(184 days)
The Kent Camera is intended for use by healthcare professionals as a non-invasive tissue oxygenation measurement system that reports an approximate value of:
- oxygen saturation (StO2),
- relative oxyhemoglobin level (HbO2), and
- relative deoxyhemoglobin (Hb) level
in superficial tissue. The Kent Camera displays two-dimensional color-coded images of tissue oxygenation of the scanned surface and reports multispectral tissue oxygenation measurements for selected tissue regions.
The Kent Camera is indicated for use to determine oxygenation levels in superficial tissues.
The Kent Camera is a handheld digital camera based on multispectral imaging technology and performs spectral analysis at each point in a two-dimensional scanned area producing an image displaying information derived from the analysis. The Kent Camera determines the approximate values of oxygen saturation (S.O2), relative oxyhemoglobin (HbO2) and deoxyhemoglobin levels (Hb) in superficial tissues and displays a two-dimensional, color-coded image of the tissue oxygenation (StO2).
The camera consists of a camera, a recharger, and a reference card for calibration and is used by healthcare professionals in a healthcare environment to determine oxygenation levels in superficial tissues for a patient population with potential circulatory compromise.
The provided text describes a 510(k) premarket notification for the Kent Camera, a non-invasive tissue oxygenation measurement system.
Acceptance Criteria and Study Details
The primary goal of the study was to demonstrate the substantial equivalence of the modified Kent Camera (KC203, battery-powered) to its predicate device (KC103, AC-powered). The acceptance criteria revolved around demonstrating linear agreement, minimal bias, and a small scale shift between the StO2 measurements of the two devices across a clinically meaningful dynamic range.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Linear relationship of StO2 measurements between the two devices over a clinically meaningful dynamic range. | Demonstrated linear relationship. The Deming regression line of agreement has a 95% confidence interval for the slope [0.932 - 0.959] and intercept [0.020 - 0.040]. StO2 values from both cameras show an excellent linear correlation over a wide range of StO2 levels (normal, mildly ischemic, critically ischemic conditions). |
| Quantify any scale shift (slope) between the devices and estimate the 95% levels of agreement. | The slope -0.0057, with a 95% confidence interval of [-0.009, -0.002], indicates less than a 1% scale shift between the two cameras. The 95% limits of agreement (LoA) for the battery-powered minus the predicate device are -0.13 to 0.12 StO2 units. More than 85% of the paired measurements from the two cameras differ less than 0.1 StO2 units. |
| Quantify any bias (difference in mean values) between the devices. | Bland-Altman analysis shows little to no bias between the devices, with a 95% confidence interval for the intercept of [-0.004, 0.003] StO2 units (using StO2 reported on a scale of 0 to 1). |
| Devices should share a common scale. | The devices share a common scale (within 1%). |
| Devices should show minimal to no bias. | The devices show minimal to no bias. |
| Ability to report a drop in StO2 levels under ischemia and a trend consistent with physiological response. | The study demonstrated that StO2 values from both cameras report a drop from basal StO2 levels under conditions of known ischemia and report a trend in StO2 values consistent with the physiological response expected for forearm ischemia - reperfusion. |
| StO2 readings are not statistically and operationally significantly different. | The two devices show an excellent linear relationship and provide StO2 readings which statistically and operationally are not significantly different. |
2. Sample Size for the Test Set and Data Provenance
- Sample Size: 17 volunteers (7 females, 10 males)
- Data Provenance: The study was a "pre-clinical study" conducted using a "forearm ischemia protocol" in an unnamed location. The volunteers "self-reported as being healthy." The study was prospective in nature, as it involved taking measurements from human subjects under controlled conditions for the purpose of the study.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts
The study did not involve experts establishing a "ground truth" in the traditional sense of diagnostic interpretation. Instead, the study assessed the agreement between two devices by comparing their measurements against each other and against an induced physiological state (forearm ischemia/reperfusion). The "ground truth" was essentially the known physiological changes induced in the forearm, and the device measurements were compared against each other, not against an expert-derived interpretation.
4. Adjudication Method for the Test Set
No adjudication method was described, as the study design was an agreement study comparing two devices' direct measurements, not an interpretation task requiring expert consensus.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No MRMC comparative effectiveness study was done. The study focused on device-to-device agreement, not the improvement of human readers with AI assistance.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done
The study implicitly evaluated the standalone performance of the device's algorithm by comparing the StO2 measurements generated by the KC203 directly with those generated by the KC103. Both devices generate StO2 values independently, and the comparison assesses the equivalence of these generated values. Human operators were involved in taking the measurements, but the performance being evaluated (StO2 measurement accuracy and agreement) is that of the device's algorithmic output.
7. The Type of Ground Truth Used
The "ground truth" for the test set was:
- Known physiological changes: The forearm ischemia protocol provided a controlled and expected range of StO2 values (normal, ischemic, reperfusion). The basis for comparison was the agreement between the two devices' measurements across these known physiological states, rather than a single absolute "ground truth" reference measurement (like pathology).
8. The Sample Size for the Training Set
The document does not specify a training set sample size. This is a 510(k) submission, typically focusing on demonstrating substantial equivalence of a modified device to a predicate device, rather than a novel algorithm development where training set details are paramount. The "training" of the device involves its inherent multispectral imaging technology and the application of a modified Beer-Lambert model, which are fundamental scientific principles rather than a machine learning training process with a distinct training dataset.
9. How the Ground Truth for the Training Set Was Established
Not applicable/not provided. As mentioned above, the device's operation is based on established physical principles of light absorption and scattering for tissue oxygenation, rather than a machine learning model trained on a specific dataset with established ground truth labels in the typical sense. The "ground truth" for developing the underlying technology would be physiological models and empirical data relating light spectroscopy to oxygen saturation, but this is not described in terms of a "training set" in the context of this regulatory document.
§ 870.2700 Oximeter.
(a)
Identification. An oximeter is a device used to transmit radiation at a known wavelength(s) through blood and to measure the blood oxygen saturation based on the amount of reflected or scattered radiation. It may be used alone or in conjunction with a fiberoptic oximeter catheter.(b)
Classification. Class II (performance standards).