Dependence between photoplethysmographic pulse transit times and blood pressure
Niemi, Topi (2021)
2021
Bioteknologian ja biolääketieteen tekniikan kandidaattiohjelma - Bachelor's Programme in Biotechnology and Biomedical Engineering
Lääketieteen ja terveysteknologian tiedekunta - Faculty of Medicine and Health Technology
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2021-12-01
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202110298020
https://urn.fi/URN:NBN:fi:tuni-202110298020
Tiivistelmä
Photoplethysmography (PPG) is an optical measurement technology capable of recording vol umetric variations in blood circulation. It offers a simple and cost-effcient option for real-time monitoring of the cardiovascular circulation.
PPG is a series of pulse waves, in which every wave represents a single cardiac cycle. This pulse wave has a plethora of interesting attributes capable of analyzing the cardiovascular system of the patient. Among these attributes, we will be focusing on the pulse transit time (PTT), which represents the time it takes from the pulse wave to travel from one arterial site to another. In this paper we tested the possibility of calculating PTTs from fngers and toes. We also wanted to see how the PTTs behaved in relate to different blood pressures (systolic blood pressure, diastolic blood pressure and mean arterial pressure) of the patient.
Ten voluntary individuals took part in the measurements, where PPGs, electrocardiogram (ECG) and blood pressures were measured. The orientation of the patient was altered during the measurement from a slight incline to horizontal position, in order to see how this affected the results. The PTTs were then calculated from the acquired data and analyzed in relate to differ ent stages of the measurement and blood pressures. The blood pressures were measured using commercial Finapres NOVA, which offers a two-piece height correction unit (HCU). The HCU unit compensates the height difference of the subjects arm and fnger in the measurement results.
The PTTs were calculated separately for right and left side circulation, using index fngers and second toes as arterial sites. This bi-lateral approach offered us a way to compare different sides of the circulation. The differences in both right and left PTTs were statistically signifcant between the incline and horizontal positions of the patient.
When height-corrected blood pressure readings from the reference blood pressure measure ment were analyzed, in roughly half of the patients the PTTs increased according to the theory when the blood pressures decreased. Because of that, also the dependence between non-height compensated blood pressures from fnger cuff and PTT were analyzed.
We found a clear dependence between fnger diastolic pressure (fDIA) and PTT, which would explain the changes in PTTs. This also raises the motivation to test the behaviour of the height correction.
In conclusion, PTT can be calculated from fngers and toes offering more fexible options for patient monitoring. Further research with larger population would be required to test the behaviour of blood pressure. Since multiple conditions affect the cardiovascular system, the patients could be questioned more thoroughly about their health in order to minimize wrong conclusions made from differentiating results.
PPG is a series of pulse waves, in which every wave represents a single cardiac cycle. This pulse wave has a plethora of interesting attributes capable of analyzing the cardiovascular system of the patient. Among these attributes, we will be focusing on the pulse transit time (PTT), which represents the time it takes from the pulse wave to travel from one arterial site to another. In this paper we tested the possibility of calculating PTTs from fngers and toes. We also wanted to see how the PTTs behaved in relate to different blood pressures (systolic blood pressure, diastolic blood pressure and mean arterial pressure) of the patient.
Ten voluntary individuals took part in the measurements, where PPGs, electrocardiogram (ECG) and blood pressures were measured. The orientation of the patient was altered during the measurement from a slight incline to horizontal position, in order to see how this affected the results. The PTTs were then calculated from the acquired data and analyzed in relate to differ ent stages of the measurement and blood pressures. The blood pressures were measured using commercial Finapres NOVA, which offers a two-piece height correction unit (HCU). The HCU unit compensates the height difference of the subjects arm and fnger in the measurement results.
The PTTs were calculated separately for right and left side circulation, using index fngers and second toes as arterial sites. This bi-lateral approach offered us a way to compare different sides of the circulation. The differences in both right and left PTTs were statistically signifcant between the incline and horizontal positions of the patient.
When height-corrected blood pressure readings from the reference blood pressure measure ment were analyzed, in roughly half of the patients the PTTs increased according to the theory when the blood pressures decreased. Because of that, also the dependence between non-height compensated blood pressures from fnger cuff and PTT were analyzed.
We found a clear dependence between fnger diastolic pressure (fDIA) and PTT, which would explain the changes in PTTs. This also raises the motivation to test the behaviour of the height correction.
In conclusion, PTT can be calculated from fngers and toes offering more fexible options for patient monitoring. Further research with larger population would be required to test the behaviour of blood pressure. Since multiple conditions affect the cardiovascular system, the patients could be questioned more thoroughly about their health in order to minimize wrong conclusions made from differentiating results.
Kokoelmat
- Kandidaatintutkielmat [9898]