Surgical cassette proximity sensing and latching apparatus

• US 4,810,242 A
• Filed: 07/31/1986
• Issued: 03/07/1989
• Est. Priority Date: 09/26/1985
• Status: Expired due to Term

• Current Assignee: Alcon Manufacturing Limited (Alcon Incorporated)
• Original Assignee: Alcon Laboratories Incorporated (Alcon Incorporated)
• Inventors: Rogers, Daniel D., Sundblom, Leif J.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Shay, David
• Application Number:
  US06/892,356
• Time in Patent Office: 950 Days
• Field of Search: 604/22, 604/27, 604/30, 604/32, 604/33-35, 604/65, 604/67, 604/118, 604/119, 604/131, 422/64, 422/65, 422/100, 360/72.3, 360/99, 73/44.2, 73/52
• US Class Current: 604/28
• CPC Class Codes: A61B 2017/00544 pneumatically
• CPC Class Codes: A61B 2017/00973 pedal-operated
• CPC Class Codes: A61F 9/00736 Instruments for removal of intra-ocular material or intra-ocular injection, e.g. cataract instruments A61F9/008 takes precedence
• CPC Class Codes: A61M 1/72 Cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 1/74 Suction control underwater drainage A61M1/61
• CPC Class Codes: A61M 1/75 Intermittent or pulsating suction A61M1/63, A61M1/772 take precedence
• CPC Class Codes: A61M 1/772 operating alternately
• CPC Class Codes: A61M 1/784 by filtering, sterilising or disinfecting the exhaust air, e.g. swellable filter valves
• CPC Class Codes: A61M 1/804 using Laval or Venturi jet pumps
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 3/0201 Cassettes therefor

Abstract

There is disclosed herein a system for providing control of multiple functions needed to perform eye surgery. A microprocessor based system controls a vacuum generation system using venturis and linear valves and a pneumatic system for driving vitrectomy probes and pneumatic scissors in either a variable frequency, multicut mode or a proportional cut mode where the cutting pressure is proportional to the position of a foot operated position sensor. The frequency of the vitrectomy probe cutting action can also be controlled and the level of vacuum can be controlled from a foot operated position sensor which can also be used to turn on or off a fragmentation device. The footswitch can also be used to turn irrigation fluid on or off, and the flow rate can be controlled from a control on the front panel. By making a certain foot motion in any certain aspiration modes, reflux of the aspiration line can be controlled. The vacuum level is continuously monitored over all aspiration conditions and adjusted to stay as close as possible to the desired vacuum level. A cassette proximity sensing system senses the presence of a cassette, and aids the user in drawing in and latching the cassette. The vacuum integrity of the cassette is automatically checked by the microprocessor each time one is drawn into the machine. The microprocessor also monitors the cassette for fullness an initiates a transfer to empty one bottle of the cassette into another bottle for storage when the first bottle becomes full. A back-up system checks the accuracy of cassette liquid level sensing apparatus by double checking for liquid in the line leading to the vacuum generation system. If water is detected, a fluid transfer from one bottle of the cassette to the other is initiated.

Claims

1. A method of handling a cassette having a vacuum port surrounded by a vacuum seal in a surgical instrument having a vacuum generation system and a cassette receptacle for receiving said cassette, said receptacle having a matching vacuum port surrounded by a vacuum seal and coupled to said vacuum generation system and having a cassette pulling mechanism for engaging said cassette and pulling said cassette vacuum port into sealing engagement with said vacuum port in said cassette receptacle, and having a switch with an arm which extends into said cassette receptacle and which causes said switch to change states when a cassette has been pushed into said cassette receptacle far enough for said cassette pulling mechanism to engage said cassette, and having a vacuum sensor coupled to said vacuum port for reading the vacuum level in said cassette, and having a computer coupled to said switch, said vacuum sensor, said vacuum generation system and said cassette pulling mechanism, comprising the steps of:

reading the status of said switch with said computer to determine if a cassette has been pushed far enough into said cassette receptacle to be engaged by said cassette pulling mechanism;

if said switch indicates that a cassette has been pushed far enough into said cassette receptacle to be engaged by said cassette pulling mechanism, sending control signals via said computer to said cassette pulling mechanism to cause said cassette pulling mechanism to engage said cassette and pull said cassette into sealing engagement between said vacuum port on said cassette and said vacuum port in said cassette receptacle;

sending signals to said vacuum generation system to cause vacuum to be generated and coupled into said cassette via said vacuum ports;

testing the vacuum level in said cassette by reading said vacuum sensor to determine if a predetermined vacuum level has been maintained.

2. The method of claim 1 further comprising a failure counter, and wherein said step of testing the vacuum level further comprises reading said vacuum sensor for a predetermined interval to determine if said predetermined vacuum level has been achieved sometime during said interval.

3. The method of claim 2 further comprising the step of incrementing a failure counter if said predetermined vacuum level is not achieved during said predetermined interval and further comprising the step of determining the count in said failure counter, and if the count is less than a predetermined number, returning to said steps of sending signals to said vacuum generation system to cause vacuum to be generated and testing said vacuum level, and if the count is greater than a predetermined number, for displaying a warning of failure of vacuum.

4. The method of claim 2 further comprising the steps of sending control signals to said vacuum generation system to cause cessation of vacuum generation if said predetermined vacuum level was reached within said predetermined interval and to isolate said cassette from atmospheric pressure, and waiting a second predetermined interval, and reading said vacuum sensor again, and determining whether the vacuum level has dropped more than a predetermined amount.

5. The method of claim 1 further comprising the steps of incrementing said failure counter if the vacuum level in said cassette has dropped more than a predetermined amount and further comprising the step of determining the count in said failure counter, and if the count is less than a predetermined number, returning to said steps of sending signals to said vacuum generation system to cause vacuum to be generated and testing said vacuum level, and if the count is greater than a predetermined number, for displaying a warning of failure of vacuum.