Category: Life Scope multi-parameter patient monitors product review
In
this knowledge-sharing record we reviewed why NIHON KOHDEN (日本光電 ) Smart
Cables & Multi Connector Sockets are outdated, costly and only
intended as a distraction to deflect attention away from the fact the
manufacturer has lost the ability to make modular monitors. Clear and detailed explanation of the NIHON KOHDEN Life Scope Smart Cable design developed in the 1990s.
Smart things do not last
Smart
is
a magic word much touted in the market place; however, what was a latest smart
phone just months ago is no longer that smart today. What then can be said about a smart piece of cable that is more than twenty years old? Common sense tells us they should have been dumped long time ago. For this reason, we are curious to examine a line of
Smart Cables launched in August 1998 as accessories of a
medical patient monitor which are still on life support today; one must wonder the unusual reason for its longevity and where on the Product Life Cycle curve are these Smart cables hanging on to?
The
Smart Cables are each marked with an identification digital hexadecimal code on its yellow plug to engage a similarly-colored yellow sockets known as MULTI-parameter (or MULTI) sockets.
The digital code is stored in an EEPROM chip mounted on a small flexible PC board electrically wired to the pins of the cable plug. The hexadecimal code in the EEPROM is inserted at the factory and not allowed to change after production. It is actually not difficult to make the Smart Cables but they are being priced highly by the manufacturer; only the common IBP cable can be sourced from China suppliers at a reasonable price.
NIHON KOHDEN had identified five types of internal hardware that can be linked to the MULTI-parameter sockets and to make use of these hardware, a cable with the correct code must be plugged into one of the MULTI-parameter sockets. Each socket selects only one channel of the hardware, except for Temperature allowing two channels of hardware to be selected.
Principle of Operation |
One MULTI-parameter socket can select two Temperature hardware channels.
Each MULTI-parameter socket can take two channels of Temperature measurements |
In addition, the MULTI-parameter sockets double as serial ports without selecting any hardware. This is meaningful when facing the constraint of space but illogical when such constraint is not present.
One should know the overall cost is very high to share connector sockets using Smart Cables
The Smart Cables were originally devised only to resolve a product issue, and it is a big mistake to pick the Smart Cables as a product selling point. There is no proper viability assessment and is only leading customers into having an unrealistic expectation of what the Smart Cables can actually deliver. The apparent flexibility of the MULTI sockets is in reality an adaptation with negative captured value for the users.
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. Five types of internal analog hardware were found suitable for time-sharing two modified connector sockets, 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 modify two connector sockets for sharing use |
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The Saturn module turned to sharing two modified connector sockets as solution to the constraint of space for more sockets |
The method selected by NIHON KOHDEN was to make use of coded measurement cables known as Smart Cables to share two modified connector sockets. The patient monitoring hardware were separated into two blocks in the Saturn module.
(NORMAL BLOCK) The hardware using dedicated sockets and ordinary measurement cables:
- ECG
- SpO2
- NIBP
(MULT-PARAMETER UNIT BLOCK with two MULTI-parameter sockets) The hardware only use 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
Huge amount of hardware had to share two modified connector sockets as a compromise |
The adapting MULTI-parameter sockets were additionally allowed to be diverted to act as a costly digital serial ports