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.

 

The Vismo PVM-2703 was released in February 2011, capable of monitoring ECG, Respiration, SpO2, NIBP, Temperature, IBP or CO2. This is not a true 7-parameter monitor because it is either IBP or mainstream CO2, but not both. Does that sound like a compromise? Yes, it is!

 

The differentiating feature of the VISMO PVM-2703 bedside monitor against the competitions is the utilization of a flexible MULTI (short for multi-parameter) socket that is for sharing use, and this socket is colored yellow. The yellow MULTI socket can be connected to internal analog hardware for IBP monitoring, or diverted to be a digital serial port for mainstream CO2 kit sets.

 

The shared-use MULTI socket, however, demands the use of proprietry measurement cables with valid NIHON KOHDEN digital hexadecimal parameter codes embedded in their connection plugs to work; this is a prerequisite because the socket is shared for two parameters. The parameter code informs the monitor what internal hardware and software are needed to support a newly plugged-in measurement cable (as there are more than one type).

 

Unfortunately, the market reaction to the use of the MULTI socket and coded measurement cables is not what the company wanted. Using the flexible MULTI socket means one physical connector sockets is missing from the monitor, which upsets users. This means the manufacturer is looking at the wrong way to provide benefits of socket flexibility, more efforts and technology are needed in order to be of value to customers worldwide.

 

There is really nothing wrong with using one fixed-use socket for Invasive Blood pressure and another fixed-use socket for mainstream CO2, which is the norm in the industry, and a far superior way since the monitor can do all 7 parameters at once.

The archaic concept of a MULTI-PARAMETER UNIT (MPU) from the 1990s

 

Veiled in secrecy, NIHON KOHDEN does not explain to the market how they could make sockets that are flexible enough for a total five types of internal hardware, as well as being diverted for use as serial ports for self-contained kit sets. Almost all sales and marketing people employed in Japan Head Office have no engineering background, so there are plenty of "company secrets" that should not be discussed with the distributors or customers.

Here are the relevant facts, and it was a quest to find a solution for limitation of panel space area to mount enough connector sockets.

 

Back in the 1990s,  NIHON KHODEN identified five types of analog hardware (Temperature, IBP, Cardiac Output, Thermistor Respiration, FiO2) to form a hardware community that link to only two sockets meant for sharing use. These flexible communal sockets are known as MULTI (short for multi-parameter) sockets and colored yellow. The hardware community, known as a MULTI-PARAMETER UNIT (MPU), was actually a design to reduce the number of physical sockets on a front panel with limited space area, resulting in an MPU with the unusual characteristics of having more hardware than MULTI sockets. We need to view the MPU from the right perspective to understand that this is not a design to adopt when there is sufficient panel space to mount all the necessary sockets.

 

 

To access each type of hardware, an external measurement cable with a digital parameter code stored in its plug needs to be inserted into one of the two MULTI sockets. These measurement cables that come with yellow coded plugs are collectively cited as Smart Cables by the manufacturer and each embedded digital parameter code pinpoints the exact type of internal hardware and software needed by a particular measurement cable.

 

Each yellow MULTI socket selects only one channel of the internal hardware, except for Temperature allowing two channels of hardware to be selected.

One MULTI socket can take two channels of Temperature measurements

  

Note the hardware mentioned here (Temperature, IBP, Cardiac Output, Thermistor Respiration and FiO2) are linked to the shared-use MULTI socket internally, and not from the outside

 

An external measurement cable with a valid digital code embedded in its plug selects the intended internal hardware (only if available)

Below image shows the MULTI-PARAMETER UNIT (MPU), complete with two yellow MULTI sockets for communal sharing. An external Smart Cable with a valid parameter code selects the needed hardware in the MPU using one of the MULTI sockets.

 

The design dictates that all MULTI sockets must be capable of doing IBP monitoring, each MULTI socket therefore comes attached with a dedicated IBP hardware for its own use.

Principle of operation

A MULTI socket can only access its own dedicated IBP hardware, and makes use of its when an IBP measurement cable is plugged into it. For non-IBP monitoring, both MULTI sockets can access the common hardware pool comprising Temperature, Cardiac Output, Thermistor Respiration and FiO2 hardware in the MPU.

 

It is observed that the quantity of MULTI sockets in the MPU is not a number that can be decided at will, but corresponds exactly to the number of internal IBP hardware channels that are intended to be placed inside each MPU.

 

Given the large amount of hardware in the MPU, more MULTI sockets are needed to make good use of the hardware that would otherwise be idling. As illustrated in the above image, this is achieved by using an external expansion box filled with more MULTI sockets (each with own dedicated IBP amplifier hardware).

The additional MULTI sockets are integrated using analog interface, and limited to a maximum of four sockets to avoid signal deterioration caused by voltage drop and noise.

The MULTI sockets are additionally diverted to be serial ports to save on one more physical socket

 

A MULTI socket can be diverted to be a serial port by bypassing the internal analog hardware

 

The design concept of MPU was to solve the problem of limited panel space area, and by using it as serial port does help in furthering the reduction of a physical socket on the front panel. The serial port in the original design was only for use by mainstream CO2 serial kit sets.

 

Original label on the MULTI sockets when they were first used

 

Shown above is the original label for the yellow MULTI sockets. It shows each socket can be utilized for IBP, Temperature, Cardiac Output, FiO2, Thermistor Respiration, as well as diverted to be a serial port for use by mainstream CO2 kit sets.

 

Professionally, many are actually puzzled by the contents of the MPU but refrained from asking or faced with a wall of silence, why is this a design that has many internal hardware queuing up to share a limited number of low-cost sockets? The truth is because it was originally devised to solve the problem of limited panel space area not sufficiently enough to mount all the necessary connector sockets. In situations when panel space area is more than enough to accommodate all the necessary connector sockets, there is no longer a need for the MPU and related (MULTI sockets/ Smart Cables).

 

It is such a waste of money to use an MPU design when the need does not exist; its continued use regardless of need prompted us there is more than meets the eye and the reason to question its relevance.

You can confidently tell there is only one channel of internal IBP hardware inside the PVM-2703

 

Knowing a functional MULTI socket always come with its own dedicated one-channel IBP hardware, a user can accurately tell the number of IBP monitoring hardware channels supplied with any monitor, just by counting the total number of available yellow MULTI sockets. 

The key word here is "functional" because a non-functional (fake) yellow MULTI socket does not need to care about the capability to do IBP monitoring, such a socket can indeed be found on the CardioLife TEC-5600 series defibrillators. The fake yellow MULTI socket on said TEC-5600 series defibrillators is just a serial port that cannot be used for any other parameter except mainstream CO2 kit sets.

Variations to the basic theme

There are variations to the basic theme, such as

a. doing without use of external expansion box,

b. increasing the number of MULTI-parameter sockets in the MPU,

c. reducing the hardware configured in the MPU.

In the VISMO PVM-2703 bedside monitor, only one channel of IBP hardware is configured in the MPU, out of five possible hardware types for use by Smart Cables. This being a simple monitor, the expansion box is not necessary.

You can see the parameters NIBP, SpO2, ECG and one channel of Temperature on the Vismo PVM-2703 monitor are not using Smart Cables, they are therefore not part of the MPU.

The digital hexadecimal code is programmed into a non-volatile EEPROM chip (Electrically Erasable Programmable Read-only Memory) mounted on a small flexible PC board, and soldered to some pins of the yellow plug at the factory; users cannot change the parameter code using settings on the monitors. It is not difficult to make the Smart Cables but they are being priced highly by the manufacturer; only the IBP cable can be sourced at a reasonable price from China suppliers because it is a common cable with some demand.

A non-volatile digital parameter code is embedded in the plug of the measurement cable

It is simple-minded to think the use of Smart Cables can actually upgrade a configured monitor to be modular
 

A MULTI socket by itself does not automatically mean all the five types of mentioned parameters are available for measurements; it still depends on which hardware are decided for placement inside the MPU for selection by Smart Cables. The amount of hardware in an MPU is not standardized but customized for each case.

Additional parameter capability can only be added using serial kit sets or via interfaces to external equipment.
When a model is not equipped with FiO2 hardware internally, no amount of MULTI sockets is going to provide this measurement capability. The amount of configured hardware placed in each MPU varies, so is the system software support for serial kits and external devices.

Examples of 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

Obviously, VISMO PVM-2703 bedside monitor making use of Smart Cables is still a configured monitor. The only advantage of using Smart Cables is to allow sharing of connector sockets (which are of negligible hardware cost), but the costs needed to make use of Smart Cables are far way higher. The customers are paying for the unnecessary higher costs, only to be led into having an unrealistic expectation of what the Smart Cables and MULTI sockets can actually deliver.

The manufacturer chooses to ignore the captured value from using Smart Cables is negative for users

Without any use of Smart Cables, both one channel of IBP and one channel of mainstream CO2 are freely available for carefree use via their respective dedicated sockets. The use of Smart Cables just makes things unnecessarily complicated and requires deliberate operator attention and a conscious efforts to choose between IBP and mainstream CO2; this is unwarranted attention, stress and inconvenience. What is the benefit of having such a choice?

The output of the CO2 kit sets are processed digital output data that should go straight for digital processing in the DPU

The mainstream CO2 parameter is supplied as a self-contained serial kit set with processed digital output ready to go directly to the digital processing stage of the monitor; there is no need to compete for use of the MULTI socket with the IBP measurement cable.

Manufacturers make their profits by providing product benefits to users but the dual-purpose MULTI socket on PVM-2703 bedside monitor has no benefit. In fact, socket shortage is the unanticipated problem for users having to share a single MULTI socket for IBP and mainstream CO2.

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

 

It does not make economic sense to save the cost of a cheap connector socket. 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! 

 

Productive efforts should be 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, and the purpose is to make it possible for the same hardware to be used for different purpose at different time.

 

This design shares the expensive hardware, not the cheap sockets

There is no monitoring hardware embedded in the NIHON KOHDEN Smart Cables and this makes a big difference as to how you appraise a monitor that comes with MULTI sockets

 

In this section, we want to show beyond any doubt, there is absolutely no active electronics in the Smart Cables.

 

The marketing messages "New Modular Technology" and "The Module is in the cable!" are just the imaginations of people without the necessary electronics knowledge.

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.

The continued repetitions of an assertion without offering any proof does not make it the truth!

This is just wild assertion without offering 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 being soldered 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 non-volatile digital EEPROM chip is being used to code the Smart Cable.

 

A non-volatile 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 parameter code (defined by NIHON KOHDEN) on its plug.

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 NIHON KOHDEN Smart Cable registered with US FDA as a medical device?

Make no mistake, 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 (just like any other manufacturers) 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 J and 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, which was launched before the Life Scope TR bedside monitors.

In BSM-2301 service manual, you can see the IBP and thermistor respiration are internal hardware inside the Life Scope BSM-2301 monitor. These hardware are clearly shown being linked internally to the yellow MULTI 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 socket can be diverted to be a serial port by bypassing the internal analog hardware, going straight to the digital APU (Analog-block Processing Unit) and onward to the DPU.  For a parameter using the internal analog hardware, the analog signal needs to converted to digital before going to the APU for 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, and that there is no IBP amplifier hardware embedded in the plug of the IBP Smart Cable.

 

A past lesson to let go of the MULTI socket (Life Scope BSM-2300K series bedside monitors case study)

Preceding VISMO PVM-2703 bedside monitor was the Life Scope BSM-2300K series monitors, let's see how this 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 socket flexible enough for three types of measurements, namely:

 

a. Invasive Blood Pressure

b. Thermistor Respiration

c. Mainstream CO2 (using self-contained serial kit sets)

 

Without any use of Smart Cables, all three parameters (IBP, Thermistor Respiration and mainstream CO2 are freely available for carefree use via their respective dedicated sockets. The use of Smart Cables makes things unnecessarily complicated and requires deliberate operator attention and choice to choose one among three (IBP, Thermistor Respiration and mainstream CO2), but why introduced a need to choose?

 

This is obviously unwarranted stress and inconvenience, what is wrong with the conventional way of using three dedicated sockets for the job? If MULTI socket is such a superior proposal, why is the Temperature socket a dedicated one?

 

Life Scope-i does not have enough connector sockets

 

The patient monitoring hardware in the Life Scope BSM-2301 bedside monitor are divided into a conventional block and an MPU block. The conventional block uses dedicated sockets and ordinary measurement cables while the MPU block makes use of Smart Cables with different parameter code for different hardware.

CONVENTIONAL BLOCK

- 1-ch TEMP

- ECG

- SpO2

- NIBP

MPU BLOCK with one MULTI sockets

- 1-ch IBP

- Thermistor Respiration

- <MULTI socket as serial port> Mainstream CO2 kit sets

 

The reality is the shortage of two connector sockets, and an avalanche of complaints from users. The manufacturer was pressured to respond with an updated model, BSM-2303K. The solution from new model BSM-2303K is to add a new isolated yellow MULTI socket that can only do IBP monitoring.

 

The MPU of the Life Scope BSM-2301K was not designed to take on expansion, and any additional MULTI socket will load the operation of existing MPU, causing it to malfunction. The additional (fake) MULTI socket is not linked to the MPU, just an independent socket with its own dedicated IBP amplifier hardware.

The new socket relieved existing functional MULTI socket to only measure either Thermistor Respiration or act as serial port for the mainstream CO2 kit set, leaving the former to just focus on doing IBP monitoring. It was ironical, a solution relying on a dedicated socket for IBP.

 

It was a lesson to henceforth do away with the MULTI socket, but here in a later Vismo monitor you are still seeing one in use. Why is the manufacturer still holding onto the MULTI sockets?

 

Under pressure, the manufacturer returned a dedicated socket for IBP

As expected, users soon found the single MULTI socket on VISMO PVM-2703 Bedside Monitor is not enough for use

The situation for VISMO PVM-2703 Bedside Monitor is the same as Life Scope BSM-2301K Bedside Monitor, the customers just want their physical sockets back! To that the manufacture responded with the new PVM-4000 series bedside monitors.

 

In new PVM-4000 series bedside monitors, the VISMO PVM-4763, PVM-4753 and PVM-4733 bedside monitors are again dodging the key issue. The new series now offer users two MULTI sockets, each MULTI socket comes with its own one-channel IBP amplifier hardware.

 

What you are really seeing is a VISMO PVM-4763 bedside monitor adding one redundant IBP hardware channel just to do what the PVM-2703 monitor could already do if the manufacturer had made use of dedicated sockets! The users certainly did not ask for an additional channel of IBP hardware.

There is just no reason to continue the use of Smart Cables except to meet the manufacturer's own agenda in Japan, and they can keep doing it in the Japanese domestic market because users have low bargaining power in a protected market.