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Nelson Water Systems' Water Purification for Hemodialysis is intended to be used for purifying the water used in hemodialysis treatment. It removes organic, inorganic, and microbial contaminants from the water.

The water purification system is a complete system accepting the influent facility water and providing purified water meeting AAMI standards for hemodialysis use. It removes organic, inorganic, and microbial contaminants from the water. The heart of the system includes carbon filters along with a reverse osmosis (RO) unit and/or portable exchange (PE) mixed-bed (MB) deionization (DI) tanks along with appropriate alarms. This equipment removes the oxidants such as chlorine and chloramines and mineral salts (dissolved solids) from the water. The specific configuration of the equipment will depend upon the customer's water quality desires (specifications) beyond the minimum AAMI standards. Pretreatment is used before the RO unit to match the specific influent water quality to those needs of the RO unit and/or final water specifications. Pretreatment can include pressure boosting, sediment and colloidal material filtration, water softening, pH balancing and specific element or compound reduction such as iron. The system usually includes a storage tank that is conical-bottomed and sealed. It has an air-filtered vent, checked over-flow, level switches and sprayer. Repressurizing pump(s) are used to deliver the water to the hemodialysis system. Deionization is used either to polish the RO water or to remove total dissolved solids (TDS) from the influent water. The latter will occur either in emergency conditions when an RO is being used in the system and it is being by-passed or as an alternative to an RO unit. When PE MB DI tanks are used, two tanks are always used with resistivity indicators/alarms following each one. Then following the tanks are a resin trap, sub-micron filter(s), and optionally a shut-down valve and ultraviolet (UV) disinfection. The system is self-monitored and alarms are activated when operator attention is needed. Pressure gauges and sample ports are strategically placed throughout the system for system performance monitoring. A conductivity monitor/controller is placed in sight of the nurses' station. Its probe is located at the end of the watertreatment system. Alarms at site and/or remotely located near the nurses' station sound when an alarm condition exists with the RO unit, the water level in the tank drops to a pre-set level, the conductivity at the exit of the watertreatment system exceeds the pre-set level, and if PE MB DI tanks are used, the outlet resistivity falls below the pre-set limit.

Here's an analysis of the provided text, focusing on acceptance criteria and the study used to demonstrate compliance:

Acceptance Criteria and Device Performance Study

The Nelson Water Treatment System for Hemodialysis is designed to provide purified water meeting AAMI (Association for the Advancement of Medical Instrumentation) standards for hemodialysis use.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for the device are the AAMI standards for water used in hemodialysis. The reported device performance is based on measurements taken from a system installation after 48 hours of residence time.

Note: For Mercury, the reported permeate (0.0002 mg/L) exactly matches the AAMI Standard (0.0002 mg/L), indicating it meets the standard.

2. Sample Size for the Test Set and Data Provenance

• Sample Size: The data presented appears to be from a single installation in Houston. The results are from measurements taken "after 48 hours of residence time in system." This implies a limited, possibly single, sample for each component at a specific time point.
• Data Provenance: The data is stated to be from "an installation in Houston meeting the design specifications of the proposed system." This suggests the data is retrospective measurements from an existing operational system. The country of origin is the USA.

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

This information is not provided in the document. The ground truth (AAMI Standards) is a predefined regulatory standard, not established by experts for this specific testing.

4. Adjudication Method for the Test Set

This information is not applicable/provided. The evaluation is against predetermined AAMI standards, not human interpretation requiring adjudication.

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 done. This type of study is relevant for evaluating the impact of AI on human reader performance, which is not pertinent to a water purification system's performance evaluation against chemical/physical standards.

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

No, a standalone algorithm performance study was not done in the context of an AI algorithm. The device itself is a physical water purification system, and its performance is assessed directly by measuring the water produced.

7. The Type of Ground Truth Used

The ground truth used is established regulatory/industry standards (AAMI Standards) for water quality in hemodialysis.

8. The Sample Size for the Training Set

This information is not applicable/provided. This device is a physical system, not an AI model that requires a training set. The "design specifications" mentioned for the Houston installation would be based on engineering principles and AAMI standards, not a data training set.

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

This information is not applicable/provided, as there is no training set for this type of device. The design and performance targets are based on the AAMI Standards.

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