Life Scope VS (BSM-3500 and BSM-3700 series) bedside monitors from NIHON KOHDEN

Category: Product Review of NIHON KOHDEN Life Scope VS (Venus) series bedside monitors and related. The Life Scope VS series consists of BSM-3521, BSM-3552, BSM-3562, BSM-3572, BSM-3733, BSM-3753, BSM-3763 and BSM-3773.

 

Launched in early 2011, the configured LIFE SCOPE VS (BSM-3500 and BSM-3700) series patient monitors targets mid-acuity sites with the configured BSM-3500 series using a 12.1 inch touchscreen display while the configured BSM-3700 series uses a 15-inch touchscreen display. (The BSM-3500 series was belatedly launched in the USA market in 2016).

 

Configured Life Scope VS (BSM-3000) series models

There are four models for the 12.1-inch configured BSM-3500 series, namely

a. Life Scope BSM-3532 bedside monitor

b. Life Scope BSM-3552 bedside monitor

c. Life Scope BSM-3562 bedside monitor

d. Life Scope BSM-3572 bedside monitor

The difference among the monitors is the SpO2 algorithm; the latest international version is refrained from use in the USA market for undisclosed reasons.

 

Another four models are for the 15-inch configured BSM-3700 series, namely

a. Life Scope BSM-3753 bedside monitor

b. Life Scope BSM-3755 bedside monitor

c. Life Scope BSM-3763 bedside monitor

d. Life Scope BSM-3773 bedside monitor

 

The prominent feature of Life Scope VS bedside monitors is the utilization of flexible common-use multi-parameter (MULTI) sockets that are colored in yellow. These yellow common-use sockets do not accept ordinary measurement cables but only measurement cables that have NIHON KOHDEN parameter codes embedded in their yellow plugs. The end result of using these yellow flexible connector sockets means a good amount of needed connector sockets are removed from the monitor, which is undesirable. In reality, there is zero benefit from socket flexibility since the shortage of connector sockets will lead to serious inflexibility for users!

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 for five types of internal hardware, as well as being able to accept a number of independent self-contained serial kit sets whose output are already-processed digital data. Almost all sales and marketing people employed in Japan Head Office have no engineering background, so there is no shortage of "company secrets" that must not be discussed with the distributors or customers.

Here are the relevant facts. Back in the 1990s,  NIHON KHODEN identified five types of analog hardware (Temperature, IBP, Cardiac Output, Thermistor Respiration and FiO2) that can be linked internally to common-use MULTI sockets that are colored yellow. To make use of these internal hardware, an external measurement cable with a valid digital code on its plug needs to be inserted into one of the yellow common-use sockets. These measurement cables that comes with coded plugs are collectively cited as Smart Cables by the manufacturer and the embedded digital codes are also known as parameter-selection codes.

 

Each yellow flexible 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 select two Temperature hardware channels.

Each 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 MULTI socket from the inside, and not from the outside

 

An external measurement cable with a valid digital code embedded in its plug can make use of the corresponding internal hardware if available

The configured internal hardware (that are making use of external Smart Cables) are grouped into an electronic block known as MULTI-PARAMETER UNIT (MPU), complete with a small number of yellow MULTI sockets. The number of flexible MULTI sockets in an MPU is not arbitrary, but corresponds exactly to the number of internal IBP hardware channels intended.

 

It is the design rule that all yellow MULTI sockets are capable of doing IBP monitoring, and to adhere to this rule each socket comes with its own dedicated IBP amplifier hardware. The term "dedicated" denotes the attached IBP hardware to each yellow socket is not intended for sharing by other MULTI sockets in the MPU block, and each MULTI socket can only access its own dedicated IBP amplifier hardware.

Principle of operation

During use, a MULTI socket can only make use of its own dedicated IBP hardware when an IBP measurement cable is plugged into it. For non-IBP monitoring, the socket can access a common pool comprising Temperature, Cardiac Output, Thermistor Respiration and FiO2 hardware that are put in place in the MPU, which all MULTI sockets can link to.

 

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

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

 

Professionally, many are actually puzzled by the contents of the MPU but refrained from asking or simply 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 in exchange for the flexibility of common use? The truth is because it was originally devised to solve the problem of limited panel space area not sufficiently big enough to mount all the needed connector sockets. In situations when panel space area is more than enough to accommodate all the necessary connector sockets, there is no need to share connector sockets.

 

It is a waste of money to adopt this design when the need does not exist. Its continued use regardless of need shows us there is more than meets the eye and a good reason to question its relevance.

The manufacturer does not discuss this, but users can always find out by yourself how many channels of internal IBP hardware are supplied

 

Knowing a  functional yellow MULTI socket always come with its own dedicated one-channel IBP hardware, a user can accurately tell how many IBP monitoring hardware channels are supplied with any monitor, just by tallying the total number of available yellow multi-parameter sockets. For example, if your monitor is delivered with five functional yellow MULTI sockets, you had unknowingly paid for five channels of built-in IBP hardware when you may indeed only need one or two.

This being the design rule, and the key word is "functional" because a non-functional (fake) MULTI socket does not need to care about the capability to do IBP monitoring, such a socket can 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 dressed as a common-use socket 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 Life Scope 3500 series bedside monitors which has two MULTI-parameter sockets each, the configured hardware in the MPU includes two channels of IBP amplifiers, two channels of Temperature and one channel of Cardiac Output.

In the Life Scope 3700 series bedside monitors which has three MULTI-parameter sockets each, the configured hardware in the MPU includes three channels of IBP amplifiers, two channels of Temperature and one channel of Cardiac Output.

It is important to know the Life Scope VS series was not designed for using expansion units, this was an after-thought and adaptation following massive complaints from users that the yellow MULTI sockets on Life Scope VS monitors are not enough for use. The manufacturer should make clear the limitations of the adapted expansion units.

The NIBP, SpO2, ECG and two channels of Temperature in said input units or Life Scope PT monitor are not using Smart Cables and therefore not part of the MPU

 

The digital hexadecimal parameter code is programmed into a non-volatile EEPROM chip (Electrically Erasable Programmable Read-only Memory) mounted on a small flexible PC board wired to plug of a Smart Cable at the factory, and users cannot change the code after production using settings on the monitors. It is not costly 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 non-volatile digital parameter code is embedded in the plug of the measurement cable

 

The MULTI sockets are additionally diverted to serve as digital serial ports

This is the part that involves using external monitoring hardware, but these are all self-contained kit set units with an already-processed digital output in serial format, using the yellow connector socket only as a link to the digital processing stage of the monitor.

 

As explained earlier, the design concept of MPU was to solve the problem of limited panel space, and by using MULTI sockets as serial ports does help in furthering the reduction of mounted sockets and is the reason for this arrangement. This being an easy task since there is no need for additional internal analog hardware; the processed digital signals from the serial kit sets just bypass the analog stage and go straight to the digital processing stage of the monitor.

Shown below is the original label for the yellow MULTI sockets, indicating the five specific hardware and also serving as serial port for mainstream CO2 serial kits; the purpose of this arrangement was to minimize the number of sockets being used on a limited panel space. Outside of this context, the arrangement does not make sense because of cost.

 

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

 

Straying from the original intention, which was only for mainstream etCO2 serial kit set, there is now proliferation of self-contained digital serial kits using the MULTI sockets as serial ports to link to the monitor. Currently, 2nd SpO2, BIS and NMT kit sets etc. are all using the MULTI sockets as serial port, and this is happening when there is no panel space area problem. This is a questionable development, as if there is no concern for the high cost.

 

 

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

Additional parameter capability can 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 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 and external interfaces.

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

It is obvious monitors using Smart Cables are still configured monitors. The only advantage of using Smart Cables is to allow sharing of connector sockets, which are of negligible hardware cost; on the other hand, the cost needed to make use of Smart Cables is way far higher! Customers are just being 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!

The use of Smart Cables has unintended negative captured value for the users, as can be seen from below illustration. Users of the left monitor (BSM-3500 series with 2 channels of IBP) requires five connection sockets but only two yellow MULTI sockets can be provided for sharing because the channels of IBP amplifier hardware intended for placement inside the MPU is only two. 

 

Without any use of Smart Cables, all five parameters are freely available for carefree use via their respective dedicated sockets. The use of Smart Cables just makes things unnecessarily complicated and requires operator choice to choose two among the five, but not all. It is so obvious using five dedicated sockets is a far superior design!

 

Similarly, users of the right monitor (BSM-3700 series with 3 channels of IBP) requires six connection sockets for carefree use but the manufacturer insists three yellow common-use sockets are enough for use. This of course means only three channels of IBP amplifier hardware are intended for placement in the MPU.

 

How does such dire shortage of connector sockets benefit a users? The apparent flexibility of the yellow MULTI sockets is in reality an adoption with negative captured value for the users.

These monitors are in dire short of necessary connector sockets, the value captured by users is negative

Manufacturers make their profits by providing product benefits to users but the yellow multi-parameter sockets have no benefit. Instead, it is a burden to the users.

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

 

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

 

Under US FDA rule, a cable is only a cable if it does not change the signal that passes through it. A Smart Cable embedded with a non-volatile digital 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 definitely requires FDA registration. Can you find any stand-alone NIHON KOHDEN Smart Cable registered with US FDA as a medical device? We do not.

Make no mistake, when the Smart Cables are used with serial kit sets, such as mainstream etCO2 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.

 

It is unsubstantiated marketing messages and we are going to show you beyond any doubt, there is absolutely no active electronics in the Smart Cables. Messages such as "New Modular Technology" and "The Module is in the cable!" are just the wild 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 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 board confirms a cheap non-volatile 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.

 

Irrefutable proof the IBP amplifier hardware is configured internally, an important fact no longer shown on later monitor manuals

The Life Scope BSM-2301 bedside monitor was launched before the Life Scope TR and Life Scope J 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 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 doubles as a serial port without any need for internal patient-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 micro-controller APU (Analog-block Processing Unit) and is forwarded to the DPU.  For a parameter using the internal analog hardware, the analog signal needs to be converted to digital before it can go to the APU for digital processing. 

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

You should be absolutely sure by now the IBP amplifier hardware inside the monitor is the reason a BSM-3500 series bedside monitor can do two channels of IBP monitoring, it is the same reason BSM-3700 series bedside monitor can do three channels of IBP monitoring.

What you had just seen is that the number of yellow MULTI socket on a monitor is not an arbitrary number, but peg to the number of internal IBP hardware channel intended. Adding an extra yellow MULTI socket has the unintended consequence of adding another channel of internal IBP hardware. Take a step back and ask the question, why do you need such yellow flexible sockets? 

The patient monitoring hardware inside the Life Scope BSM-3500 series (12-inch) bedside monitors can be easily concluded:

CONVENTIONAL BLOCK

(These hardware make use of dedicated connector sockets and ordinary measurement cables)

- ECG

- SpO2

- NIBP

MPU BLOCK with two MULTI sockets

(Use only Smart Cables for connections)

- 2 channels of IBP  (2 MULTI sockets = 2-ch IBP)

- 2 channels of TEMP  (1 MULTI socket = 2-ch TEMP)

- Cardiac Output

- Self-contained serial kit sets <BIS, APCO, mainstream CO2 and NMT>

Note:

Other third party parameter options are connected using the external device interface, not by using the multi-parameter sockets.

The hardware in the MPU of BSM-3500 series monitor

Similarly, the patient monitoring hardware inside the Life Scope BSM-3700 series (15-inch) bedside monitors are concluded as:

CONVENTIONAL BLOCK

(These hardware make use of dedicated connector sockets and ordinary cables)

- ECG

- SpO2

- NIBP

MPU BLOCK with three yellow sockets

(Use only Smart Cables for connections)

- 3 channels of IBP (3 MULTI sockets = 3-ch IBP)

- 2 channels of TEMP (1 MULTI socket = 2-ch TEMP)

- Cardiac Output

- Self-contained serial kit sets <BIS, APCO, mainstream CO2 and NMT>

The hardware in the MPU of BSM-3700 series monitor

As seen, the difference between the BSM-3500 series and the BSM-3700 series is the addition of one yellow MULTI socket, and of course it also means an additional IBP amplifier hardware.

 

Origin and purpose of the MPU design from the last century

In the 1990s, when developing the first digital modular monitor, the development team encountered a problem of insufficient front panel space for all needed connector sockets on the first digital multi-parameter module being made. The Smart Cables were originally devised only to resolve a product issue.

 

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. 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.

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. However, putting a lot of hardware into the Saturn module also means more panel space needed for connector sockets.

The Saturn module was intended to be physically small in size

The solution from NIHON KOHDEN for panel space limitation of Saturn module was to introduce a MULTI-PARAMETER UNIT with many hardware sharing two yellow sockets for common use.

 

The Saturn module turned to sharing two modified connector sockets as solution to the constraint of space for more sockets

In the Saturn module, the hardware are divided into two blocks, a conventional and a MPU block.

CONVENTIONAL BLOCK

(These hardware make use of dedicated sockets and ordinary measurement cables)

- ECG

- SpO2

- NIBP

MPU BLOCK with two yellow MULTI sockets

(Use only 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

- Self-contained serial kit sets <Mainstream etCO2)

Huge amount of configured hardware in the Saturn module

The MPU design has many hardware sharing only two MULTI sockets, this is to solve the problem of limited panel space. This, however, is only the first part of the solution.

More MULTI sockets are of course needed to make good use of the hardware that would otherwise be idling in the MPU. This is achieved by using an external expansion box filled with MULTI sockets, each with its own dedicated IBP amplifier hardware.

This is a process of adding more sockets, not more monitoring parameters

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

The image gives an impression of scalability but this is scalability of connector sockets, and not the scalability of monitoring parameters that is being sought after by the market. All necessary hardware are already placed in the MPU of the Saturn module except for additional IBP amplifier which must always come with each MULTI socket.

 

A MULTI socket can only make use of its own IBP hardware when a Smart Cable with an IBP code is plugged into it; for the other four parameters, the sockets are linked to the common pool of Temperature, Cardiac Output, Thermistor Respiration and FiO2 hardware already placed in the MPU of the Saturn module.

Each MULTI socket has its own dedicated IBP hardware that is not shared

The extension Smart module is therefore a 2-channel IBP box adding two MULTI sockets for use by the Saturn module. Remember, the analog interface limits the number of Smart modules that can be added to the Saturn module to two, which is a total of four MULTI sockets.

The MULTI sockets were additionally allowed to be diverted to act as a costly digital serial ports so that mainstream CO2 serial kit sets can also use it; we must remember this aids the purpose of minimizing connector sockets on the Saturn module, as it does not make sense outside this context.

Keep in mind, a MULTI socket is a high-cost serial port when it does not select any internal hardware

MULTI-parameter socket utilized as a costly serial port

The initial arrangement was only for mainstream CO2 serial kit sets, but later extended enthusiastically to BIS kit set, 2nd-SpO2 kit set, APCO kit set, NMT kit set etc. when there is no longer need for it. This greatly increases the interface cost compared to a plain serial port.

The use of Smart Cables for serial communication does give a false illusion of mighty MULTI sockets but the capabilities are in reality coming from the system software.

 

Make no mistake, the serial kit sets are self-contained and whether a particular kit set is supported depends on the system software, not on the type of connector sockets being used.

To put it plainly, there is no difference if you connect digital serial data to the monitor using Smart Cables or ordinary serial cables

This is how you connect the BIS processor kit to a yellow MULTI socket

Using Smart Cables for serial interface means an unnecessary jump in demand for more MULTI sockets when there is no technical need for the serial kit sets to use the MULTI sockets. Putting things into perspective, most patient monitoring parameters cannot be made into self-contained serial kits; for example, the AE-918P Neuro Unit or a strip chart recorder cannot be linked to a MULTI socket as a serial kit set. They are connected as external devices to a monitor.

 

The AE-918P Neuro unit and recorder module are examples that cannot make use of the a MULTI socket

The MULTI-PARAMETER UNIT is an official term found in the service manuals

The Saturn module, together with two satellite boxes adding 4 channels of IBP to the Saturn module is shown below. The four MULTI sockets on the satellite boxes have access to the MPU of the Saturn module. Together, six IBP channels and six shared-use MULTI sockets are available to the users.

The sockets on the satellite boxes compensate for the missing connector sockets on the Saturn module

 

 

Life Scope BSM-2300K series bedside monitors case study

Preceding Life Scope VS bedside monitors 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 one yellow MULTI socket flexible enough for three types of measurements, namely:

 

a. Invasive Blood Pressure

b. Thermistor Respiration

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

 

Without any use of Smart Cables, all one channel of IBP, Thermistor Respiration and one channel of mainstream etCO2 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 choice to choose among IBP, Thermistor Respiration and mainstream etCO2, but what if you need all? This is unwarranted stress and inconvenience, and the use of three dedicated sockets is obviously a far superior design!

 

We should ask why is there a need for users to endure the pain of two missing sockets in exchange for one flexible socket capable of connecting to three types of measurement cables? 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 two blocks of patient monitoring hardware in the Life Scope BSM-2301 bedside monitor are:

CONVENTIONAL BLOCK

(The hardware make use of dedicated sockets and ordinary cables)

- 1-ch TEMP

- ECG

- SpO2

- NIBP

MPU BLOCK with one yellow MULTI socket

(Use only Smart Cables for connections)

- 1-ch IBP

- Thermistor Respiration

- Self-contained serial kit sets - Mainstream etCO2

The reality is the shortage of two connector sockets, and users are all insisting the single MULTI connector socket on the BSM-2301K is not enough. The manufacturer was pressured to respond with an updated model an updated model, BSM-2303K. The solution from new model BSM-2303K is to add a new isolated yellow MULTI socket.

 

The MPU design in the BSM-2301K was not designed to take on expansion, and the isolation was needed not to load the operation of existing MPU. It means the additional MULTI socket is a fake one and only could make use of its own associated IBP amplifier hardware.

The fake MULTI socket was intended solely for IBP monitoring, effectively relieving existing functional MULTI socket to only measure either Thermistor Respiration or act as serial port for the mainstream etCO2 kit set. It was not a solution, as a logical one would be to do away with the MULTI sockets, but there was a need for the manufacturer to keep using the Smart Cables.

 

There was no actual demand for additional IBP channels in the targeted segment, but the manufacturer was cornered to declare BSM-2303 bedside monitor was a response to market demand for 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

As expected, users soon found out the small number of MULTI sockets on Life Scope VS bedside monitors are not enough for use

Electrically, the manufacturer can add more MULTI sockets using an external box that comes with more MULTI sockets. The interface is an analog one and only a maximum of four MULTI sockets can be integrated, to avoid signal deterioration caused by voltage drop and noise pickup.

However, recall the Life Scope VS bedside monitors were launched without options of expansion units; the situation is similar to Life Scope BSM-2301K bedside monitor, but the customers are desperate to have their sockets back!

As seen in below picture, the expansion units from Life Scope TR are offered to overcome the man-made problem. The makeshift solution makes the bedside monitor look awkward, resembling a product prototypes.

Like the BSM-2301K, the Life Scope VS monitors were not designed for extension socket boxes, are the MULTI sockets on the expansion units fully functional? Field demonstration to verify all claims must be done for proper assessment of suitability for use.

Socket boxes from Life Scope TR had to be offered as makeshift solution to overwhelming complaints of socket shortage

 

Sharing cheap connector sockets does not make economic sense

 

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 for the customers but time-sharing of a cheap connector socket does not

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

WATCH OUT the dangerous use of semi-quantitative CO2 measurements and ignorantly displaying a flawed CO2 waveform

Nihon Kohden lacks sidestream CO2 sampling expertise and buys OEM units to offer them as expensive standalone. The AG-400 CO2 unit as shown, for example, is technology from Oridion Medical. For monitoring such as post-surgery recovery, integration of the sidestream CO2 into the monitor is a mandatory requirement because an external unit requires additional power socket besides necessitating the use of a trolley.

 

For some unknown weakness, Nihon Kohden monitors have never been able to offer benefits of integrated sidestream CO2 measurement.

 

The inability to integrate the sidestream CO2 unit into the patient monitor main unit

The adoption of semi-quantitative mainstream CO2 measurement was to reduce cost and its simplicity also help in miniaturization of the transducers. The first solution offered by Nihon Kohden was the mainstream cap-ONE TG-920P CO2 sensor kit (order code P907) that can be used on non-intubated patients.

 

The cap-ONE TG-920P CO2 sensor kit (P907) has very small sensors because semi-quantitative measurement is adopted, the method is not commonly seen and many are not aware of the risks of obtained CO2 readings from the semi-quantitative CO2 kit sets, and to make matter worse, the semi-quantitative measurements are also being made used of to display a flawed continuous CO2 waveform.

 

Nihon Kohden cap-ONE P907 (TG-920P) mainstream CO2 sensor kit

How to remove a relatively big disposable adapter from the two tiny transducers after use?

 

When the sensors become smaller, it also means the disposable adapter becomes relatively much bigger as seen in this below picture. When trying to remove the disposable adapter from the transducers, it is difficult to separate the two because of the latching mechanism. A small size transducer means anything that latches onto it must be even smaller.

It is not easy to separate the disposable adapter from the Cap-ONE transducers after use

 

When removing disposable adapter from the mini sensors, users tend to just pull from the cables and this action quickly weakens the joint holding the sensors and cables. The action will cause stress to the two joints and quickly degenerate the performance of the transducers. This means the transducers are unlikely to last.

 

Users just doing the inevitable

 

Shown below is another TG-900P etCO2 kit set (order code P903) that makes semi-quantitative CO2 measurements on a traditional mainstream CO2 sensor. The TG-901T3 kit set (order code P906) is the same thing but using a non-coded connection plug. The medical devices from same manufacturer that make use of semi-quantitative CO2 kit sets for patient CO2 measurements and waveform include:

- Life Scope patient monitors

- Vismo patient monitors

- Cap-STAT OLG-2800

- CardioLife defibrillators

- Neurofax EEG machines etc.

 

Nihon Kohden semi-quantitative CO2 kit sets with traditional mainstream transducer

The manufacturer is not aware semi-quantitative CO2 measurements are only estimates

 

To save costs, the semi-quantitative kit sets do not make measurement during the inspiration phase. The important point is there is a measurement duty cycle and it is as shown; there is no way to know the actual CO2 measurements during the inspiration phase because CO2 measurements are not made.

Semi-quantitative means there is a duty cycle, and measurements are not continuous

 

Semi-quantitative measurement is also of low-accuracy type, performed using one IR detector instead of the usual two to save cost. This is reflected in the measurement tolerance.

 

Contrasting, quantitative measurement delivers high accuracy for critical care. To ensure the necessary high accuracy, quantitative measurement employed two IR detectors for simultaneous CO2 measurements at different wavelength for results comparison. CO2 measurements are also being made continuously.

 

Quantitative measurement employs two detectors to make continuous measurement at different wave-lengths to compare readings for high accuracy

NIHON KOHDEN specification for TG-901T CO2 sensor kit shows even the specified low accuracy of CO2 measurement using semi-quantitative method no longer holds true once CO2 is present during the inspiration phase.

This is because actual CO2 value is higher than what is being measured.

 

Semi-quantitative design cannot assure users the CO2 level is definitely zero during each inspiration phase!

 

Measurements are invalid when CO2 is present during inspiration, but the design does not measure the CO2 level during this period!

 

As seen from the duty cycle, there is no measurement being made during the inspiration phase, how does the manufacturer assure measurement accuracy? The specified measurement tolerance is conditional and has no meaning for the users!

Each semi-quantitative CO2 measurement is in fact only an estimation.

In addition, since the users are not alerted on screen that there is no CO2 measurement being made during the inspiration phase, they are unknowingly made to take on an unnecessary risk.

 

Semi-quantitative methodology means cost-effective estimations but the design cannot be used in a general way, only on a selective basis with known risks

 

For example, semi-quantitative methodology can be used as a simple estimation tool for obtaining the numerical value of End-tidal Carbon Dioxide level (etCO2).

 

Below picture shows the semi-quantitative method in the way it was intended for, estimating only the etCO2 numerical value for purpose of airway tube placement confirmation. It is not for continuous waveform display.

A hand-held semi-quantitative etCO2 estimation tool (with SpO2) for airway tube placement confirmation

The manufacturer ended up ignorantly displaying a flawed continuous CO2 waveform using semi-quantitative measurement kits that do not have ability to make continuous measurements

NIHON KOHDEN also allows data from semi-quantitative measurements to be displayed on screen with the non-measurement period reset to zero level. The insistence to display a continuous waveform using discontinuous measurement data from semi-quantitative mainstream CO2 estimation kits is unacceptable; the manufacturer is just subjecting the monitored patients and users to dangerous misinterpretation risks.

 

A zero CO2 reading on the waveform means zero measured value. No measurement can only mean a defective sensor, not by design!

Note the end tidal CO2 (etCO2) value shown is also not alerted as "estimated etCO2" only.

 

A flawed CO2 waveform with non-measurement intervals reflected as zero measured CO2 value

 

As seen from the two true CO2 traces below, expiratory upstrokes do not always start from zero CO2 level!

Quantitative measurements confirming expiratory upstrokes do not always start from zero CO2 level

  

Check the latest updated table to make sure you only use quantitative method for critical measurements and to display a true CO2 waveform on the screen.

 

Use only quantitative method for waveform display; the quantitative TG-950P (P905) shown here was already discontinued.

 

 

What you should know about fully-quantitative type miniaturized mainstream CO2 sensors

The TG-907P CO2 Sensor kit (order code P909) shown in above table is declared as using quantitative method. This sensor was designed for non-intubated adult CO2 monitoring, as well as neonatal CO2 monitoring. Nihon Kohden is thus offering an alternative to sidestream CO2 sampling methodology.

 

The miniaturized CO2 sensor is easily broken by the bigger and stronger adapter

 

In addition to the dead space problem, they had not foreseen miniaturized mainstream CO2 sensors could be easily broken by the disposable adapters. This happened because the disposable adapters are now relatively bigger and stronger!

These are common defects of a TG-970P CO2 sensor kit (P909). The design is impractical.

The fragile miniaturized CO2 sensor are clearly of poor design, and easily broken

The key point is, it does not last

 

 

 

Beware the mandatory need for network isolation units for patient safety when connecting to a Central Nurse Station

 

For hardwired Ethernet networking, a Life Scope VS bedside monitor (equipped with a non-isolated Ethernet LAN interface) connecting to a real-time LAN network is a danger to the patient. It is mandatory to observe patient electrical safety by using a network isolation unit to protect the vulnerable patients.

NIHON KOHDEN network isolation transformer

 

When an isolated monitor with an non-isolated Ethernet port is connected to a hardwired network, it is no longer a medical device unless the above-shown network isolation transformer is introduced between the monitor and network. If the network isolation transformer is not installed, dangerous electric shocks can be delivered to a monitored patient through the wired Ethernet network. Such dangerous electric shocks are potentially lethal and no hospital should ignore this mandatory requirement.

For telemetry networking, the ZS-900P Telemetry Transmitter is optionally required. This is required specification for the Japanese domestic market due to government subsidy but unpopular outside of Japan because of cost.

Telemetry networking is not popular outside of Japan due to absence of government subsidy

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