CLABSI Prevention Device

Problem & Need

Central Line-Associated Bloodstream Infections (CLABSIs) occur when bacteria enter the bloodstream via a central line. 40,000 CLABSIs occur annually in the US, costing hospitals approximately $1.9B per year — and 65–70% are completely preventable with proper disinfection.

The current standard of care is the Scrub-the-Hub technique, which relies entirely on nurse compliance with manual protocol. Infections arise from human error and inconsistent adherence to workflow. This device removes that dependency.

Need Statement: Hospital nurses need a quick, reliable, and user-friendly system to disinfect central lines to maintain adherence to proper protocols and reduce infection risk in patients.

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Why UV-C Disinfection?

DNA and RNA strongly absorb 260 nm UV-C incident light. The high-energy photons create nitrogenous base lesions, distorting the helix structure and blocking transcription and translation — effectively sterilizing the hub surface without chemicals, contact, or manual technique.

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Device Design

Mechanical

The enclosure is resin-printed to prevent UV-C light leakage. Key mechanical elements:

#	Component	Role
1	Resin-Printed Casing	Contains UV-C, prevents leakage
2	Disinfection Chamber	Where the catheter hub is inserted
3	RGB LED	Color-coded status during operation and errors
4	Activation Button	Single-button start/abort
5	Opening Aperture	Seals around the catheter to prevent leakage
6	Safety Interlocks (×2)	Abort if device opens prematurely

Electrical

Three custom KiCad PCBs make up the electrical system:

Board	Function
Main	nRF54L15 MCU, power management, BMS (MAX17260), RGB LED driver (LP5815)
UVC	UV-C LED driver with current-limiting elements
Base	Mechanical base and connector board

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Firmware

Written in C on Zephyr RTOS (nRF Connect SDK), targeting the nRF54L15. The application runs a hierarchical state machine (Zephyr SMF):

INIT → IDLE ──► DISINFECTING ──► IDLE
            ──► CHARGING      ──► (abort via button or interlock)
            ──► ERROR

State	Behavior
INIT	Initialize GPIO, PWM, I2C, BMS, safety interlocks
IDLE	Awaiting button press; battery SOC displayed on RGB LED
CHARGING	Charge in progress; RGB indicates charge level
DISINFECTING	UV-C LED at full PWM; instant abort on interlock open or button press
ERROR	RGB error pattern + buzzer; cleared by button press

The critical safety path: interlock GPIO interrupts submit a work item that disables PWM output before the SMF state transition completes — mean shutoff time of 17 ± 2 ms, well within the 450 ms safety limit derived from ISO 15858.

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Testing Results

Germicidal testing used DH5α bacteria incubated, seeded, and adhered to catheter hubs at room temperature. Hubs were irradiated with UV-C at 0, 2, and 4 hours, then vortexed for CFU counts by serial dilution — achieving a 4-log reduction.

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Regulatory & Market

The CLAB-Free device will be classified as a Class II FDA device given the inherent risk of UV light and catheter use. Two potential pathways:

• 510(k) — Preferred: If determined similar enough to existing UV surface-disinfecting devices
• De Novo: If disinfection through catheter tubing constitutes a novel use case

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Conclusion & Next Steps

The device successfully disinfects central line hubs using UV-C light in the germicidal range, achieves a 4-log CFU reduction, and operates safely within ISO 15858 exposure limits. It is portable, one-handed, and reusable between patients.

Planned next steps:

• Nurse usability testing
• Design of docking/recharging stations
• Autoclavable disinfection chamber redesign
• Head-to-head testing against proper and improper Scrub-the-Hub technique