Muscle control and monitoring system

• US 5,358,519 A
• Filed: 07/15/1993
• Issued: 10/25/1994
• Est. Priority Date: 12/06/1989
• Status: Expired due to Term

• Current Assignee: Gregory P. Gadson
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Grandjean, Pierre A.
• Primary Examiner(s): SHAY, RANDY CITRIN
• Application Number:
  US08/092,180
• Time in Patent Office: 467 Days
• Field of Search: 623/3, 600/16-18
• US Class Current: 623/3.12
• CPC Class Codes: A61M 2205/054 with electrotherapy
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/3303 Using a biosensor
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/04 Heartbeat characteristics, e.g. ECG, blood pressure modulation
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)
• CPC Class Codes: A61M 2230/50 Temperature
• CPC Class Codes: A61M 2230/60 Muscle strain, i.e. measured on the user
• CPC Class Codes: A61M 60/148 in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
• CPC Class Codes: A61M 60/161 mechanically acting upon the outside of the patient's blood vessel structure, e.g. compressive structures placed around a vessel
• CPC Class Codes: A61M 60/191 mechanically acting upon the outside of the patient's native heart, e.g. compressive structures placed around the heart
• CPC Class Codes: A61M 60/274 the inlet and outlet being the same, e.g. para-aortic counter-pulsation blood pumps
• CPC Class Codes: A61M 60/289 Devices for mechanical circulatory actuation assisting the residual heart function by means mechanically acting upon the patient's native heart or blood vessel structure, e.g. direct cardiac compression [DCC] devices
• CPC Class Codes: A61M 60/515 Regulation using real-time patient data
• CPC Class Codes: A61M 60/531 using blood pressure data, e.g. from blood pressure sensors
• CPC Class Codes: A61M 60/861 Connections or anchorings for connecting or anchoring pumps or pumping devices to parts of the patient's body
• CPC Class Codes: A61M 60/878 Electrical connections within the patient's body
• CPC Class Codes: A61M 60/882 Devices powered by the patient, e.g. skeletal muscle powered devices
• CPC Class Codes: A61N 1/36042 of grafted tissue, e.g. skeletal muscle
• CPC Class Codes: A61N 1/36557 controlled by chemical substances in blood

Abstract

Apparatus and method for monitoring the performance of skeletal muscle used in a skeletal muscle powered cardiac assist system. The longest term monitoring is performed by an oxygen sensor which determines the adequacy of circulatory support to the skeletal muscle. An adequately supported skeletal muscle can offer the desired cardiac assistance chronically. Insufficient support indicates that the skeletal muscle will easily fatigue if adequate vascularization is not achieved. If the circulatory support is chronically insufficient, the risk of ischemia becomes high and additional surgical intervention may be required. A somewhat shorter term concern is the adequacy of the conditioning needed to render a fast twitch skeletal muscle useful in assisting the slow twitch myocardium. A pressure transducer is used to measure conditioning sufficiency. A third type of monitoring provides an indication of changes in cardiac requirements utilizing an activity sensor. This indication of cardiac requirements may be used to vary skeletal muscle loading by adjusting duty cycle. The shortest term monitoring and control technique uses a temperature sensor to monitor efficiency skeletal muscle cardiac assist. Efficiency may be improved by adjusting the phase relationship between cardiac contraction and skeletal muscle stimulation.

Claims

1. A cardiac assist system for assisting a natural heart having ventricles which contract at a ventricular rate, said cardiac assist system adapted for coupling to a surgically prepared muscle responsively coupled to said heart and to a circulatory system, and said cardiac assist system comprising:

a. control means adapted to be coupled to the heart and to the muscle for stimulating the muscle and for causing it to contract in synchrony with said ventricles of said heart; and

b. means, coupled to said control means and adapted to be responsively coupled to the muscle, for monitoring a parameter indicative of a predetermined level corresponding to adequacy of circulatory support to the muscle.

2. The cardiac assist system according to claim 1 wherein said monitoring means comprises:

a. means for sensing blood perfusion of the muscle; and

b. means, responsively coupled to said sensing means, for storing data from said sensing means.

3. The cardiac assist system according to claims 2 further including means for telemetering out the data stored by said storing means.

4. A cardiac assist system according to claim 2 wherein said sensing means is an oximeter.

5. A cardiac assist system according to claim 4 wherein said oximeter is a two wavelength reflectance oximeter.

6. The cardiac assist system according to claim 4 further including means for telemetering out the data stored by said storing means.

7. The cardiac assist system according claim 1, wherein said monitoring means includes means for sensing a level of oxygen in the muscle.

8. An assist system for assisting an organ, said assist system adapted for coupling to a surgically prepared muscle responsively coupled to said organ and to a circulatory system- has been inserted after "muscle". the assist system comprising:

a. control means adapted to be coupled to the organ and to the muscle for stimulating the muscle and for causing it to contract in a predetermined sequence; and

b. means, coupled to said control means and adapted to be responsively coupled to the muscle, for monitoring a parameter indicative of a predetermined level corresponding to adequacy of circulatory support to the muscle.