FDA QSR Guidelines

## Requirement: REQ-001

**Title:** Patient Vital Signs Display
**Type:** Functional
**Source:** User Needs Document, Section 3.2
**Priority:** Essential

### Description
The system shall display patient vital signs (heart rate, blood pressure,
oxygen saturation) in real-time with updates every 2 seconds.

### Acceptance Criteria
1. Heart rate displayed in BPM (range: 30-250)
2. Blood pressure displayed in mmHg (systolic/diastolic)
3. SpO2 displayed as percentage (range: 50-100%)
4. Update latency < 500ms from sensor reading
5. Visual and audio alarms for out-of-range values

### Risk Reference
RISK-015: Delayed vital sign display may delay intervention

### Traceability
- User Need: UN-042
- Test Cases: TC-001, TC-002, TC-003

## Software Design Specification: SDS-001

**Related Requirement:** REQ-001
**Version:** 1.2
**Author:** John Smith
**Approved:** Jane Doe (2024-01-15)

### Architecture
[Component diagram showing data flow from sensors to display]

### Interface Specification
```typescript
interface VitalSigns {
  heartRate: number;      // BPM, 30-250
  systolic: number;       // mmHg, 60-200
  diastolic: number;      // mmHg, 40-140
  spO2: number;           // %, 50-100
  timestamp: Date;
}

interface DisplayConfig {
  updateIntervalMs: 2000;
  alarmThresholds: AlarmConfig;
}

### Design Verification

Verify that design outputs meet design inputs:

| Input Requirement | Output Specification | Verification Method | Result |
|-------------------|---------------------|---------------------|--------|
| REQ-001 | SDS-001 | Unit Test UT-001 | PASS |
| REQ-002 | SDS-002 | Integration Test IT-001 | PASS |

### Design Validation

Validate that the device meets user needs:

| User Need | Test Protocol | Participants | Result |
|-----------|---------------|--------------|--------|
| UN-042 | VP-001 | 10 clinicians | Validated |
| UN-043 | VP-002 | 8 nurses | Validated |

---

## Software Development Lifecycle (IEC 62304)

### Required Activities by Class

| Activity | Class A | Class B | Class C |
|----------|---------|---------|---------|
| Software development planning | ✓ | ✓ | ✓ |
| Software requirements analysis | ✓ | ✓ | ✓ |
| Software architecture design | - | ✓ | ✓ |
| Software detailed design | - | - | ✓ |
| Software unit implementation | ✓ | ✓ | ✓ |
| Software unit verification | - | ✓ | ✓ |
| Software integration | ✓ | ✓ | ✓ |
| Software integration testing | - | ✓ | ✓ |
| Software system testing | ✓ | ✓ | ✓ |
| Software release | ✓ | ✓ | ✓ |

### Traceability Matrix

![Traceability Matrix](/traceability-matrix.svg)

---

## Risk Management (ISO 14971)

### Risk Analysis

| Hazard | Harm | Severity | Probability | Risk Level | Mitigation |
|--------|------|----------|-------------|------------|------------|
| Incorrect dose calculation | Patient injury | 4 | 3 | High | Redundant calculation, validation |
| Display failure | Delayed treatment | 3 | 2 | Medium | Alarm system, redundant display |
| Data corruption | Wrong patient data | 4 | 1 | Medium | Checksums, verification |

### FMEA Example

```markdown
## Failure Mode: Software crash during operation

**Effect:** Display goes blank, no vital signs shown
**Cause:** Memory leak, unhandled exception
**Severity:** 4 (Serious)
**Occurrence:** 2 (Low)
**Detection:** 3 (Moderate - watchdog timer)
**RPN:** 24

### Mitigation Measures
1. Implement watchdog timer with auto-restart (D: 2)
2. Conduct code review for memory management (O: 1)
3. Add exception handling throughout (O: 1)

**Post-Mitigation RPN:** 8