MediaWiki:Gadget-calculator-fluidManagement.js
From WikiAnesthesia
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( function() {
mw.calculators.addUnitsBases( {
hgb: {
toString: function( units ) {
units = units.replace( 'hgbperdL', '/dL' );
units = units.replace( /\s?pcthct/, '%' );
return units;
}
},
mEqperL: {
toString: function( units ) {
units = units.replace( 'mEqperL', 'mEq/L' );
units = units.replace( 'mmolperL', 'mmol/L' );
}
}
} );
mw.calculators.addUnits( {
pcthct: {
baseName: 'hgb'
},
ghgbperdL: {
baseName: 'hgb',
prefixes: 'short',
definition: '3 pcthct'
},
mEqperL: {
baseName: 'mEqperL'
},
mmolperLUnivalent: {
baseName: 'mEqperL',
definition: '1 mEqperL'
}
} );
mw.calculators.addVariables( {
caseDuration: {
name: 'Case duration',
type: 'number',
abbreviation: 'Duration',
minValue: '1 min',
defaultValue: '4 hr',
maxLength: 3,
units: [
'hr',
'min'
]
},
hct: {
name: 'Current hematocrit/hemoglobin',
type: 'number',
abbreviation: 'Current hct/HgB',
minValue: '10 pcthct',
maxValue: '75 pcthct',
defaultValue: '45 pcthct',
maxLength: 4,
units: [
'pcthct',
'ghgbperdL'
]
},
minHct: {
name: 'Minimum hematocrit/hemoglobin',
type: 'number',
abbreviation: 'Min hct/HgB',
minValue: '10 pcthct',
maxValue: '45 pcthct',
defaultValue: '21 pcthct',
maxLength: 4,
units: [
'pcthct',
'ghgbperdL'
]
},
npoTime: {
name: 'Time spent NPO',
type: 'number',
abbreviation: 'NPO time',
minValue: '0 hr',
defaultValue: '8 hr',
maxLength: 2,
units: [
'hr'
]
},
serumSodium: {
name: 'Current serum sodium',
type: 'number',
abbreviation: 'Current Na<sup>+</sup>',
minValue: '100 mEqperL',
maxValue: '170 mEqperL',
defaultValue: '140 mEqperL',
maxLength: 3,
units: [
'mEqperL',
'mmolperLUnivalent'
]
},
serumSodiumGoal: {
name: 'Goal serum sodium',
type: 'number',
abbreviation: 'Goal Na<sup>+</sup>',
minValue: '100 mEqperL',
maxValue: '170 mEqperL',
defaultValue: '140 mEqperL',
maxLength: 3,
units: [
'mEqperL',
'mmolperLUnivalent'
]
},
surgicalTrauma: {
name: 'Severity of surgical trauma',
type: 'string',
abbreviation: 'Surgical trauma',
defaultValue: 'Minimal',
options: [
'Minimal',
'Moderate',
'Severe'
]
}
} );
// Fluid management
mw.calculators.addCalculations( {
ebv: {
name: 'Estimated blood volume',
abbreviation: 'EBV',
data: {
variables: {
required: [ 'weight', 'age' ]
}
},
digits: 0,
units: 'mL',
description: '<ul><li>Preterm: 95 mL/kg</li><li>0-1 month old: 85 mL/kg</li><li>1 month-1 year old: 80 mL/kg</li><li>≥ 1 year old<ul><li>Female: 65 mL/kg</li><li>Male: 75 mL/kg</li></ul></li></ul>',
references: [
'Morgan & Mikhail\'s Clinical Anesthesiology. 5e. p1168'
],
calculate: function( data ) {
var weight = data.weight.toNumber( 'kgwt' );
var age = data.age.toNumber( 'yo' );
var ebvPerKg;
if( age >= 1 ) {
if( data.gender === 'F' ) {
ebvPerKg = 65;
} else {
ebvPerKg = 75;
}
} else if( age >= 1/12 ) {
ebvPerKg = 80;
} else if( age >= 0 ) {
ebvPerKg = 85;
} else {
ebvPerKg = 95;
}
return weight * ebvPerKg;
}
},
fluidMaintenanceRate: {
name: 'Fluid maintenance rate',
abbreviation: 'Fluid maint.',
data: {
variables: {
required: [ 'weight' ]
}
},
description: 'Uses 4-2-1 rule:<ul><li>4 mL/kg for the first 10 kg</li><li>2 mL/kg for the next 10 kg</li><li>1 mL/kg for the remaining weight</li></ul>',
digits: 0,
units: 'mL/hr',
formula: '',
references: [
'Miller\'s Anesthesia 7e, section IV, pg. 1728'
],
calculate: function( data ) {
var weight = data.weight.toNumber( 'kgwt' );
// Uses 4-2-1 rule
var maintenanceRate = 4 * Math.min( weight, 10 );
if( weight > 10 ) {
maintenanceRate += 2 * Math.min( weight - 10, 10 );
}
if( weight > 20) {
maintenanceRate += weight - 20;
}
return maintenanceRate;
}
},
intraopFluids: {
name: 'Intraoperative fluid dosing',
abbreviation: 'Intraop fluids',
data: {
calculations: {
required: [ 'fluidMaintenanceRate' ]
},
variables: {
required: [ 'weight', 'npoTime', 'surgicalTrauma' ]
}
},
type: 'string',
references: [
'Corcoran T, Rhodes JE, Clarke S, Myles PS, Ho KM. Perioperative fluid management strategies in major surgery: a stratified meta-analysis. Anesth Analg. 2012 Mar;114(3):640-51. doi: 10.1213/ANE.0b013e318240d6eb. Epub 2012 Jan 16. PMID: 22253274.'
],
calculate: function( data ) {
var weight = data.weight.toNumber( 'kgwt' );
var maintenanceRate = data.fluidMaintenanceRate.toNumber( 'mL/hr' );
var npoTime = data.npoTime.toNumber( 'hr' );
var surgicalTrauma = data.surgicalTrauma;
var output = '';
var npoDeficit = npoTime * maintenanceRate;
var surgicalLossMin, surgicalLossMax;
if( surgicalTrauma === 'Minimal' ) {
surgicalLossMin = 2 * weight;
surgicalLossMax = 4 * weight;
} else if( surgicalTrauma === 'Moderate' ) {
surgicalLossMin = 4 * weight;
surgicalLossMax = 6 * weight;
} else {
surgicalLossMin = 6 * weight;
surgicalLossMax = 8 * weight;
}
var firstHour = Math.round( npoDeficit / 2 ) + maintenanceRate;
var nextHoursMin = Math.round( npoDeficit / 4 ) + maintenanceRate + surgicalLossMin;
var nextHoursMax = Math.round( npoDeficit / 4 ) + maintenanceRate + surgicalLossMax;
var remainingHoursMin = maintenanceRate + surgicalLossMin;
var remainingHoursMax = maintenanceRate + surgicalLossMax;
output += 'NPO deficit: ' + Math.round( npoDeficit ) + ' mL<br/>';
output += 'Surgical losses: ' + surgicalLossMin + '-' + surgicalLossMax + ' mL/hr<br/>';
output += '1st hour: ' + firstHour + ' mL<br/>';
output += '2nd hour: ' + nextHoursMin + '-' + nextHoursMax + ' mL<br/>';
output += '3rd hour: ' + nextHoursMin + '-' + nextHoursMax + ' mL<br/>';
output += '4+ hours: ' + remainingHoursMin + '-' + remainingHoursMax + ' mL<br/>';
return output;
}
},
maxAbl: {
name: 'Maximum allowable blood loss',
abbreviation: 'Max ABL',
data: {
calculations: {
required: [ 'ebv' ]
},
variables: {
required: [ 'weight', 'age', 'hct', 'minHct' ]
}
},
digits: 0,
units: 'mL',
formula: '<math>\\mathrm{ABL_{max}} = \\mathrm{EBV} * \\frac{\\mathrm{Hct_{current}} - \\mathrm{Hct_{minimum}}}{\\mathrm{Hct_{current}}}</math>',
references: [
'Morgan & Mikhail\'s Clinical Anesthesiology. 5e. p1168'
],
calculate: function( data ) {
var currentHct = data.hct.toNumber( 'pcthct' );
var minHct = data.minHct.toNumber( 'pcthct' );
if( currentHct < minHct ) {
return '-';
}
return data.ebv.toNumber( 'mL' ) * ( currentHct - minHct ) / currentHct;
}
},
minUop: {
name: 'Minimum urine output',
abbreviation: 'Min UOP',
data: {
variables: {
required: [ 'weight', 'age' ],
optional: [ 'caseDuration' ]
}
},
type: 'string',
formula: '<math>\\mathrm{UOP_{min}} = \\begin{cases}1 \\text{ mL/kg/hr} & \\text{if age} < 1 \\\\0.5 \\text{ mL/kg/hr} & \\text{if age} \\geq 1\\end{cases}</math>',
references: [
'Klahr S, Miller SB. Acute oliguria. N Engl J Med. 1998 Mar 5;338(10):671-5. doi: 10.1056/NEJM199803053381007. PMID: 9486997.',
'Arant BS Jr. Postnatal development of renal function during the first year of life. Pediatr Nephrol. 1987 Jul;1(3):308-13. doi: 10.1007/BF00849229. PMID: 3153294.'
],
calculate: function( data ) {
var weight = data.weight.toNumber( 'kgwt' );
var age = data.age.toNumber( 'yo' );
var caseDuration = data.caseDuration ? data.caseDuration.toNumber( 'hr' ) : null;
var minUop;
if( age >= 1 ) {
minUop = 0.5 * weight;
} else {
minUop = 1 * weight;
}
if( caseDuration ) {
minUop = minUop * caseDuration + ' mL';
} else {
minUop = minUop + ' mL/hr';
}
return minUop;
}
},
freeWaterDeficit: {
name: 'Free water deficit in hypernatremia',
abbreviation: 'H<sub>2</sub>O deficit',
data: {
variables: {
required: [ 'weight', 'age', 'gender', 'serumSodium', 'serumSodiumGoal' ]
}
},
digits: 0,
units: 'mL',
formula: '<math>\\mathrm{UOP_{min}} = \\begin{cases}1 \\text{ mL/kg/hr} & \\text{if age} < 1 \\\\0.5 \\text{ mL/kg/hr} & \\text{if age} \\geq 1\\end{cases}</math>',
references: [
'Adrogué HJ, Madias NE. Hypernatremia. N Engl J Med. 2000 May 18;342(20):1493-9. doi: 10.1056/NEJM200005183422006. PMID: 10816188.'
],
calculate: function( data ) {
var weight = data.weight.toNumber( 'kgwt' );
var age = data.age.toNumber( 'yo' );
var gender = data.gender;
var serumSodium = data.serumSodium.toNumber( 'mEqperL' );
var serumSodiumGoal = data.serumSodiumGoal.toNumber( 'mEqperL' );
var totalBodyWater, waterFraction, freeWaterDeficit;
if( age < 18 ) {
waterFraction = 0.6;
} else if( age < 65 ) {
if( gender === 'F' ) {
waterFraction = 0.5;
} else {
waterFraction = 0.6;
}
} else {
if( gender === 'F' ) {
waterFraction = 0.45;
} else {
waterFraction = 0.5;
}
}
totalBodyWater = waterFraction * weight;
freeWaterDeficit = totalBodyWater * ( serumSodium / serumSodiumGoal - 1 );
return freeWaterDeficit;
}
}
} );
}() );