The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 21, 1992
Filed:
May. 21, 1990
Steve M Gehlbach, Los Altos, CA (US);
Other;
Abstract
An ultrasonic transducer apparatus includes an ultrasonic transducer coupled to a backing member, with a cylindrically shaped hole for accepting a hypodermic needle. The transducer transmits ultrasonic sound waves through the skin and toward the vessel of interest. A portion of the energy in the sound waves is reflected by blood cells flowing within an underlying vessel. The reflected energy is 'Doppler shifted' in frequency from the transmitted sound waves because the blood cells are moving relative to the position of the transducer, with the shift in frequency being proportional to the velocity of the blood cells flowing in the vessel. The Doppler shifted reflected signal is detected and amplified and then used to drive an audio speaker, thereby generating an audible signal. As the needle is brought closer to a vessel, the Doppler sounds become stronger in amplitude and the angle of the needle with respect to the vessel affects the pitch of the Doppler shifted signal. These audible indications are used by a clinician, while varying the angle of the needle, to identify the proper direction to proceed in order to insert the needle in the vessel.