Blood Flow Measurements in the Ears of Patients Receiving Cochlear Implants

2002 ◽  
Vol 111 (11) ◽  
pp. 998-1001 ◽  
Author(s):  
Tsutomu Nakashima ◽  
Taku Hattori ◽  
Eisuke Sato ◽  
Michihiko Sone ◽  
Mitsuo Tominaga
Keyword(s):  
Blood Flow ◽  
Cochlear Implants ◽  
Cochlear Implantation ◽  
Internal Auditory Canal ◽  
Laser Doppler ◽  
Outer Diameter ◽  
Cochlear Blood Flow ◽  
Flow Measurements ◽  
Doppler Flowmetry ◽  
Blood Flow Measurements

We measured cochlear blood flow in 12 patients who received cochlear implants, using a laser-Doppler probe with an outer diameter of 0.8 mm. The subjects had congenital deafness, idiopathic progressive sensorineural hearing loss, Waardenburg's syndrome, narrow internal auditory canal, or sudden deafness. Putting the probe tip to the site of drilling for cochlear implantation, we measured blood flow before, during, and after the cochlear bony wall was opened. The laser-Doppler output was confirmed even after the tip of the probe was inserted into the perilymphatic space in all cases. Our results revealed that blood flow was maintained in all cochleas, although there was a probability of reduction in blood flow volume. We conclude that laser-Doppler flowmetry is both relatively safe and useful for measuring blood flow in the ears during cochlear implantation procedures.

Recent Advances in Cochlear Blood Flow Measurements

1988 ◽  
Vol 97 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Jonathon S. Sillman ◽  
Michael J. Larouere ◽  
Alfred L. Nuttall ◽  
Merle Lawrence ◽  
Josef M. Miller
Keyword(s):  
Blood Flow ◽  
Hearing Loss ◽  
Inner Ear ◽  
Laser Doppler ◽  
Control Mechanisms ◽  
Clinical Value ◽  
Cochlear Blood Flow ◽  
Flow Measurements ◽  
Local Flow ◽  
Doppler Flowmetry

Changes in blood flow to the inner ear have been thought to influence or underlie a number of cochlear diseases, including some forms of noise-induced hearing loss, sudden hearing loss, and Meniere's disease. Recently, important advances have been made in two technologies for the study of cochlear blood flow. The first is in the area of vital microscopic studies of cochlear microcirculation, and the second is based on the introduction of laser technology in the form of laser Doppler flowmetry. In this report, measurements are given of changes in cochlear circulation caused by carbon dioxide breathing, intravenous phenylephrine injection, systemic hemodilution, positive end expiratory pressure, and direct electrical stimulation of the cochlea. From these changes, we observe that cochlear blood circulation responds to systemic blood pressure alterations and is subject to local flow control mechanisms. Linearity and speed of response of the laser Doppler instrumentation also are shown. These advances show promise for contributing to our knowledge of control mechanisms of inner ear blood flow and for revealing the influence of various pharmacologic agents of potential clinical value.

Hybrid blood flow probe for simultaneous H2 clearance and laser-Doppler velocimetry

1987 ◽  
Vol 253 (4) ◽  
pp. G573-G581 ◽  
Author(s):  
G. R. DiResta ◽  
J. W. Kiel ◽  
G. L. Riedel ◽  
P. Kaplan ◽  
A. P. Shepherd
Keyword(s):  
Blood Flow ◽  
Laser Doppler Velocimetry ◽  
Regional Blood Flow ◽  
Laser Doppler ◽  
Doppler Velocimetry ◽  
Flow Probe ◽  
Flow Measurements ◽  
Blood Flow Measurements ◽  
Light Guides ◽  
The Relationship

To perform two independent regional blood flow measurements in tissue volumes of similar dimensions, we designed a hybrid blood flow probe capable of measuring regional perfusion by both laser-Doppler velocimetry (LDV) and H2 clearance. The probe consisted of two fiber-optic light guides to conduct light between the surface of tissue of interest and a laser-Doppler blood flowmeter. Also contained within the probe were a platinum 25-microns H2-sensing electrode and a 125-microns H2-generating electrode. The probe can thus be used to measure local perfusion with H2 clearance. The H2 can either be inhaled or can be generated electrochemically at the locus of interest. Evaluation of the probe in the canine gastric mucosa indicated 1) that the relationship between mucosal flow measurements made simultaneously with H2 clearance and LDV was highly significant and linear and 2) that H2 clearance could potentially be used to calibrate the laser-Doppler blood flowmeter in absolute units. The methods of constructing the flow probes are discussed in detail.

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