Medical Missionaries of Divine Mercy

Paper to Field-Ready EMR

A non-clinician student led the transition of a volunteer medical mission from paper records to a self-hosted, offline-first OpenEMR system — deployed live in Costa Rica and headed to Laredo, Texas.

This is the technical record: the decisions, the failures, the rebuilds, and what it took to run a clinical system 60 miles from the nearest server farm.

1,121

Patients served

Costa Rica 2026

6

Custom forms

built from paper originals

8

Station accounts

across the clinic

Nov 4–10

Laredo

primary deployment

What Was Built

Self-Hosted, Offline-First

OpenEMR 7.0 on Ubuntu 22.04 LTS, running on a hardened VM. No cloud, no public IP, no internet dependency during clinic operations. Designed for remote sites with intermittent connectivity.

Encrypted, HIPAA-Aligned

Private certificate authority for LAN-only TLS. Per-device trust installed pre-mission. All traffic encrypted. Firewall hardened with default-deny inbound. HIPAA-aligned hybrid model for Laredo.

Built for Real Field Use

Six station-specific custom forms designed from paper originals with station-lead input. Vitals entered once, propagated everywhere. Routing thresholds editable mid-mission without code changes.

Project Timeline

  1. Paper-only missionsShipped

    Medical Missionaries of Divine Mercy (MMDM) operated free clinics in Costa Rica and Laredo using only paper forms. Records were restricted to a single physical copy, and thermal autorefractor printouts routinely faded within months.

  2. Microsoft nonprofit consultationShipped

    MMDM's 501(c)(3) status confirmed. First meeting with a Microsoft representative to assess how nonprofit licensing and cloud resources could support the mission's digital infrastructure.

  3. Build in-house: saving $6,000Shipped

    A Microsoft subsidiary offered to configure cloud and networking infrastructure for $6,000. After reviewing scope with the MMDM president — a former Microsoft employee — the decision was made to build it in-house. Full cloud infrastructure stood up independently.

  4. Cloud infrastructure establishedShipped

    Secured a Microsoft nonprofit grant providing free access to the Azure portal and Copilot. Transitioned the organization away from passing USB drives by provisioning @mmdm.org Outlook and SharePoint accounts, establishing MMDM's first centralized cloud infrastructure.

  5. Bill of Materials approvedShipped

    Hardware specification presented to MMDM leadership. TP-Link Omada network gear, Lenovo tablets, and supporting equipment approved for procurement.

  6. Hardware arrives and testing beginsShipped

    Full hardware order arrives: 8-port PoE+ switch, Gigabit VPN gateway, Wi-Fi 6 AX3000 access points (indoor and outdoor), Lenovo IdeaTabs for each station. First configuration and connectivity tests run against the existing Windows/XAMPP setup.

  7. OpenEMR formulary planningShipped

    Consulted with Dr. Byrd, Head of Pediatrics and a veteran of 32 MMDM missions over 20 years. Outlined the clinical and operational requirements for integrating a pharmacy formulary into the OpenEMR deployment.

  8. Linux migrationShipped

    MariaDB system tables corrupt on the original Windows host. The SQL dump is intact. Decision: stop repairing, migrate to Ubuntu 22.04 LTS on a hardened VM. Clean import; fresh baseline established.

  9. Private CA and HTTPSShipped

    A private certificate authority provides LAN-only TLS without a public CA. Per-device trust installed once before each mission. All clinic traffic encrypted from day one.

  10. On-mission resetShipped

    Patient-creation flow breaks mid-clinic. Fallback build lacks required security updates. Decision: full OpenEMR reset in place during the mission. Rebuilt, confirmed working, no patient records lost.

  11. Costa Rica field trialShipped

    First deployment: paper-primary with evening EMR entry across eleven stations. 39 missionaries and 13 local translators served a record 1,121 patients — including 151 during a one-day outreach to Bloriñak. Connectivity held at every fixed station. Network gaps in outdoor corridors and a switch capacity limit identified and logged. MMDM's 10th anniversary mission.

  12. Post-mission analysisShipped

    Volunteer survey drives form refinements. Recruiting program launches. Leadership deck and speaker script prepared for June 4 board meeting.

  13. Leadership meetingUpcoming

    Board approval request, dental form authority introductions, HIPAA-aligned hybrid model endorsement, and recruiting-plan support on the agenda.

  14. Laredo deploymentPlanned

    Primary full deployment: HIPAA-aligned, US jurisdiction, pharmacist on-site with e-prescribing to local pharmacies. Catholic Charities intake handoff, cross-street network bridge, Laredo-specific form configuration.

  15. Philippines deploymentPlanned

    Batangas, Philippines. First international deployment outside of the Western Hemisphere. Scope and form configuration for this mission are being determined.

  16. Costa Rica — Grano de OroPlanned

    Annual return to the Cabécar community in Grano de Oro. Full digital-primary deployment target if Laredo trial is successful.

Explore the Project

Every decision has a reason.

The Build page covers the full technical picture — stack, architecture, security model, and the trade-offs that shaped each choice. The Journal is where the work happens in public.

andrewcastor.dev · GitHub