Category: Product Review, Polarity of "ActiBiphasic" waveform.
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 declared by the manufacturer |
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| Declared characteristics of the Acti-Biphasic discharge 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 |
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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.
- 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?
- 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?
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| 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 |
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The
CardioLife TEC-7000 series defibrillators had two models, the
CardioLife TEC-7721K and CardioLife TEC-7731K (built-in pacing unit).
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| The first Acti-Biphasic defibrillators |
| Output discharged by CardioLife TEC-7700K series defibrillators is consistent with the declared waveform |
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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.
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| 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? |
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| 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 does not follow US FDA guide for safety and effectiveness,
it was not possible for the Acti-Biphasic defibrillation shock to get the necessary approval for sales in the US market.
Nihon Kohden could have engaged a consultant to
ensure a proper and acceptable clinical validation process if they were determined in obtaining US FDA approval, but the company gave up the US market.
The persistent remarks we often heard on American Heart
Association recommendations turned out to be meaningless to Acti-Biphasic
defibrillators.
Note current CE certification does not guarantee clinical performance since it is not included in evaluation. This means you need clinical papers in addition to CE certification, which is for safety. What is the use of safety without assurance of treatment effectiveness? It is so unfair to the patients needing immediate treatment in a life-threatening situation.
There are therefore two very important questions:
1. What was the hidden factor that gave the manufacturer the confidence that no further validation was needed for the Acti-Biphasic defibrillation energy?
2. Why should the manufacturer willingly give up the big US bi-phasic defibrillator market when they were already in the US mono-phasic market?
| NIHON KOHDEN development team had got it all wrong |
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In May 1997 Nihon Kohden released the first CardioLife defibrillators with a semi-automatic AED mode for export, they were the
predecessors of the AED-2100K series, discharging the same monophasic
defibrillation as CardioLife TEC-7500 series defibrillators. The summary of this TEC-2200K series defibrillators can be found in the 1997 Product Guide.
This
was
a monophasic model using the non-proprietary Edmark single-phase pulse
as illustrated below. This
was in response to the emerging demand for AED but the use of
rechargeable battery for energy made it inconvenient for public use.
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| Edwark, Single Phase Pulse defibrillation waveform used by monophasic CardioLife TEC-2200K series in 1997 |
The monophasic output discharge waveform shape is shown below.
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| CardioLife TEC-2200K mono-phasic output waveform recorded on a strip chart dated April 1995 |
Tokyo was unaware biphasic defibrillation was already taking hold worldwide in 1997.
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.
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| 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; HP was showing the way what Nihon Kohden should also do.
With such a major change in the international market, there
was therefore zero interest in the monophasic TEC-2200 series
defibrillators offered by Nihon Kohden and the products had to be withdrawn from exporting.
| Global Demand for Biphasic Technology caught Nihon Kohden by surprise |
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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 meant the company's
defibrillator development team was helplessly doing nothing. 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.
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| The Cardiac Science STAR biphasic waveform was validated in accordance with US FDA guides for Safety and Effectiveness |
| The Acti-Biphasic defibrillation shock waveform was done in a hurry |
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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.
| Unsuspecting Customers were sold Unproven Defibrillators |
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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 customers were sold unproven defibrillators by taking advantage of their good faith, because 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 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.
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| Acti-Biphasic defibrillators started to be exported from 2002 |
| The company only started selling Acti-Biphasic defibrillators in Japan from December 2005 |
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After a long period of three years for Japanese Regulatory Authority approval, NIHON KOHDEN was finally able to announce the launch of TEC-7700 series defibrillators for sales in
Japan market on December 1st, 2005.
| CardioLife TEC-7700K series defibrillators were the last to use the Acti-Biphasic discharge output for export |
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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?
The "Acti-Biphasic" TEC-5500 series defibrillators started to be exported from August 2004, more than a year before the TEC-7700K series defibrillators were allowed for sales in Japan.
The shape of the discharge envelope is different from the TEC-7700K series defibrillators. It is a version that is flipped vertically upside down from that of the TEC-7700K series defibrillators! This was not officially announced at the
time of launch.
Unlike the TEC-7700K series defibrillators, there was not the slightest clinical evidence to support its use.
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| CardioLife TEC-5500K series started to be exported from August 2004 |
| The Timeline |
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| Export of CardioLife TEC-5500K series started in August 2004, more than one year before Japan MHLW actually approved the TEC-7700 series |
| A top prestigious University Hospital in Taiwan |
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