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Keywords:
Haemodynamics / Flow dynamics, Instrumentation, Ultrasound, Vascular
Authors:
M. Laganà1, M. Di Rienzo2, F. Rizzo2, L. Forzoni3, S. D'Onofrio3, P. Cecconi4; 1Milan/IT, 2Milano/IT, 3Firenze/IT, 4Como (CO)/IT
DOI:
10.1594/ecr2014/C-0223
Conclusion
This preliminary study allowed us to verify the feasibility of the respiratory activity measurement,
simultaneously with all the US modalities of interest for the venous examination.
Positioning the respiratory sensor on the clothes in 9 subjects revealed no degradation in the signal characteristics,
in comparison to those 2 with the sensor not positioned on the clothes.
This supports the described setting as usable in a clinical context,
since it is simple and quick to be positioned,
it is not invasive for the examined subject and it provides a real-time information synchronous with US examination.
Although tested in two subjects only,
the quality of the ECG signal and the respiratory signal,
that were acquired together and showed on US system,
was good.
QDP technology was particularly useful in cases of big movements of the examined subject’s neck veins during different respiratory activities.
In these cases,
QDP overcame the well known limitation of PW,
whose SV can partially sample outside the vessel when the subject breathes and/or moves [16,
17].
Our results confirmed the one of previous studies [20] regarding the IJV and VV flows,
which are influenced by breathing while the BVR is not.
The synchronous and the aligned visualization of all the signals (US modality of interest,
ECG and respiration) on the US screen provided an immediate,
even though qualitative,
evidence of the breathing influence on the vessel morphological or hemodynamic characteristics.
This can be used for a more precise and affordable review,
subsequent to the exam and for improving the clinical documentation,
which matches the respiratory condition and the US imaging,
especially when specific maneuvers have been used.
This setting can also be used to quantitatively measure the blood flow in specific respiratory acts (i.e.
at the end of inspiration or expiration,
after a Valsalva maneuver) and to study how the blood velocity is related and influenced by the heart beat and the respiration.
In conclusion,
a new US setting with simultaneous acquisition of respiration and heart beat was proposed for the analysis of cervical and cerebral veins.
We showed the feasibility of the integration of a respiratory sensor to the standard ECG input in a commercially available US device.
Although future confirmations should be performed on a larger sample size,
the preliminary data obtained support the usefulness of the new setting for the analysis of anatomical,
functional and hemodynamic characteristics of the cervical and cerebral districts,
in relationship with the intra thoracic pressure changes,
induced by respiration.
In particular,
our setting allowed to obtain: first,
a clear time reference among IJV,
VV and BVR blood flows,
with respect to the respiratory and the ECG signal and second,
a clear time reference between IJV dynamic behavior and valve flap movement,
in relation with the respiratory phases.