Ocular pneumoplethysmograph and method of operation

• US 3,911,903 A
• Filed: 10/11/1973
• Issued: 10/14/1975
• Est. Priority Date: 10/11/1973
• Status: Expired due to Term

• Current Assignee: Electro-Diagnostic Instruments
• Original Assignee: Chester A. Smith Jr, Clarence E. Hinsen, William Gee
• Inventors: Gee, William, Smith, Chester A. Jr., Hinsen, Clarence E.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/405,511
• Time in Patent Office: 733 Days
• Field of Search: 128/2R,2T,2.5A,2.5E,2.5N,2.5Q,2.5R,2.5V 73/80
• US Class Current: 600/501
• CPC Class Codes: A61B 3/10 Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence

Abstract

A pneumatic device for determining blood pressure pulse waves at constantly changing levels of external vacuum as an indication of blood flow to a particular part of a human body including means (such as an eye cup) attachable to a body portion (such as the ocular globe) to deform the body portion in response to changing sub-atmospheric pressure (vacuum) external to the body portion; means (such as a vacuum system) for subjecting the body portion to external sub-atmospheric pressure; means for detecting pressure changes in the external sub-atmospheric pressure in response to pulsatile changes in the volume or pressure of the body portion; means for continuously varying the external subatmospheric pressure over a predetermined pressure range and a predetermined time span and means for continuously recording the pressure changes caused by the volume changes without regard to changes in the external sub-atmospheric pressure while simultaneously recording the change in the external subatmospheric pressure; which device may contain two simultaneously operating systems for recording blood pressure pulse waves from two particular body portions, and which is particularly applicable to the diagnosis of stenosis or occlusion in an internal carotid artery and for determining the extent of collateral circulation between the two internal carotid arteries.

Claims

1. An apparatus for determining blood pressure pulse waves at constantly changing levels of external vacuum as an indication of blood flow to a particular part of a human body comprising:

a. vacuum transmitting means attachable to a body portion to deform said portion in response to changing sub-atmospheric pressure in a system external to the body portion;

b. detecting means for detecting pressure changes in said system in response to changes in the volume of the body portion;

c. vacuum control means for continuously varying the sub-atmospheric pressure in said external system over a predetermined pressure range;

d. said detecting means comprising a first chamber separated by a diaphragm from a second chamber, each of said chambers being operatively connected to said vacuum control means through a flow restrictor;

e. said vacuum transmitting means being operatively connected to one of said chambers independent of said flow restrictor and operatively connected to said vacuum control means through said flow restrictor;

f. and recording means for continuously recording pressure changes caused by said volume changes.

2. The apparatus of claim 1 wherein said vacuum transmitting means is attachable to the sclera of the eye by means of an eye cup.

3. The apparatus of claim 1 additionally comprising second recordinG means for measuring and recording said continuously varying sub-atmospheric pressure.

4. The apparatus of claim 1 wherein said detecting means is a transducer.

5. An apparatus for simultaneously determining and comparing a pair of blood pressure pulse waves in the two ocular globes of a human being at constantly changing levels of external vacuum as an indication of blood flow through the internal carotid arteries and of collateral circulation between the body portions served by the internal carotid arteries comprising;

a. a pair of vacuum transmitting means attachable to the ocular globes to deform said globes in response to changing subatmospheric pressure in a system external to said globes;

b. a pair of detecting means for detecting pressure changes in said system in response to changes in the volumes of said ocular globes individually;

c. vacuum control means for continuously varying the subatmospheric pressure in the external system over a predetermined pressure range;

d. a pair of recording means associated individually with each of said detecting means for continuously recording the pressure changes in said system by the volume changes in each ocular globe as a differential above or below said continuously varying sub-atmospheric pressure; and

e. means for measuring and recording said continuously varying sub-atmospheric pressure.

6. An apparatus for simultaneously determining and comparing a pair of blood pressure pulse waves in the two ocular globes of a human being at constantly changing levels of external vacuum as an indication of blood flow through the ophthalmic arteries via the internal carotid arteries and of collateral circulation between the body portions served by the internal carotid arteries comprising;

a. a pair of vacuum transmitting means attachable to the ocular globes to deform said globes in response to changing sub-atmospheric pressure in a system external to said globes;

b. a pair of detecting means for detecting pressure changes in said system in response to changes in the volumes of said ocular globes individually;

c. vacuum control means for continuously varying the sub-atmospheric pressure in the external system over a predetermined pressure range;

d. each of said detecting means comprising a first chamber separated by a diaphragm from a second chamber, each of said chambers being operatively connected to said vacuum control means through a flow restrictor;

e. each of said vacuum transmitting means being operatively connected to one of said chambers independent of said flow restrictor, and operatively connected to said vacuum control means through said flow restrictor;

f. a pair of recording means associated individually with each of said detecting means for continuously recording the pressure changes in said system by the volume changes in each ocular globe as a differential above or below said continuously varying sub-atmospheric pressure; and

g. means for measuring and recording said continuously varying sub-atmospheric pressure.

7. A process for simultaneously determining and comparing a pair of blood pressure pulse waves in the two ocular globes of a human being at constantly changing levels of external vacuum as an indication of the blood flow through the internal carotid arteries and of collateral circulation between the body portions served by the internal carotid arteries which comprises, a. deforming both ocular globes simultaneously by the application of vacuum thereto to the point where blood flow in the ocular globes is terminated;

b. allowing said vacuum to diminish toward ambient pressure;

c. recording simultaneously the extent of vacuum application and the blood flow pulses generated in each ocular globe as the pressure increases to ambient by measuring the pressure adjacent the ocular globe as a differential above and below the applied vacuum, and d. repeating said process while compressing manually one of the common carotiD arteries.

8. An apparatus for determining blood pressure pulse waves at constantly changing levels of external vacuum as an indication of blood flow to a particular part of a human body comprising:

a. vacuum transmitting means attachable to a body portion to deform said portion in response to changing sub-atmospheric pressure in a system external to the body portion;

b. transducer means for detecting pressure changes in said system in response to changes in the volume of the body portion;

c. vacuum control means for continuously varying the sub-atmospheric pressure in said external system over a predetermined pressure range;

d. said detecting means comprising a transducer operatively connected to said vacuum control means through a flow restrictor;

e. said vacuum transmitting means being operatively connected to said transducer independent of said flow restrictor and operatively connected to said vacuum control means through ssaid flow restrictor; and

f. recording means for continuously recording pressure changes caused by said volume changes.