periop-calculators
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Evidence-based perioperative risk assessment calculators for healthcare professionals
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# periop-calculators
[](https://www.npmjs.com/package/periop-calculators)
[](https://opensource.org/licenses/MIT)
[](https://www.typescriptlang.org/)
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
```bash
npm install periop-calculators
```
or
```bash
yarn add periop-calculators
```
## Quick Start
```typescript
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.
```typescript
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:
```typescript
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.
```typescript
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
```typescript
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
```typescript
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
```typescript
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
```typescript
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
```typescript
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.
```typescript
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
```typescript
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.
```typescript
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
```typescript
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
1. Chung F, et al. STOP-Bang Questionnaire: A Tool to Screen Patients for Obstructive Sleep Apnea. Anesthesiology. 2008;108(5):812-821.
2. 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
1. 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.
2. 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
1. Kamath PS, et al. A model to predict survival in patients with end-stage liver disease. Hepatology. 2001;33(2):464-470.
2. Wiesner R, et al. Model for end-stage liver disease (MELD) and allocation of donor livers. Gastroenterology. 2003;124(1):91-96.
3. Teh SH, et al. Risk factors for mortality after surgery in patients with cirrhosis. Gastroenterology. 2007;132(4):1261-1269.
### Apfel Score References
1. 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.
2. Apfel CC, et al. Evidence-based analysis of risk factors for postoperative nausea and vomiting. Br J Anaesth. 2012;109(5):742-753.
## Development
```bash
# 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.
1. Fork the repository
2. Create your feature branch (`git checkout -b feature/new-calculator`)
3. Commit your changes (`git commit -m 'Add RCRI calculator'`)
4. Push to the branch (`git push origin feature/new-calculator`)
5. Open a Pull Request
## Future Calculators
Planned additions to this package:
- [x] RCRI (Revised Cardiac Risk Index) ✅
- [x] MELD Score ✅
- [ ] P-POSSUM Score
- [x] Apfel Score for PONV ✅
- [ ] Caprini Score for VTE Risk
- [ ] ASA Physical Status Calculator
## License
MIT © [Syed Haider Hasan Rizvi, MD](https://github.com/rizvimd)
## Author
**Dr. Syed Haider Hasan Rizvi**
- Board-certified anesthesiologist and physician-developer
- Creator of [CoagRX](https://coagrx.com) and PeriopAI
- [GitHub](https://github.com/rizvimd) | [LinkedIn](https://linkedin.com/in/drsyedrizvi)
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*Built with ❤️ by a physician who codes*