Medical Compliance

Audit Logging Requirements

What to Log (Process Safety Focus)

• WHO performed the action (userId)
• WHAT action was performed (scan, insert, complete)
• WHEN it happened (server timestamp)
• WHICH resources were affected (applicatorId, treatmentId)

Audit Log Pattern

await ApplicatorAuditLog.create({
  applicatorId: applicator.id,
  action: "STATUS_CHANGE",
  previousStatus: oldStatus,
  newStatus: newStatus,
  userId: req.user.id,
  timestamp: new Date(),
  details: JSON.stringify({ reason }),
});

Retention

• Audit logs must be retained for minimum 6 years (FDA 21 CFR Part 11)
• Never delete audit logs in application code
• Use database-level archival for old records

Treatment State Machine

SCHEDULED → ACTIVE → COMPLETED
    ↓          ↓
 CANCELLED  CANCELLED

Transition Rules

• VALIDATE transitions before allowing
• LOG all state changes
• PREVENT invalid transitions (return 400 error)

const validTransitions = {
  SCHEDULED: ["ACTIVE", "CANCELLED"],
  ACTIVE: ["COMPLETED", "CANCELLED"],
  COMPLETED: [], // Terminal
  CANCELLED: [], // Terminal
};

if (!validTransitions[currentStatus].includes(newStatus)) {
  throw new Error(`Invalid transition: ${currentStatus} → ${newStatus}`);
}

Fail-Safe Principles

When Uncertain, BLOCK

• ERP offline + no cache = BLOCK
• ERP offline + stale cache (>24h) = BLOCK
• Cannot verify expiry = BLOCK
• Local says USED, ERP says available = BLOCK (trust local)

Never Fail-Open

Medical devices must never default to "allow" when verification fails.

// WRONG - Fail-open
if (!canVerify) {
  console.warn("Cannot verify, proceeding anyway");
  return true; // DANGEROUS
}

// CORRECT - Fail-closed
if (!canVerify) {
  throw new Error("SAFETY BLOCK: Cannot verify applicator");
}

Transaction Requirements

When to Use Transactions

• Treatment status changes
• Patient data modifications
• Multi-step workflows
• Any operation affecting multiple tables

Transaction Pattern

const transaction = await sequelize.transaction({
  isolationLevel: Transaction.ISOLATION_LEVELS.SERIALIZABLE
});
try {
  await Treatment.update({ status: 'COMPLETED' }, { transaction });
  await Activity.create({ ... }, { transaction });
  await transaction.commit();
} catch (error) {
  await transaction.rollback();
  throw error;
}

Pre-Commit Checklist

• No soft deletes on clinical data (use is_voided)
• Audit logging for all state changes
• State transitions validated
• Transactions used for multi-step operations
• ERP offline = BLOCK (fail-safe)
• Local DB checked BEFORE ERP for safety decisions