(786 days)
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
| Metric / Comparison Point | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| Cardiac Output Measurement (Main Function) | Similar to predicate device (Philips ICG System) and Swan-Ganz catheter (thermodilution). | Clinically demonstrated to "record cardiac output similar to the predicate device and also to the Swan-Ganz catheter using thermodilution." |
| Other Cardiac Parameters | Similar to parameters measured by predicate device. | The parameters and signals are "essentially identical" except for Contractility Index (CTI) on PhysioFlow being similar to Acceleration Index (ACI) on Philips ICG. |
| Technological Characteristics | Similar to predicate device. | Utilizes "same basic technology" (thoracic electrical bioimpedance), "very similar" low current/high-frequency signals, and similar measurement procedures. |
| Safety and Efficacy | Comparable to predicate device. | Deemed "substantially equivalent" in safety and efficacy. |
Study Information
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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.
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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.
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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.
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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.
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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).
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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.
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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.
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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.
§ 870.2770 Impedance plethysmograph.
(a)
Identification. An impedance plethysmograph is a device used to estimate peripheral blood flow by measuring electrical impedance changes in a region of the body such as the arms and legs.(b)
Classification. Class II (special controls). The device, when it is a body composition analyzer which is not intended to diagnose or treat any medical condition, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 870.9.