105 lines
3.3 KiB
C#
105 lines
3.3 KiB
C#
using StackExchange.Redis;
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public static class News2Calculator
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{
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// The 7 NEWS2 parameter codes. Order is stable for MGET.
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public static readonly IReadOnlyList<string> ParameterCodes = new[]
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{
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"RESP_RATE", "SPO2", "SYSTOLIC_BP", "HEART_RATE", "AVPU", "TEMP_C", "SUPPLEMENTAL_O2"
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};
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public static RedisKey[] AllParameterKeys(Guid encounterId) =>
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ParameterCodes
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.Select(code => (RedisKey)$"news2:{encounterId}:{code}")
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.ToArray();
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public static string ParameterKey(Guid encounterId, string code) =>
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$"news2:{encounterId}:{code}";
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public static bool IsNews2Code(string observationCode) =>
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ParameterCodes.Contains(observationCode);
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// --- Individual parameter scoring ---
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// Each method returns 0-3 per the official NEWS2 scoring table.
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public static int ScoreRespRate(decimal value) => value switch
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{
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<= 8 => 3,
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<= 11 => 1,
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<= 20 => 0,
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<= 24 => 2,
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_ => 3 // >= 25
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};
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// Scale 1 (standard). Scale 2 (hypercapnic respiratory failure) is not implemented.
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public static int ScoreSpo2(decimal value) => value switch
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{
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<= 91 => 3,
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<= 93 => 2,
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<= 95 => 1,
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_ => 0 // >= 96
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};
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public static int ScoreSystolicBp(decimal value) => value switch
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{
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<= 90 => 3,
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<= 100 => 2,
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<= 110 => 1,
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<= 219 => 0,
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_ => 3 // >= 220
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};
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public static int ScoreHeartRate(decimal value) => value switch
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{
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<= 40 => 3,
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<= 50 => 1,
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<= 90 => 0,
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<= 110 => 1,
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<= 130 => 2,
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_ => 3 // >= 131
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};
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// AVPU: Alert=0, Voice/Pain/Unresponsive=3 (any non-Alert scores 3)
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public static int ScoreConsciousness(decimal value) => value switch
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{
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0 => 0, // Alert
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_ => 3 // Voice (1), Pain (2), Unresponsive (3)
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};
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public static int ScoreTemperature(decimal value) => value switch
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{
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<= 35.0m => 3,
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<= 36.0m => 1,
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<= 38.0m => 0,
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<= 39.0m => 1,
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_ => 2 // >= 39.1
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};
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// 0 = room air, 1 = on supplemental oxygen
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public static int ScoreSupplementalO2(decimal value) =>
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value >= 1 ? 2 : 0;
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// Dispatch to the correct scoring function by observation code.
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public static int ScoreParameter(string observationCode, decimal value) =>
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observationCode switch
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{
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"RESP_RATE" => ScoreRespRate(value),
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"SPO2" => ScoreSpo2(value),
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"SYSTOLIC_BP" => ScoreSystolicBp(value),
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"HEART_RATE" => ScoreHeartRate(value),
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"AVPU" => ScoreConsciousness(value),
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"TEMP_C" => ScoreTemperature(value),
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"SUPPLEMENTAL_O2" => ScoreSupplementalO2(value),
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_ => throw new ArgumentOutOfRangeException(nameof(observationCode))
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};
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// Determine risk level from total score and single-param-3 flag.
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public static string DetermineRiskLevel(int totalScore, bool hasSingleParamThree) =>
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totalScore switch
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{
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>= 7 => "HIGH",
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>= 5 => "MEDIUM",
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_ when hasSingleParamThree => "LOW_MEDIUM",
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_ => "LOW"
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};
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} |