Pneumograph
| Pneumograph | |
|---|---|
.jpg) Illustration | |
| Synonyms | pneumatograph or spirograph |
| Purpose | To record velocity and force of chest movements in respiration |
A pneumograph, also known as a pneumatograph or spirograph, is a device for recording velocity and force of chest movements during respiration. While spirometry measures respiratory rate and other markers of respiratory health via analysis of the airflow from the lungs during inhalation and exhalation, pneumography measures the respiratory rate via chest motion.
Principle of operation
[edit]There are various kinds of pneumographic devices, which have different principles of operation.
Mechanical
[edit]In one mechanism, a flexible rubber vessel is attached to the chest. The vessel is equipped with sensors such as accelerometers, piezoelectric sensors, or a fiber Bragg grating[1] to measure chest motion and obtain respiratory rate.
Electrical
[edit]Other mechanisms are impedance based. In these methods, a high-frequency (tens to hundreds of kHz), low-amplitude current is injected across the chest cavity. The voltage resulting from this current injection is measured and the resistance is derived from the application of Ohm's Law: . Current flows less easily through the chest as the lungs fill, so the resistance rises with increasing lung volume.[2]
References
[edit]- ^ Vitazkova, Diana; Foltan, Erik; Kosnacova, Helena; Micjan, Michal; Donoval, Martin; Kuzma, Anton; Kopani, Martin; Vavrinsky, Erik (6 February 2024). "Advances in Respiratory Monitoring: A Comprehensive Review of Wearable and Remote Technologies". Biosensors (Basel). 14 (2). MDPI Pub.: 90. doi:10.3390/bios14020090. PMC 10886711. PMID 38392009.
- ^ Grenvik et al., (1973). "Impedance Pneumography: Comparison between Chest Impedance Changes and Respiratory Volumes in II Healthy Volunteers", Chest, 62:439-443.
- Freundlich, Jerome J.; Erickson, James C. (1974). "Electrical Impedance Pneumography for Simple Nonrestrictive Continuous Monitoring of Respiratory Rate, Rhythm and Tidal Volume for Surgical Patients". Chest. 65 (2): 181–184. doi:10.1378/chest.65.2.181. PMID 4810676.