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Indicated for use in adults only.

The PhysioFlow Q-Link noninvasively measures cardiac output and other related cardiac parameters. These parameters include:

CI Cardiac Index
CO Cardiac Output
CTI Contractility Index
dZ / dt max Maximum value dZ / dt
EDV End Diastolic Volume
EF Ejection Fraction
HR Heart Rate
LCWI Left Cardiac Work Index
PEP Pre-Ejection Period
SV Stroke Volume
SVR Systemic Vascular Resistance
SVRI Systemic Vascular Resistance Index
TFI Thoracic Fluid Index
VET Ventricular Ejection Time
ZO Base Impedance

The PhysioFlow Q-Link is intended for use under the direct supervision of a licensed healthcare practitioner or personnel trained in its proper use within a hospital or facility providing healthcare.

The PhysioFlow Q-Link is a noninvasive, hemodynamic monitor that utilizes thoracic electrical bioimpedance technology to measure cardiac output and related cardiac parameters. It consists of a small, portable, lightweight electronic unit that attaches to the patient via a six lead, patient cable using commercially available silver/silver chloride skin electrodes. Monitor data is transmitted to a host computer running the PhysioFlow PF107 software. Communication to the host computer is via USB wired technology. The PhysioFlow PF107 software performs multiple tasks including signal processing and analysis, measured parameter computation, user interface display and control, measurement process control, event marker management, and output display/report generation. Available accessories include the patient and USB cables.

Here's an analysis of the provided text regarding the acceptance criteria and study for the PhysioFlow Q-Link device:

The provided document (a 510(k) summary) is very limited in its description of specific acceptance criteria and detailed study data. It primarily focuses on demonstrating substantial equivalence to a predicate device rather than providing a standalone validation study report for the new device.

Here's what can be extracted and what is explicitly not available from the text:

1. Table of Acceptance Criteria and Reported Device Performance

Based on the provided text, specific numerical acceptance criteria (e.g., accuracy +/- X%) and corresponding reported performance metrics are NOT available.

The document states:
"Design verification tests were performed on representative samples of the PhysioFlow Q-Link as a result of a comprehensive product development and risk management plan. All tests were verified to meet the pre-specified acceptance criteria."

This confirms that acceptance criteria exist internally, and the device met them, but the criteria themselves and the detailed performance results are not reported in this summary. The summary implies the acceptance criteria were met by comparison to the predicate device's performance, as the core argument for substantial equivalence.

2. Sample Size for the Test Set and Data Provenance

• Test Set Sample Size: Not explicitly stated. The document refers to "representative samples" for design verification tests, but the number of devices or subjects is not quantified.
• Data Provenance: Not explicitly stated. The nature of the tests ("design verification tests") suggests these were likely bench tests or in-house engineering evaluations rather than clinical studies with human subjects. The comparison is made to the previous device's performance, but no information is given about the original predicate device's data provenance either in this document.

3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications

Not applicable/Not stated. This type of information (experts, their qualifications) is typically associated with studies involving human interpretation (e.g., radiologists reviewing images) or clinical trials requiring expert assessment. The "design verification tests" described here do not involve such expert review for ground truth establishment in the way typically seen in diagnostic AI/medical imaging devices. For a hemodynamic monitor, "ground truth" often refers to a reference standard (e.g., invasive cardiac catheterization) which is not mentioned here.

4. Adjudication Method for the Test Set

Not applicable/Not stated. As no expert review process for ground truth establishment is described, no adjudication method would be relevant.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, an MRMC comparative effectiveness study was not done.

This type of study is relevant for devices where human readers interpret data (e.g., images) and the AI aims to assist or replace that interpretation. The PhysioFlow Q-Link is a non-invasive hemodynamic monitor that provides objective physiological parameters. There is no human "reading" of the data in the sense that an MRMC study would apply. Therefore, no effect size for human readers improving with AI assistance is applicable or reported.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

Yes, in essence, a standalone performance assessment was done, but the details are minimal.

The "design verification tests" assess the device's ability to measure physiological parameters. Since it's a direct measurement device, its "standalone" performance is its fundamental operation. The summary does not describe a human-in-the-loop component in the measurement or calculation process that would necessitate a distinction between standalone and assisted performance. However, specific performance metrics for this standalone operation are not detailed in the summary.

7. Type of Ground Truth Used

Not explicitly stated, but inferred to be a reference standard or validated measurement method.

For a device measuring cardiac output and related parameters, the "ground truth" in a comprehensive validation study would typically be established using an invasive, gold-standard method (e.g., thermodilution via pulmonary artery catheter) or another well-validated non-invasive method. The summary does not specify how the "pre-specified acceptance criteria" were derived or validated, nor what reference method was used to establish the true values of the parameters being measured during the verification tests. Given the context of a 510(k) for a modification (Q-Link compared to Enduro PF-07), the implicit "ground truth" for the Q-Link's performance would be its agreement with the predicate device's measurements.

8. Sample Size for the Training Set

Not applicable/Not stated.

This device is not an AI/Machine Learning algorithm that undergoes a distinct "training" phase. It uses established thoracic electrical bioimpedance technology. Therefore, there is no "training set" in the context of an AI model. Its operational algorithms are based on physiological principles, not on learning from a dataset.

9. How the Ground Truth for the Training Set Was Established

Not applicable/Not stated.

As there is no training set for an AI/ML model, the concept of establishing ground truth for a training set does not apply. The device's underlying physical models and algorithms would have been developed using established physiological principles and prior research in bioimpedance.

Summary of what's provided for acceptance criteria and studies:

The provided 510(k) summary for the PhysioFlow Q-Link is brief and focuses on demonstrating substantial equivalence to its predicate device (PhysioFlow Enduro Model PF07) due to being a modification rather than a fundamentally new device. It asserts that "Design verification tests were performed on representative samples... All tests were verified to meet the pre-specified acceptance criteria." However, it does not provide the following crucial details:

• The specific numerical values for the "pre-specified acceptance criteria."
• Detailed quantitative performance data for the PhysioFlow Q-Link against those criteria.
• The sample size of items or subjects used in the verification tests.
• The method or reference standard used to establish "ground truth" for these tests, beyond implied comparison to the predicate.
• Any information regarding expert review, adjudication methods, or MRMC studies, as the device type does not involve human interpretation in that manner.
• Information about training sets or how ground truth was established for a training set, as it is not an AI/ML device relying on trained models.

Essentially, the document states that tests were done and criteria were met, but it does not reveal what those criteria or results were in this public summary. This level of detail is typically found in the full 510(k) submission or an internal design verification report, not usually in the summary provided.

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Indicated for use in adults only. The PhysioFlow Enduro PF07 noninvasively measures cardiac output and other related cardiac parameters. These parameters include: CI (Cardiac Index), CO (Cardiac Output), CTI (Contractility Index), dZ / dt max (Maximum value dZ / dt), EDV (End Diastolic Volume), EF (Ejection Fraction), HR (Heart Rate), LCWI (Left Cardiac Work Index), PEP (Pre-Ejection Period), SV (Stroke Volume), SVR (Systemic Vascular Resistance), SVRI (Systemic Vascular Resistance Index), TFI (Thoracic Fluid Index), VET (Ventricular Ejection Time), and ZO (Base Impedance). The Enduro System Model PF-07 is intended for use under the direct supervision of a licensed healthcare practitioner or personnel trained in its proper use within a hospital or facility providing healthcare.

The PhysioFlow Enduro Model PF07 is a noninvasive, hemodynamic monitor that utilizes thoracic electrical bioimpedance technology to measure cardiac output and related cardiac parameters. It consists of a small, portable, lightweight (less than 250 gm with batteries) electronic unit that attaches to the patient via a six lead, patient cable using commercially available silver/silver chloride skin electrodes. The electronic unit incorporates recorder capabilities, enabling it to capture and store up to 24 hours of monitor data for later transmission to a host computer running the PhysioFlow PF107 software. Communication options include Bluetooth wireless and USB wired technology. The PhysioFlow PF107 software performs multiple tasks including signal processing and analysis, measured parameter computation, user interface display and control, measurement process control, event marker management, and output display/report generation. Available accessories include the patient cable, a Bluetooth antenna. USB cable, and electronic unit carrying case.

Here's an analysis of the acceptance criteria and the study that proves the device meets them, based on the provided text:

Acceptance Criteria and Device Performance

The provided document describes a "Special 510(k)" submission for the PhysioFlow Enduro Model PF07, which is a modification of a previously cleared device, the PhysioFlow System Model PF05. Special 510(k)s typically rely on demonstrating that modifications to an existing device do not raise new questions of safety or effectiveness and that the modified device performs as intended and is substantially equivalent to the predicate.

In this case, the acceptance criteria for the new device (PhysioFlow Enduro Model PF07) are directly tied to its performance relative to the predicate device (PhysioFlow System Model PF05).

1. Table of Acceptance Criteria and Reported Device Performance:

Summary of Performance: The device's performance, showing a difference of less than 4% compared to the predicate, meets the acceptance criteria as this difference is below the acceptable clinical variability of 5%.

2. Sample Size Used for the Test Set and Data Provenance:

• Sample Size for Test Set: The document states "Design verification tests were performed on representative samples" and "Product validation tests were performed in a simulated use setting." However, no specific numerical sample size (e.g., number of patients/subjects or test cases) for the test set is provided.
• Data Provenance: Not explicitly stated. The tests were performed as part of product development and validation, but the country of origin or whether it was retrospective or prospective data is not mentioned. Given it's a simulated use setting test for validation, it likely refers to testing under controlled conditions rather than a clinical trial with patient data.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:

• Number of Experts: Not mentioned.
• Qualifications of Experts: Not mentioned.

4. Adjudication Method for the Test Set:

• No information provided regarding an adjudication method. The testing described focuses on comparing the subject device's output to the predicate device's output, essentially using the predicate device's performance as the reference.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done:

• No, an MRMC comparative effectiveness study was not done. The study described is a device-to-device comparison for technical performance, not a human reader performance study. Therefore, there's no information on the effect size of how much human readers improve with AI vs. without AI assistance. The device is a direct measurement tool, not an AI-assisted diagnostic aid for interpretation by human readers.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done:

• Yes, a standalone performance assessment was effectively done. The "Design verification tests" and "Product validation tests performed in a simulated use setting" compared the device's output (algorithm + hardware) to the predicate device's output. The performance report of "less than 4% difference" refers to the device's standalone measurements.

7. The Type of Ground Truth Used:

• The "ground truth" for the performance study was the performance of the predicate device (PhysioFlow System Model PF05). The study established "a difference between the subject and predicate devices of less than 4% across the measured parameters." This implies the predicate device's established measurements served as the reference for evaluating the new device.

8. The Sample Size for the Training Set:

• Not applicable/Not mentioned. This device is a physiological monitor based on bioimpedance technology, not a machine learning or AI algorithm that requires a "training set" in the conventional sense. Its underlying principles are established physiological measurements. The document describes traditional "design verification tests" and "product validation tests," not machine learning model training.

9. How the Ground Truth for the Training Set Was Established:

• Not applicable/Not mentioned. As explained above, there is no "training set" for this type of device in the context of the provided document. The device's functionality relies on established physics and physiology, not data-driven machine learning.

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The PhysioFlow System noninvasively measures cardiac output and other related cardiac parameters on adults. These parameters include: CI, Cardiac Index; CO, Cardiac Output; CTI, Contractility Index; EDV, End Diastolic Volume; EF, Ejection Fraction; HR, Heart Rate; LCWI, Left Cardiac Work Index; PEP, Pre Ejection Period; SV, Stroke Volume; SVR, Systemic Vascular Resistance; SVRI, Systemic Vascular Resistance Index; TFI, Thoracic Fluid Index; LVET, Left Ventricular Ejection Time. The PhysioFlow System is intended for use under the direct supervision of a licensed healthcare practitioner or personnel trained in its proper use within a hospital or facility providing healthcare.

The PhysioFlow System is a noninvasive hemodynamic monitor that uses thoracic electrical bioimpedance technology to measure cardiac output and related parameters. It has three main components: 1. An electronic device that generates a low magnitude, high frequency electrical current, sends it through the body of the patient via a patient cable and pre-gelled electrodes, and receives it after it has crossed the patient thorax. The impedance modulation (ΔΖ) is extracted from the received signal, providing a pulsatile waveform used by the software to compute stroke volume. The device also records one lead of a passive electrical signal that is similar to the ECG, in order to provide a time basis and trigger for the analysis of the impedance waveform, and to provide a measurement of heart rate. This ECG signal is not used for electrocardiography analysis. The device filters and digitizes both the impedance and the ECG signals, and transmits them to a computer via a serial communications link. The device has an analog output option, which makes the following signals available: ΔZ, ECG, Cardiac Output trend, and Stroke Volume trend. 2. A computer that runs a MS-Windows operating system, and performs the following tasks: Reception of digitized signal samples from the device via a serial port; Platform to operate the PhysioFlow software; Physical user interface (keyboard, mouse, display); Patient data storage capacity (on hard disk); (Optional) Reception of blood pressure values from an external blood pressure monitor device via a serial port (This device does not measure blood pressure); Management of a printer using the appropriate driver. 3. The PhysioFlow software, which performs following tasks: Signal processing and analysis; Computation of measured parameters; User interface and control of the measurement process (entering patient data, calibration procedure, monitoring phase, post processing of measurement results); Transmitting cardiac output and stroke volume values back to the device via a serial data link for analog output purposes; Management of event markers; Setup of measurement and screen configuration (averaging ratio, scales, screen appearance, printout options); Display of signal, trends, and graphics; Management of imported data (blood pressure values from external monitor); Management of patient data; Export of measurement data in text format (for import into programs such as Excel); Generating hard copy output.

Here's a breakdown of the acceptance criteria and study information for the PhysioFlow device, based on the provided text:

Acceptance Criteria and Device Performance

The provided 510(k) summary does not explicitly list quantitative acceptance criteria in a table format with specific thresholds. However, it states that the device was compared to a predicate device and a Swan-Ganz catheter, implying that its performance needed to be similar to or substantially equivalent to these established methods. The overall conclusion is that the PhysioFlow System is "substantially equivalent to the Philips ICG System" (the predicate) in its overall intended use, functioning, safety, and efficacy.

Table 1: PhysioFlow Performance & Equivalence

Study Information

1. Sample Size Used for the Test Set and Data Provenance:

   • Sample Size: "84 subjects"
   • Data Provenance: The study was conducted at "two centers." The text does not specify the country of origin for the data or whether it was retrospective or prospective.

2. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:

   • The document does not provide information on the number of experts used or their qualifications for establishing ground truth. The ground truth was established by comparison to the "Swan-Ganz catheter using thermodilution," which is a reference measurement device rather than expert interpretation.

3. Adjudication Method for the Test Set:

   • The document does not specify an adjudication method. The comparison was directly against objective measurements from the Swan-Ganz catheter and the predicate device.

4. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

   • No, an MRMC comparative effectiveness study was not conducted as this device does not involve human readers interpreting diagnostic images or data in a way that would require an MRMC study. It is a measurement device where the output is directly calculated by the algorithm.

5. Standalone Performance (Algorithm Only without Human-in-the-Loop Performance):

   • Yes, the study effectively represents standalone performance. The PhysioFlow System is a noninvasive hemodynamic monitor that calculates parameters automatically based on collected bioimpedance and ECG signals. The study compared the device's output (its algorithm's performance) directly against established measurement methods (Swan-Ganz and predicate device).

6. Type of Ground Truth Used:

   • The ground truth was established by direct measurement using a reference device: the "Swan-Ganz catheter using thermodilution." This is a gold-standard invasive method for measuring cardiac output. The predicate device (Philips ICG) also served as a comparative reference.

7. Sample Size for the Training Set:

   • The document does not specify a separate training set sample size. It only mentions the 84 subjects for the clinical study which appears to be the primary dataset for performance evaluation.

8. How the Ground Truth for the Training Set was Established:

   • Since no separate training set is mentioned, the method for establishing ground truth for any potential internal development or calibration would likely mirror the method used for the clinical study: comparison to established invasive cardiac output measurement techniques (like thermodilution). However, this is not explicitly stated for a training set.

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