Erratum

ERRATUM

The following author’s reply appeared in the October 2000 issue of the Journal without the original letter of comment.

Sepsis and the systemic inflammatory response syndrome
2000; 45 (3): 178-82

Sir: We agree that the concept and need to define sepsis and SIRS as described in Dr Paterson and Professor Webster’s review but wish to comment on the definition of SIRS proposed by the American College of Chest Physicians and American Society of Critical Care Medicine.¹ The definition relies on easily measurable clinical parameters and it therefore fulfils the intention to aid early diagnosis and therapeutic intervention1 but it is too broad and inadequate for research purposes.

While attempting to define and quantify the inflammatory response to AAA surgery (research in progress) we have observed a large variation in the magnitude of clinical response in those patients who according to this definition would be classified as SIRS(+). In our own series, 72% of patients were SIRS(+), ranging from one episode of tachycardia and tachypnoea during the whole postoperative period to a swinging pyrexia with tachycardia and raised WCC for several days. On the other hand, leukocytosis associated with pyrexia under 38.00C but not tachycardia or tachypnoea would not count as SIRS. Categorising patients as simply SIRS(+) or SIRS(-) is not sufficiently discriminatory for comparative studies after major surgery. Moreover, many medical conditions independent of the inflammatory process may affect the parameters measure for SIRS, e.g. pulmonary oedema due to fluid overload will usually present with tachypnoea and tachycardia. Unfit subjects may develop tachycardia to the least stress while those on beta-blockers may not respond with tachycardia at all. Assessing SIRS using the above clinical definitions can therefore be difficult and inaccurate. Measuring systemic inflammatory mediators as described in the above review and by others² may be a better way of quantifying and differentiating inflammatory from non-inflammatory conditions.³

While the currently available definition of SIRS¹ is a useful clinical indicator of the inflammatory response to insult, it needs to be developed in to a more discriminatory scoring system consisting of clinical and biochemical parameters if it is to be used as a valuable research tool.

REFERENCES

American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference. Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. Crit Care Med 1992; 20: 864-74
Gabay C, Kushner I. Acute-phase proteins and other systemic responses to inflammation. New Engl J Med 1999; 340: 448-54
Gosling P. Microalbuminuria: a marker of systemic disease. Br J Hosp Med 1995; 54: 285-90

L. WOLOWCZYK AND P.M. LAMONT
Bristol Royal Infirmary, Bristol, U.K.

Author’s reply

The comments of Mr Wolowczk and Mr Lamont are, of course, pertinent. The consensus definitions of sepsis and systemic inflammatory response syndrome (SIRS) were necessary because of the increasing numbers of trials in patients with an infection. Most of the therapeutic compounds being tested at that time had been shown to be effective in either an endotoxin or live bacteria infusion models of septic shock in animals. It was, therefore, generally believed that these compounds would be most efficacious in patients who had sepsis. At the same time it was appreciated that some patients who appeared to have an infection undoubtedly did not. There is no specific treatment for SIRS unlike sepsis where at least antibiotics would not be expected to be of some value.

While on can argue about the merits of the particular values which dictate the presence of either sepsis or SIRS according to the definition, I do believe that it has been useful to have agreement in what constitutes an abnormal situation. Prior to the definitions, patients were enrolled in to sepsis studies with slightly differing criteria - for example pyrexia greater than 38.50C rather than 38.00C, or white count greater than 10 rather 12 x 109/l. While these are only small differences it is useful to have agreed entry criteria between similar studies since it allows easy comparison at least of the controls. The same arguments apply for the multitude of organ dysfunction scores that are currently in use.

As is suggested in the letter SIRS is an inflammatory insult in many cases and clearly some clinical interpretation of the definition is required. I also agree that there are other methods to assess minor inflammatory responses. There are problems with all such definitions and scoring systems and re-evaluation is always needed. For instance I often get SIRS when walking up a flight of stairs. More seriously, as far as I am concerned, according to the APACHE II score I also have a defined mortality risk during my intensive care ward round since I now qualify for age points.

N.R. WEBSTER
Aberdeen Royal Infirmary, Aberdeen, U.K.