cst) is obtained following the construction of a pressure-volume curve. In this maneuver, the respiratory system is typically inflated and deflated in a step-wise manner, with at each plateau, a period of no gas flow for equilibration.

If performed under closed-chest conditions, C_st reflects the elastic properties of the respiratory system (i.e. lungs and chest walls) at rest. Measurements of static compliance can also be performed under open chest conditions, where it will now reflect intrinsic distensibility the lungs.

Read more

Bates, JHT, 2009. Lung mechanics: an inverse modeling approach. Cambridge University Press.

Carbonara, P, Eidelman, DH, 2005. Pulmonary statics in disease, in: Hamid, Q, Shannon, J, Martin J (Eds), Physiologic basis of respiratory disease. BC Decker Inc., Lewiston NY USA, pp. 69-76.

West, JB, 2012. Respiratory physiology: the essentials. Lippincott Williams & Wilkins.

Don't miss the opportunity!

Do not miss the opportunity to learn on key laboratory techniques used in respiratory research by attending the workshop on Phenotyping Mouse Models of Human Lung Disease hosted by the Jackson Laboratory in beautiful Bar Harbor, Maine.

The workshop provides a unique forum to acquire strong theoretical and practical basis on key techniques such as respiratory mechanics measurements, airway hyperresponsiveness assessment, or lung volume determination. The organization of the event also favors networking with peers as well as with established researchers in the field. For years now, SCIREQ has been an active player in this event, as part of a long collaboration with the Jackson Laboratory educational programme. The workshop is therefore also a great opportunity to meet us, to see our products in action, and to get to work with them under the supervision of trained instructors and scientists.

Schedule Highlights

Please see below some highlights from the comprehensive schedule recently published:

Mouse Models of Lung Disease - Wayne Mitzner, Ph.D., John Hopkins Bloomberg School of Public Health

Aerosol Delivery Systems - Lennart K.A. Lundblad, Ph.D., The University of Vermont

The Trials and Tribulations of Using Mice to Model Acute and Chronic Lung Diseases - Charles Irvin, Ph.D., University of Vermont

Foundations of Lung Function and assessment with forced oscillation - Lennart K.A. Lundblad, Ph.D., The University of Vermont

Concurrent, rotating labs:
- Introduction to the flexiVent - Annette Robichaud, Ph.D., SCIREQ Scientific Respiratory Equipment Inc.
- Aerosol Delivery Systems - Lennart K.A. Lundblad, Ph.D., The University of Vermont

For the complete schedule, please click here.

Register today!

Date: September 15-19, 2015
Location: Bar Harbor, ME

Register here: Jackson Lab Worshop on Phenotyping Mouse Models of Human Lung Disease