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STANN for Foetal Monitoring - transcript
From 23rd Annual Society for Maternal-Fetal
Medicine (SMFM) Conference held in San Francisco, California - February
2003
STANN for Foetal Monitoring
Karl Rosen, MD interviewed by Hans van der Slikke, MD, PhD
Hans van der Slikke, MD, PhD: “We are at the Society for Maternal Foetal Medicines meeting in San Francisco, February 2003. Next to me is Karl Rosen from Gothenburg, Sweden. Welcome!”
Karl Rosen, MD: “Thank you, Hans.”
Hans van der Slikke, MD, PhD: “Well; I can say that you're a little bit
the man of the STANN.”
Karl Rosen, MD: “I should hope so after more than thirty years, I think I can claim that.”
Hans van der Slikke, MD, PhD: “Yes, and talking about foetal monitoring, this is the most recent, you have been working with for more than thirty years, but it's now, in recent years, that it becomes a real option.”
Karl Rosen, MD: “Yup. Today we have about 200 STANN monitors out there in more than 100 European hospitals, with more than 1,000 colleagues being certified and, hopefully, understanding the principles and the physiology behind what we are trying to achieve. And, then we just completed a large European two-year program of 8,000 deliveries, fully monitored, and we can now see how the population seems to benefit from this technology. In particular, obviously, back home in Gothenburg, I wouldn't be sitting here unless I would know that it would work back home.”
Hans van der Slikke, MD, PhD: “I understand. First, before we talk about the results of the trials, could you explain in a few words again the essentials of the STANN?”
Karl Rosen, MD: “The essential is that we are now combining heart rate with what we call ST-wave form analysis of the foetal electrocardiogram and it's adding a tool, which provides direct information on how the foetal heart is managing the stress of labour. As we know, labour is a stress and the foetal heart isn't very well equipped to meet with the challenges. So then over the years from experimental work, we have shown that when glycogen, the sugar that is stored in the foetal heart, is being utilised because of chemical agents, because of hypoxia developing, then we see a rise in T-wave and there is a T/QRS-ratio, a digital figure, that we can monitor and can look for trends and we are allowing a computer to go into and interpret what takes place. And then, obviously, there are the clinical guidelines that have been developed for about fifteen years and with the aid of the computer; people now seem to be able to follow these guidelines pretty accurately.”
Hans van der Slikke, MD, PhD: “And you told as well that the big change came now with the new Pentium processors so that the computer could do some part of our work.”
Karl Rosen, MD: “Yes, I mean, as you can imagine, we are talking about very tiny microVolt changes and in a situation where the mother and the foetus may be moving around a bit, so it's a rather sensitive signal and you have to have very good engineering capacity to develop the tools required to make it work, sort of 95% of the time in labour, which is now the case, even in second-stage labour, and when the mother is up and running and doing whatever she likes, there are no limitations on that one.”
Hans van der Slikke, MD, PhD: “And what are the results now of this most recent European study?”
Karl Rosen, MD: “Well, it was after the Swedish randomised trial that was published in
The Lancet in August 2001 we could demonstrate a reduction in what we call metabolic acidosis in the cord artery and we could see less operative interventions. Just the other week, in the January issue of the American Journal, we published the neonatal outcome and you may say, that probably is the most important aspect: could we reduce the risk of term infants being affected and showing neurological symptoms as a consequence of a diverse outcome of labour? Yes, we could. We reduced that from 3.3 per 1,000 to 0.4 per 1,000, and I believe that is the first randomised trial within foetal monitoring showing an impact on neonatal outcome, which is quite significant.
Now, then there is the issue, how could this technology be implemented in routine care? I went to Brussels some years ago and obtained funding setting ten centres of excellence up across Europe; Finland in the north and Italy down in the south and so we worked that program for two years. We had 8,000 deliveries fully monitored, and we can look at the outcome and actually, over the last year, we had one year where the technology is being introduced because nothing happens by itself, it's a gradual process and people need the time to earn the experience and earn the trust in the technology. After this year, we've seen achievements, which are even better than we saw in the Swedish randomised trial during the second phase of the trial, when those within the trial had earned their experience and trusted the technology.
Still, there are obviously things one can probably improve even further and that is now something I'm working on in the next year program. So there is a continual line of developments taking place, but we have a very good basis on which to found and where to start new developments and, today, there is a substantial number of hospitals and clinics using it and they're providing good feedback.”
Hans van der Slikke, MD, PhD: “Does STANN make it possible to work without foetal blood sampling?”
Karl Rosen, MD: “Well, we just completed an analysis together with our colleagues in Berlin, who are the ultimate experts, as you may know, on foetal blood sampling and obviously examples have been taken while after STANN has been signalling and, if that is the case, we see low PHs being recorded. I think if we say that we want to have continuous information in a situation of stress, in particular, second stage labour, then as we see the data today, there is nothing to beat this STANN concept. We don't miss anything. In fact, there are situations where foetal blood samples may say a normal reading, where the STANN says it's not normal, where the STANN tells the truth. So it has to do with the physiology behind the change in PH and so on.”
Hans van der Slikke, MD, PhD: “That comes later, the changing?”
Karl Rosen, MD: “Yes, but I'm very pleased with the sensitivity and the specificity of the system now that we have more than 14,000 deliveries, term deliveries in active labour, fully monitored with full outcome data.”
Hans van der Slikke, MD, PhD: “And is there a comparison with foetal pulse oximetry?”
Karl Rosen, MD: “There's only been one little study conducted in the Czech Republic on that issue, where the small number, but the STANN had the highest sensitivity than the
SP02.”
Hans van der Slikke, MD, PhD: “That is a small study.”
Karl Rosen, MD: “It is small, but there are some studies, in particular, in Prague going on at this point in time.”
Hans van der Slikke, MD, PhD: “So, altogether, we seem to come closer to an ideal way of monitoring the foetus during labour.”
Karl Rosen, MD: “Well, we still need to put in electrodes on the foetus, a scalp electrode. Whether we will be able to get away from that, I'm not sure at this point in time, but clearly, yes, that would be fantastic if that could be achieved even. But today I am quite pleased with what is being done and we can see how it improves neonatal outcome.”
Hans van der Slikke, MD, PhD: “Thank you
very much, Karl.”
Karl Rosen, MD: “Thank you.”
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