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The CoVa Monitoring System 2 is intended for adult patients under the direction of a licensed medical professional or by clinical personnel trained in its proper use. It is intended to record, store, and transmit the following physiological data: i) heart rate including heart rate variability; ii) respiration rate; iii) thoracic impedance; in) estimated stroke volume; v) estimated cardiac output; and vi) posture. It displays these physiological data, along with ECG and impedance waveforms, to the licensed medical professionals and/or clinical personnel. The information should be integrated into the context of all clinical data to make determinations of patient status.

The CoVa Monitoring System 2 is indicated for patients with fluid-management disorders managed by regular use of diuretics, and/or suffering from a disease or medical condition characterized by an increase in fluid, such as kidney failure, heart failure, and/or edema caused by a chronic disease (e.g. heart failure) normally treated with a diuretic.

The following are contraindications for the CoVa Monitoring System 2:

· The System is not defibrillator-proof. Thus its Sensor should be removed from a patient before using an external defibrillator.

· The System includes magnetically active materials, and thus should not be used by patients undergoing a procedure involving magnetic resonance imaging (MRI).

· The System should not be used by patients diagnosed with severe cardiac arrhythmias.

· The System should not be used by critically ill patients.

toSense's CoVa TM 2 features a body-worn Sensor, Gateway, and Web-based System. The Sensor has the same mechanical form factor and functionally equivalent electronic systems as the CoVa TM 1 Sensor. Both Sensors perform measurements by non-invasively sensing and processing single-lead electocardiogram (ECG) and thoracic bioimpedance (TBI) waveforms. The Sensor in CoVa TM 2, like that in CoVa TM 1, uses these two waveforms to measure heart rate (HR), heart rate variability (HRV), respiration rate (RR), and thoracic impedance (TI). The specifications for these measurements, calculated using the rank-regression method, are included in the 510(k) Summary for K142087. Embedded software within the CoVa TM 2 Sensor has been modified to also estimate stroke volume (SV) and cardiac output (CO) from the ECG and TBI waveforms. Additionally, both Sensors measure skin temperature (TEMP) and posture using, respectively, a temperature sensor and accelerometer. The Sensor has a form factor similar to a conventional necklace, with the electronics built into its strands and base. To make a measurement, a pair of customized disposable Electrodes-each featuring two electrode regions-snaps into a magnetic interface on the backside of the base and then attaches to the patient's chest. The Sensor is typically used for measurement periods less than 5 minutes but can also be used for longer periods (e.g. several hours).

Using a Bluetooth™ transceiver, the Sensor wirelessly transmits measurement information from the patient to a Gateway, such as a tablet computer or mobile phone running the Android operating system. These systems receive information from the Sensor, and then forward it to the Web-based System through either a local-area network (e.g., network based on 802.11), or a wide-area cellular network (e.g. AT&T). The Web-based System displays information and can forward it to a thirdparty system through a web-services interface.

The provided text describes the CoVa Monitoring System 2 (CoVa™ 2) and its clinical study to demonstrate substantial equivalence, particularly for Stroke Volume (SV) and Cardiac Output (CO) measurements.

Here's the breakdown of the acceptance criteria and the study that proves the device meets them:

1. Acceptance Criteria and Reported Device Performance

The acceptance criteria for SV and CO measurements were established as demonstrating non-inferiority to a predicate device (CardioDynamics BioZ monitor) when compared against a gold-standard reference device (GE Medical Systems Discovery MR 450 cardiac MRI). Specifically, the agreement between the test device (CoVa™ 2) and the reference device should be as good or better than the agreement between the acceptance-standard device (BioZ monitor) and the reference device.

"Agreement" was determined from the 95% limits of agreement (LOA) and also evaluated using mean squared error (MSE).

Here's a table summarizing the performance compared to the acceptance criteria for the intended-use subgroup:

Conclusion from Table: For both SV and CO measurements, the reported performance of CoVa™ 2 (test device) demonstrated better agreement with the reference device (c-MRI) than the acceptance-standard device (BioZ monitor), thus meeting the non-inferiority, and in fact showing superiority based on MSE analysis.

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

• Sample Size:

  • Total volunteer subjects initially recruited: 60
  • Subjects excluded (due to severe arrhythmias during measurement): 6
  • Final analysis sample size: 54 subjects
  • Intended-use sub-group: 26 subjects (15M, 11F) with medical conditions such as fluid-management disorders managed by diuretics, recent cardiac surgery, or chronic diseases (e.g., obstructive pulmonary disease, cardiomyopathy, edema, kidney disease).
  • Healthy volunteers: 28 subjects

• Data Provenance: The study was a prospective clinical study conducted on human volunteer subjects. The document does not explicitly state the country of origin, but given the FDA submission and the company location in San Diego, CA, it's highly likely to be U.S.-based data.

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

The ground truth (reference SV and CO values from c-MRI) was established by analyzing images. The analysis was performed off-site by Precision Image Analysis ('PIA') based in Kirkland, WA. The number and specific qualifications of the experts (e.g., cardiologists, radiologists) at PIA who performed this analysis are not explicitly stated in the provided text. However, c-MRI analysis for cardiac output and stroke volume requires specialized expertise, implying that qualified professionals (e.g., radiologists or cardiologists with MRI expertise) would have performed this.

4. Adjudication Method for the Test Set

The document does not describe an adjudication method for the ground truth (c-MRI analysis). It states the analysis was performed by "Precision Image Analysis ('PIA')". This suggests a single, presumably expert, analysis was used to establish the ground truth for each subject. There is no mention of multiple readers or an adjudication process (e.g., 2+1, 3+1).

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not performed. This study focused on the device's accuracy in measuring physiological parameters (SV and CO) itself, by comparing it against a reference and predicate device. It was not designed to measure the improvement of human readers with or without AI assistance, as it is a medical device providing direct measurements, not an AI-assisted diagnostic tool for image interpretation.

6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done

Yes, a standalone performance study was done for the device's measurements of SV and CO. The clinical study directly compared the CoVa™ 2 System (test device) measurements (which would be algorithm-derived from the sensor data) against the c-MRI reference. The BioZ monitor (acceptance-standard device) also represents standalone performance. The results tabulated in Tables 1, 2, 3, and 4 represent the direct algorithmic performance of the CoVa™ 2 device. The system is designed to record, store, and transmit data, and then display it, suggesting the algorithmic processing of measurements happens internally before human interpretation.

7. The Type of Ground Truth Used

The ground truth used for Stroke Volume (SV) and Cardiac Output (CO) was cardiac MRI (c-MRI), specifically using a GE Medical Systems Discovery MR 450. This is considered a "gold-standard reference device" in the context of cardiovascular physiological measurements.

8. The Sample Size for the Training Set

The document does not provide information on the sample size for the training set for the algorithms within the CoVa Monitoring System 2. The study described (Clinical Study 3 – CoVa™ 2) is explicitly stated as for "evaluat[ing] CoVa™ 2's new measurements of SV and CO" and demonstrating non-inferiority, thus serving as a validation or test set for regulatory submission.

The document mentions that "Embedded software within the CoVa™ 2 Sensor has been modified to also estimate stroke volume (SV) and cardiac output (CO) from the ECG and TBI waveforms" and that "its SV estimation differ slightly from that used in the BioZ monitor, the exact form of which is an unpublished trade secret." This implies that the algorithms were developed and potentially refined using other data, but that training data and its size are not disclosed in this 510(k) summary.

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

Since the training set information is not provided, the method for establishing its ground truth is also not described in the document.

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The CoVa™ Monitoring System is intended for use under the direction of a licensed medical professional by adult patients at home to record, store, and transmit the following physiological data: i) Heart Rate including Heart Rate Variability; ii) Thoracic Impedance; iii) Respiration Rate; and iv) Posture. The CoVaTM Monitoring System only displays these physiological data to licensed medical professionals.

The CoVaTM Monitoring System is indicated for patients: i) with fluid-management problems; ii) taking diuretic medication; iii) living with heart failure; iv) living with end-stage renal disease; v) recovering from a coronary artery disease-related event; and/or vi) suffering from recurrent dehydration.

toSense's CoVaTM Monitoring System features a body-worn Sensor, Gateway, and Web-based System.

The Sensor non-invasively measures heart rate (HR), heart rate variability (HRV), respiration rate (RR), and thoracic index (TI). To determine these parameters, the Sensor measures and processes single-lead electrocardiogram (ECG) and thoracic bioimpedance (TBI) waveforms. Additionally, the Sensor measures skin temperature (TEMP) and posture using, respectively, a temperature sensor and accelerometer.

The Sensor has a form factor similar to a conventional necklace, with all measurement electronics built into its strands and base. A pair of customized disposable Electrodes, each featuring two electrode regions, snaps into a magnetic interface on the backside of the base, and then attaches to the patient's chest to make a measurement. The Sensor is designed for measurement periods less than about 5 minutes.

Using a Bluetooth transceiver, the Sensor wirelessly transmits information it measures from the patient to a Gateway, which can be a tablet computer or mobile phone running the Android operating system. Each of these systems receives information from the Sensor, and then forwards it to a Web-based System through either a local-area network (e.g., network based on 802.11), or a wide-area cellular network (e.g. AT&T). The Web-based System displays information, and can also forward it to a third-party system through a web-services interface.

The provided text describes the acceptance criteria and the studies conducted for the CoVa Monitoring System.

Here's an analysis of the requested information:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria in terms of specific performance thresholds (e.g., minimum correlation coefficient, maximum mean absolute error). Instead, it presents the results of regression models (slope and intercept) comparing the CoVa system to reference devices and simulators. The implicit acceptance criterion appears to be "substantially equivalent" to predicate devices, as stated in the conclusion.

Further performance details:

• Thoracic Impedance (Clinical Study 1): Average Pearson's correlation with fluid removed by hemodialysis: r = 0.93 (p < 0.0001). Measurement sensitivity: 1.72 Ohms/Liter. Measurement precision for long-term monitoring: 1-2 Ohms. Measurement precision for short-term monitoring: < 1 Ohm.

2. Sample Sizes Used for the Test Set and Data Provenance

• Clinical Study 1 (Thoracic Impedance):
  • Sample Size: 33 subjects, 13 test devices, 500 measurements.
  • Provenance: Retrospective/Prospective not explicitly stated, but implies prospective collection as subjects "receiving chronic maintenance hemodialysis." Location (country) not specified, but typically assumed to be the US for FDA submissions unless otherwise noted.
  • Subject Type: Subjects "receiving chronic maintenance hemodialysis and, in some cases, suffering from congestive heart failure."
• Clinical Study 2 (Thoracic Impedance):
  • Sample Size: 23 subjects, 2 test devices, 560 measurements.
  • Provenance: Retrospective/Prospective not explicitly stated, but implies prospective collection as measurements were made "daily in the home environment over an extended period of time." Location not specified.
  • Subject Type: Subjects "all having fluid-management issues, such as congestive heart failure."
• Clinical Study 3 (Respiration Rate):
  • Sample Size: 19 subjects, 2 test devices, 682 measurements.
  • Provenance: Retrospective/Prospective not explicitly stated, but implies prospective ("adult subjects undergoing breathing patterns"). Location not specified.
  • Subject Type: "Healthy volunteers using breathing patterns with variable rates and tidal volumes that simulate those encountered by intended-use populations."
• Clinical Studies 4a-e (Absolute Accuracy):
  • Sample Size:
    • 4a (TI): 8 devices, 88 measurements
    • 4b (RR): 1 device, 15 measurements
    • 4c (HR): 1 device, 67 measurements
    • 4d (HRV): 1 device, 15 measurements
    • 4e (TEMP): 1 device, 40 measurements
  • Provenance: Bench studies using simulators. Location not specified.
  • Subject Type: Simulator.

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

The document does not mention the use of experts to establish a "ground truth" for the test set in the traditional sense (e.g., expert consensus on image interpretation). Instead, the ground truth for these studies was established by FDA-cleared reference devices or calibrated simulators.

• Clinical Studies 1, 2, 3: Ground truth was established by "FDA-cleared reference devices" or an "acceptance-standard device" (for RR in Clinical Study 3). The qualifications of personnel operating these reference devices are mentioned as "Trained personnel."
• Clinical Studies 4a-e: Ground truth was established by "calibrated simulators."

4. Adjudication Method for the Test Set

Not applicable. The ground truth was established by reference devices or simulators, not human adjudication.

5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs Without AI Assistance

No MRMC comparative effectiveness study involving human readers and AI assistance is mentioned in the provided text. The studies focus on the performance of the device itself against reference standards.

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

Yes, the studies described are standalone performance evaluations of the CoVa Monitoring System's algorithms and sensors. The device directly measures and processes physiological data, comparing its output to reference devices or simulators. There is no mention of a human-in-the-loop component in these performance evaluations. The system "only displays these physiological data to licensed medical professionals," implying that professional interpretation occurs after the device has performed its measurements and calculations.

7. The Type of Ground Truth Used

• Clinical Studies 1, 2, 3 (Clinical Trials): FDA-cleared reference devices measuring the same physiological parameters (thoracic impedance, respiration rate).
• Clinical Studies 4a-e (Bench Studies): Calibrated simulators designed to accurately produce known values for thoracic impedance, respiration rate, heart rate, heart rate variability, and skin temperature.

8. The Sample Size for the Training Set

The document primarily describes validation studies and does not provide information on the sample size used for the training set of any algorithms within the CoVa Monitoring System. It focuses on the evaluation of the device's performance post-development.

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

Since the document does not discuss the training set, it does not describe how ground truth for a training set was established.

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