Final Report > Chapter 20: Understanding and Assessing the Quality of Clinical Care in Bristol > The Inquiry's independent assessment of the quality of the PCS service in Bristol > Mortality

Mortality

21 As regards the statistical analysis, the Experts' principal finding was that:

`The single most compelling aspect of the data is the magnitude of the discrepancy between the outcomes observed at Bristol and those observed elsewhere. For children aged under one year undergoing open surgery between 1988 and 1994, the observed mortality rate at Bristol was roughly double that observed elsewhere in 5 out of 7 years. While the national trend over this period was for mortality rates to fall substantially, no such trend was seen in the Bristol results. In spite of the many flaws in the data sources, we do not believe that statistical variation or any systematic bias in data collection can explain a divergence of this magnitude. We therefore conclude that there is strong evidence of divergent performance at Bristol in the areas identified above, and we believe that the imperfections of the data do not cast serious doubt on these conclusions.' [23] They concluded further that a substantial and statistically significant number of excess deaths, between 30 and 35, occurred in children under 1 undergoing PCS in Bristol between 1991 and 1995. As is clear in their report, `excess deaths' is a statistical term which refers to the number of deaths observed over and above the number that would be expected if the unit had been `typical' of other PCS units in England. The term does not refer to any particular child's death. The `excess' mortality over the period 1991-1995 was probably double the rate in England at the time for children under 1, and even greater for children under 30 days. We accept our Experts' conclusions.

22 This higher mortality rate in Bristol was not restricted to the neonatal Switch and AVSD operations. As our experts told us, even without taking these two higher risk groups into account, there was considerable evidence of divergent performance in Bristol. Moreover, differences in mortality rates could not be accounted for on the ground of case mix. Importantly, 25% of the excess mortality was accounted for by those whose operations were concentrated just prior to the first birthday. The statistical evidence which we received suggests that surgery may have been delayed, and this observation is supported by other evidence. Witnesses told us that children were not always treated when they needed to be. [24] We have come to the view that, having been delayed, children were scheduled (or squeezed in) just before they fell outside the qualifying age group, so as to maintain Bristol's designation as an SRS, in other words for reasons of status as much as for any financial reason. We note further our Experts' observation that in other centres there was a trend over time towards a reduction in the rate of mortality. This did not happen in Bristol. We note a failure to progress, rather than necessarily a deterioration in standards. Such a failure is much more difficult to identify and, if identified, far easier at the time to explain away.

23 Despite this objective, retrospective evidence, our Experts were anxious to caution that:

`Clearly there is a consistent and on-going pattern of poor outcomes (from the CSR data) but it is difficult to know what weight should have been put on these data at the time (our emphasis), with there being questions over the data quality and with inadequate statistical tools to adjust for case mix and to analyse accumulating data from many different centres.' [25]

There was no one, nor any group, with the specific responsibility of examining such data and making known any findings, either within the UBHT or outside. The Society of Cardiothoracic Surgeons of Great Britain and Ireland certainly did not perceive that it had any such responsibility. We note that Mr Julien Dussek told the General Medical Council that in his capacity as Secretary to the Society from 1990 to 1995:

`I rarely made any check on the forms other than to ensure that the columns were correctly filled in. On one occasion I did write back to a particular unit to check that their mortality figure was low (and it was) although I never wrote to confirm that a mortality rate was particularly high.' [26]

He stated that: `... at no time did the subject of Bristol ever come up at our Executive meetings or our Annual Business Meetings.' [27] We note that the approach of the Society has since changed. The Society decided that from April 1997 `surgeon-specific outcome data' would be returned and that the `President of the Society will seek clarification from any surgeon whose performance lies outside pre-defined limits. ... If concerns persist ... the Medical Director of the Trust will be contacted and the Society will provide, in conjunction with the Royal College of Surgeons, a discrete and supportive external review.' [28] At the time, however, the explanations offered by the clinicians to themselves and others went unchallenged. Mr Wisheart thought that his bad results in AVSD were explained by a run of unusually complex cases. As regards the neonatal Switch, Mr Dhasmana thought the explanation lay in a combination of the learning curve, surgical technique, organisation of the staff in the operating theatre and pre- and post-operative management. [29]

Footnotes

[23] See Annex B, 4a: Spiegelhalter D, et al. `Overview of statistical evidence presented to the Bristol Royal Infirmary Inquiry concerning the nature and outcomes of paediatric cardiac surgical services at Bristol relative to other specialist centres from 1984 to 1995.' September 2000. Dr Spiegelhalter, et al. state: `Particular emphasis was placed on the analysis of data from 1991 to 1995, since data were available for that period from both of the national data sources'. See also Annex A Chapter 19

[24] See Annex A Chapter 12 on waiting times

[25] See Annex B, 6c and 7f

[26] GMC 0014 0093 Mr Dussek

[27] WIT 0067 0011 Mr Dussek

[28] WIT 0163 0002 Mr Keogh

[29] WIT 0084 0113 Mr Dhasmana