# US 5,343,868 A · Method and apparatus for detecting artifacts in a blood pressure measuring system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,343,868 A - Document ID: US5343868A - Status: Granted - Kind: A - Application number: 08/038,672 - Filed: 1993-03-26 - Granted: 1994-09-06 - Earliest claimed: 1992-04-02 - Assignees: Hewlett-Packard Company - Inventors: Regina Kurscheidt; Martin Felger; Michael P. Beech - Web page: https://patentgrep.com/patent/US5343868A ## CPC - A61B 5/0215: by means inserted into the body - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A method for detecting artifacts in a blood pressure measuring system, in particular artifacts caused by sampling or flushing in an invasive blood pressure measuring system, disables the related alarms if a sample in a time sequence is larger than a mean value, and when it exceeds a predetermined limit, and when its slope is beyond another limit, and if all of these conditions apply for a certain time period. The end of an artifact is detected if the slope falls beyond a limit, a pulsation is detected, the absolute value is beyond a limit for a certain amount of time, or a long timeout occurs. ## Claims ### Claim 1 A method for detecting artificial artifacts in a blood pressure measuring system comprising the steps of: obtaining a time sequence of samples representative of the actual blood pressure of a being, calculating a short-term mean value based on preceding values of the blood pressure, comparing at least one of said samples of said time sequence with said mean value, repeating said step of comparing for a period of time, indicating an artificial artifact if substantially all of said comparisons reveal that the samples exceed said mean value, and inhibiting said indicating step if pulsations is detected. ### Claim 2 (depends on 1) The method according to claim 1, characterized in that said mean value is a moving average. ### Claim 3 (depends on 1) The method according to claim 1, characterized in that said mean value is calculated from the mean beat-to-beat blood pressure. ### Claim 4 (depends on 1) The method according to claim 1, comprising the additional step of indicating an artificial artifact only if substantially all samples compared during said period of time exceed, or are equal to, a predetermined threshold. ### Claim 5 (depends on 1) The method according to claim 1, comprising the additional step of indicating an artificial artifact only if the difference between substantially every sample and the sample preceding it in time is greater than, or equal to, a predetermined limit, said samples occurring during said period of time. ### Claim 6 (depends on 1) The method according to claim 1, comprising the additional step of varying the amplitude of said mean value in dependence of preceding detected artifacts. ### Claim 7 (depends on 6) The method according to claim 6, wherein the amplitude of said mean value is increased if an artificial artifact has not been detected for a predetermined time period. ### Claim 8 (depends on 1) The method according to claim 1, wherein said indicating step is inhibited if the difference between a sample and preceding sample falls below a predetermined limit. ### Claim 9 (depends on 1) The method according to claim 1, wherein said indicating step is inhibited if a sample falls below a predetermined limit. ### Claim 10 (depends on 1) The method according to claim 1, wherein said indication is removed if a predetermined time period has expired since its last onset. ### Claim 11 (depends on 1) The method according to claim 1, comprising the step of suppressing or disabling an alarm as long as an artificial artifact is indicated. ### Claim 12 (depends on 1) The method according to claim 1, wherein said method is set up for the detection of artifacts caused by sampling in an invasive blood pressure measuring system. ### Claim 13 (depends on 1) The method according to claim 1, wherein said method is set up for the detection of artifacts caused by a flushing in an invasive blood pressure measuring system. ### Claim 14 (depends on 1) The method according to claim 1, wherein the repeating step includes repeating the calculating step. ### Claim 15 (depends on 1) The method according to claim 1, wherein said period of time is defined by a predetermined number of samples. ### Claim 16 (depends on 15) The method according to claim 15, wherein said samples are substantially equally spaced. ### Claim 17 (depends on 1) The method according to claim 1, wherein said period of time is a predetermined amount of time. ### Claim 18 (depends on 1) The method according to claim 1, wherein said indicating step is inhibited if the samples occurring during said period of time fall below a predetermined limit. ### Claim 19 A blood pressure measuring system, in particular an invasive blood pressure measuring system, comprising: blood pressure sensing means for receiving electronic signals representative of a being's blood pressure from a blood pressure transducer; blood pressure calculating means for calculating the blood pressure, in particular the mean beat-to-beat blood pressure, from said electronic signals received from said blood pressure sensing means; alarm generating means set up to generate an alarm if said calculated blood pressure fulfills at least one predetermined alarm condition, in particular if it falls below or exceeds a predetermined limit; and artificial artifact detection means for comparing samples representative of said being's actual blood pressure with a mean value based on preceding values of the blood pressure for repeating said comparison for a predetermined number of samples and for generating an artificial artifact indicating signal if substantially all of said comparisons reveal that the samples exceed said mean value or values unless pulsation is sensed by said blood pressure transducer; wherein said artificial artifact indicating signal is fed to said alarm generating means causing the alarm generating means to suppress alarms as long as said artificial artifact indicating signal is in its active state.