# US 2018/0020928 A1 · Patient monitoring method and monitoring device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0020928 A1 - Document ID: US20180020928A1 - Status: Published application - Kind: A1 - Application number: 15/640,049 - Filed: 2017-06-30 - Published: 2018-01-25 - Earliest claimed: 2011-09-30 - Assignees: Guy's and St. Thomas' NHS Foundation Trust, of The Counting House, Guy's Hospital; King's College London of Strand - Applicants: Guy's and St. Thomas' NHS Foundation Trust, of The Counting House, Guy's Hospital; King's College London, of The Strand - Inventors: Nicholas Hart; John Moxham; Fiammetta Fedele - Web page: https://patentgrep.com/patent/US20180020928A1 ## CPC - A61B 5/0205: Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition - A61B 5/08: Measuring devices for evaluating the respiratory organs - A61B 5/397: Analysis of electromyograms - A61B 5/0245: by using sensing means generating electric signals, {i.e. ECG signals} - A61B 5/366: Detecting abnormal QRS complex, e.g. widening - A61B 5/7203: {for noise prevention, reduction or removal} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A method of monitoring a patient includes measuring neural respiratory drive using a monitoring device (10), repeating the measurement either continuously or at regular time intervals, and comparing the measurements obtained in order to predict treatment failure and/clinical deterioration and/or re-admission. In embodiments of the invention, the neural respiratory drive is measured by obtaining a measure of the second intercostal space parasternal electromyogram. A monitoring device (10) includes a signal input (20), a processing unit (30), and a output unit (50), and is arranged to measure the neural respiratory drive, store the measured value and compare it to a previously measured value for the neural respiratory drive. ## Claims ### Claim 1 A method of monitoring a patient, including: measuring neural respiratory drive using a monitoring device; repeating the measurement continuously and/or at regular time intervals; and comparing the measurements obtained in order to predict treatment failure and/or clinical deterioration and/or admission from home or re-admission to hospital. ### Claim 2 (depends on 1) A method as claimed in claim 1, wherein the neural respiratory drive is measured by obtaining a measure of the second intercostal space parasternal electromyogram. ### Claim 3 (depends on 1) A method as claimed in claim 1, including obtaining a value for the neural respiratory drive time index by multiplying the value of the neural respiratory drive time product by the respiratory rate. ### Claim 4 (depends on 1) A method as claimed in claim 1, including: 1) obtaining a value for a normalized neural respiratory drive (which may be calculated as EMGpara/EMGparamax and termed EMGpara%max); 2) obtaining the respiratory rate of the patient, expressed as breaths per minute (RR/min); 3) obtaining a value for the neural respiratory drive index by multiplying the value of the neural respiratory drive obtained in Step 1 by the respiratory rate (EMGpara%max.RR); 4) repeating Steps 1 to 3 continuously and/or after a first given period of time and comparing the two neural respiratory drive index values obtained. ### Claim 5 (depends on 4) A method as claimed in claim 4, wherein Steps 1 to 3 are carried out upon admission into hospital and repeated just prior to discharge from hospital. ### Claim 6 (depends on 1) A method as claimed in claim 1, including: 1) obtaining a value for a normalized neural respiratory drive by: a) carrying out parasternal electromyography to obtain a raw signal during normal breathing; identifying and obtaining the root mean square of the raw signal to obtain a rectified trace; identifying and obtaining the peak magnitude of the rectified trace for each inspiration; calculating the mean of the peak magnitudes identified (EMGparapeak); b) carrying out parasternal electromyography to obtain a raw signal during at least two (or preferably at least three) sniff maximal maneuvers; obtaining the root mean square of the raw signal to obtain a rectified trace; identifying and selecting the peak magnitude of the rectified trace (EMGparamaxpeak); c) expressing the mean of the peak calculated in Step 1a as a percentage of the peak magnitude selected in Step 1b (EMGpara%maxpeak) 2) obtaining the respiratory rate of the patient, expressed as breaths per minute; 3) obtaining a value for the neural respiratory drive index by multiplying the value of the EMGpara%maxpeak (NRD) obtained in Step 1c by the respiratory rate; 4) repeating Steps 1 to 3 continuously and/or after a first given period of time and comparing the two neural respiratory drive index values obtained. ### Claim 7 (depends on 1) A method as claimed in claim 1, including: obtaining a value for the neural respiratory drive time product by carrying out parasternal electromyography to obtain a raw signal during normal breathing; obtaining the root mean square of the raw signal to obtain a rectified trace; measuring the area under the rectified trace; obtaining a value for the neural respiratory drive time product index by multiplying the neural respiratory drive time product by the respiratory rate; and comparing the two neural respiratory drive time index values obtained. ### Claim 8 (depends on 7) A method as claimed in claim 7, including: identifying and obtaining the area under the curve of the rectified root mean square of the raw signal; calculating the mean of the area under the curves identified (EMGparaAUC); identifying and selecting the area under the curve of the rectified trace (EMGparamaxAUC); expressing the mean area under the curve as a percentage of the maximum area under the curve (EMGpara%maxAUC); and obtaining neural respiratory drive time index by multiplying the value of the EMGpara%maxAUC (NRDTP) by the respiratory rate. ### Claim 9 (depends on 1) A method as claimed in claim 1, wherein the patient has respiratory disease, for example, wherein the respiratory disease is: (1) an acute exacerbation of chronic obstructive pulmonary disease; (2) an acute exacerbation of chronic respiratory disease; (3) acute respiratory failure; (4) chronic respiratory disease; (5) chronic respiratory failure; (6) acute exacerbation of chronic heart failure; (7) acute heart failure; or (8) chronic heart failure. ### Claim 10 (depends on 6) A method as claimed in claim 6, wherein the peak magnitude is obtained for each inspiration over a time period of approximately 30 seconds to 3 minutes. ### Claim 11 A monitoring device including: a signal input, and a processing unit, the monitoring device being arranged to: (1) receive a first raw parasternal electromyography signal at the signal input; execute computer program code in the processing unit to: (2) determine the root mean square of the raw parasternal signal to obtain a rectified trace; (3) identify the peak magnitude of the rectified parasternal trace for each inspiration over a second given period of time; (4) calculate the mean of the peak magnitudes identified; (5) receive further and determine raw parasternal electromyography signals during at least two (preferably at least three) sniff maneouvres; (6) determine the root mean square of the raw signal to obtain a further rectified trace; (7) determine the peak magnitude of the further rectified trace; (8) express the mean of the first peak magnitude as a percentage of the peak magnitude of the further rectified trace obtained during the sniff manouevre; (9) receive data on the respiratory rate of the patient, expressed as breaths per minute; (10) determine a value for the neural respiratory drive index by multiplying the value of the neural respiratory drive by the respiratory rate; and (11) store the measured/determined values of the neural respiratory drive a data repository. ### Claim 12 (depends on 11) A monitoring device as claimed in claim 11, being arranged to determine a subsequent neural respiratory drive index and compare with the stored value. ### Claim 13 (depends on 11) A monitoring device as claimed in claim 11, operable to identify the area under the curve of the rectified root mean square of the raw parasternal signal for each inspiration over a second given period of time to display the measured/determined neural respiratory drive values in real time; to calculate the mean of the area under the curves identified; and to determine the values for NRDTP and NRDTI from the area under the curve of the rectified trace. ### Claim 14 (depends on 1) A method as claimed in claim 1, including carrying out substantially real time processing of biological signals received from surface electrodes, and converting them into a physiological biomarker by processing the signals from the electrodes to obtain and display heart rate (HR), respiratory rate (RR), neural respiratory drive (NRD), neural respiratory drive index (NRDI). ### Claim 15 (depends on 14) A method as claimed in claim 14, including obtaining and displaying neural respiratory drive time product (NRDTP) and neural respiratory drive time index (NRDTI). ### Claim 16 (depends on 14) A method as claimed in claim 14, wherein neural respiratory drive (NRD) is determined from the electromyogram of the 2nd intercostal parasternal muscles (EMGpara) by using electrodes and amplifiers, and processing the signals using analog to digital conversion followed by digital filtering and arithmetic conversion of the signal. ### Claim 17 (depends on 1) A method as claimed in claim 1, wherein signals are recorded during resting breathing to provide an indication of a patient's current respiratory effort determined by objectively measuring EMGpara activity, and wherein the patient performs repeated maximum sniff manoeuvres in order to allow the signal to be normalised for an individual patient maximum effort (EMGpara%max). ### Claim 18 (depends on 1) A method as claimed in claim 1, including the following steps: 1) identifying patients at potential risk of deterioration; 2) placing surface electrodes over the parasternal muscles of the second intercostal space along with a reference electrode over the electrically neutral clavicle; 3) amplifying electrical signals from the two recording electrodes; 4) passing the amplified signal to an analog to digital converter to allow for further computer processing; and 5) integrating the signals to produce the essential biological variables for clinical interpretation. ### Claim 19 (depends on 14) A method as claimed in claim 14, wherein the signal is amplified to a factor of 1000 and analog filtered at 10 Hz and 2000 Hz to remove contributions from other muscle activity and maximize signal from the parasternal muscles. ### Claim 20 (depends on 1) A method as claimed in claim 1, including at least one of the following features: Signal quality assessment (including initial signal) ECG (QRS) detection and HR calculation ECG artifact accommodation or removal from EMGpara signal Calculation of RMS EMGpara analysis including peak-peak analysis to calculate respiratory rate, peak value to calculate EMGpara%maxpeak and multiplication by respiratory rate to calculate NRDI EMGpara analysis to calculate area under the curve of the signal to calculate EMGpara%maxAUC by normalizing for the EMGparamaxAUC and multiplying by respiratory rate to calculate NRDTI.