NIHON KOHDEN CardioLife TEC-5600 series defibrillators and mainstream semi-quantitative CO2 kit

Category: NIHON KOHDEN CardioLife Defibrillators, Acti-Biphasic Defibrillations, CardioLife TEC-5601 defibrillator, CardioLife TEC-5611 defibrillator, CardioLife TEC-5621 defibrillator, CardioLife TEC-5631 defibrillator.

 

There are four basic models of the CardioLife TEC-5600 series defibrillators, namely:

 

1. CardioLife TEC-5601 defibrillator

2. CardioLife TEC-5611 defibrillator

3. CardioLife TEC-5621 defibrillator

4. CardioLife TEC-5631 defibrillator

 

The Pacing Unit is not an optional item, but part of CardioLife TEC-5631 model. This means the design is rigid, and users cannot add the pacing unit in the field.

CardioLife TEC-5600 series comparison table

Distributors and dealers frequently face the dilemma how many TEC-5621 and TEC-5631 each to stock up respectively when competitors only make the same decision for one model with the pacing unit as an optional item.

 

Which of the four models should you keep stock?

For all four models, the manufacturer offers an optional panel to upgrade with SpO2 and CO2 capabilities.

 

The CO2 is mainstream semi-quantitative type, as shown in below picture. It can be seen the connector socket for the mainstream CO2 kit set is different from the previous model, necessitating a new set of accessory even though the transducer is the same old one.

 

A CardioLife TEC-5600 defibrillator and its side connectors

 

Notice a yellow flexible MULTI socket is being used for the mainstream CO2 serial kit set but the MULTI socket is a standalone; unlike the additional MULTI socket on BSM-2303K this one does not even come with an IBP amplifier. This is a totally naked socket, equipped to only identify the Smart Cable parameter code of TG-900P mainstream CO2 serial kit set (Supply Code P903) which the system software supports.

 

 

The above illustration on the promotion brochure is so distorted. The MULTI socket is only acting as a serial port in this case, and we know serial ports are interchangeable for use. The kit set is identified by the header of the serial communication data string, and there is no problem on any device to recognize a serial kit set so long as the device's firmware supports it. We had detailed elsewhere about the futile efforts to continue the use of the MULTI socket, do look it up if you are interested.

 

The TEC-5600 series has little connectivity to offer, there is manual Bluetooth communication to a Life Scope bedside monitor but the data just stays at the patient monitor without any concept of onward connectivity since the same data cannot be seen at the Central Monitor or Gateway Server. There is No LAN Capability and data transfer is only by using SD card. Defibrillation DATA MANAGEMENT software is also NOT AVAILABLE (*this is different from QP-551VK defibrillator report viewer software).

 

For those who already had bought the mainstream CO2 sensor kit for TEC-5500 series, this is just additional expenditure when you had intended to use the existing CO2 kit set on the new defibrillator. The CardioLife TEC-5600 series defibrillators have no reason to use a new type socket different from that of the TEC-5500 series when there is no new benefit.

 

The P903 on the left is for TEC-5600 series while the P906 on the right is for TEC-5500 series. The two are identical except for the connector plug.

 

A word of caution, whether it is P903 (TG-900P) or P906 (TG-901T3), the mainstream serial kit sets are doing only semi-quantitative measurements. Semi-quantitative measurements are only estimations, not for critical care use.

Why you need to watch out the Careless and Dangerous use of estimated CO2 values as true values

The adoption of semi-quantitative mainstream CO2 measurement by NIHON KOHDEN 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 of the adoption of semi-quantitative measurements; the method is not commonly seen and many are not aware of the risks of CO2 readings from the semi-quantitative CO2 kit sets. To make matter worse, the semi-quantitative measurements are also being used to display a flawed continuous CO2 waveform on screen to the users.

 

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

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

 

 

Semi-quantitative CO2 measurements are not a cheap alternative to quantitative measurements

 

To save costs, the semi-quantitative kit sets do not make measurement during the inspiration phase. The measurement duty cycle is shown in below image.

 

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

 

Semi-quantitative measurements are also of low-accuracy type, performed using one IR detector instead of the usual two to save cost.

 

Contrasting, quantitative measurements deliver high accuracy for critical care. To ensure the necessary high accuracy, quantitative measurements employ two IR detectors for simultaneous CO2 measurements at different wavelength for results comparison. CO2 measurements are also being made continuously, and therefore can be a feed for CO2 waveform.

Quantitative measurements employ 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 measurements using semi-quantitative method no longer holds true once CO2 is present during the inspiration phase. This is because actual CO2 levels can be much higher.

 

In other words, it is an acknowledgement that:

 

1. The measured CO2 value is not the true CO2 level,

 

2. The true CO2 level = (measured CO2 value + x); where x is the unknown CO2 value carried forward from the inspiration phase. Only when x = zero will the measured CO2 value reflect the true CO2 level.

 

It is thus unprofessional to specify a measurement tolerance when there is an unknown in the equation

 

This is not professional specifications

 

As seen from the duty cycle, there is no measurement being made during the inspiration phase, how do the manufacturer or users know the measured CO2 value is the true CO2 level?

 

The specified measurement tolerance is conditional on this assurance and the CO2 value shown to users is therefore wrong and misleading! Each semi-quantitative CO2 measurement is in fact only an estimation, because the users have no way to tell if the x value is indeed zero. It is only assumed to be zero.

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

 

 

Semi-quantitative measurements are for selective uses with known risks

 

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 to estimate the value of etCO2 for airway tube placement confirmation. It cannot be used for continuous waveform display.

 

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

It is a flawed continuous waveform when fed by a source that does not have the ability to make continuous measurements

 

The manufacturer ended up carelessly displaying a flawed continuous CO2 waveform using semi-quantitative measurement kits that do not have ability to make continuous measurements. This is unacceptable, as the manufacturer is subjecting the monitored patients and users to dangerous misinterpretation risks.

 

When there is no measurement being made during the inspiration phase, the displayed CO2 level is forced to a clean zero by design. Is the manufacturer aware that a zero CO2 reading on the waveform means zero measured value, not that you are not measuring? This is basic professional knowledge.

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

 

The dangerous assumption that expiratory upstrokes always start from zero CO2 level

 

Below image confirms it is dangerous to assume the CO2 level during the inspiration phase is always zero. 

 

Dangerous assumption the manufacturer is making

 

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.

CardioLife TEC-5600 series defibrillators are described as using Acti-Biphasic defibrillation shock energy

From advertising material, as well as operating and service manuals of CardioLife Acti-Biphasic defibrillators, we know the declared Acti-Biphasic waveform looks like what is shown in below picture. This is also the waveform submitted to obtain regulatory approvals around the world, supported by a Certificate of Free Sales from Japanese regulatory authority, MHLW and/or CE Certification.

 

THE ACTI-BIPHASIC DISCHARGE OUTPUT WAVEFORM DECLARED BY THE MANUFACTURER

Declared characteristics of the Acti-Biphasic waveform in advertising, operator and service manuals

The basic concept of a bi-phasic shock energy is to add a negative follow-up phase to the conventional mono-phasic shock to achieve the same defibrillation result using lesser energy

  

 

 

The characteristics of NIHON KOHDEN Acti-Biphasic defibrillation can be summarized as:

 

1. First (Launch) Phase

The Acti-Biphasic waveform is seen as operating in an open loop during the first phase (period).

 

- It is a positive truncated exponential pulse with a duration depending on the patient impedance.
- It is of a longer duration than the second period.

 

2. Second (Follow-up) Phase

The Acti-Biphasic waveform operates in a closed loop during the second phase. In a closed loop the duration of the width can be deliberately set to a specific duration.

 

- This second phase (period) is shorter in duration and of negative polarity.
- The duration in this phase is fixed to a constant 3.4ms duration regardless of patient impedance. How was the optimal duration of 3.4ms arrived at? It is also not clear how was the maximum energy of 270 Joules concluded?

Note the first phase (period) is positive and a wider pulse than the second phase

The first to use Acti-Biphasic waveform were the CardioLife TEC-7700K series defibrillators

The CardioLife TEC-7000 series defibrillators had two models, the CardioLife TEC-7721K and CardioLife TEC-7731K (built-in pacing unit).

 

The first Acti-Biphasic defibrillators

 

Output discharged by CardioLife TEC-7700K series defibrillators is consistent with the declared waveform

 

The discharge waveform of the CardioLife TEC-7700K series on a strip chart is as shown below. The recording correctly reflects the first phase as a positive pulse.

The recording shows the voltage first swings to the top (positive saturation), then to negative saturation after some time; this is fully consistent with the official description of the Acti-Biphasic waveform.

 

The reason we are not seeing the full shape of the Acti-Biphasic waveform on the recording is because the sensitivity is set to see the smaller ECG waveform, and not the defibrillation shock which are much higher in magnitude.

 

This strip chart recording shows output of CardioLife TEC-7700K series is consistent with the declared description

 

How can we know if the Acti-Biphasic defibrillation shock actually works on patients?

The margin of error is high for data from a small 75 investigated cases

 

There is no white paper available. The Acti-Biphasic defibrillators were hurriedly launched (for export) before completion of proper clinical validation and the small sample size of seventy five investigated cases meant a high margin of error; we cannot be sure the Acti-Biphasic defibrillation shock works on patients! In addition, how can we be absolutely sure the investigated cases were done in an acceptable manner?

As the mono-phasic defibrillators are not predicate devices so the FDA 510(K) process cannot be used to clear the product for sales in the US market. Since the clinical data and methodology adopted by NIHON KOHDEN fell short of US FDA guide for safety and effectiveness, the Acti-Biphasic defibrillation shock is not allowed for sales in the US market; Nihon Kohden could have engaged a consultant to ensure a proper and acceptable clinical validation process if they had wanted to do it right. This implies the design is not yet good for use, and further improvements are needed for it to meet US FDA requirements.

It is necessary here to clarify that current CE certification does not guarantee clinical performance since clinical validation is not included. This means you need clinical papers in addition to CE certification.

The persistent remarks we often heard from NIHON KOHDEN marketing staff on American Heart Association recommendations are in reality, meaningless to Acti-Biphasic defibrillators.

Outside of the US market, we need to question the point of buying such critical treatment devices and placing them on standby to save lives? Remember, compliance to just safety standards is no guarantee of performance! It is so unfair to the patients needing immediate treatment in a life-threatening situation!

Biphasic defibrillation was a nightmare, one that caught NIHON KOHDEN development team off guard

In May 1997 Nihon Kohden released a new defibrillator with a semi-automatic AED mode for export using mono-phasic defibrillation. The details of this TEC-2200K series can be found in the 1997 Product Guide.

The monophasic CardioLife TEC-2200K series was launched for export in May 1997

 

This was a mono-phasic model using the non-proprietary Edmark single-phase pulse as illustrated and the use of rechargeable battery for energy made it very inconvenient for public use.

Edwark, Single Phase Pulse defibrillation waveform used by monophasic CardioLife TEC-2200K series in 1997

The monophasic output discharge waveform shape is shown below. Note its shape as we will later show Acti-Biphasic AED-2100K, AED-2150K, AED-2152K and AED-3100 automated external defibrillators all discharge the same monophasic energy.

 

CardioLife TEC-2200K mono-phasic output waveform recorded on a strip chart dated April 1995

 

Just a few months after the TEC-2200 series was released, then market leader Hewlett Packard made announcement to acquire Heartstream Inc. in a stock-swap deal.

 

Heartstream ForeRunner

Biphasic defibrillation waveform was becoming the new preference as it allowed for a smaller and lighter defibrillator design; more importantly it uses less current and this means less damage defibrillation will do to the heart and skin. The deal with Heartstream was how the then defibrillator market leader HP acquired biphasic technology, since to develop one would take time and speed to market was a top priority. 

 

With a changing trend in the international market, there was therefore zero interest in the monophasic TEC-2200 series defibrillators offered by Nihon Kohden for ex-Japan market and the products had to be withdrawn from exporting.

 

Unlike the monophasic pulse, biphasic waveform comes in various forms; each type of shape is proprietary and cannot be copied freely. This means the energy envelopes of manufacturers in the market are all different. For some waveform, the manufacturers only recommend a maximum of 200 joules while another can recommend energy as high as 360 joules. All manufacturers must therefore justify the use of their proprietary output waveform in some reasonable ways, preferably in accordance with US FDA guide for safety and effectiveness, which calls for clinical research validations or the manufacturers should at least cite published clinical papers which had been properly subjected to peer review.

 

NIHON KOHDEN was further thrown off balance by the speed of global shift to biphasic technology

 

It was a market disruption that NIHON KOHDEN was unprepared for. The company was at a loss for the next four years how to obtain the technology to offer biphasic defibrillators; this means the company's defibrillator development team was helpless in the face of disruption from changing technology. It was obvious to any observer they could only solve the problem by buying the technology from someone.

When the demand for biphasic AEDs eventually emerged in the Japanese domestic market, the company resorted to find a suitable partner with biphasic technology for co-operation. A strategic OEM distribution agreement was announced in January 2002 that Nihon Kohden would market Cardiac Science's line of AEDs under Nihon Kohden's trade name. This arrangement was a big success and many AED-9200 and AED-9231 were sold in Japan as reflected in annual reports and presentations.

 

Mark the date January 2002, and subsequent release of first Acti-Biphasic defibrillators (CardioLife TEC-7700 series) by NIHON KOHDEN in November 2002.

  

NIHON KOHDEN CardioLife AED-9200 and AED-9231 were highlighted to have very good sales in FY2006 financial results presentation

The Cardiac Science STAR biphasic waveform was validated by researchers at Cleveland Clinic and Cedars-Sinai Medical Center in accordance with US FDA guides for Safety and Effectiveness

 

The success of the STAR biphasic shock in the domestic market however, could not be replicated for exports to foreign markets since distributors could buy the original models at much cheaper prices from Cardiac Science directly.

 

To our surprise, instead of licensing the proprietary biphasic defibrillation design from Cardiac Science, a few engineers in NIHON KOHDEN could suddenly conclude a workable, proprietary Acti-Biphasic shock waveform just by playing with biphasic circuitry on pigs with minimal clinical supervision and collaboration, it is no wonder that the company had great difficulty securing the necessary clinical support to advance the number of investigated cases for proper clinical validation. To date, there is not a single clinical paper published on Acti-Biphasic defibrillation.

It is deplorable customers were sold unproven defibrillators by taking advantage of their good faith.

 

Before completion of proper clinical validations, the company was bold enough to go ahead with exporting the unproven TEC-7700 series Acti-Biphasic defibrillators from November 2002, taking advantage of its established distribution network for mono-phasic defibrillators. The sales were done based on blind faith, for there was no published clinical paper to show that it works. This November 2002 export launch was three long years ahead of the date Japan MHLW officially approved its use for the domestic market.

The absence of Internal Safeguards

 

The desperate action was taken in response to the rapid changing preference for biphasic defibrillators in the market but the process totally overlooked the seriousness of mandatory successful clinical studies before marketing; the fact that Ministry of Health, Labour and Welfare (MHLW) had not yet approved the sales of TEC-7700 series defibrillators in Japan domestic market reflected the disturbing absence of internal safeguards in corporate conduct.

 

Up to this point, the company had never exported a new product before first launching it in Japan, showing the company was in complete disarray. It is not just loss of credibility in overseas markets as a leading defibrillator exporter from Japan but a ticking time bomb with important issues left unattended.

Nihon Kohden began exporting unproven proprietary Acti-Biphasic defibrillators in 2002, before completion of proper clinical validations

 

Japanese Regulatory Authority took three long years to grant sales approval for the TEC-7700 series defibrillators in Japan

 

This meant the application was turned down several times and serious doubts by the Regulatory Authority to grant its use. What prompted the decision to clear it after three years' wait is something we should know, is the manufacturer willing to share the fact? By the time of receiving approval to sell in Japan, many CardioLife TEC-7700 series defibrillators were already exported.

 

NIHON KOHDEN was only able to announce the launch of TEC-7700 series defibrillators for sales in Japan market on December 1st, 2005.

 

Did NIHON KOHDEN give up the original Acti-Biphasic defibrillation output waveform?

 

Nihon Kohden incredibly launched another unproven Acti-Biphasic TEC-5500 series defibrillators for export sales in August 2004, more than a year before the above announcement; it was as if the two are unrelated. The urgent launch of TEC-5500 series defibrillators for export did not make sense, the event sent a subtle message something fundamental had changed.

We were therefore not surprised to later find the waveform discharged by the TEC-5500 series defibrillators different from the TEC-7700K series defibrillators. It is a version that is flipped vertically upside down from that of the TEC-7700 series defibrillators! The change in the shape of the waveform was not officially announced at the time of launch, it was only discovered later by accident in the field.

 

Was the manufacturer under pressure to stop using the declared discharge waveform (that is still currently being published on the service and operator manuals)?

This was happening prior to Japan MHLW approval for the TEC-7700 series, and without showing any clinical evidence to support its use!

Dubious CardioLife TEC-5500K series started to be exported from August 2004, when Japan MHLW had not approved the sales of CardioLife TEC-7700 series

The Timeline

Export of dubious CardioLife TEC-5500K series started in August 2004, more than one year before Japan MHLW actually approved the TEC-7700 series

CardioLife TEC-5500 series defibrillators were quickly approved for sales in Japan after the approval was given for CardioLife TEC-7700 series, based on the principle of declared substantial equivalence with the newly-approved TEC-7700 series. In Japan, the Acti-biphasic waveform discharged by Japanese version TEC-5500 series defibrillators is unlikely to be different from that discharged by TEC-7700 series defibrillators.

However, the export models of the TEC-5500 series, TEC-5600 series and TEC-8300 series defibrillators were all found to have their discharged waveform inverted, but submission documents to foreign regulatory authorities were all based on the TEC-7700 series. Are these regulatory approvals valid?

A top prestigious University Hospital in Taiwan was the first to find the polarity of TEC-5500K discharge waveform inverted from what was declared in the operator and service manuals

  

In the next image below, we received an adverse report from a competent Biomedical Engineering Team in National Taiwan University Hospital (Taipei City) that the polarity of measured waveform discharged by two tested CardioLife TEC-5500K series defibrillators were inverted (i.e. opposite in polarity) from what the manuals had described.

There was no doubt since they had tested both models TEC-5521K (S/N 09xx4) and TEC-5531K (S/N 05xx4) to arrive at the same conclusion; the suffix K is for export models using English language as interface (for example the suffix J is for Japan domestic models), indicating more than 9000 units of TEC-5521K and more than 5000 units of TEC-5531K had been produced before the two tested units respectively. Detailed comparison was also done with defibrillators from another manufacturer (Philips) using the same testing equipment (Fluke Impulse 7000DP with 7010 Selectable Load) and the polarity was consistent with the manual descriptions of Philips.

 

This was an input from professionals that the Acti-Biphasic waveform discharged by CardioLife TEC-5500K series defibrillators starts with a negative polarity and ends with a positive polarity; it is the exact opposite polarity (inversion) of what were shown on the operator and service manuals. As far as we know, there is no known manufacturer with a discharged biphasic waveform that starts with a negative polarity, NIHON KOHDEN is unique in this approach but there is no clinical research done to validate its use on patients!

 

Is this equivalent to a delayed fixed-width mono-phasic discharge?

The following image showed the illustration from another distributor (Thailand) sending in a Nihon Kohden defibrillator analyzer AX-103VK (OEM device) for repair.

 

The AX-103VK defibrillator analyzer has a discharge waveform output on the rear panel for oscilloscope display

The analyzer was concluded by their technical staff to be defective because the display on the oscilloscope was inverted; the analyzer was of course working fine. Said Thailand distributor is a top distributor who had sold the highest number of CardioLife TEC-7700K series defibrillators in the world and knew too well what is the "Correct Graph", confident of the defect conclusion. The conclusion turned out to be erroneous because the service manual wrongly informed them a TEC-5500K series defibrillator has similar output as a TEC-7700K series defibrillator.

Guess what? Someone from Tokyo Support has the audacity to ask the distributor staff to "just flip the APEX/ STERNUM connections" to obtain the "correct graph"!

Why should changing an "Evaluation machine" from a TEC-7700K defibrillator to a TEC-5500K defibrillator make a difference?

What could be the reason for the sudden change of mind? Was it due to copyright pressure? Does the inverted waveform only apply to export models since Japan MHLW solely approved the TEC-7700 series version?

 

The declared current flow direction of NIHON KOHDEN Acti-Biphasic shock energy is the one on the left while we discovered actual biphasic flow is the one shown on the right

The clinical trial data cited to regulatory authorities is based on the TEC-7700 series defibrillators for all Acti-Biphasic defibrillators, including the TEC-5500 series, TEC-8300 series and latest TEC-5600 series.

There were only some clinical data from TEC-7700 series defibrillators

 

When the discharge waveform is flipped upside down, the already-scanty TEC-7700 series clinical data cited becomes totally irrelevant

 

It is serious matter if the actual output waveform is different from the manual descriptions, as well as any inaccurate description documents submitted together with operator/ service manuals to regulatory authorities.

It means there is no approval from regulatory authorities to use a discharge waveform that is flipped upside down, and this is a ticking time bomb.

Change in current direction demands fresh clinical trial and validation

As a responsible company, NIHON KOHDEN should have by now long recalled all Acti-Biphasic defibrillators from the market. There is no denying customers are still buying Acti-Biphasic defibrillators based on blind faith.