Letters

Pre-hospital deaths from accidental injury

BMJ 1994; 309 doi: https://doi.org/10.1136/bmj.309.6946.57 (Published 02 July 1994) Cite this as: BMJ 1994;309:57

EDITOR, - In their article assessing the preventability of deaths from injuries, L M Hussain and A D Redmond present convincing evidence that some accident victims are dying because of ignorance about basic airway management at the scene.1 However, their assessment that death was preventable in at least 39% of those who died from accidental injury before they reached hospital is tenuous.

Their assessment is based principally on the fact that 46 of 152 patients who died before reaching hospital had an estimated survival probability greater than 50%. The probability estimates for the survival of these patients were based not only on calculations on data that are over 30 years old, as the authors state, but also on Bull's data, which were collected only for deaths in hospital.2 Bull explicitly excluded pre- hospital deaths from his calculations. Even allowing for the likelihood that survival probabilities are higher now than 30 years ago when the data were collected, it is difficult to see how “Bull's probits” relating age and injury severity score to the chance of survival after reaching hospital alive in 1961 relate to the chance of surviving until reaching hospital in 1987–90.

The authors also claim that, excluding inevitable deaths in patients with injury severity scores of 75, those who died before reaching hospital were not more seriously injured than those who died in hospital. This is not true (X25=16.2, P=0.005).

In trauma research the practice of using “norms” or “standards,” whether from England 30 years ago or, more commonly, from America 10 years ago, is widespread. Although these norms may provide a useful tool for audit, they cannot be used in research for measuring effectiveness.

Author's reply

  1. J Nicholl,
  2. A D Redmond
  1. Medical Care Research Unit, University of Sheffield, Sheffield S1 4DA North Staffs Trauma Centre, Stoke on Trent ST4 7LN.

    EDITOR, - I share Jon Nicholl's (and others') criticisms of mathematical models for predicting outcome from injury. Nevertheless, there is no truly objective alternative, although groups across Britain are working on discovering one.

    We observed that the injury severity scores of those who died of their injuries before reaching hospital did not suggest that immediate death was inevitable. Accepted wisdom had hitherto assumed that those who died so early from their injuries must have incurred injuries so severe that death was inevitable. The injury severity scores indicated that only a fifth of those who died before reaching hospital had injuries incompatible with life. The profile of the remainder was not dissimilar to that of those who died in hospital, although we did not investigate this difference further. Our study was focused on those who died before reaching hospital. Nevertheless, I appreciate Nicholl's efforts in providing further statistical analysis of this aspect of our study, but his findings are not central to the main theme of the paper.

    We showed successfully that the death of those who died before reaching hospital was potentially preventable in many cases. Moreover, death might have been averted by simple first aid protection of the airway. It was the observation that airway obstruction was a factor that led us to the earlier work of Yates, who had also investigated airway patency in fatal accidents and used Bull's probits to predict outcome.1 Our concerns about using this technique were expressed in the paper, but the lack of any modern British alternative highlights the paucity of work.

    Nicholl agrees that norms can provide a useful tool for audit and so presumably supports our use of them in this audit of pre-hospital deaths. We made no claims with regard to effectiveness.

    We identified a group of patients thought to have been unsalvageable but who might have been saved. We were careful in the paper to identify the speculative nature of giving a total of preventable deaths, but 14 patients had injuries that would not have been classified as major trauma and many others had injuries, though serious, that would not normally be associated with a fatal outcome.

    Continuing concerns about statistical methods used to predict outcome from injury must not be allowed to divert attention from the indisputable findings that pre-hospital deaths from injury are not inevitable and that at least some can be prevented by simple first aid measures.

    References

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