Wednesday, December 28, 2005
Community acquired pneumonia-Pneumonia severity index falls short
One of the operational rules of the medical-quality "thought leaders" is that "variation is bad" and it must be mitigated.(The borg has a similar philosophy and more effective implementation methods).According to an interesting and useful article by Marrie and Huang (American Journal of Medicine:118:1357,2005)marked variation in the admission rate for community acquired pneumonia(CAP) lead to the development by Fine et al of the pneumonia severity of illness(PSI) score as a guide to the admission decision. These AJM authors reviewed 3065 admissions in Edmonton with a diagnosis of CAP over a 2 year period. 586 (19.1%) were classified as "low risk" using the PSI. Was the hospitalization of " low risk" patients a shameless, thoughtless waste of precious medical resources? Apparently not. Almost half ( 48.4%) were sick enough to be in the hospital for more than five days.19% suffered one or more complications and 31% were still unable to ear or drink to maintain hydration by the fifth hospital day. Clearly the admitting physician's clinical judgment appropriately overruled the PSI score. Fine's classification system keys to mortality rate.Those in risk classes I to III have a < 1 % mortality rate.The authors point out that the PSI does not work if the patient has COPD or pulmonary fibrosis or HIV infection or immuno suppression, etc. etc. and there are important prognostic factors not captured by the Fine index including nausea,shortness of breath and diarrhea . Their final sentence is: " It is clear that low-risk patients are a heterogenous group and that a low risk for mortality is not the only factor to be considered in admission decisions".Fortunately for a significant number of patients with CAP, the admitting physicians used what seems to often elude guidelines and algorithms namely clinical judgement.Of course,low risk patients are heterogenous:patients are heterogenous-biological variability is what it is all about. All patients classified as having the same illness are not the same,patients do not all react to the same treatment in the same way.Our ability to figure everything out ahead of the facts as they unfold is very limited.Humans dealing with the human condition are doomed to have to improvise and be inventive and use judgement.Off-the-shelf rules do not and never will adequately cover all the contingencies that we face in medicine or for that matter in most everything else. Credit is due to the authors of the Emonton pneumonia critical pathway which seemed to have emphasized that "physician judgement should take precedence over guidelines" an insight seemingly unable to penetrate into the bean counter mentality.