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The SurgiCount+ System Software is a multifunctional software application intended to be used as an adjunct in the estimation of blood loss and management of surgical sponges and other absorbent items. The system incorporates three distinct software configurations: Triton AI, SC+ Sponge Counting, and Triton QBL. Additionally, combined workflows (SC+ AI and SC+QBL) are provided for use in clinical environments that require both the tracking of absorbent surgical items and estimation of patient blood loss.

The Triton AI configuration is intended to be used with surgical sponges, software, hardware and accessory devices that have been validated for use with the application to estimate the hemoglobin (Hb) mass contained on used surgical sponges. The configuration is also intended to calculate an estimate of blood volume on used surgical sponges from the estimated Hb mass and a user-entent Hb value. The validated surgical sponges, hardware, software, accessory devices and Hb mass ranges are listed in the Instructions for Use.

The SC+ Sponge Counting configuration is intended for use as an adjunctive technology for augmenting the manual process of counting, displaying and recording the number of RFID-tagged absorbent articles used during surgical procedures, and providing a non-invasive means of locating RFID-tagged absorbent articles within an operating room and surgical sites.

The Triton QBL (Quantification of Blood Loss) configuration is intended to be used to record the weight of used surgical sponges and other absorbent items in order to calculate the quantity of fluid volume on the sponges/absorbent items.

The SurgiCount+ [SC+] System Software is a multi-functional software application that is intended to be used as an adjunct in the estimation of blood loss and management of surgical sponges and other surgical substrates. The system incorporates three distinct software configurations: Triton AI, SC+ Sponge Counting, and Triton Quantitative Blood Loss [QBL]. Additionally, combined workflows (SC+AI and SC+QBL) are provided for use in clinical environments that require both the tracking of absorbent surgical items and estimation of patient blood loss. Two of the five software configurations (Triton Al and SC+Al) are Class II functions. The remaining configurations are Class I functions.

The Class II Triton Al software configuration estimates the hemoglobin (Hb) mass contained on used surgical sponges using an AI algorithm that analyzes the image of each sponge. It also calculates an estimate of blood volume on used surgical sponges from the estimated Hb mass and a user-entered patient Hb value. The Triton Al software configuration's sponge counting functionality has been modified to enhance the product's surgical sponge counting/management functionality, compared to the predicate device. New workflow steps allow users to scan, identify, and count RFID-tagged surgical sponges and other absorbent items, and to locate missing surgical sponges inside the operating room and, noninvasively, in surgical sites.

The SaMD product includes the following nonmedical device and Class I consumable and hardware accessories: a mobile device (Apple iPad Pro), RFID-tagged surgical sponges/absorbent items, an RFID reader, a bluetooth-enabled scale, and a stand (or optional wall mount) that houses the hardware accessories and connects the accessory devices to electrical power.

The provided text describes the Stryker SurgiCount+ System, an image processing device for estimating external blood loss. Here's a breakdown of the acceptance criteria and study details based on the provided FDA 510(k) summary:

1. Acceptance Criteria and Reported Device Performance

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

• Hb Algorithm Performance Validation: The text states, "Testing was conducted to evaluate the accuracy of the Hb algorithm in estimating the Hb mass on surgical sponges, compared to the known Hb mass on each sponge as determined by a reference assay." This implies that a set of surgical sponges was used, each with a "known Hb mass." However, the exact sample size (number of sponges) for this test set is not explicitly stated.
• Sponge Recognition Algorithm (SRA) Performance Validation: The text states it was "used to detect a representative 18x18 inch sponge type." The specific sample size (number of images or instances) for this test is not explicitly stated.
• Human Factors Validation: "Fifteen nurses participated in a complete, end-to-end, usability validation."
• Data Provenance: The document does not specify the country of origin of the data or whether the study was retrospective or prospective. It describes non-clinical (bench) testing and human factors validation, suggesting controlled environments rather than real-world patient data collection for the primary performance validations.

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

• The text does not provide information regarding the number or qualifications of experts used to establish ground truth for the Hb Algorithm or SRA performance validations. The ground truth for the Hb algorithm was established by a "reference assay."
• For Human Factors Validation, "Fifteen nurses" participated as users, but they were not establishing ground truth, rather their performance and feedback were observed and evaluated.

4. Adjudication Method for the Test Set

• The document does not specify any adjudication methods (e.g., 2+1, 3+1) for the performance validation test sets. The ground truths were established via objective measures (reference assay for Hb, assumed prior knowledge for SRA, and structured observation for Human Factors).

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size

• No, an MRMC comparative effectiveness study was not described. The performance data provided are for the standalone device capabilities (Hb algorithm accuracy, SRA failure rate) and human factors validation (usability and safety), not a comparative analysis of human readers with vs. without AI assistance. The device is intended as an adjunct to blood loss estimation and sponge management, implying it supports human users, but a formal MRMC study to quantify human improvement with AI assistance is not mentioned.

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

• Yes, standalone performance was evaluated for the core AI components:
  • Hemoglobin (Hb) Algorithm Performance Validation: This tested the algorithm's accuracy in estimating Hb mass compared to a known reference, which is a standalone evaluation of the algorithm's output.
  • Sponge Recognition Algorithm (SRA) Performance Validation: This assessed the algorithm's ability to detect sponges and its failure rate, which is also a standalone evaluation.

7. The Type of Ground Truth Used

• Hemoglobin (Hb) Algorithm: The ground truth was established by a "reference assay" for the "known Hb mass on each sponge." This implies a laboratory measurement or biochemical analysis.
• Sponge Recognition Algorithm (SRA): The ground truth implicitly was the actual presence/absence and type of sponge, likely determined by controlled experimental setup where the correct sponge type was presented.
• Human Factors Validation: The "ground truth" here was the observational data of user performance collected through "clinically realistic scenarios" and user input, evaluated against predetermined safety and usability criteria.

8. The Sample Size for the Training Set

• The document states, "The algorithms generate the same output for a given input (are fixed) and have been trained using machine learning techniques to recognize the sponges and to estimate Hb mass and blood loss volume on the imaged substrates."
• However, the sample size for the training set is not provided in the given text.

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

• The document states the AI algorithms were "trained using machine learning techniques to recognize the sponges and to estimate Hb mass and blood loss volume on the imaged substrates."
• While it mentions "known Hb mass" for the a test set, the method for establishing ground truth for the training set is not explicitly described. Given the nature of Hb mass estimation, it is highly probable that the training data also included images of sponges with independently measured "known Hb mass" established through venipuncture and lab analysis, similar to the method used for the testing data. For sponge recognition, it would likely involve labeled images indicating the presence and type of sponges.

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The Triton Sponge System is a software application intended to be used as an adjunct in the estimation of blood loss and management of surgical sponges. The Triton Sponge System is intended to be used with surgical sponges, software, hardware and accessory devices which have been validated for use with the Triton Sponge System to estimate the hemoglobin (Hb) mass contained on used surgical sponges. The Triton Sponge System is also intended to calculate an estimate of blood volume on used surgical sponges from the estimated Hb mass and a user-entered patient serum Hb value. The validated surgical sponges, hardware, software, accessory devices and Hb mass ranges are listed in the Instructions for Use. The Triton Sponge System is also indicated for use to aid in counting surgical sponges and may be used to record and display case-specific blood components infused over time. The Triton Sponge System is additionally indicated for use to aid in managing surgical sponges, including providing a visual record of sponge images, and to record the user-entered weight of used surgical sponges in order to calculate an estimate of fluid volume on the sponges.

The Triton Sponge System is a software application intended to be used as an adjunct in the estimation of blood loss and management of surgical sponges. The Triton Sponge System is intended to be used with surgical sponges, software, hardware and accessory devices which have been validated for use with Triton Sponge System to estimate the hemoglobin (Hb) mass contained on used surgical sponges. This version of the Triton Sponge System includes 4 updates from the predicate Triton System (K160338): Qualified new hardware accessory: Apple's iPad Pro to be used with Triton Sponge System. Qualified new accessory for imaging sponges: Users will use a commercially available 3D IR laser depth sensor (referred to as the Natural User Interface or NUI Sensor in the submission) that allows for automatic detection of sponges as well as a touch-free interface with the device to facilitate imaging of the sponge on Apple's iPad Pro device. To allow the use of the NUI Sensor with the Triton Sponge System, a new algorithm called the Sponge Recognition Algorithm (SRA) was added to the System. The SRA analyzes the depth maps provided by the NUI Sensor to determine whether or not a User is presenting a sponge for imaging. To allow the NUI Sensor to securely connect to the iPad Pro, NUI mounting brackets are provided to connect the NUI Sensor to the iPad Pro. Addition of a step to include imaging a calibration placard with Triton Sponge App to normalize ambient light settings. The calibration card is provided to standardize the image of each sponge. Updates to the Hemoglobin Algorithm to improve hemoglobin mass estimates by performing scene normalization as well as utilizing new data provided by the calibration palette and NUI Sensor.

The provided text describes the Triton Sponge System, a software application intended to be used as an adjunct in the estimation of blood loss and management of surgical sponges. It explains the acceptance criteria for this device and the studies conducted to prove it meets these criteria.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are derived from the "Special Controls Required for 21 CFR §880.2750" (Table 6-1 on page 14). The device performance is summarized from the "Special Control Met" column and the "PERFORMANCE DATA" section (pages 10-14).

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

• Sample Size for performance testing (bench-top and system validation): The document states "Testing involved running the software app/system test protocol with sample specimens" for bench testing and for system validation, it used "mock surgical case simulated by reconstituting whole blood samples of known Hb concentration from units of human packed red blood cells and plasma to create various pre-specified blood volumes. Serial dilution with sterile saline yielded sponge blood samples reconstituted to ranges of fluid volume, dilution, and Hb mass representative of a surgical operation."
  • The exact number of "sample specimens" or "blood volumes" / "dilution levels" is not explicitly stated in the provided text.
• Data Provenance: The data used for performance testing (bench-top and system validation) appears to be prospective and simulated in a laboratory/mock surgical setting. The blood samples were "reconstituted" and "serial dilution with sterile saline" was performed. There is no indication of patient data or data from a specific country of origin, suggesting it's synthetic or laboratory-generated.

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

The ground truth for the performance tests (bench and system validation) was established using "pre-measured Hb mass (Assay sHbL)" of the samples. This indicates a direct quantitative measurement rather than expert interpretation.

• Therefore, no experts were used to establish the ground truth in the traditional sense of clinical assessment (e.g., radiologists, pathologists). The ground truth was based on laboratory assay measurements.
• The qualifications of individuals performing these assays are not specified, but it's implied to be standard laboratory practice for measuring hemoglobin mass.

4. Adjudication Method for the Test Set

Since the ground truth for performance testing was based on pre-measured laboratory assays, there was no adjudication method involving multiple human readers or experts. The comparison was directly between the device's output and the established objective measurement.

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

No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not conducted involving human readers with and without AI assistance to measure effect size. The studies described are primarily technical performance validation (accuracy of Hb estimation) and human factors usability of the device itself.

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

Yes, standalone performance testing was done for the algorithm's core function. The bench-top and system validation tests evaluated the algorithm's ability to estimate hemoglobin mass (sHbL) from imaged sponges by comparing "Triton sHbL" (algorithm output) to "Assay sHbL" (pre-measured ground truth).

• The process involved the App capturing images, transferring them to a server-based hemoglobin algorithm software, which then calculated the Triton sHbL. This calculated value was then compared to the Assay sHbL. This effectively represents the algorithm's standalone performance in estimating Hb mass from image input.

7. The Type of Ground Truth Used

The type of ground truth used for the quantitative performance studies (bench-top and system validation) was objective laboratory measurement of hemoglobin mass, referred to as "pre-measured Hb mass (Assay sHbL)". This involved depositing known quantities of blood with known Hb mass on surgical sponges.

8. The Sample Size for the Training Set

The document does not explicitly state the sample size for the training set used to develop or refine the Hemoglobin Algorithm, nor does it specify if a separate training set was used for the Sponge Recognition Algorithm (SRA). The text focuses on the testing and validation of the device.

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

The document does not provide information on how the ground truth for any training set was established. It primarily details the methods for creating test data and establishing ground truth for validation purposes.

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The Triton System is a software application intended to be used as an adjunct in the estimation of blood loss and management of surgical sponges.

The Triton System is intended to be used with surgical sponges, software and accessory devices which have been validated for use with the Triton System to estimate the hemoglobin (Hb) mass contained on used surgical sponges. The Triton System is also intended to calculate an estimate of blood volume on used surgical sponges from the estimated Hb mass and a user-entered patient serum Hb value. The validated surgical sponges, hardware, accessory devices and Hb mass ranges are listed in the Instructions for Use.

The Triton System is also indicated for use to aid in counting surgical sponges and may be used to record and display case-specific blood components infused over time. The Triton System is additionally indicated for use to aid in managing surgical sponges, including providing a visual record of sponge images, and to record the user-entered weight of used surgical sponges in order to calculate an estimate of fluid volume on the sponges.

The Triton System is a software program (mobile medical application) used on an Apple iPad® tablet to capture images of used surgical sponges to assist surgical personnel in the management of surgical sponges after surgical use and to aid in the estimation of blood loss.

Here's a breakdown of the acceptance criteria and the study information for the Triton System, based on the provided document:

1. Table of Acceptance Criteria and Reported Device Performance

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

The provided document does not specify the sample size used for the test set. It mentions "previous non clinical testing" for the performance criteria and verification testing for the current submission, but lacks details on the number of cases or samples.

The data provenance is not explicitly stated (e.g., country of origin). However, given that Gauss Surgical Inc. is located in Los Altos, California, USA, and this is an FDA submission, it's highly probable that the studies were conducted in the United States. The document does not specify if the data was retrospective or prospective.

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

The document does not provide information regarding the number of experts used to establish the ground truth for the test set or their qualifications.

4. Adjudication Method for the Test Set

The document does not specify an adjudication method.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done

The document does not mention a multi-reader, multi-case (MRMC) comparative effectiveness study. The submission focuses on comparing the Triton System to a predicate device (Pixel 3 System) based on technological characteristics and indications for use, rather than human reader performance with and without AI assistance.

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

The document describes the Triton System as a "software application intended to be used as an adjunct in the estimation of blood loss." This implies that it's designed to assist human users, rather than being a fully standalone diagnostic tool replacing human expertise. The performance data mentioned largely relates to the device's ability to measure hemoglobin mass and blood volume, which is a standalone function of the algorithm itself, to then be used by clinicians. However, no specific "standalone" study separate from its "adjunct" role is detailed. The focus is on the algorithm's accuracy in its intended use.

7. The Type of Ground Truth Used

The document mentions that the non-clinical performance data involved "comparison to a scientifically valid alternative method for measuring deposited hemoglobin mass." This indicates that the ground truth for blood loss estimation (specifically hemoglobin mass) was established using a scientifically valid, presumably quantitative, laboratory or reference method rather than expert consensus, pathology, or outcomes data in this context. While not explicitly named, it would likely be a gold standard measurement for hemoglobin.

8. The Sample Size for the Training Set

The document does not provide the sample size for the training set.

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

The document does not explicitly detail how the ground truth for the training set was established. It implicitly suggests that the ground truth for hemoglobin mass would be established through a "scientifically valid alternative method" as mentioned for the performance testing.

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The Triton Canister System is a software application intended to be used as an adjunct in the estimation of blood loss.

The Triton Canister System is intended to be used with blood bearing canisters, software, hardware, and accessory items which have been validated for use with the Triton Canister System to estimate the hemoglobin (Hb) mass contained within canisters with the input of the total volume in each canister. The Triton Canister System is also intended to calculate an estimate of blood volume in blood bearing canisters from the estimated Hb mass and a user-entered patient serum Hb value. The validated canister types, hardware, software, accessory devices, and Hb mass ranges are listed in the Instructions for Use.

The Gauss Surgical Triton Canister System is an image processing system to estimate the external blood lost from patients into a suction canister used to collect fluid during surgical procedures. The system is comprised of the software which runs on a mobile platform (Apple® iPad®) and two accessories provided by Gauss Surgical, a Canister Type Specific Insert and a Canister Scanning Label. The Insert and Label ensure variables associated with imaging are standardized.

Here's a breakdown of the acceptance criteria and study information for the Triton Canister System:

Acceptance Criteria and Device Performance

The general acceptance criteria for "Non-clinical performance data" is that the device performs as intended under anticipated conditions of use, with a comparison to a scientifically valid alternative method for measuring deposited hemoglobin mass. Specific conditions tested include:

• Lighting conditions
• Range of expected hemoglobin concentrations (and hemolysis levels)
• Range of expected blood volume absorption in canisters
• Presence of other non-sanguineous fluids (e.g., saline irrigation fluid)

The study employed Bland-Altman analysis to establish the bias and limits of agreement between the device's estimated hemoglobin mass (Triton cHbL) and the pre-measured hemoglobin mass (Assay cHbL).

• Deposited known quantities of blood volume and Hb mass into canisters.
• Canister fluid samples represented clinically-expected ranges and distributions of fluid volume, dilution (by saline), Hb mass, hemolysis levels, ambient light illuminance, and serum patient Hb.
• Triton Canister App used to capture scans under three different ambient lighting conditions.
• User-entered volumes were recorded.
• Images and volumes transferred to server-based software to calculate Triton cHbL.
• cHbL compared to pre-measured Hb mass (Assay cHbL).
• Result: Strong positive linear correlation between Triton cHbL and Assay cHbL across tested conditions.
• Result: Bias and outer 95% CIs of the Bland-Altman Limits of Agreement fell within pre-determined acceptance criteria.
• This testing informed look-up tables and "error estimate" values displayed on the user interface. |
  | Software display of cumulative error | Software display must include an estimate of the cumulative error associated with estimated blood loss values. | Met: An estimate of the cumulative error associated with blood loss values is displayed to the user with each estimated hemoglobin mass and blood loss value. The results of verification testing and Bland-Altman methods inform these displayed values. |
  | Human factors testing and analysis | Validate that the device design and labeling are sufficient for appropriate use by intended users of the device. | Met: A usability study was conducted in a simulated setting with personnel who track blood loss during surgical procedures. Both quantitative and qualitative survey data were collected. All users successfully completed tasks per protocol pass/fail criteria. |
  | Electromagnetic Compatibility (EMC) and wireless performance | Appropriate analysis and non-clinical testing must validate the EMC and wireless performance of the device. | Met: EMC and wireless coexistence testing completed for the predicate device (Pixel 3 System) using the same iPad 2 was reviewed. The iPad 2 was found to be EMC compatible with the operating room environment (Class B requirements of IEC 60601-1-2:2007) and maintained essential wireless functionality under noisy conditions. |
  | Software verification, validation, and hazard analysis | Appropriate software verification, validation and hazard analysis must be performed. | Met: Software is considered a moderate level of concern. All elements of software information for moderate LOC devices (per FDA Guidance May 11, 2005) were provided, including development program, hazard analysis (patient's and user's standpoint), validation process, system-level test protocols, pass/fail criteria, results, and cybersecurity risk mitigation. Testing demonstrated software performs as intended and risks are mitigated. |
  | Labeling | Labeling must include:
  A. Warnings, cautions, and limitations for safe use;
  B. Detailed summary of performance testing pertinent to use, including bias and variance;
  C. Validated surgical materials, range of hemoglobin mass, software, hardware, and accessories;
  D. EMC and wireless technology instructions and information. | Met: Labeling includes all required details from the special controls. |

Study Details for Performance Testing Bench

1. Sample Size used for the test set and the data provenance:

   • The document states, "Whole blood samples of known Hb concentration and various pre-specified volumes were reconstituted from units of human packed red blood cells and plasma." It also mentions, "Serial dilution yielded canister samples reconstituted to ranges of fluid volume, dilution, hemolysis levels and Hb mass."
   • The exact numerical sample size for the test set (number of canisters/samples) is not explicitly stated in the provided text.
   • Data Provenance: The blood samples were reconstituted from units of human packed red blood cells and plasma. The testing was retrospective in nature, as it involved preparing samples with known characteristics in a lab setting ("bench testing") rather than collecting data from live surgical procedures. The country of origin for the data is not specified, but given it's an FDA submission, it's highly likely to be within the United States.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g., radiologist with 10 years of experience):

   • The ground truth for the test set was established by "pre-measured Hb mass (Assay cHbL)" of the reconstituted samples. This implies a laboratory assay was used, which would typically be performed by trained lab technicians or scientists.
   • The document does not specify the number or qualifications of individuals who established this ground truth, beyond referencing the "scientifically valid alternative method" of laboratory assay.

3. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

   • The ground truth was established by direct measurement (Assay cHbL) rather than expert consensus on interpretive data. Therefore, an adjudication method for human readers is not applicable in this context.

4. 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, an MRMC comparative effectiveness study was not done. This study focuses on the standalone performance of the device in estimating hemoglobin mass in canisters, not on human reader performance with or without AI assistance. The device is described as "an adjunct in the estimation of blood loss," implying it provides data to clinicians, rather than directly assisting in the interpretation of images by human readers in a diagnostic setting.

5. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:

   • Yes, a standalone performance study was done for the algorithm. The "Performance Testing Bench" described the "ability of the Triton Canister System (including algorithm, app, server and accessories – Insert and Scanning Label) to estimate canister hemoglobin mass loss and canister blood volume loss in comparison to a scientifically valid method of estimating hemoglobin mass and blood volume contained in canisters." The algorithm calculated the "Triton cHbL" which was then compared to the "Assay cHbL." While a user-entered volume is an input, the core estimation of Hb mass from the image is an algorithmic, standalone function.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

   • The ground truth used was laboratory assay / direct measurement of hemoglobin mass ("Assay cHbL") in the prepared samples. This is a highly objective, quantitative form of ground truth.

7. The sample size for the training set:

   • The document does not explicitly state the sample size used for the training set for the Triton Canister System's algorithm. It describes the testing of the performance of the algorithm.

8. How the ground truth for the training set was established:

   • The document does not explicitly describe how the ground truth for the training set was established. However, given the nature of the device and the performance testing, it is highly probable that the training data would also utilize laboratory-measured hemoglobin mass in similar prepared samples, just like the test set.

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The Pixel 3 System is a software application intended to be used as an adjunct in the estimation of blood loss and management of surgical sponges.

The Pixel 3 System is intended to be used with surgical sponges, software, hardware and accessory devices which have been validated for use with the Pixel 3 System to estimate the hemoglobin (Hb) mass contained on used surgical sponges. The Pixel 3 System is also intended to calculate an estimate of blood volume on used surgical sponges from the estimated Hb mass and a user-entered patient serum Hb value. The validated surgical sponges, hardware, software, accessory devices and Hb mass ranges are listed in the Instructions for Use.

The Pixel 3 System is also indicated for use to aid in counting surgical sponges and may be used to record and display case-specific blood components infused over time. The Pixel 3 System is additionally indicated for use to aid in managing surgical sponges, including providing a visual record of sponge images, and to record the user-entered weight of used surgical sponges in order to calculate an estimate of fluid volume on the sponges.

The Pixel 3 System is a software program (mobile medical application) used on an Apple iPad® tablet to capture images of used surgical sponges to assist surgical personnel in the management of surgical sponges after surgical use and to aid in the estimation of blood loss. The main functions of the device are summarized below.

The Pixel 3 System provides an estimate of the Hb mass lost onto the sponge (sHbL), which is derived from a software algorithm that analyzes images of sponges sent to the Gauss off-site server along with user-entered information about the type of sponge. An estimate of the cumulative blood volume lost onto the sponges (sEBL) is subsequently calculated by dividing the sHbL for each sponge by a user-entered value for the patient's laboratory-derived serum Hb level at the time of image capture. Whereas sHbL is estimated independently from the laboratory-derived serum Hb (i.e., directly from each image), sEBL is derived from a calculator whose inputs are adjustable by the user. The Pixel 3 System provides this estimate of blood content on sponges (i.e., sEBL by sHbL method) and estimate of sHbL only for the validated laparotomy sponge types listed in Table 1.

The Pixel 3 System may also be used to track the weight of soaked surgical sponges recorded by the user. The device may aid in the estimation of blood loss by calculating an estimate of the cumulative sEBL by weight, provided that a dry and wet weight has been entered for each sponge. This estimate (i.e., sEBL by weight method) is based on the total weight of the soaked sponges less their dry weights normalized by the density of whole blood (1.060 g/mL). For the sEBL by weight method, a user may manually enter sponge types other than those validated for the sEBL by sHbL method (see Table 1 above); however, those sponge types can only be used to calculate sEBL by weight.

The Pixel 3 System also allows surgical personnel to categorize sponges by sponge type and provides an automated ongoing count of the total number of sponge images and sponge images by tag. The device allows for the input and display of case-specific values pertaining to fluid management during surgical procedures (e.g., packed red blood cell volume administered over time, fresh frozen plasma volume administered over time, platelet volume administered over time), as detailed in the Instructions for Use. The Pixel 3 System also provides a visual record of images for further evaluation during the surgical case.

To use the device, the user mounts the iPad tablet onto an IV pole; the device contains alignment indicators to help the user align the IV pole. The user then places a sponge in view of the iPad camera (the device contains a camera-bounding box to help the user with sponge placement), and scans an image of the sponge by touching the iPad screen or using an optional wireless foot pedal. The device also contains an ambient light indicator, which helps the user determine when a poor (indicator is yellow) or appropriate (indicator is white) level of ambient light is present for image capture.

The full-screen display of sHbL and sEBL by sHbL outputs includes an estimate of the cumulative error of the Pixel 3 System, computed as the 95% Bland-Altman Limits of Agreement (and denoted as "95% limits Bland Altman" on the display). The display of estimated error is updated on a real-time basis, as successive sponges are accumulated and scanned. A Bland-Altman plot in biostatistics is a method of data plotting used to analyze the agreement between two different assays. Bias is defined as the arithmetic mean of the differences between the device's output value and measurements obtained using a reference standard. The Bland- Altman Limits of Agreement represent two standard deviations (1.96 x SD) of the differences around the bias, and represent the error range within which 95% of all differences between the device's output and the reference standard's measures are expected to lie.

Here's a summary of the acceptance criteria and the study that proves the Pixel 3 System meets them, based on the provided document:

Acceptance Criteria and Device Performance

Study Details

1. Sample sizes used for the test set and data provenance:

• Bench Testing:

  • Test Set (sponges): 50 sponges of each of the four validated types (NovaPlus, AMD Ritmed, RFDetect Premium, Allegiance Disposable).
  • Total Scans: (b)(4) Trade Secret/CCI scans per sponge type. The exact total number of sponges in the test set isn't explicitly stated as a single number but would be 50 sponges/type * 4 types = 200 sponges. Each sponge was scanned multiple times.
  • Data Provenance: Not explicitly stated, but likely laboratory-controlled settings (simulated blood loss).

• Human Factors Testing:

  • Subjects: Registered nurses (circulating nurses).
  • Test Set: (b)(4) Trade Secret/CCI live surgical case evaluations and 8 simulated task-based evaluations.
  • Data Provenance: Single-center study (location not specified), prospective.

• Preliminary Clinical Testing (Study 1):

  • Patients: 46 patients
  • Sponges: 758 laparotomy sponges ([b]4] Trade Secret/CCI, RFDetect, and AMD Ritmed).
    • 167 sponges analyzed on a per-sponge basis.
    • 591 sponges analyzed in batches.
  • Data Provenance: Prospective, multi-center (3 clinical sites, location not specified). Conducted between July and November 2012.

• Confirmatory Clinical Testing (Study 2):

  • Patients: 50 patients
  • Sponges: 791 laparotomy sponges (RFDetect laparotomy sponges). All individually assayed.
  • Data Provenance: Prospective, single-center (1 clinical site, location not specified). Enrollment from July 2013 to October 2013.

2. Number of experts used to establish the ground truth for the test set and their qualifications:

• Bench Testing: The ground truth was established by pre-measured Hb mass deposited in controlled amounts. No human experts were used for this ground truth as it was a direct measurement.
• Clinical Studies (Study 1 & 2): The ground truth for Hb mass was established using a "mechanical extraction method (assay sHbL)" or "rinsing and photometric assay of the effluent (reference method)." This indicates a laboratory method rather than expert human interpretation.

3. Adjudication method for the test set:

• Bench Testing: Not applicable, as ground truth was direct measurement.
• Clinical Studies (Study 1 & 2): Not applicable, as ground truth was established by a laboratory reference method.

4. 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:

• A formal MRMC study comparing AI-assisted human readers to unassisted human readers was not explicitly described in the provided text.
• However, the Confirmatory Clinical Testing (Study 2) did compare the Pixel 3 System's performance (sEBL) to traditional human methods:
  • Visual (single-rater) estimates by the anesthesiologist.
  • Gravimetric (weighing sponges) methods.
• Effect Size (Comparison to traditional methods): In Study 2, the Pixel 3 System's sEBL (end of case) displayed a consistently lower variance and higher precision than both visual estimates and gravimetric methods. The gravimetric method overestimated blood loss by 359 ml per patient compared to the Pixel 3 System in Study 1. This suggests significant improvement in accuracy and precision over traditional human-driven methods.

5. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

• Yes, the Bench Testing was a standalone evaluation of the algorithm's accuracy in estimating Hb mass compared to a pre-measured reference.
• The Clinical Studies (Study 1 and 2) also evaluated the Pixel 3 System's output (sHbL and sEBL) as a standalone estimate compared to the laboratory reference method, noting its bias and correlation. While users were present to scan, the performance metrics (bias, correlation, limits of agreement) directly reflect the algorithm's output against the ground truth.

6. The type of ground truth used:

• Bench Testing: Direct measurement of pre-deposited Hb mass on sponges.
• Clinical Studies (Study 1 & 2): Laboratory-based reference method involving "mechanical extraction" or "rinsing and photometric assay of the effluent" to measure Hb mass. This is a highly objective, quantifiable ground truth.

7. The sample size for the training set:

• The document does not explicitly state the sample size for the training set. It focuses on the validation studies.

8. How the ground truth for the training set was established:

• Since the training set size and details are not provided, information on how its ground truth was established is also not available in the given text. However, given the methodology of the test sets, it is highly probable that similar laboratory-based reference methods would have been used for training data ground truth.

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