Category: NIHON
KOHDEN Vismo bedside monitors and networking. In this article we review both the PVM-2701, PVM-2703 and PVM-4763 Vismo patient monitors, the thinking and illogical approach of the product series.
The first Vismo monitor was the PVM-2701 model announced by Signal 718 dated November 2009. Notice this was the first model to do away with the suffix. Vismo came from Vital Signs Monitor.
In a pilot move, the new Vismo series was designed in Japan with as many parts sourced in China. Although initial shipment were assembled and shipped from Japan, this arrangement was changed from release of PVM-2703.
The Monitor that is short of one connector socket |
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The 7-parameter Vismo PVM-2703 was released in February 2011 equipped with a yellow shared-use MULTI socket for monitoring Invasive Blood Pressure or mainstream etCO2. There is shortage of one connector socket, if the user could have one dedicated socket for Invasive Blood pressure and another dedicated socket for mainstream etCO2, that would be a far superior design since the monitor can now do all 7 parameters at once.
From the release of PVM-2703, shipment for both PVM-2701 and PVM-2703 models started to be directly from Shanghai, China.
The manufacturer's insistence on Vismo PVM-2703 monitor having Invasive Pressure and mainstream CO2 serial kit sharing one yellow MULTI socket is a great puzzle, since dedicated sockets makes for flexible and unconstrained monitoring.
The yellow MULTI sockets are part of a legacy circuit known as a Multi-parameter Unit; sacrifices must be made to make use of them, but this is not explained to the market and easily leads customers into having an unrealistic expectation of what the yellow MULTI sockets can actually deliver. In addition, the MULTI sockets cannot be accessed using ordinary cables, but only by coded measurement cables cited as "Smart Cables".
The use of a Multi-parameter Unit in in a monitor, accessed only by coded Smart Cables, cannot be justified. Here are the details.
The legacy Multi-parameter Unit was originally devised only to solve a product issue |
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In the 1990s, when developing the first digital modular monitor, the development team encountered a problem of insufficient front panel space for connector sockets on the first digital multi-parameter module being made. A few sockets were specially adjusted for time-sharing use by a group of five types internal analog hardware to overcome the space limitation; to differentiate them, they were colored yellow and known as MULTI sockets.
At the time NIHON KOHDEN was responding to an important emerging trend of using a high-density digital multi-parameter module as basic building block for modular monitors |
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In analog modular monitors, only single parameter modules were produced by NIHON KOHDEN. When designing the first digital modular monitor, the company discovered the critical care market had already moved to using a digital multi-parameter module with higher density of electronic components as a basic building block for modular monitors.
Apart from the higher electronic density, the difference between a single parameter module and a multi-parameter module is the presence of a CPU processor in the latter; the output of a multi-parameter module is thus processed digital data. This new development of distributed processing made it possible for patient data to be stored and moved with the module. Digital modules can also be connected directly to a (proprietary) digital data-exchange network as a node.
NIHON KOHDEN wanted to follow the trend by offering the first digital multi-parameter module, and the first digital multi-parameter module made by the company was named the Saturn module.
Responding to new trend in the 1990s using a multi-parameter module with higher electronic density as a basic building block for modular monitor |
Even occupying a 3-slot width of the module rack, the Saturn multi-parameter module (August 1998) was not big enough to hold all necessary connector sockets |
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Nihon Kohden intended a module rack integrated physically with the main unit to form a limited footprint just big enough to stack the display monitor on top of it (see below illustration). The physical size of the Saturn module was therefore constrained; in addition, the multi-parameter module must work in combination with other parameter modules like recorder, sidestream CO2, BIS, EEG, Flow/ PAW, SvO2 in the module rack.
The Saturn module was intended to be physically small in size |
The elegant but expensive solution from NIHON KOHDEN for the physical size limitation of the Saturn module was to adjust two of the connector sockets for sharing use |
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Two yellow MULTI sockets had to be adjusted for time-sharing use because there was not enough free space on the Saturn module for more sockets |
The solution from NIHON KOHDEN was to make use of coded measurement cables, promoted as "Smart Cables" to share connector sockets. There are two blocks of patient monitoring hardware in the Saturn module.
(Part A) The hardware using dedicated connector sockets and ordinary measurement cables:
- ECG
- SpO2
- NIBP
(Part B) The hardware sharing the two adapting MULTI sockets in a separate Multi-parameter Unit using coded "Smart Cables" for connections:
- 2 channels of IBP (2 MULTI sockets = 2-ch IBP)
- 4 channels of Temperature (2 MULTI sockets = 4-ch TEMP)
- Cardiac Output
- FiO2
- Thermistor Respiration