The MULTI Socket on the NIHON KOHDEN Vismo PVM-2703 Patient Monitor

Category: NIHON KOHDEN (日本光電) VISMO monitors, Life Scope BSM-2300 series (BSM-2301, BSM-2303, BSM-2351, BSM-2353), PVM-2701, PVM-2703 MULTI sockets and Smart cables.  In this knowledge-sharing review, we look at the Vismo PVM-2701 and Vismo PVM-2703 multi-parameter monitors and how they make use of the yellow MULTI sockets. Reference is also made to the earlier Life Scope BSM-2300K series monitors.

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In this article we reviewed the launch of the Vismo PVM-2701, and later the PVM-2703 with a yellow sharing socket. The same yellow sharing socket accepts non-continuous semi-quantitative CO2 monitoring and is our alert for such an approach.

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.

 

 

This is a monitor that is short of one connector socket

 

The 7-parameter Vismo PVM-2703 was released in February 2011 equipped with a yellow MULTI-parameter socket for either Invasive Blood Pressure or mainstream etCO2 monitoring use. 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 prominent feature of the VISMO PVM-2703 bedside monitor is the utilization of one yellow MULTI-parameter socket. The yellow socket does not accept ordinary measurement cables but only cables embedded with codes defined by NIHON KOHDEN.

NIHON KOHDEN had identified five types of internally configured 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. These coded cables are collectively cited as Smart Cables by the manufacturer and the code is also known as the parameter code. Each socket selects only one channel of the hardware, except for Temperature allowing two channels of hardware to be selected.

(Of the five types of hardware configured for use by Smart Cables, only one channel of IBP hardware is configured in the VISMO PVM-2703 bedside monitor.)

 

A coded measurement cable can make use of any of the internally configured hardware shown here

The configured hardware are grouped into a block known as MULTI-parameter Unit. Since it is not possible to perform more IBP monitoring channels than the number of MULTI-parameter sockets, it means IBP hardware should always correspond to the number of MULTI-parameter sockets and each MULTI-parameter socket comes with its own IBP hardware. A MULTI-parameter socket makes use of its own IBP hardware when a measurement cable with a IBP code is plugged into it; it is the design that if a MULTI-parameter socket does not come with its own one-channel IBP hardware, it does not have the ability to perform IBP monitoring.

Remember,

A functional MULTI-parameter socket always come with its own one-channel IBP hardware.

This being a hardware rule, and the key word is "functional" because a non-functional MULTI-parameter socket may not need to care about the capability to do IBP monitoring, such as a socket found on the CardioLife TEC-5600 series defibrillators solely for mainstream CO2 kit sets.

Principle of operation

Given the large amount of hardware in the MULTI-parameter Unit block, it may be necessary to add more MULTI-parameter sockets; this is done by using an external expansion box filled with MULTI-parameter sockets with associated IBP amplifier hardware.

The additional sockets are added using analog interface with a limit set at a maximum of four MULTI-parameter sockets. The limitation is to avoid signal deterioration caused by voltage drop and noise.

The digital hexadecimal code is stored in an EEPROM chip mounted on a small flexible PC board electrically wired to the pins of the cable plug. It is 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.

A parameter code is stored in the plug of the measurement cable

One MULTI-parameter socket can select two Temperature hardware channels.

Each MULTI-parameter socket can take two channels of Temperature measurements

The MULTI-parameter sockets are additionally allowed to be diverted as costly digital serial ports, this being an easy task since there is no need for any internal analog hardware and the digital serial signals just go straight to the monitor main unit. The mainstream CO2, 2nd SpO2, BIS and NMT hardware are supplied as self-contained digital serial kits using the MULTI-parameter sockets only as a link to the monitor.

(In VISMO PVM-2703 bedside monitor, only mainstream CO2 serial kit sets are supported using Smart Cables.)

The original label for the yellow MULTI socket indicated the five specific hardware plus mainstream CO2 serial kits using it as a serial port.

 

The original label for the yellow MULTI-parameter sockets when they were first used

 

Using Smart Cables does not make VISMO PVM-2703 bedside monitor modular

 

A yellow MULTI-parameter socket by itself does not automatically mean all the five types of mentioned parameters are available for measurements; it still depends on whether what hardware are actually being placed inside for selection.

 

When a model is not equipped with FiO2 hardware internally, no amount of yellow MULTI-parameter sockets is going to provide this measurement capability. The amount of configured hardware linked to each multi-parameter socket varies, so is the system support for serial kits.

Configured hardware and serial kits using Smart Cables

It is the built-in hardware that determine the parameter capability; and in the case of serial kit sets, the system software. This of course, is the same description as a configured patient monitor

 

Actual internal hardware and system support for serial kits varies for each multi-parameter unit

This means VISMO PVM-2703 bedside monitor making use of Smart Cables is still a configured monitor.

The value captured by users using the Smart Cables is negative

 

Without sharing, both one channel of IBP and one channel of mainstream CO2 are freely available for use by plugging a non-coded measurement cable into their respective dedicated socket; it is poor logic to save the cost of a cheap connector socket at the expense of compromised sharing!

The output of the CO2 kit sets are processed digital serial data needed by the DPU

The mainstream CO2 parameter is supplied as a self-contained serial kit set with digital serial processed data ready for use by the DPU of the monitor, using the MULTI-parameter socket only as a link. Why compete with an IBP transducer for a socket to connect?

Manufacturers make their profits by providing product benefits to users but the yellow MULTI-parameter sockets have no benefit. The first vehement complaint from users is always the yellow MULTI-parameter sockets on the monitor are not enough for use.

What benefit can it offer users when necessary connector sockets go missing?

To save the cost of a cheap connector socket, the monitor has been compromised to do only one of the parameter at any one time, it is in reality making for inflexible and constrained monitoring.

Elaborate time-sharing are applied to things that are expensive (high in demand, an asset), and not worth the efforts for things that are cheap (high in supply, a commodity) like a connector socket or a switch! It only makes sense to see productive efforts being made to time-share a CPU, a car, a hotel room, a yacht, an airplane but not a calculator, a pencil or a pair of scissors.

 

Time-sharing of a car (an asset) creates value

The next picture shows Philips time-sharing one channel bio-amplifier hardware between IBP and Temperature measurements, and there was no sharing of connector socket; this is exactly the opposite of what Nihon Kohden is doing. The said manufacturer merely ensures physically it is not possible to make use of both the PRESS and the TEMP socket at the same time.

 

Only share the expensive hardware, not the cheap sockets

In case you are thinking we are not aware there are monitoring hardware being embedded in the NIHON KOHDEN Smart Cables, we had not missed it. This is a wrong understanding in the market and we can prove there are indeed no active electronics in the Smart Cables.

The marketing messages "New Modular Technology" and "The Module is in the cable!" are mere imaginations.

What do the manufacturer mean by this statement? 

It started with the Life Scope TR (BSM-6000) series monitors in the USA market and gradually adopted officially for International markets. These are precise statements.

This is just assertion without showing any proof

 

Chip makers need huge demand to justify each of their products, so which chip manufacturer is supplying NIHON KOHDEN the variety of analog chips given the extremely low volume in demand? If we were to open up the plug of a Smart Cable, what do we see? A small PC board is seen attached to some pins of the yellow plug.

 

A small PC Board is soldered to some pins of the yellow connection plug

 

The PC board confirms a cheap digital EEPROM chip is being used to code the Smart Cable.

 

A cheap digital EEPROM chip was what we found inside the yellow Smart Cable plug

If we were to open up the plug of a compatible IBP cable from China suppliers, what do we see? It is the same thing, a plug with a digital code defined by NIHON KOHDEN.

Under US FDA rule, a cable is only a cable if it does not change the signal that passes through it. A Smart Cable with a hexadecimal code is just a cable and does not change a signal passing through it, but if it has an amplifier it becomes a medical device and requires FDA registration. Can you find any stand-alone Smart Cables registered with US FDA as a medical device?

When the Smart Cables are used with serial kit sets, such as mainstream CO2 kit sets or the NMT AF-101P kit set, the registration is for the active serial kit set and not the passive Smart Cable.

Irrefutable Proof the IBP amplifier hardware is configured internally, an important fact withdrawn from later monitor manuals

 

The Life Scope BSM-2301 bedside monitor was launched before the Life Scope TR bedside monitors, and the Service Manual is clear on the design; manuals for later models stop providing such information. The major move to curb details in manuals started from Life Scope J (BSM-9101) Bedside Monitor, launched before the Life Scope TR bedside monitors.

In below BSM-2301 service manual, you can see the IBP and thermistor respiration are hardware inside the Life Scope BSM-2301 monitor. These internal hardware are linked to the MULTI-parameter socket, and to make use of either hardware, a Smart Cable with the correct code must be plugged into the MULTI socket.

 

Can you see the IBP amplifier and thermistor respiration hardware are internal components of the Life Scope BSM-2301 monitor?

The MULTI-parameter socket doubles as a serial port without any need for internal monitoring hardware, only as a link to the monitor. In the block diagram below, the processed digital serial data from a CO2 kit set goes straight to the digital microcontroller APU (Analog-block Processing Unit) and is forwarded to the DPU.  For a parameter using the internal analog hardware, the analog signal needs to pass through an Analog-Digital converter before coming to the APU for digital processing. 

Relevant page in the combined Service Manual for BSM-2301A, BSM-2301K, BSM-2303K, BSM-2304A

You should know by now the IBP amplifier hardware inside the monitor is the reason the VISMO PVM-2703 bedside monitor can do one channel of IBP monitoring.

NIHON KOHDEN has never been able to justify the use of the Smart Cables when out of context

Preceding VISMO PVM-2703 bedside monitor was the Life Scope BSM-2300K series monitors, let's see how the sole yellow MULTI socket was actually being used in this series.

 

The portable 8.4-inch Life Scope i (BSM-2301K)

 

To insist the use of Smart Cables, the Life Scope BSM-2301K monitor has a yellow MULTI-parameter socket for three types of measurements, namely:

 

a. Invasive Blood Pressure

b. Thermistor Respiration

c. Digital self-contained mainstream CO2 serial kit sets.

 

The MULTI-parameter socket does not mean flexibility because you can only do one of the above parameter at any one time. Using three dedicated sockets is a far superior proposal; why suffer pain of two missing sockets to gain use of one flexible socket? It is illogical because the manufacturer just wants to use the Smart Cables.

 

Life Scope-i does not have enough connector sockets

 

The use of a MULTI-parameter socket is self-contradictory from the start. We have to ask why is the monitor avoiding the use of MULTI-parameter socket to access the Temperature hardware if sharing a socket is preferred capability? This is a slap on the face for anyone proposing use of Smart Cables on a bedside monitor!

The two blocks of patient monitoring hardware in the Life Scope BSM-2301 bedside monitor are:

(ORDINARY BLOCK) The hardware using dedicated sockets and ordinary cables:

- 1-ch TEMP

- ECG

- SpO2

- NIBP

(MULTI-PARAMETER UNIT) The hardware sharing the single yellow MULTI-parameter socket in this block only use Smart Cables for connections:

- 1-ch IBP

- Thermistor Respiration

The mainstream CO2 comes in the form of a self-contained kit set with processed digital serial output, utilizing the MULTI socket only as a serial port

The reality is the shortage of two connector sockets, and the flood of complaints from users insisting the single MULTI-parameter connector socket on the BSM-2301K was not enough. The manufacturer was pressured to respond with an updated model (BSM-2303K) with an isolated MULTI-parameter socket added. The isolation was done so as not to disturb existing circuitry with an additional MULTI-parameter socket. It means the additional MULTI-parameter socket is not a functional one and only could make use of the IBP amplifier hardware that come with it.

The isolated MULTI-parameter socket was intended solely for IBP monitoring, effectively relieving the existing functional MULTI-parameter socket to only measure either Thermistor Respiration or act as serial port for the mainstream CO2 kit set. The solution was only partial, and it reduced two missing sockets to one missing socket; a total solution would have been just using dedicated sockets as there is no need for socket sharing. There was no need for the Smart Cables.

There was no actual demand for additional IBP channel, but the BSM-2303 bedside monitor was camouflaged as an upgraded monitor with 2 channels of IBP.

Under pressure, an additional isolated MULTI-parameter socket acting solely as an IBP amplifier had to be introduced

Similar to BSM-2301 bedside monitor, the Vismo PVM-2703 could not justify use of the MULTI-parameter socket

Just like BSM-2301 bedside monitor, users want their socket back on the PVM-2703 bedside monitor so that they can do both IBP monitoring and mainstream CO2 measurement without hesitation. In new PVM-4000 series bedside monitors, the VISMO PVM-4763 does just that. The users can have two MULTI-parameter sockets as they wished, but each MULTI-parameter sockets comes with its own one-channel IBP amplifier hardware. Thus, the VISMO PVM-4763 bedside monitor is adding one more channel of IBP hardware just to do what the PVM-2703 monitor could already do using dedicated sockets because the users are not asking for an additional channel of IBP hardware!

It is a such a big mistake to continue the use of Smart Cables.