NIHON KOHDEN Vismo PVM-4000 series bedside monitors

Category: NIHON KOHDEN Vismo PVM-4000 series bedside monitors and networking.

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Vismo stands for "Vital signs monitor" and not intended for sales in the USA market.

There are six models in the Vismo 4000 series bedside monitors, three basic models that use ordinary measurement cables are:

1. PVM-4731 (Masimo SpO2) bedside monitor

2. PVM-4751 (Nellcor SpO2) bedside monitor

3. PVM-4761 (Nihon Kohden SpO2) bedside monitors

The difference among the models are the type of SpO2 algorithm being used.

The next three models come with additional two yellow MULTI-parameter sockets that do not use ordinary measurement cables:

1. PVM-4763 bedside monitor (Nihon Kohden SpO2)

2. PVM-4753 bedside monitor (Nellcor SpO2)

3. PVM-4733 bedside monitor (Masimo SpO2)

The prominent feature of the PVM-4763, PVM-4753 and PVM-4733 bedside monitors is the utilization of yellow MULTI-parameter sockets. The MULTI-parameter sockets do not accept ordinary measurement cables but only cables embedded with codes defined by NIHON KOHDEN.

 

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. These coded cables are collectively cited as Smart Cables by the manufacturer and the codes are also known as parameter codes. Each socket selects only one channel of the hardware, except for Temperature allowing two channels of hardware to be selected.

 

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.

There are variations from the basic theme, such as doing without use of external expansion box, or increasing the number of MULTI-parameter sockets in the MULTI-parameter Unit, or reducing the hardware configured in the Multi-parameter Unit.

In the VISMO PVM-4763, PVM-4753 and PVM-4733 bedside monitors, only two channels of IBP hardware are configured out of the five types of hardware configured for use by Smart Cables.

NIBP, SpO2, ECG and two channels of Temperature are configured using dedicated measurement cables.

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-4763, PVM-4753 and PVM-4733 bedside monitors, 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-4763, PVM-4753 and PVM-4733 bedside monitors 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

This means VISMO PVM-4763, PVM-4753 and PVM-4733 bedside monitors making use of Smart Cables are still configured monitors. The only advantage of using Smart Cables is to allow the sharing of connector sockets, which are of negligible hardware cost; the cost needed to make use of Smart Cables is however, far higher. It does not make logical sense, the true purpose of using Smart Cables is to divert your attention away from something the manufacturer does not want you to know.

The value captured by users using the Smart Cables is negative

 

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. There is no need to compete for a MULTI-parameter socket to connect.

The output of the CO2 kit sets are processed digital serial data that should go straight to the DPU

Without sharing, both two channels 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.

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

If you have the misconception there are monitoring hardware embedded in the NIHON KOHDEN Smart Cables, we are going to show you 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 mere 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.

Keep in mind, the continued repetitions of an assertion without the ability to show any proof does not make it the truth!

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?

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 and not the passive Smart Cable.

Indisputable proof the IBP amplifier hardware is configured, an important fact withdrawn from later monitor manuals

 

The Life Scope BSM-2301 Service Manual is clear on the design; manuals for later models stop providing details. The major move to curb details in manuals started from Life Scope J (BSM-9101) Bedside Monitor.

In below 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 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 going 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 two IBP amplifier hardware inside the monitors is the reason they can each perform two channels of IBP monitoring.

Knowing there are two built-in IBP amplifier hardware inside the PVM-4763, PVM-4753 and PVM-4733 bedside monitors allows us to conclude the rest of the configured hardware after confirming all parameters that can be measured by the input unit.

First we filter out the parameters using self-contained serial kit sets, and this is only mainstream CO2. We can conclude the patient monitoring hardware in the PVM-4763, PVM-4753 and PVM-4733 bedside monitors to be:

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

- 2-ch TEMP

- ECG

- SpO2

- NIBP

(MULTI-PARAMETER UNIT BLOCK with one MULTI-parameter socket) The hardware only use Smart Cables for connections:

- 2-ch IBP

Note:

The mainstream CO2 hardware comes in the form of self-contained serial kit sets using the MULTI sockets only as serial ports without need for any internal hardware. The MULTI-parameter sockets only provide a link to the monitor.

Honestly,  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. 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.

Responding to new trend in the 1990s using a multi-parameter module with higher electronic density as a basic building block for modular monitor

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

The patient monitoring hardware were separated into two blocks in the Saturn module.

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

- ECG

- SpO2

- NIBP

(MULTI-PARAMETER UNIT) The hardware sharing the two adapting MULTI sockets in this block 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 sharing two modified connector sockets as a compromise

The adapting MULTI sockets were additionally allowed to be diverted to act as costly digital serial ports so that mainstream CO2 digital serial kit sets can also use it; this being an easy task since no internal analog hardware is being involved.

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

Remember this is for purpose of minimizing the number of connector sockets on the Saturn multi-parameter module, as it does not make sense outside this context.

A yellow MULTI-parameter socket is a high-cost serial port when it does not select any internal hardware

 

MULTI-parameter socket poorly 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., whose motivation is highly questionable given 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-parameter 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 reiterate, 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 yellow MULTI-parameter sockets and there is no technical need for the serial kit sets to use the yellow MULTI-parameter 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 yellow MULTI-parameter socket as serial kit as shown. 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 yellow MULTI sockets

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

 

The two MULTI-parameter sockets on the Saturn module are not enough for use

 

For such a huge amount of hardware in the Saturn module, more sockets are badly needed. The shortage of sockets could be improved by linking more external MULTI-parameter sockets to the hardware in the MULTI-parameter Unit of the Saturn module. The picture below shows two satellite boxes with two MULTI-parameter sockets offered as options to the Saturn module. As this is an analog solution, only a maximum of four MULTI-parameter sockets can be added this way.

Analog solution of adding up to four MULTI-parameter sockets using external boxes

The image gives an impression of scalability but this is scalability of connector sockets, not the scalability of monitoring parameters that is being sought after by the market. All necessary hardware are already configured in the Saturn module except for additional IBP amplifiers which must be tied to the number of available MULTI-parameter sockets.

The Saturn module only has two yellow MULTI-parameter sockets, it is impossible to perform more than two channels of IBP monitoring; this means IBP hardware must always correspond to the number of MULTI-parameter sockets available and each MULTI-parameter socket comes with their own IBP hardware. A MULTI-parameter socket makes 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 Temperature, Cardiac Output, Thermistor Respiration and FiO2 hardware already embedded in the MULTI-parameter Unit of Saturn module.

A MULTI-parameter socket that does not come with its own IBP hardware is not capable of monitoring IBP

What you are seeing is making use of space external to the Saturn module to compensate up to four missing sockets on the Saturn module. The extension Smart module is therefore a 2-channel IBP box with two MULTI-parameter sockets.

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

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

Users rebuffed the use of Smart Cables when out-of-context

Preceding the Life Scope Vismo 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 use of Smart Cables, the Life Scope BSM-2301K monitor offered one 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 serial kit set, 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 overwhelming. 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 Multi-parameter Unit 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 comes 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

The VISMO PVM-4000 series bedside monitors were developed in response to the overwhelming complaint of a single MULTI socket on the PVM-2703 bedside monitor being not enough for use.

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-4000 series with two MULTI-parameter sockets are doing 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-4000 series with two MULTI-parameter sockets are 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!

WATCH OUT the dangerous use of uncertain semi-quantitative CO2 measurements and 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 reason, Nihon Kohden monitors have never been able to offer benefits of integrated sidestream CO2 measurements.

 

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 (order code 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

 

Do the users know semi-quantitative CO2 measurements are only estimations?

    

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 will be more.

It is impossible for users to know if measurements are reliable when they cannot tell if CO2 is present during inspiration!

   

Measurements are invalid when CO2 is present during inspiration, but CO2 is not measured 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 has no meaning for the users!

It should be clear each semi-quantitative CO2 measurement is only an estimation since its accuracy is rendered uncertain by the inability to confirm if CO2 is present during the inspiration phase.

Since the users are also not alerted on screen there is no CO2 measurement being made during the inspiration phase, they are unknowingly made to take on unnecessary risk.

Semi-quantitative methodology means cost-effective estimations and 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

How can you properly display a continuous CO2 waveform when your semi-quantitative measurement kits do not have the 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 true CO2 waveform display on screen.

 

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

 

 

How about fully-quantitative type miniaturized mainstream CO2 sensor?

 

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 is clearly of poor design, and easily broken

 

 

Key point is, it does not last

 

iNIBP measurements

 

We can see the Vismo 4000 series monitors make use of iNIBP measurement during the cuff-inflation phase (iNIBP), which is only a speed advantage for spot monitors. The technique is similar to Welch Allyn's SureBP technology introduced way back in 2006 and a technique widely acknowledged to be pioneered by Collin Corporation of Japan. Collin Corporation was a business partner to Nihon Kohden Corporation supplying NIBP components running on older Life Scope 8000 series patient monitors.

 

When in the case of an iNIBP measurement being unsuccessful (i.e. not completed after a certain time), the monitor can only obtain a reading using the conventional deflation measurement algorithm; this means you have to add the iNIBP measurement time to the conventional method, which will be exceptionally long.

 

In addition, the success of a Nihon Kohden iNIBP measurement requires the use of special YAWARA CUFF 2 type NIBP cuff for performance delivery; Yawara cuff (without the 2) or other cuffs are not recommended for iNIBP measurements. The 5cm and 7cm YAWARA CUFF 2 (meant for Infants and Children) are also too small for iNIBP use and these sizes must only use the deflation measurement algorithm.

 

The market expectation is Nihon Kohden should achieve quick NIBP measurement with inflation-phase algorithm using only ordinary cuffs.

 

Users should beware the mandatory need for network isolation units when connecting Vismo bedside monitors to a Central Nurse Station

For networking, a Vismo bedside monitor equipped with a non-isolated Ethernet LAN interface when 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 patient.

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.