Case study 02
HEART / DiDi
A privacy-first clinical AI assistant inside a hospital-wide smart-care ecosystem
- Period
- Ongoing research initiative
- Context
- HEART (Networked Ecosystem for eXplainable and Ubiquitous Smart-care), with deployment at Centro Chirurgico Toscano
- Role
- AI strategy, RAG design, and edge-cloud deployment requirements
- +40%
- comprehension of out-of-range values
- 2000/15
- RAG chunk size / top-K for MedGemma
Problem
- Patient safety depends on rigorous hygiene protocols (hand-washing) to prevent healthcare-associated infections — but compliance is hard to monitor.
- After discharge, there is no transparent tool for monitoring surgical wounds, which leads to avoidable readmissions.
- Traditional rule-based clinical decision-support systems generate too many false alarms, eroding clinicians' attention.
Target user
Clinicians and nursing staff at the Centro Chirurgico Toscano: surgeons and scrub nurses in the operating block, and the medical staff who query patient records — experts who need trustworthy answers with sources, not a black box that decides for them.
My role
Within the technology team I focused on the language-model side of the ecosystem (the computer-vision hand-washing monitoring was led by colleagues):
- AI strategy and investigation — analyzing the use of models such as Gemini to integrate OCR directly into the system, simplifying the technology stack.
- Requirements and deployment — defining the technical requirements for installation on the hospital’s server and contributing to the edge-cloud architecture design.
- DiDi, the clinical assistant — prototyped on Lovable/Supabase, focused on privacy-first document processing and LLM-generated clinical summaries.
Process
- Retrieval-augmented generation — a RAG system built on models such as MedGemma to query patients' clinical data.
- Human-in-the-loop design — an interface that does not replace the clinician but stimulates critical thinking, following a dialogic AI framework aligned with the EU AI Act.
- In parallel, the wider team implemented computer-vision monitoring of hand-washing (duration, soaping and rinsing phases) via cameras in the operating block.
Key decisions
- Hybrid Edge+Cloud architecture: OCR and anonymization run locally to protect patient privacy, while Gemini powers the clinical chat.
- RAG tuning for precision: a chunk size of 2,000 characters with 200 of overlap and top-K of 15 fragments, maximizing MedGemma’s accuracy without saturating memory.
- Semantic boosting: clinical tags weighting related terms (e.g. +0.8 between “fever” and “hyperpyrexia”) to improve retrieval of relevant records.
Final result
- Real-world monitoring data: most hand-washes last two to three minutes, against the five minutes recommended for the first wash — evidence the hospital can act on.
- In one documented case, the AI acted as a neutral mediator in a therapeutic disagreement between clinicians, contributing to the correct treatment choice for a critical patient.
- Rendering CSV data as natural language increased comprehension of out-of-range values by 40% in tests.
What I learned
- Bias lives in the data model. Distinguishing professional roles (surgeon vs. scrub nurse) in the data was essential to avoid distorted performance statistics.
- Experts accept AI that shows its sources. Always citing the clinical record or literature was the single biggest factor in the system’s credibility with senior staff.
- Hospital-grade means load-tested. Blocking FastAPI endpoints are a real scalability risk with concurrent users; load testing is not optional in a clinical environment.