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Cochlear blood flow measured by averaged laser Doppler flowmetry (ALDF).
Hear Res. 1994 Jun 15; 77(1-2):200-6.HR

Abstract

This report describes a new approach to estimate the hydromechanical properties of a vascular system. Averaged laser Doppler flowmetry (ALDF) was developed by averaging the flux signal of a laser Doppler flowmeter (LDF) synchronized to the heart cycle. The usefulness of this method was verified by manipulation of the cochlear microvasculature. Twelve pigmented guinea pigs under pentobarbital/fentanyl anesthesia were used. The cochlea was surgically exposed and the LDF probe placed on the bony surface of the first turn to monitor cochlear blood flow (CBF). The LDF flux signal (0.2 s time constant) was sampled by an A/D board at 2 kHz for 255 ms and averaged with synchronization to the heart beat. The mean blood flow, peak to peak amplitude, and time (phase) delay of pulsatile flow were measured from the averaged signal. According to a transmission line model of the vascular system, under a given perfusion pressure, mean flow reflects resistance while amplitude and time delay of the pulsatile flow are related to the reactance component of the impedance of the vascular system. During the formation of photochemically-induced thrombosis in the cochlear microvasculature, there was a dramatic mean flux decrease (90.1 +/- 3.4% from baseline (BL), N = 6). Additionally, a time-dependent decrease in amplitude and time delay of pulsatile flow were indicated by ALDF. These results suggest a large increase in vascular resistance and significant decrease in compliance.(

ABSTRACT

TRUNCATED AT 250 WORDS)

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Authors+Show Affiliations

Ren T
Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor 48109-0506.
Brechtelsbauer PB
No affiliation info available
Miller JM
No affiliation info available
Nuttall AL
No affiliation info available

MeSH

AnimalsBlood Flow VelocityCochleaCochlear DiseasesGuinea PigsLaser-Doppler FlowmetryMicrocirculationNitroprussideRound Window, EarThrombosisVascular Resistance

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

7928732

Citation

Ren, T, et al. "Cochlear Blood Flow Measured By Averaged Laser Doppler Flowmetry (ALDF)." Hearing Research, vol. 77, no. 1-2, 1994, pp. 200-6.
Ren T, Brechtelsbauer PB, Miller JM, et al. Cochlear blood flow measured by averaged laser Doppler flowmetry (ALDF). Hear Res. 1994;77(1-2):200-6.
Ren, T., Brechtelsbauer, P. B., Miller, J. M., & Nuttall, A. L. (1994). Cochlear blood flow measured by averaged laser Doppler flowmetry (ALDF). Hearing Research, 77(1-2), 200-6.
Ren T, et al. Cochlear Blood Flow Measured By Averaged Laser Doppler Flowmetry (ALDF). Hear Res. 1994 Jun 15;77(1-2):200-6. PubMed PMID: 7928732.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cochlear blood flow measured by averaged laser Doppler flowmetry (ALDF). AU - Ren,T, AU - Brechtelsbauer,P B, AU - Miller,J M, AU - Nuttall,A L, PY - 1994/6/15/pubmed PY - 1994/6/15/medline PY - 1994/6/15/entrez SP - 200 EP - 6 JF - Hearing research JO - Hear Res VL - 77 IS - 1-2 N2 - This report describes a new approach to estimate the hydromechanical properties of a vascular system. Averaged laser Doppler flowmetry (ALDF) was developed by averaging the flux signal of a laser Doppler flowmeter (LDF) synchronized to the heart cycle. The usefulness of this method was verified by manipulation of the cochlear microvasculature. Twelve pigmented guinea pigs under pentobarbital/fentanyl anesthesia were used. The cochlea was surgically exposed and the LDF probe placed on the bony surface of the first turn to monitor cochlear blood flow (CBF). The LDF flux signal (0.2 s time constant) was sampled by an A/D board at 2 kHz for 255 ms and averaged with synchronization to the heart beat. The mean blood flow, peak to peak amplitude, and time (phase) delay of pulsatile flow were measured from the averaged signal. According to a transmission line model of the vascular system, under a given perfusion pressure, mean flow reflects resistance while amplitude and time delay of the pulsatile flow are related to the reactance component of the impedance of the vascular system. During the formation of photochemically-induced thrombosis in the cochlear microvasculature, there was a dramatic mean flux decrease (90.1 +/- 3.4% from baseline (BL), N = 6). Additionally, a time-dependent decrease in amplitude and time delay of pulsatile flow were indicated by ALDF. These results suggest a large increase in vascular resistance and significant decrease in compliance.(ABSTRACT TRUNCATED AT 250 WORDS) SN - 0378-5955 UR - https://www.unboundmedicine.com/medline/citation/7928732/Cochlear_blood_flow_measured_by_averaged_laser_Doppler_flowmetry__ALDF__ L2 - https://linkinghub.elsevier.com/retrieve/pii/0378-5955(94)90267-4 DB - PRIME DP - Unbound Medicine ER -