SubQ-Confirm
A delivery-confirmation subsystem for wearable insulin pumps, designed for integration by pump manufacturers. Built as an individual capstone project for a graduate Medical Device Product Management course, covering the full lifecycle a PM owns: clinical need and market sizing, product requirements, FDA regulatory and reimbursement strategy, clinical evidence planning, risk and human factors, and go-to-market economics.
Silent infusion-site failures go undetected
People using wearable insulin pumps can have a site failure — the cannula backs out, the tissue can't absorb, or insulin leaks at the hub — 18 to 36 hours into wear, and current pumps never know it. Occlusion alarms only watch line pressure, so leakage and displacement stay invisible until blood glucose climbs and, in the worst cases, ketoacidosis develops. Clinicians can't tell device failure from patient dosing error at a follow-up visit; patients find out hours later, from a glucose reading, not an alarm.
Dual-modality sensing in the infusion set
SubQ-Confirm splits the job across three components. The disposable infusion set carries a pressure sensor at the cannula hub plus two electrodes under the adhesive that detect when fluid bridges them. A reusable module snaps onto the set and runs the detection logic, sending an authenticated signal to the pump. The partner pump surfaces the fault on its own existing alarm system within 500 milliseconds — SubQ-Confirm never issues a delivery command itself.
The logic tracks four states from just two signals, pressure and moisture: normal delivery, occlusion (pressure high, site dry), site leak (pressure below 60% of normal, site wet), and cannula-out (pressure low, site dry). A leak only reports after 3 of 5 consecutive deliveries stay below that threshold within 30 seconds — the debounce that keeps sweat and showering from triggering a false alarm. Constraints were set to disappear into existing pump wear: under 5 grams, under 3mm added height, IP-rated to 1m for 30 minutes, and a minimum 96-hour run time between charges.
| State | Pressure | Site |
|---|---|---|
| Normal delivery | Normal | Dry |
| Occlusion | High | Dry |
| Site leak | < 60% of normal | Wet |
| Cannula-out | Low | Dry |
A sequenced pathway for two components
The disposable set and the electronics module needed different FDA tracks. The set follows a straightforward 510(k) against an existing predicate (BD FlowSmart / MiniMed Pro-Set) — same device class, same regulation, and the added hub sensor changes no lumen dimension or delivery accuracy. The electronics module has no matching product code, so it goes through either an accessory request under §513(f)(6) or a De Novo pathway, run in parallel with the set's 510(k).
The design was also built to avoid needing a new billing code: the set bills under the existing pump-supply pathway, the module under the existing pump code. The economic case to a hospital's value-analysis committee rests on one averted DKA hospital admission (~$27,000) against roughly $1,300 of a patient's annual sets.
| US | EU | Canada |
|---|---|---|
| 510(k) 4–8 mo · accessory/De Novo 9–18 mo | MDR 2017/745 Class IIa, 18–24 months | MDB Class II, 15-day target |
Evidence sized to event incidence, not enrollment
Clearance doesn't need a powered clinical trial — substantial equivalence rests on bench verification: a gel-block rig run through all four detection states 30 times each, plus induced-fault testing confirming every fault code reaches the pump within 500ms. A 30-subject pre-market cohort checks tolerability and false-positive rate, not accuracy. Real accuracy evidence — sensitivity and specificity of the alarm — accrues post-market through a 465-subject registry, co-funded with the OEM partner, tracking DKA admissions per 1,000 user-years against baseline.
Risk and human factors: the top hazards all trace back to the same failure shape — a silent, undetected non-alarm. A module that seats but doesn't latch, electrodes that never make contact, a lost wireless link, or a detached electrode reading as “no fault” would each let monitoring quietly stop while the user believes it's active. Every one of these was closed at the design or software stage — a keyed snap that can't seat wrong, a power-on self-test of electrode continuity, an authenticated link with a heartbeat and its own loss-of-monitoring alarm, and a third “indeterminate” state instead of defaulting failures to “no fault.” Usability testing (IEC 62366-1) targets zero prompting and 100% critical-task success across adolescents, adults, and caregivers in a simulated home environment.
100% critical-task success in summative usability testingCommercialization through the OEM channel
SubQ-Confirm sells through pump manufacturers, not direct to patients — no sales force of its own. The set runs a razor-and-blade model: a $10–12 per-set premium to the OEM against roughly $3.20 in cost of goods, a 71% gross margin, while the reusable module is placed as capital at $180 against $62 in cost, a 66% margin. At 122 sets per user per year and 75,000 users by year five, that's roughly 9.2 million sets and $101M in set revenue alone.
Two academic endocrinology centers anchor the accuracy registry and its publications. The funding path is a $3.5M seed to resolve the electronics module's regulatory route, then a $12M Series A to carry the disposable set through verification, clearance, and launch. Likely acquirers at exit: Medtronic Diabetes, Abbott, Dexcom.
Full-lifecycle product management, end to end
SubQ-Confirm was built to exercise the full scope a medical device PM actually owns: sizing a clinical need into a real market, writing requirements a hardware and firmware team could build against, choosing and defending a regulatory strategy, planning the evidence a submission and a payer both need, running risk and human-factors analysis to ALARP, and turning all of it into a fundable business case. The full requirements traceability, hazard analysis, and financial model live in the executive pitch deck below.