Method and device for determining the hydrodynamics of the cerebrospinal fluid system

• US 8,784,331 B2
• Filed: 02/27/2006
• Issued: 07/22/2014
• Est. Priority Date: 02/28/2005
• Status: Active Grant

• Current Assignee: Likvor AB
• Original Assignee: Likvor AB
• Inventors: Malm, Jan
• Primary Examiner(s): Hindenburg, Max
• Assistant Examiner(s): Pani, John
• Application Number:
  US11/885,137
• Publication Number:
  US 20080306403A1
• Time in Patent Office: 3,067 Days
• Field of Search: 600/561, 600/300, 600/301, 600/485, 600/486, 604/9
• US Class Current: 600/561
• CPC Class Codes: A61B 5/032 Spinal fluid pressure
• CPC Class Codes: A61B 5/4064 Evaluating the brain A61B5/031, A61B5/369, A61B5/14553 take precedence

Abstract

The present invention relates to a method and a device for determining the hydro-dynamic properties of the fluid system surrounding the brain and the spinal cord, the so called cerebrospinal fluid system, whereby the method comprises continuous pressure measurement through a fluid contact passage and active infusion of artificial cerebrospinal fluid through another fluid contact passage to a number of pressure-flow levels, and analysis of the connections between the measured pressures and flows. The method uses an adaptive way of procedure which on each pressure-flow level takes account for the measure time and the patient'"'"'s fluctuations in physiologic signals for calculating in real time when the relation between the measure time and measure accuracy in pressure and flow on the actual pressure-flow level is sufficient and at an optimum, whereupon the investigation or examination is automatically proceeding to the next level according to a predetermined protocol. In this way, the method gives rise to an investigation with measurements having sufficient pressure and flow information on each level, which forms a base for determination in a correct manner, with an uncertainty estimate, of the patient'"'"'s hydrodynamic parameters. The device comprises a hose pump (1) for infusion of artificial cerebrospinal fluid in a bottle or bag (2), a standardized hose set including a pump hose (3) and pressure transducers (4) for continuous registration of the intracranial pressure, an invasive contact object (5) for creating fluid contact with the cerebrospinal fluid system and consisting of needles or a catheter, as well as a computer (12) with software for computerized collection and analysis as well as control of pump speed. The device uses a computerized implementation of the above-mentioned adaptive method in order to systematically and safely carry through a standardized protocol which generates pressure and flow information which the software of the measure system then uses for determining in real time and with an uncertainty estimate, the hydrodynamic parameters of the system.

Claims

1. A device for automatically determining hydrodynamic characteristics of a patient cerebrospinal fluid system, comprising:

(a) a hose pump for infusion of artificial cerebrospinal fluid from a container into or out of the patient cerebrospinal fluid system for continuous pressure measurement through a first fluid contact passage and active infusion of artificial cerebrospinal fluid through a second fluid contact passage;

(b) a pump hose through which the artificial cerebrospinal fluid is fed from the container;

(c) pressure transducers for continuous measurement of intracranial pressure;

(d) an invasive contact object, connected to the pump hose, with two lumens for creating fluid contact with the cerebrospinal fluid system; and

(e) a computer for control of the hose pump, the computer having software for computerized collection and analysis, and programmed according to a predetermined protocol that generates or provides pressure and flow information and uses the information for determining, with an uncertainty estimate, the hydrodynamic characteristics of the patient,

wherein the computer is programmed to initially measure each level of pressure and flow for predetermined time intervals, and to automatically proceed to a next level of pressure and flow based upon a determination by the computer that a sufficient accuracy or precision of the hydrodynamic properties has been obtained.

2. A device for automatically determining hydrodynamic characteristics of a patient cerebrospinal fluid system, comprising:

(a) a hose pump for infusion of artificial cerebrospinal fluid from a container into or out of the patient cerebrospinal fluid system for continuous pressure measurement through a first fluid contact passage and active infusion of artificial cerebrospinal fluid through a second fluid contact passage;

(b) a pump hose through which the artificial cerebrospinal fluid is fed from the container;

(c) pressure transducers for continuous measurement of intracranial pressure;

(d) an invasive contact object, connected to the pump hose, with two lumens for creating fluid contact with the cerebrospinal fluid system; and

(e) a computer for control of the hose pump, the computer having software for computerized collection and analysis, and programmed according to a predetermined protocol that generates or provides pressure and flow information and uses the information for determining, with an uncertainty estimate, the hydrodynamic characteristics of the patient,

wherein the computer is programmed to;

(i) make a determination that a patient has large fluctuations in physiological signal if the computer determines physiological signal fluctuations meet predetermined conditions, and based upon that determination, measure pressure and flow for a first time period of a first length; and

(ii) make a determination that a patient has a small fluctuation if the computer determines physiological signal fluctuations do not meet the predetermined conditions, and based upon that determination, measure pressure and flow for a second time period of a second length, where the second length is less than the first length.