Abstract
Pulmonary capillary pressure is the blood pressure in the
smallest vessels of pulmonary circulation. This pressure
is one major factor of pulmonary edema. Pulmonary edema
is a life-threatening state, often seen in critically ill
patients. Pulmonary capillary pressure should be known to
avoid pulmonary edema, e.g., in connection with fluid
therapy. Currently, there are no methods for directly
assessing the pulmonary capillary pressure. The aim of
this work is to find a method for automatic estimation of
pulmonary capillary pressure and implement it using
digital signal processing.
In this study, the pulmonary capillary pressure is
estimated from the data obtained in connection with right
heart catheterization. The pulmonary capillary pressure
is obtained by analyzing the pressure transient following
balloon occlusion. The signal was measured from intact
lungs without stopping the mechanical ventilation.
The pulmonary capillary pressure was obtained by fitting
a single exponential curve to the pressure decay
following the balloon occlusion and by extrapolating back
to the time of occlusion. The results were compared with
visual estimates, individually done by three clinicians.
The results show that the methods successfully used by
other research groups in animal tests are not directly
applicable to intact lungs and clinical practice. The
computer estimates differ about 3 mmHg from the mean of
visual estimates. The results are, however, so promising
that future plans have been made to verify the developed
methods with a new data library.
Original language | English |
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Qualification | Master Degree |
Awarding Institution |
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Place of Publication | Tampere |
Publisher | |
Publication status | Published - 1997 |
MoE publication type | G2 Master's thesis, polytechnic Master's thesis |
Keywords
- pulmonary edema
- pulmonary capillary pressure
- right heart catheterization
- single-occlusion technique
- single-exponential method