The intended use of the HC500 is to provide therapeutic levels of heat and humidity to a patient's inspired respiratory gases, when using an artificial ventilation system. This includes use with systems such as portable volume ventilation systems, pressure support ventilation and continuous positive airway pressure (CPAP) devices. These systems may bypass the patient airway (using an endotracheal tube) or use mask ventilation. Providing heat and humidification to these gases counteracts the effects of bypassing the nose, pharynx and trachea, where this function would normally be carried out by the body. Addition of heat and humidity to the supply of cold and dry respiratory gases provided through mask ventilation is similarly beneficial to prevent drying of the patient airways. The HC500 is primarily intended for a home-use situation, typically for patients requiring long-term respiratory assistance of a non-critical nature (ie not requiring hospital or intensive care levels of attention).
Device Story
HC500 is a servo-controlled heated respiratory humidifier for home use. Inputs: gas flow, temperature from heater plate thermistor, and airway temperature probes. Operation: PID algorithm controls heater plate and optional circuit heater wire to maintain set temperature/humidity. Outputs: heated/humidified respiratory gas; visual/audible alarms for high temperature (≥41°C at patient end, ≥47°C at chamber), probe disconnection, or faults. Operated by home caregiver or patient. Healthcare provider sets parameters; output prevents airway drying and rainout. Benefits: provides therapeutic heat/humidity for patients bypassing natural airway functions.
Clinical Evidence
Bench testing only. Mechanical, electrical, software, and performance testing conducted. Includes mechanical shock/vibration, electrical safety (leakage current), and functional software verification. Performance testing compared heated/non-heated wire modes against predicates, confirming equivalent absolute humidity and temperature delivery within specified flow limits.
Indicated for patients requiring long-term respiratory assistance of a non-critical nature, including those using portable volume ventilation, pressure support ventilation, or CPAP devices via endotracheal tube or mask.
Regulatory Classification
Identification
A respiratory gas humidifier is a device that is intended to add moisture to, and sometimes to warm, the breathing gases for administration to a patient. Cascade, gas, heated, and prefilled humidifiers are included in this generic type of device.
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Fisher & Paykel
HEALTHCARE
K953392
Fisher & Paykel Electronics Limited
25 Carbine Road, Panmure, Auckland, New Zealand
PO. Box 14 348, Panmure, Auckland, New Zealand
Tel: +64-9-574 0100 Fax: +64-9-574 0158
14 July, 1995
MAR 12 1996
# 510(k) Summary of Safety and Effectiveness Information
Model Number / Name: HC500 Servo-Controlled Heated Respiratory Humidifier
Classification Name: Humidifier, Respiratory Gas, Direct Patient Interface - 73 BTT Anesthesiology Devices, 21 CFR §868.5450
Predicate Devices: Fisher & Paykel, MR730 Respiratory Humidifier, K913368
Fisher & Paykel, MR410 Respiratory Humidifier, K913367
This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR §807.92.
The HC500 is enclosed in a thermoplastic case that features an aluminium heater plate mounted in the top of the unit, with a chamber clamping mechanism. The device indicators, controls and temperature display are located on the front panel. Sockets for a temperature probe and heater wire, and the power switch are on the right side, and a mounting bracket is located on the back of the device. The HC500 measures 135 x 170 x 156mm and weighs 2.8kg without a humidification chamber fitted. It contains a mains transformer and Power and Control printed circuit boards. The HC500 Servo-Controlled Heated Respiratory Humidifier controls the addition of heat and humidity to respiratory gases delivered through a patient delivery circuit. The humidifier operates in two modes that are individually selected: (1) Non Heated Wire mode, and (2) Heated Wire mode.
In the Non Heated Wire mode, gas temperature and humidity is determined by the heater plate temperature and gas flow rate. The heater plate temperature is set by the control knob, from 45°C to 80°C, and controlled by a thermistor mounted on the heater plate which provides feedback to a software controlled Proportional, Integral, Derivative (PID) algorithm. The airway temperature is monitored by in line temperature probes at the exit of the humidification chamber and at the patient end of the delivery circuit. A high temperature alarm is set to 41°C at the patient end of the delivery circuit. Enabling the alarm turns off the heater element and turns on audible and visual alarm indicators, and the temperature display. In normal operation the patient airway temperature can be displayed on the front panel by pressing and holding the mute button.
In the Heated Wire mode, gas temperature and humidity is determined by controlling the heater plate and a heater wire in the patient delivery circuit. The patient delivery temperature is set by the control knob, from 32°C to 39°C. The heater plate controls the temperature at the output of the humidification chamber and there is a +2°C rise to the patient end of the delivery circuit which is controlled by the heater wire. The temperature rise in the patient delivery circuit minimises rainout in the delivery circuit.
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510(k) Summary continued - Fisher & Paykel HC500 Heated Respiratory Humidifier
Feedback to the PID software is provided by the heater plate thermistor and the airway temperature probes. If a high temperature $(\geq 41^{\circ}\mathrm{C})$ alarm is detected at the end of the patient delivery circuit, both heater elements are shut off and the audio and visual indicators and temperature display are turned on for the duration of the alarm. Chamber high temperature alarms are set at $\geq 47^{\circ}\mathrm{C}$, and $41^{\circ}\mathrm{C}$ for longer than 20 minutes. The patient airway temperature is available in the same manner as the non heated wire mode.
The HC500 features a $118^{\circ}\mathrm{C}$ thermal overheat cut-out on the heaterplate, a back-up electronic over temperature protection circuit, and connection or fault alarms for the temperature probe and heater wire.
The intended use of the HC500 is to provide therapeutic levels of heat and humidity to a patient's inspired respiratory gases, when using an artificial ventilation system. This includes use with systems such as portable volume ventilation systems, pressure support ventilation and continuous positive airway pressure (CPAP) devices. These systems may bypass the patient airway (using an endotracheal tube) or use mask ventilation. Providing heat and humidification to these gases counteracts the effects of bypassing the nose, pharynx and trachea, where this function would normally be carried out by the body. Addition of heat and humidity to the supply of cold and dry respiratory gases provided through mask ventilation is similarly beneficial to prevent drying of the patient airways. The HC500 is primarily intended for a home-use situation, typically for patients requiring long-term respiratory assistance of a non-critical nature (ie not requiring hospital or intensive care levels of attention).
To accommodate this more specific intended environment of use of the HC500 from the predicate device, the Operating Manual has been rewritten to clearly detail the responsibilities of the home caregiver and supervising clinician, provide expanded cleaning and maintenance sections, and emphasize safety precautions. The HC500 has been modified to suit home use, with unnecessary features removed, controls simplified and made less liable to inadvertent adjustment.
The technological characteristics of the HC500 are equivalent to the predicate device. The device size, shape, material construction, and location of functional components are all retained in the HC500. All significant components of the HC500 are identical to those used on the MR730 or MR410 predicate devices. These include all enclosure, mounting and chamber retaining components, heater plate assembly, internal chassis and transformer, PCB's, microprocessor, power supply cord and external connectors or sockets, and internal connectors and wiring. The devices both use a nominal 115Vac 60Hz mains supply.
The changes between the HC500 and predicate devices consist of a rearrangement and simplification of available features in order to make these more appropriate for the intended home use of the device. These differences consist of the following items. Element power is reduced to 85W and maximum heaterplate temperature reduced to $100^{\circ}\mathrm{C}$, as the reduced maximum flow specification for the HC500 requires less power for equivalent performance. The temperature control range and lower alarm limits have been adjusted to suit a home use environment. A power on indicator is added, and alarm indicators combined on the front display panel. Data
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510(k) Summary continued - Fisher & Paykel HC500 Heated Respiratory Humidifier
I/O and stand by mode features are removed as are not required in a home use application. The chamber temperature display, chamber offset control, heater wire mode switch and general temperature display features, while still available on the HC500, have been reduced in general accessibility to the user as are expected to be required very infrequently. The heaterplate temperature in non heated wire mode is software controlled, as the MR410 predicate device which uses this mode has electronic control only. The additional safety features of airway temperature monitoring and display, with temperature, connection and fault alarms, have been added to non heated wire operation.
A series of non-clinical tests have been carried out for the HC500 to establish correct operation of the device in mechanical, electrical, software and performance aspects. Mechanical shock, vibration and environmental conditions testing ensures that the HC500 can withstand extreme conditions of use without loss of function or significant physical damage to the unit. The HC500 electrical and hardware characteristics remain equivalent to the predicate devices, and maximum power usage ratings have been established by testing. All electrical safety parameters such as leakage current are within limits set by international design standard. Software changes from the predicate device have been verified through functional tests, which prove correct operation of the features which have had parameters modified for the HC500. Performance testing demonstrates that the device functions as specified under a variety of conditions of use, and with the home respiratory care equipment which the HC500 will be used with. Comparative testing for both heated wire and non heated wire operating modes ensure that performance is equivalent to the predicate devices in terms of delivery of absolute humidity or temperature levels within the specified flow limits of the HC500.
The results of the performance and other testing carried out for the HC500 establish that the device has the same or better safety and effectiveness characteristics over the predicate devices, due to the high level of similarity between these models, and the application of additional safety features not previously available in non heated wire mode use. The HC500 has equivalent or better performance characteristics over the specified range of use for the device, as the reduction in heaterplate power used in heated wire mode is compensated for by the reduced operating flow specification necessary for home use of the device.
signed: 
Chris Mander
Fisher & Paykel Healthcare
date: 14 July 1995
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Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.
