(267 days)
The Gambro Central Water Treatment System CWP 100 – WRO H is designed to produce water of adquate quality for hemodialysis, both chemically and microbiologically with an adequate flow, provided that the feed water complies with the existing standards for drinking water and has been properly pre-treated.
The Gambro Central Water Treatment System CWP 100 - WRO H is designed to produce water of adquate quality for hemodialysis, both chemically and microbiologically with an adequate flow, provided that the feed water complies with the existing standards for drinking water and has been properly pre-treated. The WRO or the base unit of the CWP system, operates under the principle of reverse osmosis (RO) which is the preferred method for the purificationof water for hemodialysis. This system removes at least 95% of the total dissolved salts (based on conductivity measurements) and more than 99% of the bacteria and endotoxins from the inlet water. The WRO H also include a heat disinfection unit for disinfection of the distribution system which utilizes hot water to minimize any form of microbial growth and biofilf formation. With this system, dialysis machines can be included in this heat disinfection cycle, provided that they have heat disinfection capability. This procedure is called integrated heat disinfection.
In order to ensure that the microbiological quality will be maintained, this system has:
- an automated disinfection procedure to keep the membrane surfaces clean and to . minimize bacterial growth;
- a hygenic design with smooth surfaces and a minimum of stagnant zones; .
- automatic flushing programs at preset intervals when the system is not in use ●
In addition, the WRO H has been designed to reduce water consumption by automatically regulating the pump speed to the actual demand of pure water.
After pretreatment (i.e. sediment filter, water softener, charcoal filter, etc.) the water enters an inlet tank (please refer to position 4 on the following diagram) via a solenoid valve (1). The inlet water tank (4) has a float valve (5) and an air gap to help isolate the flowpath from the municipal water system. The main pump (33) then creates a pressure of up to 20 bar that is required for the reverse osmosis process.
Pure water from the WRO unit is distributed directly to the distribution system in the hemodialysis unit via solenoid valves (48), (103), and (105). Excess pure water that has not been used in the hemodialysis unit is recirculated back to the inlet water tank (4) via solenoid valve (106).
In order to reduce water consumption, the speed of the pump is automatically adjusted so that the return flow of water is kept constant. Part of the reject water is recirculated back to the sucking side of the main pump via valve (71) to help minimize water consumption and to maintain a high flow velocity over the membrane surface. The rest of the reject water is, however, continuously sent to the drain via a needle valve (41).
The WRO unit utilizes a proportioning pump (45) and solution container (46) to proportion disinfectant during the disinfection cycle. The proportioning pump is disconnected from the flow path during normal operation.
The pure water line has a solenoid valve (36) for automatic flushing to drain at the start up, in conductivity alarm situations, every two hours, when the unit is in stand-by mode and at rinse during disinfection. The pure water line also has a solenoid valve arrangement to isolate the system from the distribution system during disinfection. The WRO unit has an overflow valve (64) on the pure water side to control pressure and to relieve pressure peaks.
The provided document describes the Gambro Central Water Treatment System CWP 100 – WRO H, a water purification system for hemodialysis. This device was cleared through the 510(k) pathway, which focuses on demonstrating substantial equivalence to a legally marketed predicate device rather than de novo clinical efficacy studies. Therefore, the document does not contain typical clinical study data with acceptance criteria based on patient outcomes or expert reviews. Instead, the "acceptance criteria" are implied by the performance characteristics demonstrated to establish substantial equivalence.
Here's an analysis of the available information regarding acceptance criteria and supporting studies:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implied by Predicate/Intended Use) | Reported Device Performance |
|---|---|
| Chemical Purity: Produce water of adequate chemical quality for hemodialysis. | Removes at least 95% of total dissolved salts (based on conductivity measurements). |
| In vitro performance testing confirmed normal operating performance for rejection of dissolved salts. | |
| Microbiological Purity: Produce water of adequate microbiological quality for hemodialysis. | Removes more than 99% of bacteria and endotoxins from inlet water. |
| The system has automated disinfection, hygienic design, and automatic flushing programs to maintain microbiological quality. The WRO H also includes a heat disinfection unit (60°C or 90°C) for the distribution system, capable of maintaining 85°C in a 150m piping system. | |
| In vitro performance testing confirmed normal operating performance for rejection of bacteria and pyrogen (endotoxins). | |
| Adequate Flow: Provide an adequate flow of purified water. | In vitro performance testing was performed to establish normal operating performance to include flow rates. The system automatically regulates pump speed to actual demand. The heat disinfection unit ensures continuous circulation of hot water. |
| Safety: Materials having water contact are safe. | Additional testing was performed to evaluate the safety of the materials having water contact at various temperatures. The device utilizes substantially equivalent water contact materials (pumps, tubing, fittings) as the predicate device. |
| Performance vs. Predicate: Performs as well as the predicate device. | The manufacturer concluded that the device is safe, effective, and performs as well as the predicate device based on in vitro performance testing. The device is substantially equivalent to the Osmonics Osmo 23 G Series Reverse Osmosis Machines. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not specify a "test set" in the traditional sense of a clinical study with a defined sample size of patients or images. The testing was primarily in vitro performance testing on the device itself.
- Sample Size: Not applicable in terms of "test set" for clinical data. The testing involved multiple runs or configurations of the Gambro Central Water Treatment System.
- Data Provenance: The studies were non-clinical (in vitro performance testing) conducted by Gambro Healthcare. The location of these tests or the specific country of origin for the "data" is not explicitly stated beyond Gambro Healthcare's location in Lakewood, CO. The testing is retrospective, in the sense that it was completed prior to the 510(k) submission.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
- Not applicable. This was a non-clinical performance study on a water treatment system, not a diagnostic or clinical decision-making device. Ground truth in this context would be established by validated analytical methods (e.g., chemical assays, microbiological cultures, flow measurements) rather than expert consensus.
4. Adjudication Method for the Test Set
- Not applicable. As described above, there was no "test set" requiring expert adjudication. Performance was measured objectively using instrumentation and analytical methods.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No. An MRMC study is relevant for diagnostic devices where human readers interpret medical images or data. This device is a water treatment system, not a diagnostic tool.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study
- Yes, implicitly. The "in vitro performance testing" described is essentially a standalone evaluation of the device's capabilities without human intervention influencing its core function (i.e., water purification). The device's automated features (disinfection, flushing, pump regulation) operate independently. While an operator initiates the heat disinfection cycle, the performance data (e.g., % salt rejection, % bacteria removal, flow rates) represents the machine's intrinsic capabilities.
7. Type of Ground Truth Used
The ground truth for the device's performance was established through objective laboratory measurements and analytical validated methods for:
- Conductivity (for dissolved salts rejection)
- Microbiological assays (for bacteria and endotoxins removal)
- Flow rate measurements
- Temperature measurements (for heat disinfection)
- Material compatibility testing
These methods serve as the "ground truth" to verify the device's output against established standards for water quality.
8. Sample Size for the Training Set
- Not applicable. This device is a physical water treatment system, not an AI/ML algorithm that requires a "training set" of data. Its design and operational parameters are based on engineering principles and established reverse osmosis technology, not machine learning.
9. How the Ground Truth for the Training Set Was Established
- Not applicable. As there is no training set for an AI/ML algorithm, this question is not relevant to the described device.
§ 876.5665 Water purification system for hemodialysis.
(a)
Identification. A water purification system for hemodialysis is a device that is intended for use with a hemodialysis system and that is intended to remove organic and inorganic substances and microbial contaminants from water used to dilute dialysate concentrate to form dialysate. This generic type of device may include a water softener, sediment filter, carbon filter, and water distillation system.(b)
Classification. Class II (special controls). The device, when it is a water purification subsystem disinfectant, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 876.9.