Package Exports

periop-calculators
periop-calculators/dist/index.esm.js
periop-calculators/dist/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (periop-calculators) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

periop-calculators

Evidence-based perioperative risk assessment calculators for healthcare professionals. Built with TypeScript for type safety and modern JavaScript environments.

Features

🏥 Clinical Accuracy: Implements validated perioperative risk assessment tools
🔍 Type Safe: Full TypeScript support with comprehensive type definitions
📋 Well Tested: Extensive test coverage for reliability
📚 Documented: Detailed API documentation with clinical references
🚀 Lightweight: No external dependencies, small bundle size
🔧 Flexible: Works in Node.js and browser environments

Installation

npm install periop-calculators

yarn add periop-calculators

Quick Start

import { calculateStopBang } from 'periop-calculators';

const result = calculateStopBang({
  snoring: true,
  tiredness: true,
  observed: false,
  pressure: true,
  bmi: 36,
  age: 55,
  neckCircumference: 43,
  gender: 'male'
});

console.log(result);
// {
//   score: 6,
//   risk: 'high',
//   interpretation: 'STOP-BANG score of 6 indicates high risk...',
//   components: { S: true, T: true, O: false, ... },
//   recommendations: [...]
// }

Available Calculators

1. STOP-BANG Score

Screening tool for obstructive sleep apnea (OSA) in surgical patients.

import { calculateStopBang, StopBangInput, StopBangResult } from 'periop-calculators';

const input: StopBangInput = {
  snoring: true,           // Snoring loudly
  tiredness: true,         // Daytime tiredness
  observed: false,         // Observed apnea
  pressure: true,          // Hypertension
  bmi: 36,                // BMI > 35
  age: 55,                // Age > 50
  neckCircumference: 43,  // Neck > 40cm
  gender: 'male'          // Male gender
};

const result: StopBangResult = calculateStopBang(input);

With Patient Demographics

The calculator can derive values from patient demographics:

import { calculateStopBang, PatientDemographics } from 'periop-calculators';

const demographics: PatientDemographics = {
  age: 55,
  sex: 'male',
  weight: 100,  // kg
  height: 180,  // cm
  neckCircumference: 43
};

const result = calculateStopBang(
  {
    snoring: true,
    tiredness: true,
    observed: false,
    pressure: true
  },
  demographics  // BMI, age, and gender will be calculated
);

Risk Stratification

Low Risk (0-2): Low probability of moderate to severe OSA
Intermediate Risk (3-4): Further evaluation may be warranted
High Risk (5-8): High probability of moderate to severe OSA

2. RCRI (Revised Cardiac Risk Index)

Estimates risk of cardiac complications for patients undergoing non-cardiac surgery.

import { calculateRCRI, RCRIInput, RCRIResult } from 'periop-calculators';

const input: RCRIInput = {
  highRiskSurgery: true,          // Intraperitoneal, intrathoracic, or suprainguinal vascular
  ischemicHeartDisease: false,    // History of MI, positive stress test, angina, nitrate use
  congestiveHeartFailure: false,  // History of CHF, pulmonary edema, or dyspnea
  cerebrovascularDisease: false,  // History of stroke or TIA
  insulinDependentDiabetes: true, // Diabetes requiring insulin therapy
  renalInsufficiency: false       // Creatinine > 2.0 mg/dL
};

const result: RCRIResult = calculateRCRI(input);

console.log(result);
// {
//   score: 2,
//   riskClass: 'III',
//   estimatedRisk: '6.6%',
//   riskPercentage: 6.6,
//   interpretation: 'RCRI Class III with 2 risk factors...',
//   riskFactors: { ... },
//   recommendations: [...]
// }

Risk Classification

Class I (0 points): 0.4% risk of major cardiac complications
Class II (1 point): 0.9% risk of major cardiac complications
Class III (2 points): 6.6% risk of major cardiac complications
Class IV (≥3 points): ≥11% risk of major cardiac complications

Helper Function

import { isHighRiskSurgery } from 'periop-calculators';

// Check if a surgery type is considered high risk
const isHighRisk = isHighRiskSurgery('aortic aneurysm repair'); // true
const isLowRisk = isHighRiskSurgery('cataract surgery');        // false

API Reference

Types

STOP-BANG Types

interface StopBangInput {
  snoring: boolean;
  tiredness: boolean;
  observed: boolean;
  pressure: boolean;
  bmi?: number;
  age?: number;
  neckCircumference?: number;
  gender?: 'male' | 'female';
}

interface StopBangResult {
  score: number;
  risk: 'low' | 'intermediate' | 'high';
  interpretation: string;
  components: {
    S: boolean;  // Snoring
    T: boolean;  // Tiredness
    O: boolean;  // Observed apnea
    P: boolean;  // Pressure (hypertension)
    B: boolean;  // BMI > 35
    A: boolean;  // Age > 50
    N: boolean;  // Neck circumference > 40cm
    G: boolean;  // Gender (male)
  };
  recommendations: string[];
}

RCRI Types

interface RCRIInput {
  highRiskSurgery: boolean;
  ischemicHeartDisease: boolean;
  congestiveHeartFailure: boolean;
  cerebrovascularDisease: boolean;
  insulinDependentDiabetes: boolean;
  renalInsufficiency: boolean;
}

interface RCRIResult {
  score: number;
  riskClass: 'I' | 'II' | 'III' | 'IV';
  estimatedRisk: string;
  riskPercentage: number;
  interpretation: string;
  riskFactors: {
    highRiskSurgery: boolean;
    ischemicHeartDisease: boolean;
    congestiveHeartFailure: boolean;
    cerebrovascularDisease: boolean;
    insulinDependentDiabetes: boolean;
    renalInsufficiency: boolean;
  };
  recommendations: string[];
}

MELD Score Types

interface MELDScoreInput {
  bilirubin: number;    // Serum bilirubin in mg/dL
  creatinine: number;   // Serum creatinine in mg/dL
  inr: number;          // International normalized ratio
  dialysis?: boolean;   // Dialysis twice within past week (optional)
}

interface MELDScoreResult {
  score: number;              // MELD score (6-40)
  mortalityRisk: string;      // 3-month mortality estimate
  mortalityPercentage: number; // Mortality percentage
  risk: 'low' | 'moderate' | 'high' | 'very-high';
  interpretation: string;     // Clinical interpretation
  labValues: {
    bilirubin: number;
    creatinine: number;
    inr: number;
    dialysis: boolean;
  };
  recommendations: string[];
}

Utility Functions

import { calculateBMI } from 'periop-calculators';

const bmi = calculateBMI(80, 175); // weight in kg, height in cm
// Returns: 26.1

3. MELD Score (Model for End-Stage Liver Disease)

Assesses liver disease severity and predicts short-term mortality in patients with end-stage liver disease.

import { calculateMELDScore, MELDScoreInput, MELDScoreResult } from 'periop-calculators';

const input: MELDScoreInput = {
  bilirubin: 2.5,      // Serum bilirubin in mg/dL
  creatinine: 1.8,     // Serum creatinine in mg/dL  
  inr: 1.6,            // International normalized ratio
  dialysis: false      // Dialysis twice in past week (optional)
};

const result: MELDScoreResult = calculateMELDScore(input);

console.log(result);
// {
//   score: 21,
//   mortalityRisk: '19.6%',
//   mortalityPercentage: 19.6,
//   risk: 'high',
//   interpretation: 'MELD score of 21 indicates high risk...',
//   labValues: { bilirubin: 2.5, creatinine: 1.8, inr: 1.6, dialysis: false },
//   recommendations: [...]
// }

Risk Stratification

Low Risk (6-9): 1.9% 3-month mortality risk
Moderate Risk (10-19): 6.0% 3-month mortality risk
High Risk (20-29): 19.6% 3-month mortality risk
Very High Risk (30-40): 52.6% 3-month mortality risk

Helper Functions

import { isHighRiskMELD, getMELDRiskCategory } from 'periop-calculators';

// Check if MELD score indicates high surgical risk
const isHighRisk = isHighRiskMELD(25); // true (score ≥ 20)
const isLowRisk = isHighRiskMELD(15);  // false

// Get risk category without full calculation
const riskCategory = getMELDRiskCategory(22); // 'high'

4. Apfel Score for PONV

Predicts risk of postoperative nausea and vomiting (PONV) in adult patients undergoing general anesthesia.

import { calculateApfelScore, ApfelScoreInput, ApfelScoreResult } from 'periop-calculators';

const input: ApfelScoreInput = {
  female: true,                   // Female gender
  nonSmoker: true,               // Non-smoking status
  historyOfPONV: false,          // History of PONV or motion sickness
  postoperativeOpioids: true     // Expected postoperative opioid use
};

const result: ApfelScoreResult = calculateApfelScore(input);

console.log(result);
// {
//   score: 3,
//   riskPercentage: 61,
//   risk: 'very-high',
//   interpretation: 'Apfel Score of 3 with 3 risk factors...',
//   riskFactors: { ... },
//   recommendations: [...]
// }

Risk Stratification

0 points: 10% risk of PONV (low risk)
1 point: 21% risk of PONV (moderate risk)
2 points: 39% risk of PONV (high risk)
3 points: 61% risk of PONV (very high risk)
4 points: 79% risk of PONV (very high risk)

Helper Function

import { getApfelRiskFactorInfo } from 'periop-calculators';

// Get detailed information about a specific risk factor
const info = getApfelRiskFactorInfo('female');
// Returns: "Female gender is associated with 2-3 times higher risk of PONV compared to males"

Clinical References

STOP-BANG References

Chung F, et al. STOP-Bang Questionnaire: A Tool to Screen Patients for Obstructive Sleep Apnea. Anesthesiology. 2008;108(5):812-821.
Chung F, et al. High STOP-Bang score indicates a high probability of obstructive sleep apnoea. Br J Anaesth. 2012;108(5):768-775.

RCRI References

Lee TH, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation. 1999;100(10):1043-1049.
Duceppe E, et al. Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Noncardiac Surgery. Can J Cardiol. 2017;33(1):17-32.

MELD Score References

Kamath PS, et al. A model to predict survival in patients with end-stage liver disease. Hepatology. 2001;33(2):464-470.
Wiesner R, et al. Model for end-stage liver disease (MELD) and allocation of donor livers. Gastroenterology. 2003;124(1):91-96.
Teh SH, et al. Risk factors for mortality after surgery in patients with cirrhosis. Gastroenterology. 2007;132(4):1261-1269.

Apfel Score References

Apfel CC, et al. A simplified risk score for predicting postoperative nausea and vomiting: conclusions from cross-validations between two centers. Anesthesiology. 1999;91(3):693-700.
Apfel CC, et al. Evidence-based analysis of risk factors for postoperative nausea and vomiting. Br J Anaesth. 2012;109(5):742-753.

Development

# Install dependencies
npm install

# Run tests
npm test

# Build the package
npm run build

# Run linting
npm run lint

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

Fork the repository
Create your feature branch (git checkout -b feature/new-calculator)
Commit your changes (git commit -m 'Add RCRI calculator')
Push to the branch (git push origin feature/new-calculator)
Open a Pull Request

Future Calculators

Planned additions to this package:

RCRI (Revised Cardiac Risk Index) ✅
MELD Score ✅
P-POSSUM Score
Apfel Score for PONV ✅
Caprini Score for VTE Risk
ASA Physical Status Calculator

License

Author

Dr. Syed Haider Hasan Rizvi

Board-certified anesthesiologist and physician-developer
Creator of CoagRX and PeriopAI
GitHub | LinkedIn

Built with ❤️ by a physician who codes