Reference Architecture

HealthOS ICU is a vendor-neutral supervisory layer that sits between bedside medical devices and the clinical team. This brief describes the architecture from the edge inward.

System overview

Reference architecture: four planes Bedside devices (HL7 v2/MLLP monitors, IHE PCD ventilators, SDC anaesthesia machines — not part of HealthOS ICU v0, pilot program) send data to the protocol gateway, which routes the stream to a stateful analyzer and a stateless analyzer; both call the compute core. The knowledge plane — medical knowledge graph store, knowledge compiler and compiled bundle — feeds the compiled bundle into the same compute core. The compute core outputs to the record plane: the clinical-data facade (FHIR R4), the audit event log, and the evidence-of-fact receipt. REFERENCE ARCHITECTURE BEDSIDE DEVICES Monitors(HL7 v2/MLLP) Ventilators(IHE PCD) Anaesthesiamachines(SDC — outside v0) DEVICE PROTOCOL GATEWAY Protocol Gateway StatefulRule-based Analyzer StatelessRule-based Analyzer Compute Core KNOWLEDGE PLANE Medical KnowledgeGraph Store Knowledge Compiler Compiled Bundle RECORD PLANE Clinical-Data Facade(FHIR R4) Audit Event Log Evidence-of-fact Receipt
Four planes: devices → device protocol gateway → compute core (also receives the compiled bundle from the knowledge plane) → record plane.

Edge layer

The device protocol gateway receives inbound device streams — primarily HL7 v2/MLLP from existing installations, with IHE PCD adapter slots for structured device data. All processing happens locally at the bedside; no real-time cloud dependency exists in the critical path.

The stateful rule-based analyzer and stateless rule-based analyzer wrap the Compute core, handling live stream and loaded-file inputs respectively. Both services use the same Runtime library and release-bound compiled bundle.

Knowledge plane

Clinical rules are maintained as a formal graph in the medical knowledge graph store, validated with SHACL constraints. The knowledge compiler transforms an approved snapshot of the graph into a compiled bundle — a deterministic, versioned artifact.

The bundle is deployed to the edge without network I/O at runtime. It does not update itself; updates go through the governed release process.

Record plane

The clinical-data facade exposes FHIR R4 resources to clinical information systems: Observation, Device, DeviceMetric, GuidanceResponse, Provenance, AuditEvent. This is a projection of the canonical audit event log — not the source of truth.

The evidence-of-fact receipt is a cryptographic chain from the approved knowledge graph snapshot through compilation to runtime execution, enabling full traceability of every recommendation.

Scalability and deployment

  • Single-institution deployment: device protocol gateway + services on local hardware; FHIR facade on-premise
  • Multi-site: one compiled bundle per version deployed identically across all sites; governance centralised, data sovereign at each site
  • Offline-capable: critical path (analysis, command issuance) has no cloud dependency

Documents

HealthOS ICU: Full Concept → · Standards & Interoperability →

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