Add Epic EHI Tables to CLIF mapping guide

[clifford-clif]

Summary

This PR adds comprehensive documentation for mapping Epic EHR data to CLIF format, leveraging the publicly accessible Epic EHI Export Schema.

Key Resources Documented

• Epic EHI Export Schema - Complete schema documentation for Epic EHI tables (no Epic login required!)
• Clarity Data Handbook - Clarity table documentation

Credit to Wan-Ting for sharing the open.epic.com link in the weekly call.

Files Added

• *\Epic/README.md* - Comprehensive mapping guide covering all CLIF tables
• *\Epic/epic_ehi_clif_mapping.csv* - Field-level mappings (68 mappings across 14 CLIF tables)
• *\Epic/common_flowsheet_rows.csv* - Common flowsheet row names for vitals, respiratory, position, CRRT

CLIF Tables Covered

Table	Mapping Status
patient	✅
hospitalization	✅
adt	✅
vitals	✅
labs	✅
medication_orders	✅
medication_admin_continuous	✅
medication_admin_intermittent	✅
respiratory_support	✅
crrt_therapy	✅
microbiology_culture	✅
sensitivity	✅
position	✅
code_status	✅
hospital_diagnosis	✅

Why This Matters

Previously, Epic sites needed UserWeb access to discover table mappings. This guide provides:

1. A public starting point for Epic → CLIF ETL
2. Field-level documentation for each CLIF table
3. Flowsheet row references (the most site-specific part of Epic ETL)

Notes

• Flowsheet row IDs (FLO_MEAS_ID) are site-specific - this guide provides common names to search for
• Some mappings require joins to ZC reference tables
• Medication categorization requires mapping therapeutic classes to mCIDE

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cc: @08wparker