Brief Introduction to Respiration Rate-SSM.pptx

Brief Introduction to Respiration Rate

1. MUKESH SUNDARARAJAN RESPIRATORY RATE MONITOR

2. Contents Introduction Importance of monitoring respiratory rate Various method of measuring respiratory rate Respiratory rate measurement using Piezoelectric Sensor (PZO) Respiratory rate measurement from Laser Doppler Vibrometer ( LDVi ) Respiration rate measurement system using Pyroelectric Sensor Impedance pneumography method Capnometry Respiratory rate measurement using PPG signal Conclusion References

3. Introduction Respiration rate is an important vital sign. It is, the number of breaths taken within a set amount of time. Tachypnea / Bradypnea / Apnoea, is a sensitive indicator of physiologic distress that requires immediate clinical intervention. Figure 1. Normal breathing rate [1]

4. Importance of monitoring respiratory rate [2] Tachyapnoea are an important predictor of cardiac arrest.(25-27breaths/minute) Mortality is high in Tachypnea persons. Figure 2: Causes of death (SOURCE: Sudden Cardiac Arrest Foundation)

5. Various method of measuring respiratory rate Respiratory rate measurement using Piezoelectric Sensor (PZO). Respiratory rate measurement from Laser Doppler Vibrometer ( LDVi ). Respiration rate measurement System Using Pyroelectric Sensor. Impedance pneumography method. Capnometry . Respiratory rate measurement using PPG signal.

6. Piezoelectric sensors have been used to detect breathing effects, utilizing the piezoelectric property. It directly measures the electric potential changes produced when the piezoelectric ceramic is impacted by respiratory airflow. piezoelectric film sensor made of aluminum nitride ( AlN ) material has good sensitivity. Respiratory Rate measurement using Piezoelectric Sensor (PZO) [3]

7. Respiratory Rate using Piezoelectric Sensor (PZO) [3] ( contd …) Figure 3. Respiration belt Sleep Sense 1387-kit.(Courtesy: www.biosemi.com) Figure 4. Piezoelectric output, periodogram

8. Measurement of Respiratory Rate from Laser Doppler Vibrometer ( LDVi ) [4] LDVi is a fully no-contact measurement method for monitoring of the respiration rate. This method is operated at a distance of 3m, on different point of the patient thoracic and abdominal area. Laser Doppler vibrometers   can effectively detect vibration within two hundred meters with a sensitivity on the order of 1 (mm/s)/V.  The laser sensor works with a He–Ne laser source. No special safety precautions are required since laser power is less than 1 mW .

9. Measurement of Respiratory Rate from Laser Doppler Vibrometer ( LDVi ) [4] ( contd …) Figure 6: Polytec OFV-505, an advanced laser Vibrometer head, output signal. Figure 5: Velocity signal measured on the chest area 

10. Measurement of Respiration Rate in Preterm Infants by Laser Doppler Vibrometry [5] Figure 8: scheme and procedure. Figure 7: Setup of measurement.

11. Respiration Rate Measurement System Using Pyroelectric Transducer [6] A polyvinylidene fluoride (PVDF) has faster response time than those of traditional thermal devices. A PVDF film has both piezoelectric and pyroelectric properties. The difference of temperature can be best sensed by using PVDF placed in front of the nostrils by means of a suitable holding device.

12. Respiration Rate Monitoring Gauze Mask System Using Pyroelectric Transducer [6] Figure 9: Experiment setup Figure 10:Waveform derived from belt system and experiment setup

13. Impedance Pneumography Method [7] The objective of this technique is to measure changes in the electrical impedance of the person’s thorax caused by respiration or breathing. In both of these methods, a high-frequency ac current is injected into the tissue through the drive electrodes. This potential difference is related to the resistivity of the tissue between the voltage-sensing or receive electrodes. The equivalent resistance is defined as the ratio of the voltage difference between the two receive electrodes and the current that flows through the tissue.

14. Impedance Pneumography Method [7] Figure 11: (A) Two Terminal measurement (B) Four Terminal Measurement (C) Simulator output

15. Capnography The measurement is based on the absorption property of infrared rays by certain gases (like CO 2 , CO, and NO 2 ). When infrared rays are passed through the expired air containing a certain amount of CO 2 , some of the radiations are absorbed by it. The detector changes the loss in heating effect of the rays into an electrical signal. Figure 12: Normal Capnogram

16. Respiratory rate measurement using PPG signal [8] Photoplethysmography (PPG) is the measurement of blood volumetric changes with each heartbeat. The PPG pulse obtained by the optical sensor is used for various cardiovascular parameter measurement. Frequency domain analysis of PPG signal shows a two peaks first around 0.25 to 0.35Hz and second at around 1 to 1.5Hz. Figure 13: Frequency spectrum of the PPG signal

17. Respiratory rate measurement using PPG signal [8] Figure 14: System block diagram Figure 15: PPG of subject

18. Conclusion Several techniques have been developed for the measurement. The choice of a particular method depends upon the ease of application of the transducer and their acceptance by the subject under test. Respiratory rate monitor using PVDF is cost-effective.

19. References [1 ] Cretikos M, Bellomo R, Hillman K, Chen J, Finfer S, Flabouris A, “Respiratory Rate: the neglected vital sign,”  The Medical Journal of Australia  Dec 2007. [2] Ian Smith, John Mackay, Nahla Fahrid , Don Krucheck , “ Respiratory rate measurement: a comparison of methods,” British Journal of Healthcare Assistants , vol 05 No 01, January 2011. [3] Bryson Padasdao , Olga Boric- Lubecke , “ Respiratory Rate Detection Using a Wearable Electromagnetic Generator ,“ International Conference of the IEEE EMBS Boston , Massachusetts USA, August 30 - September 3, 2011. [4] Zhigang Zhu, Ning Xiang, “Detecting Voice, Heart Beats and Respiration by a Laser Doppler Vibrometer ,” Online. [5] Lorenzo Scalise, Ilaria Ercoli, Paolo Marchionni, Enrico Primo Tomasini, Measurement of Respiration Rate in Preterm Infants by Laser Doppler Vibrometry,”IEEE,2011

20. References [6] Y. P. Huang, M. S. Young and K. N. Huang, “Respiratory Rate Monitoring Gauze Mask System Based on a Pyroelectric Transducer,” IEEE, pp 1648-1649, 2008. [7] Amit K. Gupta, “ Respiration Rate Measurement Based on Impedance Pneumography ,” Application Report, Texas Instruments, 2011. [8] Nivedita Daimiwal , M. Sundhararajan and Revati Shriram , “ Respiratory Rate, Heart Rate and Continuous Measurement of BP Using PPG,” International Conference on Communication and Signal Processing, IEEE, pp 999-1002 April 2014.

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