Annex A > Chapter 14 - Care in the Operating Theatre and the `Learning Curve' > The `learning curve' > The Arterial Switch procedure
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The Arterial Switch procedure
The `learning curve' and the Arterial Switch procedure
`I believe that the reality of the learning curve may be illustrated by the evolution of surgery for transposition of the Great Arteries in this country ... in the late 80s and the very early 90s it was generally understood and accepted that when a unit introduced the Arterial Switch operation for neonates there would initially be a period of disappointing results.' [116]
100 Professor de Leval told the Inquiry:
`In the early 1980s we were balancing the early and the late risks, and one of the questions was, what kind of lower [sic] risk can you afford, assuming that the long-term results will be better? I do not think that question has been answered. The acute problem was the decision to deal with the learning curve. When we started the Switch operation, those who had started before us started with a mortality of - I mean, the person I am quoting is Jan Quaegebeur, who has become a master of the Switch, who started with a mortality of 25 per cent.
`... which, within a few years, came down to below 10 [per cent] and now, in his results, is probably about 2 or 3 per cent.' [117]
101 Mr Dhasmana told the Inquiry that his technique was derived:
`Mainly from Great Ormond Street but that was the same technique as you would be seeing in the books and by that time books had started really printing it out in the same way and also almost all publications at that time would come with techniques how to really do ... this was also a similar technique with Mr [now Professor] Yacoub, published in 1980. A similar technique was by Dr Jatene from Brazil in 1977/1978. So technique was there, I just took it on. It is not a new technique, I did not use any new technique.' [118]
102 Mr Dhasmana was asked about referring a patient elsewhere for a Switch operation rather than operating himself, in the following exchange:
`Q. If you had thought about it, you might have seen perhaps that because of the consequences of the learning curve ... that someone who had experience in the operations might well succeed in a difficult condition in the case of a patient who in your hands at the start might not survive the operation because of the underlying problems that the child suffered from and because of the lack of experience of the Unit; did you think of that and express that at all?
`A. Again we had that problem. We are talking in 1999 about the problem as was being seen in 1986 to 1988. I have already mentioned ... when you start as a consultant paediatric cardiac surgeon, a lot of operations you are doing for the first time.
`So you could really take that analogy to all those operations when you are starting, you know right in the beginning. You know if somebody else could have operated on, I wish that was possible and I wished nobody ... has to operate on somebody for the first time but unfortunately that was the practice at that time and I was just keeping up with the practice.
`Q. Does it follow that, if you had thought about it, you might have said to yourself, "There is Mr Sethia in Birmingham (or whoever) by 1988; that there are experienced surgeons elsewhere in the country dealing with this sort of operation; that if I take the first ten cases that come to me and if they are operated on by him or by somebody else then more of those children will live than if I carry out the operation myself". If you had thought about that, one of the consequences nowadays might be to transfer the child to another centre so that the operation can take place for the benefit of the child in that other centre, might it not?
`A. That is the case in the 1990s, yes, but that was not the case in 1988.
`Q. It is a consequence of what you are saying that a deliberate decision was taken within the unit by the unit as a whole to carry out or begin a series of operations which would lead to the death of children in Bristol who would not necessarily die elsewhere; that is the consequence of the decision that was taken, is it not?
`A. Whenever you are put on any complex case anywhere there is always that possibility that the child could survive elsewhere, how do you know whether he is going to survive here or there unless you have got very clear guidelines? Unfortunately at that time there were no clear guidelines so almost every surgeon was really doing the best available practice at that time and this is the reason you have a whole team to decide on.' [119]
103 Mr Dhasmana told the Inquiry that when he commenced the Arterial Switch programme at Bristol he anticipated that:
`... mortality would be higher than what you could achieve a few years later.' [120]
The Arterial Switch programme at Bristol
104 The Arterial Switch programme for non-neonates was introduced at Bristol by Mr Dhasmana in 1988. He stated:
`By 1988 this was a well-established procedure for the treatment of Transposition of the Great Arteries in the USA, Australia and a few centres in Europe. I was aware that a few centres in the UK, like GOS [Great Ormond Street], Harefield and Brompton, were using this technique in older children with TGA and VSD.' [121]
105 After discussion with colleagues in Bristol, Mr Dhasmana stated that he decided to start the Arterial Switch procedure given that:
- `I was familiar with the operation as I had assisted and looked quite a few [sic] of these patients operated on at the GOS, London during my term as Senior Registrar during 1982-1983.
- `I had kept myself well informed with developments in this field, having attended various courses, reviews of cine-films and read available published literature, giving details of techniques and various types of coronary arterial abnormality in this condition.
- `I considered myself experienced enough to deal with major operation[s] in this condition.
- `I was already using micro-vascular surgical techniques in dealing with coronary artery anastomosis in adult patients.
- `and, most importantly, I believed that anatomical repair by Arterial Switch was the right treatment for this condition in the long run, even though the conventional operation by Sennings repair carried lower mortality this procedure was only a physiological repair with uncertain long-term prognosis.' [122]
`Though there was a gap of about 5 years since the last operation, I had kept up to date on developments by attending courses and reading the literature available from various publications I was receiving. I believed that I followed the usual practice prevalent at that time, when embarking on a new procedure. I discussed the plan amongst colleagues ... and appeared to have their support. Dr Martin joined the cardiology team during the early part of this programme, in 1988, and provided necessary advice and help, as he had been closely involved with the Arterial Switch programme at the Harefield hospital. He also gave me a copy of a section of Dr Quaegebeur's thesis on the subject, which proved very helpful.' [123]
107 Mr Dhasmana stated that Dr Sally Masey:
`... was the only anaesthetist capable of helping me with this programme ... I believe she had experience of Arterial Switch operations during the period of her training at Brompton...' [124]
`The early results of the non neonatal switch operation were disappointing in that they were less good than the results at centres where the procedure was established at that time.' [125]
109 In January 1992, Mr Dhasmana started the Arterial Switch programme for neonates:
`... there were still no guidelines, or procedures for developing new operations, or for making major changes. However, more information from various publications and courses were becoming available on the subject i.e. Arterial Switches.' [126]
110 Mr Dhasmana stated that it was decided to proceed with the neonatal programme after a review of the 14 Switch operations carried out before mid-January 1992:
`It was felt that technical competence had been achieved and that anaesthetists, cardiologists, perfusionists and nurse teams had gained enough experience. Therefore all members of the team agreed, that the procedure had proved successful in the group of older switches ... Therefore, after consideration of all the issues, in the same way as in 1988, i.e. discussion with cardiologists and anaesthetists, it was agreed to develop this operative procedure with the neonate group.' [127]
111 In the neonatal Switch programme in the period up to September 1992 all five children died. [128]
`Evaluation of the disappointing results for this operation was made difficult because in addition to the expectation of the learning curve, the situation was confused further by the occurrence of a number of significant additional risk factors in either four or five of the nine neonatal switch patients who died ...
`There were a significant number of patients with additional abnormalities in this small series so that the real cause of death remains a matter of debate.' [129]
`Q. Was there at this stage anything in the way of what you would see as a learning curve taking place at Bristol?
`A. Certainly we looked at the first few cases and looked to see if there were any lessons there. Now whether that constitutes the learning curve or not I think it is very difficult to say. I think if you look, you know, just looking at the individual cases there were, the first case there was an unsuspected Coarctation of the Aorta [130] which we felt was a contributing factor.
`The second case, there were problems with thrombosis and infection and we were concerned there may be other factors that were important, if you like, other than the surgical expertise of doing the operation.
`So I think we looked at these cases individually. If we found what we thought was a reasonable reason for that patient's death then, if you like, that colours your view as to whether it is appropriate to carry on later.
`Q. I think the question I asked was whether you thought there was something of a learning curve or not. Did you?
`A. I think we thought that possibly was part of our learning curve, yes.' [131]
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Footnotes
[116] WIT 0120 0337 - 0338 Mr Wisheart
[117] T50 p.10 Professor de Leval
[121] WIT 0084 0110 Mr Dhasmana. See Chapter 3 for an explanation of these clinical terms
[122] WIT 0084 0110 Mr Dhasmana
[123] WIT 0084 0110 Mr Dhasmana
[124] WIT 0084 0111 Mr Dhasmana
[125] WIT 0120 0352 Mr Wisheart
[126] WIT 0084 0112 Mr Dhasmana
[127] WIT 0084 0112 Mr Dhasmana
[128] UBHT 0054 0081 `Neonatal Switches'
[129] WIT 0120 0352 Mr Wisheart; Mr Wisheart is referring to the series, not just the period up to September 1992