Diagnostic aid (cardiac output determination). The LiDCO System is intended for the monitoring of cardiac output (blood flow in litres per minute) in patients of greater than 88 lbs (40 kg) in weight. Description/Route of Administration – Sterile lithium chloride (5 ml of 0.15 mmol/ml) suitable for parenteral (iv) administration. Suitable Patients – To operate the LiDCO System it is required that suitable patients will have available pre-placed peripheral arterial and central venous catheters. Locations of Use – Suitable patients will be receiving treatment/hospital care in the following areas: Medical and Surgical Intensive Care Units, Operative Suites, Step Down/High Dependency Units, Trauma/Accident & Emergency Units, Coronary Intensive Care Units.
Device Story
LiDCO System measures cardiac output via indicator dilution technique using lithium chloride as indicator. Physician/clinician injects lithium chloride bolus into central venous line; blood is withdrawn through peripheral arterial line via pump into external lithium ion-selective electrode sensor. Sensor detects lithium concentration; software calculates area under primary indicator dilution curve to determine cardiac output. Used in ICU, OR, and emergency settings. Provides numeric cardiac output (L/min) and dilution curve display to clinicians. Benefits include minimally invasive monitoring without pulmonary artery catheterization, reducing risks of vascular injury, arrhythmias, and infection associated with thermodilution catheters.
Clinical Evidence
Clinical investigations compared LiDCO System against pulmonary artery catheter (n=51) and continuous cardiac output methods (n=11). Results showed high correlation (r=0.963 and r=0.949 respectively). Bias was 0.19 L/min (precision 0.38 L/min) against PA catheter and 0.01 L/min (precision 0.55 L/min) against continuous cardiac output methods.
Technological Characteristics
System includes monitor (CM-30 series), blood withdrawal pump (CM-33), and lithium ion-selective electrode sensor. Sensor uses PVC membrane on polyurethane. Flow cell is polycarbonate. Connectivity via RS232 port. Power: 5VDC monitor, 6VDC battery-operated pump. Measurement range 0.1-20 L/min. Non-invasive to patient vasculature (external sensor).
Indications for Use
Indicated for cardiac output monitoring in patients > 40 kg (88 lbs) requiring hemodynamic assessment. Requires pre-placed peripheral arterial and central venous catheters. Contraindicated in patients receiving lithium therapy for manic depressive psychosis.
Regulatory Classification
Identification
A single-function, preprogrammed diagnostic computer is a hard-wired computer that calculates a specific physiological or blood-flow parameter based on information obtained from one or more electrodes, transducers, or measuring devices.
Predicate Devices
Baxter Edwards Model 93B-131-7F Flow Directed Thermodilution Catheter (K810352)
Baxter Edwards Model 9520 Cardiac Output Computer (K760192)
Submission Summary (Full Text)
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JAN 8 1999
702715
Confidential - LIDCo System 510(k)
LIDCo LTD
CARDIAC SENSOR SYSTEMS
16 Orsman Road,
London,
N1 5QJ,
ENGLAND.
# 1.12 Summary of Safety and Effectiveness
Statement: 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
(i) Concept: There are numerous clinical indications for cardiac output measurement. In general, the methods are either unreliable (oesophageal Doppler, thoracic impedance), difficult to perform (indocyanine green and Fick) or hazardous (thermodilution). There has long been the need for a simple safe and reliable method. The LIDCo System revisits and improves the indicator dilution technique of cardiac output determination. It avoids the complications of pulmonary artery catheterisation. The LIDCo System will have clinical utility in patients with pre-placed arterial and venous lines, where the determination of cardiac output is required minimally invasively without the insertion of a pulmonary artery catheter
(ii) Indicator & Lithium Sensor: The lithium cation provides an excellent signal (log of concentration) against a very stable baseline in blood. The indicator is not significantly lost in its first pass to the pulmonary, or systemic circuit. The lithium cation sensor is biocompatible, thermally compensated and unaffected by changes in arterial blood pressure
(iii) Software: Despite the potential complication of secondary marker recirculation, the LIDCo System software has been demonstrated in a number of bench and clinical studies to calculate the area under the primary indicator dilution curve.
(iv) Accuracy: Clinical investigations show close correlation between the LIDCo System and current clinical standard methods:
| | Patient No's | Correlation | Bias (L/Min) | Precision (L/Min) |
| --- | --- | --- | --- | --- |
| Pulmonary Artery Catheter | 51 | 0.963 | 0.19 | 0.38 |
| Continuous Cardiac Output | 11 | 0.949 | 0.01 | 0.55 |
(v) Safety: In most patients for whom cardiac output measurements are indicated, central venous and arterial catheters are already in place. To make a measurement with the LIDCo System there is no need for further cannulation with its attendant risks. Approximately 3 ml of blood are needed per determination - an insignificant amount for an adult. The dose of lithium chloride used is extremely small and has no known effects. Awake patients experience no sensation of any sort in response to the injection. Lithium pharmacology is well described in the literature with over 50 years of experience of chronic administration of high doses. LIDCo System dosing recommendations are conservative and make worst case assumptions - pathological compartmental volumes, accumulation of lithium, maximum dose given at maximum frequency. No side-effects/complications have been noted in critical care/post operative patient experience to date at: single doses or total doses 2-3 times final product recommendations. The LIDCo System reduces the risks associated with cardiac output determination compared to pulmonary artery thermodilution.
(vi) Truthful & Accurate Certification: " I certy that, in my capacity as Managing Director, I believe to the best of my knowledge that all data and information submitted in this premarket notification are truthful and accurate and that no material fact has been omitted."
Signed by Applicant: 
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Confidential - LIDCo System 510(k)
1.13 Comparison Tables With Predicate Devices
Table 1 Comparison of Features of the LIDCo System (CM-10;20;40 & 50) and Baxter Edwards Model 93B - 131 - 7F Flow Directed Thermodilution Catheter
| CRITERIA | LIDCo SYSTEM FEATURE | BAXTER / EDWARDS MODEL 93B - 131 - 7F FEATURE |
| --- | --- | --- |
| 1. Registration Status | | |
| Class 11 510 (K) | Applied for | Granted # K810352 |
| 2. Intended Use & Target Population | | |
| (i) Intended use: cardiac output determination | | Cardiac output determination & measurement of hemo-dynamic pressures in the heart and pulmonary artery |
| (ii) Target Population: Critical care anaesthesia and cardiology patients with pre-placed arterial and central venous lines | | Critical care, anaesthesia and cardiology patients |
| 3. Construction/Materials of: | | |
| (i) Device Body | Flow cell moulded from polycarbonate | 4 lumen radiopaque polyurethane extrusion |
| (ii) Sensor | Lithium ion selective electrode made from PVC membrane cast onto polyurethane | Thermistor with lead wires |
| (iii) Blood Bag & Tube | Blood contact material PVC - blood not returned to patient | N/A |
| 4. Anatomical Sites | | |
| Required location of sensor or catheter to measure cardiac output | External to body, connected to peripheral arterial line via luer lock fitting | Pulmonary artery via right side of heart |
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CRITERIA LIDCo SYSTEM FEATURE BAXTER / EDWARDS MODEL 93B - 131 - 7F FEATURE
Confidential - LIDCo System 510(k)
# 5. Physical Safety
## (i) Warnings/Complications
**Clinical:** Number of determinations limited to a cumulative dose of 3 mmol and worse case plasma level of 0.33 mmol/l. All injections of lithium including flushes should be noted. Lithium chloride is toxic at a plasma concentration of > 1.5 mmol/l. A minimum of 5 minutes should be allowed between sequential administrations of lithium chloride. Waste blood/saline should not be returned to patient. Avoid bolus administrations or infusions of muscle relaxants 1 hour prior to determination.
**Clinical:** Rupture of the pulmonary artery resulting in vascular injury and on occasion death, carbon dioxide or air embolus, thromboembolic and infectious complications, ventricular arrhythmias, anti coagulation & antibiotic protection should be considered in cases with increased risks & when long-term catheterization (>48hrs) is necessary.
**Product:** Loss of patency of sensor flow-through-cell due to blood clotting.
**Product:** The following catheter complications may occur: kinking & knotting of catheter, stretching of body of catheter with resultant loss of electrical connection, loss of patency through blood clotting.
**Storage:** Single use, not to be stored in direct sunlight, fluorescent or incandescent lighting conditions.
**Storage:** Single use, not to be stored in direct sunlight, fluorescent or incandescent lighting conditions.
## (ii) Contra-Indications
Contra - indicated in: patients currently under lithium therapy for control of manic depressive psychosis, patients < 40 kg in weight.
Use of thermodilution catheters is cautioned in patients with pulmonary hypertension.
## (iii) Biocompatibility
**Patient contacting Materials:** Polycarbonate contacts patient dermis.
**Patient Contacting Materials:** Polyurethane bonded with heparin - contacts directly with blood and cardiac tissues.
Indicator - lithium chloride injected into blood system
Indicator - 5% dextrose or saline injected into blood system.
{3}
Confidential - LIDCo System 510(k)
CRITERIA LIDCo SYSTEM FEATURE BAXTER / EDWARDS MODEL 93B - 131 - 7F FEATURE
## 6. Performance
### (i) Indicator detection technique
Dilution of injectate of salt solution - 0.075 to 0.3 mmol lithium chloride. 3 - 4 mls of blood sampled per cardiac output determination
Temperature based indicator 5% dextrose or saline injectate
Thermistor centrally positioned no blood sample required
### (iii) Clinical performance *
Clinical investigations show close correlation between the LIDCo System and predicate devices:
| | Patient No's | Correlation | Bias (L/Min) | Precision (L/Min) |
| --- | --- | --- | --- | --- |
| Pulmonary Artery Catheter | 51 | 0.963 | 0.19 | 0.38 |
| Continuous Cardiac Output | 11 | 0.949 | 0.01 | 0.55 |
* See Chapter 3.3 for full results from clinical testing
{4}
Confidential - LIDCo System 510(k)
Table 2 Comparison of Features of the LIDCo System Electronics Package CM-30 and Baxter Edwards Model 9520 Cardiac Output Computer
| CRITERIA | LIDCo SYSTEM FEATURE | BAXTER / EDWARDS MODEL 9520 FEATURE |
| --- | --- | --- |
| 1. Registration Status
Class 11 510 (k) | Applied for | Granted # K760192 |
| 2. Intended Use & Target Population
(i) Intended use: cardiac output determination
(ii) Target Population: Critical care anaesthesia and cardiology patients with pre-placed arterial and central venous lines | | Cardiac output determination & measurement of hemodynamic pressures in the heart and pulmonary artery
Critical care, anaesthesia and cardiology patients |
| 3. Patient Safety
Monitor CM-31/32:
• Power supply is by + 5VDC AC to DC Power Supply Unit
• Connection with sensor interface is optically isolated
Blood Withdrawal Pump CM-33:
• Power supply is by battery operation (6v DC)
• Low battery warning
• Fail safe against arterial blood pressure
• "One way" only insertion of pump tubing | | Baxter/Edwards 9520
• Battery operation 5 V DC
• Recorder and digital outputs by optical circuits and transformer |
{5}
Confidential - LiDCo System 510(k)
| CRITERIA | LiDCo SYSTEM FEATURE | BAXTER / EDWARDS MODEL 9520 FEATURE |
| --- | --- | --- |
| 4. Product Features | | |
| • Dimensions & Weight | 320 mm x 260 mm x 40 mm
≤ 5 lbs | 11.5 in x 3.25 in x 10.75 in
≤ 5 lbs |
| • Display of CO value | Numeric in litres / minute | Numeric in litres / minute |
| • Possible to display dilution curve ? | Yes | Yes |
| • Digital output of CO ? | Yes - via RS232 port | Yes - via serial port |
| • Calculation method | Band-Linton derived equation involving area integration of the lithium cation dilution curve with lognormal approach - curve cut at 10% down from peak | Modified form of Stewart-Hamilton equation with area integration of thermo-dilution curve based on monoexponential approach - curve cut at 30% of peak |
| • Measurement range | 0.1 to 20 litres / minute | 0.1 to 20 litres / minute |
| • Self test and/or calibration possible ? | Yes | Yes |
| • Power source - for power supplied to CO sensor | No power is supplied; not required by LiDCo sensor | From monitor |
| • Battery charger/PSU | LiDCo Model CM-34 PSU
115/230 V AC, 50 - 60 hz | Edwards models 9521& 9522, 115/230 V5 AC, 50 - 60 hz battery charger |
{6}
DEPARTMENT OF HEALTH & HUMAN SERVICES
Public Health Service
Food and Drug Administration
9200 Corporate Boulevard
Rockville MD 20850
JAN 8 1999
Dr. T. O'Brien
Managing Director
LiDCO Ltd.
16 Orsman Road
London N1 5QJ
United Kingdom
Re: K962918
LiDCO System
Regulatory Class: II (Two)
Product Code: 74 DXG
Dated: October 19, 1998
Received: October 20, 1998
Dear Dr. O'Brien:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act). You may, therefore, market the device, subject to the general controls provisions of the Act. However, you are responsible to determine that the medical devices you use as components in the kit have either been determined as substantially equivalent under the premarket notification process (Section 510(k) of the act), or were legally on the market prior to May 28, 1976, the enactment date of the Medical Device Amendments. Please note: If you purchase your device components in bulk (i.e., unfinished) and further process (e.g., sterilize) you must submit a new 510(k) before including these components in your kit. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, and labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval) it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical Devices:
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Page 2 - Dr. T. O'Brien
General regulation (21 CFR Part 820) and that, through periodic QS inspections, FDA will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, the Food and Drug Administration (FDA) may publish further announcements concerning your device in the *Federal Register*. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal Laws or Regulations.
This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market. If you desire specific advice for your device on the labeling regulation (21 CFR Part 801 and additionally 809.10 for *in vitro* diagnostic devices), please contact the Office of Compliance at (301) 594-4648. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll free number (800) 638-2041 or (301) 443-6597, or at its internet address "http://www.fda.gov/cdrh/dsma/dsmamain.html".
Sincerely yours,
Thomas J. Callahan, Ph.D.
Director
Division of Cardiovascular,
Respiratory, and Neurological Devices
Office of Device Evaluation
Center for Devices and
Radiological Health
Enclosure
{8}
Jan 08 99 12:13p Charles H. Kyper (301) 776-3166 p.9
08/01/1999 16:33 01712561645 LIDCO LTD PAGE 08
# INTENDED USE: LiDCO SYSTEM for CARDIAC OUTPUT MONITORING
510(k) Number: K962918
Device Name: LiDCO System
- Indications for Use – Diagnostic aid (cardiac output determination). The LiDCO System is intended for the monitoring of cardiac output (blood flow in litres per minute) in patients of greater than 88 lbs (40 kg) in weight.
- Description/Route of Administration – Sterile lithium chloride (5 ml of 0.15 mmol/ml) suitable for parenteral (iv) administration.
- Suitable Patients – To operate the LiDCO System it is required that suitable patients will have available pre-placed peripheral arterial and central venous catheters.
- Locations of Use – Suitable patients will be receiving treatment/hospital care in the following areas:
- Medical and Surgical Intensive Care Units
- Operative Suites
- Step Down/High Dependency Units
- Trauma/Accident & Emergency Units
- Coronary Intensive Care Units
(PLEASE DO NOT WRITE BELOW THIS LINE – CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE)
Prescription Use ☑ (Per 21 CFR 801.109)
OR Over-the-Counter Use ☐ (Optional Format 1-2-96)
Mark Kraw
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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.