# VigilCare Clinical — Climate Resilience Extension Roadmap

**Internal document | Phases 20–24 | June 2026**

**Prerequisites:** Phases 1–19 complete — full clinical CDSS pipeline, ward dashboard, simulator, and clinician feedback mode.

**Reference implementation:** POS System API Phase 10 ([phase-10-plan.md](../PosAPI/phase-10-plan.md)) — offline batch upload, async processor, two-layer idempotency, partial conflict model.

---

## Problem Statement

Hospital clinical monitoring assumes reliable connectivity between the ward, the hospital datacenter, and any cloud-hosted central services. Climate and infrastructure shocks break that assumption:

| Scenario | What fails | Clinical risk |
|---|---|---|
| Ward WiFi outage | Central API unreachable from bedside | Alerts never reach the ward dashboard |
| Hospital uplink loss (typhoon, fiber cut) | Central VigilCare unreachable for hours | Same — cloud-dependent alerting stops |
| Regional cloud outage | Central stack down | Population analytics lost; ward safety at risk if ward depends on cloud |
| Power blip (UPS handoff) | Gateway host restart | Buffered events lost if not persisted locally |
| Post-disaster partial recovery | Intermittent connectivity | Duplicate alerts or lost audit trail on sloppy sync |

VigilCare Phases 1–19 run as a **central** clinical backend. Observations ingest to PostgreSQL, fan out through Kafka, and drive alerting, scoring, and archival. That architecture is correct when the network is healthy. It is not sufficient when the ward must operate alone for typhoon-length outages.

**Climate resilience** means: **Tier 1 patient safety runs at the ward even when central is unreachable; Tier 3 analytics and archival catch up idempotently when connectivity returns.**

This extension does not change the clinical domain (hospital wards, sepsis bundles, NEWS2). It adds a **ward-first deployment model**.

---

## Design Principle — Three Tiers

| Tier | Responsibility | Runs where | Must work offline? |
|---|---|---|---|
| **Tier 1 — Safety** | Critical + warning threshold alerts, ack/resolve, local paging, ward dashboard reads | `VigilCare.WardGateway` | **Yes** |
| **Tier 2 — Reconciliation** | Buffered event upload, idempotent apply, conflict reporting | Gateway → central sync API | On reconnect |
| **Tier 3 — Analytics** | NEWS2, SIRS, qSOFA, trend, sepsis bundle, Elasticsearch, Parquet | Central `VigilCareClinicalAPI` | No — replays after sync |

**Invariant (carry into every phase plan):** Append-only observations, synchronous critical / asynchronous warning split, idempotency keys, DLQ escalation — same rules as Phases 1–19. The gateway is not a different clinical system; it is a **degraded-mode replica** of the hot path.

---

## Target Architecture

```
┌─────────────────────────────────────────────────────────────────────────┐
│  Ward (UPS-backed server) — VigilCare.WardGateway                       │
│  ┌──────────────┐  ┌─────────────────┐  ┌──────────────────────────┐  │
│  │ Local ingest │→ │ Critical+warning│→ │ Local RabbitMQ paging    │  │
│  │ + idempotency│  │ eval (Tier 1)   │  │ + DLQ escalation         │  │
│  └──────────────┘  └─────────────────┘  └──────────────────────────┘  │
│         │                    │                      │                   │
│         └────────────────────┴──────────────────────┘                   │
│                              │                                          │
│                    ┌─────────▼─────────┐                                │
│                    │ Local PostgreSQL  │                                │
│                    │ + sync buffer     │                                │
│                    └─────────┬─────────┘                                │
└──────────────────────────────┼──────────────────────────────────────────┘
                               │ POST /sync/batches (when link up)
┌──────────────────────────────▼──────────────────────────────────────────┐
│  Central — VigilCareClinicalAPI                                         │
│  ClinicalSyncBatchProcessor → ObservationService → outbox → Kafka       │
│  → NEWS2 / SIRS / qSOFA / trend / ES / Parquet (Tier 3 replay)          │
└─────────────────────────────────────────────────────────────────────────┘
```

---

## Phase Map

| Phase | Name | Deliverable |
|---|---|---|
| **20** | Site & Gateway Registry | `ClinicalSite`, `WardGateway`, API key auth, `VigilCare.ClinicalContracts` sync DTOs |
| **21** | Ward Gateway Service | New `VigilCare.WardGateway` project — local ingest, Tier 1 eval, buffer, local paging |
| **22** | Clinical Sync Batch Engine | Central batch upload + `ClinicalSyncBatchProcessor` (POS Phase 10 adapted) |
| **23** | Degraded Operations Visibility | Ops fleet APIs, dashboard ops view, Grafana panels, partition demo script |
| **24** | Climate Resilience Verification | Outage scenario, 6 chaos experiments, interview Q&A, verify script |

### Dependency graph

```
Phase 20 (registry + contracts)
    ├── Phase 21 (ward gateway service)
    └── Phase 22 (central sync engine)
            ├── Phase 23 (ops visibility)
            └── Phase 24 (verification)
```

Implementation order: **20 → 21 → 22 → 23 → 24**. Phase plans for 21 and 22 can be drafted in parallel once Phase 20 defines the sync contract.

---

## Sync Payload Contract (summary)

Shared types live in **`VigilCare.ClinicalContracts`** (class library referenced by central API and WardGateway). Scaffold and manage projects per [dotnet-solution-scaffolding.md](plans/dotnet-solution-scaffolding.md). Full field definitions in [phase-20-plan.md](phase-20-plan.md) Step 1.

```json
{
  "batchReference": "550e8400-e29b-41d4-a716-446655440000",
  "gatewayId": "...",
  "siteId": "...",
  "capturedAtUtc": "2026-06-20T14:30:00Z",
  "observations": [
    {
      "clientRef": "...",
      "idempotencyKey": "device-retry-key-001",
      "encounterId": "...",
      "observationCode": "HEART_RATE",
      "value": 118,
      "recordedAt": "2026-06-20T14:28:00Z",
      "source": "bedside_monitor"
    }
  ],
  "alertEvents": [
    {
      "clientAlertId": "...",
      "encounterId": "...",
      "alertType": "CRITICAL_HEART_RATE",
      "severity": "CRITICAL",
      "details": "...",
      "generatedAt": "2026-06-20T14:28:01Z"
    }
  ],
  "alertAcknowledgments": [
    {
      "clientRef": "...",
      "clientAlertId": "...",
      "clinicianId": "RN-Smith",
      "acknowledgedAt": "2026-06-20T14:29:00Z",
      "note": "At bedside"
    }
  ]
}
```

**Replay order inside batch processor:** observations → alert events → acknowledgments → resolve events. Ack before alert in the same batch → `ClinicalSyncConflict` with reason `ALERT_NOT_YET_SYNCED`.

**Idempotency layers (mirror POS):**

1. Batch level — unique index on `batch_reference`; re-upload returns existing batch.
2. Item level — observation `idempotency_key`; alert `client_alert_id`; silent skip on duplicate.

---

## What Is Explicitly Out of Scope

Defer to [vigilcare-clinical-roadmap.md](vigilcare-clinical-roadmap.md):

- FHIR read endpoints, real notification channels (SMS/Twilio), department-specific threshold configuration
- Full local NEWS2 / SIRS / qSOFA / trend / sepsis bundle on the gateway (central Kafka replay after sync instead)
- HIPAA / TFDA certification language
- Home / infant monitoring domain pivots

---

## Interview Talking Points

**"How is this different from just running VigilCare in the hospital datacenter?"**

Datacenter deployment still fails when the **ward-to-datacenter link** fails — common during typhoons, construction, or router failures. The gateway colocates Tier 1 safety with the ward LAN. Central adds cross-ward analytics when available.

**"Why not run everything locally and skip central?"**

NEWS2 composite scoring, SIRS window state, sepsis bundle compliance, Elasticsearch population views, and Parquet regulatory archival require the full Kafka multi-consumer pipeline. Duplicating that on every ward gateway is operationally expensive. The split is: **safety local, intelligence central**.

**"How do you prevent duplicate critical pages after reconnect?"**

Observation and alert idempotency keys survive the sync boundary. The batch processor silently skips items already applied. Alert events use `client_alert_id` — if central already has the alert from a partial sync, no second RabbitMQ page fires.

**"What happens if a nurse acknowledges an alert locally but central never receives it?"**

The acknowledgment is buffered. On sync, it applies to the matching alert by `client_alert_id`. If central never receives it (gateway lost before sync), the reconciliation job (Phase 7) still flags unacknowledged critical alerts on central — but during outage, **local** escalation (DLQ) is authoritative. Ops dashboard (Phase 23) shows buffer depth so IT knows reconciliation is pending.

**"How does this relate to POS offline sync?"**

Same pattern: edge node buffers writes, uploads batch with `batchReference`, central applies idempotently with partial conflicts, async processor via outbox + RabbitMQ. POS conflicts are inventory; clinical conflicts are ordering dependencies (ack before alert) or duplicate device retries.

---

## Document Index

| Document | Purpose |
|---|---|
| [phase-20-plan.md](phase-20-plan.md) | Site/gateway registry + shared contracts |
| [phase-21-plan.md](phase-21-plan.md) | Ward gateway service |
| [phase-22-plan.md](phase-22-plan.md) | Central sync batch engine |
| [phase-23-plan.md](phase-23-plan.md) | Ops visibility + dashboard |
| [phase-24-plan.md](phase-24-plan.md) | Verification suite |
| [resilience-learning-plan.md](../../resilience-learning-plan.md) | Chaos experiment methodology |

---

*After Phase 24, the portfolio claim becomes: "Clinical monitoring that continues during ward isolation and reconciles honestly when the link returns — with measured failure-mode evidence."*

---

## Verification Checklist (Phase 24)

Documentation complete when:

- [ ] Phase plans 20–24 written ([phase-20-plan.md](phase-20-plan.md) … [phase-24-plan.md](phase-24-plan.md))
- [ ] [ward-outage-reconnect-01.json](scenarios/ward-outage-reconnect-01.json) scenario present
- [ ] [resilience/README.md](resilience/README.md) experiment index populated
- [ ] Six chaos experiments documented with baseline/broken/fixed artifacts
- [ ] Interview questions #29–32 in [interview-questions.md](interview-questions.md)
- [ ] `scripts/verify-phase-24.ps1` passes

Implementation complete when all phase exit gates in plans 20–24 pass and integration tests green.

