From 559a1fdaf462789437ae4bec15210403914a9cc1 Mon Sep 17 00:00:00 2001
From: "Robert L. Read" <read.robert@gmail.com>
Date: Sat, 27 Jun 2020 21:31:55 -0500
Subject: [PATCH] further work on work-of-breathing
---
breath_plot.html | 155 ++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 146 insertions(+), 9 deletions(-)
diff --git a/breath_plot.html b/breath_plot.html
index 81eca68..b89e506 100644
--- a/breath_plot.html
+++ b/breath_plot.html
@@ -1407,18 +1407,92 @@ function compute_current_TRIP(TRIP_min,TRIP_max, samples)
// A routine to calculate work per breath
- function PressureVolumeWork(breath, transitions, samples) {
- // -1 for quadilateral approximation
- if (breath.vol_i == 0) {
- return("null");
- } else {
+function PressureVolumeWork(breath, transitions, samples) {
+ // -1 for quadilateral approximation
+ if (breath.vol_i == 0) {
+ return null;
+ } else {
var beginTransition = transitions[breath.trans_begin_inhale];
var beginTime_ms = beginTransition.ms;
var endTransition = transitions[breath.trans_cross_zero];
var endTime_ms = endTransition.ms;
var flows = samples.filter(s => s.event == 'M' && s.type == 'F' && s.ms >= beginTime_ms && s.ms <= endTime_ms);
var pressures = samples.filter(s => s.event == 'M' && s.type == 'D' && s.loc == 'A'&& s.ms >= beginTime_ms && s.ms <= endTime_ms);
+
+ console.log(flows);
+ console.log(pressures);
+
+ // Note: The algorithm below relies on the fact that there is
+ // only one flow or pressure with a single ms value; and that
+ // increvementing an index necessarily incremenst the .ms value.
+
+ // Without two samples, we have no duration and can't define
+ // work.
+ if (pressures.length < 2 || flows.length < 2) return null;
+
+ var ct = Math.min(flows[0].ms,pressures[0].ms);
+ var lfp = { val : flows[0].val, ms: flows[0].ms } ; // last flow point
+ var lpp = { val : pressures[0].val, ms: pressures[0].ms }; // last pressure_point
+ var fi = increment_past(flows,ct,0); // Index of next flow sample
+ var pi = increment_past(pressures,ct,0); // Index of next pressure sample
+ var w = 0; // current work
+
+ // compute flow at time ms give index and last point
+ // This is just a simple linear interpolation
+ function f(ms,cur,last) {
+ var ms0 = last.ms;
+ var ms1 = cur.ms;
+ return last.val + (cur.val - last.val)*(ms - ms0)/(ms1 - ms0);
+ }
+ function increment_past(array,ms,index) {
+ while(index < array.length && array[index].ms <= ms)
+ index++;
+ if (index >= array.length)
+ return null;
+ else
+ return index;
+ }
+
+ while ((fi + pi) < (flows.length + pressures.length)) {
+ // Invariant always increment fi or pi
+ // fi and pi point to unprocessed value
+ var ms;
+ if (pressures[pi].ms <= flows[fi].ms) { // process pressure
+ ms = pressures[pi].ms;
+ pi = increment_past(pressures,ms,pi);
+ if (flows[fi].ms <= ms) {
+ fi = increment_past(flows,ms,fi);
+ }
+ } else {
+ ms = flows[fi].ms;
+ fi = increment_past(flows,ms,fi);
+ if (pressures[pi].ms <= ms) {
+ pi = increment_past(pressures,ms,pi);
+ }
+ }
+ if ((fi === null) || (pi === null))
+ break;
+ var dur_s = (ms - ct) / 1000;
+ console.log("dur_s",dur_s);
+ var nf = f(ms,flows[fi],lfp);
+ var np = f(ms,pressures[pi],lpp);
+ var f1 = (lfp.val + nf)/2;
+ var p1 = (lpp.val + np)/2;
+ // convert 10ths of cm H2O to pascals..
+ var p1_pa = (p1 * 98.0665) / 10;
+
+ // convert flows in lpm to cubic meters per seconds
+ var f1_m_cubed_per_s = f1 / (1000 * 1000 * 60);
+
+ // work is now in Joules!
+ w += dur_s * p1_pa * f1_m_cubed_per_s;
+ lfp = { val : f1, ms: ms };
+ lpp = { val : p1, ms: ms };
+ ct = ms;
+ }
console.log("begin transition time, end transition time:",beginTime_ms,endTime_ms);
+
+ console.log("ms,w",ms,w);
//var pressureVolume_prod= 0;
//for(var j = a; j < z-1; j++) {
// // I'll use qadrilateral approximation.
@@ -1449,17 +1523,80 @@ function compute_current_TRIP(TRIP_min,TRIP_max, samples)
fAv_lpm /= flows.length;
console.log("flows:",flows,"\npressures:",pressures)
console.log("pAv, vAv = ",pAv_cm,fAv_lpm);
- var flow_cubicMetersPerSecond = fAv_lpm/1000/60; //lpm to cmps
+ var flow_cubicMetersPerSecond = fAv_lpm/1000/60; //lpm to cmps
var avPower = pressures_pascales*flow_cubicMetersPerSecond; // Watts
var avWork = avPower * (endTime_ms - beginTime_ms)/1000; // Joules
+
+
console.log("Power (Watts):",avPower);
console.log("Work (Joules):",avWork);
- return avWork;
+
+ console.log("ms, Work main (Joules)",ms,w);
+ return w;
+ }
+}
+
+// Let's first set up a perfectly square 1-second
+function generate_synthetic_trace() {
+ const SAMPLES_PER_PHASE = 1000;
+ const SAMPLES_MS_PER_SAMPLE = 1;
+ var trace = [];
+ var cur = 0;
+ function push_samples(start,num,d,f) {
+ for(var i = start; i < start+num; i++) {
+ trace.push(
+ {
+ event: "M",
+ loc: "A",
+ ms: i,
+ num: 0,
+ type: "D",
+ val: d
+ });
+ trace.push(
+ {
+ event: "M",
+ loc: "A",
+ ms: i,
+ num: 0,
+ type: "F",
+ val: f
+ });
}
}
-
+ push_samples(0,SAMPLES_PER_PHASE,-200,-50000);
+ push_samples(SAMPLES_PER_PHASE,SAMPLES_PER_PHASE,200,50000);
+ push_samples(SAMPLES_PER_PHASE*2,SAMPLES_PER_PHASE,-200,-50000);
+ push_samples(SAMPLES_PER_PHASE*3,SAMPLES_PER_PHASE,200,50000);
+ return trace;
+}
+
+
+function testWorkSynthetic(){ // breaths give us inspiration transition points
+ var samples = generate_synthetic_trace();
+
+ const JOULES_IN_BREATH = 1 * 1961.33 * 50000 / (60e+6);
+
+
+ var flows = samples.filter(s => s.event == 'M' && s.type == 'F');
+ var first_time = flows[0].ms;
+ var last_time = flows[flows.length - 1].ms;
+ var duration = last_time - first_time;
+ console.log(flows);
+
+ const vm = 10;
+ // There is a problem here that this does not create a transition at the beginning.
+ var transitions = compute_transitions(vm,flows);
+ var breaths = compute_breaths_based_without_negative_flow(transitions,flows);
+ console.log(breaths);
+ for(i = 0; i<breaths.length; i++) {
+ var w = PressureVolumeWork(breaths[i], transitions, samples);
+ console.assert((w == null) || (w == JOULES_IN_BREATH));
+ console.log("final = ",w);
+ }
+}
function testWork(samples){ // breaths give us inspiration transition points
@@ -1516,7 +1653,7 @@ function compute_current_TRIP(TRIP_min,TRIP_max, samples)
// that level of sophistication needed.
// We still want to track zeros, but now must strack them
// as a falling signal.
-
+
function compute_breaths_based_without_negative_flow(transitions,flows) {
var beg = 0;
var zero = 0;
--
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