function [BeatQ, r] = jSQI(features, onset, abp) % JSQI ABP waveform signal quality index. % [BEATQ, R] = JSQI(FEATURES, ONSET, ABP) returns a binary signal quality % assessment of each beat in ABP. This algorithm relies on detecting % abnormalities of numeric values in FEATURES and ONSET. % % In: FEATURES --- features extracted from ABP using abpfeature.m % ONSET --- onset times of ABP using wabp.m % ABP --- arterial blood pressure waveform (125Hz sampled) % % Out: BEATQ --- SQI of each beat: 0=good, 1=bad % Col 1: logical OR of cols 2 thru 10 % 2: P not physiologic (<20 or >300 mmHg) % 3: MAP not physiologic (<30 or >200 mmHg) % 4: HR not physiologic (<20 or >200 bpm) % 5: PP not physiologic (<30 mmHg) % 6: abnormal Psys (beat-to-beat change > 20 mmHg) % 7: abnormal Pdias (beat-to-beat change > 20 mmHg) % 8: abnormal period (beat-to-beat change > 1/2 sec) % 9: abnormal P(onset) (beat-to-beat change > 20 mmHg) % 10: noisy beat (mean of negative dP < -3) % R <1x1> fraction of good beats in ABP % % Usage: % - FEATURES must be obtained using abpfeature.m % - ONSET must be obtained using wabp.m % % Written by James Sun (xinsun@mit.edu) on Nov 19, 2005. % - v2.0 - 1/18/06 - thresholds updated to reduce false positives % - v3.0 - 2/10/06 - added "..101..." detection - see lines 92-96 if length(onset)<30 BeatQ = []; r = []; return end % thresholds rangeP = [20 300]; % mmHg rangeMAP = [30 200]; % mmHg rangeHR = [20 200]; % bpm rangePP = [20 inf]; % mmHg dPsys = 20; dPdias = 20; dPeriod = 62.5; % 62.5 samples = 1/2 second dPOnset = 20; noise = -3; % get ABP features Psys = features(:,2); Pdias = features(:,4); PP = features(:,5); MAP = features(:,6); BeatPeriod = features(:,7); mean_dyneg = features(:,8); HR = 60*125./BeatPeriod; % absolute thresholding (flag unphysiologic beats) badP = find(Pdias < rangeP(1) | Psys > rangeP(2)); badMAP = find(MAP < rangeMAP(1) | MAP > rangeMAP(2)); badHR = find(HR < rangeHR(1) | HR > rangeHR(2)); badPP = find(PP < rangePP(1)); % first difference thresholding (flag beat-to-beat variations) jerkPsys = 1 + find(abs(diff(Psys)) > dPsys); jerkPdias = find(abs(diff(Pdias)) > dPdias); jerkPeriod = 1 + find(abs(diff(BeatPeriod)) > dPeriod); jerkPOnset = find(abs(diff(abp(onset))) > dPOnset); % noise detector noisy = find(mean_dyneg < noise); % SQI final bq = zeros(length(onset),10); bq(badP, 2) = 1; bq(badMAP, 3) = 1; bq(badHR, 4) = 1; bq(badPP, 5) = 1; bq(jerkPsys, 6) = 1; bq(jerkPdias, 7) = 1; bq(jerkPeriod, 8) = 1; bq(jerkPOnset, 9) = 1; bq(noisy, 10) = 1; bq(:,1) = bq(:,2)|bq(:,3)|bq(:,4)|bq(:,5)|bq(:,6)|bq(:,7)|bq(:,8)|bq(:,9)|bq(:,10); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % make all "...101..." into "...111..." y = bq(:,1); y(find(diff(y,2)==2)+1)=1; bq(:,1)=y; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BeatQ = logical(bq); % fraction of good beats overall r = length(find(bq(:,1)==0))/length(onset);