Surgical fluid and tissue loss monitor

• US 5,944,668 A
• Filed: 01/15/1998
• Issued: 08/31/1999
• Est. Priority Date: 05/03/1994
• Status: Expired due to Fees

• Current Assignee: Thierry G. Vancaillie
• Original Assignee: Aquintel, Inc.
• Inventors: Vancaillie, Thierry G., Mitchiner, Robert K., Newton, David W.
• Primary Examiner(s): Stright, Ronald
• Assistant Examiner(s): NGUYEN, ANH TUAN TUONG
• Application Number:
  US09/008,099
• Time in Patent Office: 593 Days
• Field of Search: 604/4, 604/20, 604/246, 604/318, 600/309, 600/310, 600/315, 600/316, 600/318, 600/322, 600/326, 600/328, 600/573, 600/476, 600/477
• US Class Current: 600/477
• CPC Class Codes: A61B 5/02042 Determining blood loss or bleeding, e.g. during a surgical procedure
• CPC Class Codes: A61M 1/77 Suction-irrigation systems aspiration tips supplying fluids A61M1/85; specific for negative pressure wound therapy A61M1/92; combined with tracheal tubes A61M16/0463
• CPC Class Codes: A61M 1/777 Determination of loss or gain of body fluids due to suction-irrigation, e.g. during surgery
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3393 by weighing the reservoir
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: A61M 2209/082 Mounting brackets, arm supports for equipment
• CPC Class Codes: A61M 2209/084 Supporting bases, stands for equipment
• CPC Class Codes: A61M 3/0204 Physical characteristics of the irrigation fluid, e.g. conductivity or turbidity
• CPC Class Codes: A61M 3/0212 after use
• CPC Class Codes: A61M 3/022 Volume; Flow rate
• CPC Class Codes: A61M 3/0233 characterised by liquid supply means, e.g. from pressurised reservoirs
• CPC Class Codes: A61M 3/0283 with at least two inner passageways, a first one for irrigating and a second for evacuating suction-irrigation systems A61M1/77; aspiration tips with fluid supply means A61M1/85; for negative pressure wound therapy A61M1/92
• CPC Class Codes: A61M 3/0287 with an external liquid collector
• CPC Class Codes: A61M 5/16895 by monitoring weight change, e.g. of infusion container
• CPC Class Codes: G01G 17/04 for weighing fluids, e.g. gases, pastes
• CPC Class Codes: G01G 19/00 Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups electric measuring arrangements involving comparison with a reference value G01R17/00

Abstract

A monitor to provide substantially real-time estimates of fluid absorption rate and tissue loss rate in a patient during a surgical procedure. The monitor estimates fluid source flow rates and waste fluid flow rates based on weight changes per unit time or direct reading fluid flow rate meters. Tissue loss flow rates are estimated based on tissue concentration measurable in waste irrigation fluid using an optical comparator, and are used to correct waste fluid flow rates. Correct waste fluid flow rates are used in turn to obtain estimated fluid absorption rates.

Claims

1. An optical comparator, comprising

a light source;

adjustable diffuser means proximate said light source and intercepting at least a portion of light from said light source to produce variably scattered light emanating from said adjustable diffuser means;

at least two comparator fluid chambers positioned to intercept at least a portion of said variably scattered light to produce output light emanating from each of said comparator fluid chambers;

a detector comprising a plurality of light receptors, at least a portion of output light emanating from each of said comparator fluid chambers impinging on a light receptor corresponding to each of said comparator fluid chambers, and each said corresponding light receptor producing a signal substantially proportional to a parameter of said intercepted portion of output light impinging on said receptor; and

comparing means for comparing each said light receptor signal to at least one other said light receptor signal to produce a comparator signal.