医療における判断と不確定性

Abstract

Several characteristics of physicians'decision making are disucussed. As a model, history taking and the selection among various diagnostic/therapeutic strategies for a patient with probable common cold is analyzed. A decision tree analysis shows that the best choice wound vary from observation to order lab test and then to prescribe antibiotics, as the prior probability or the risk of pneumonia increases. Thus the quantitative assessment of the risk of pneumonia is required for each patient before choosing the best strategy. The series of initial questions followed by a short physical examination, such as an experienced physician would do, is probably the most efficient way of assessing the risk of pneumonia, although its would be very difficult for a physician to define his algorithm. The answer to the questions or the presence of signs revealed by physical examination has the same value in estimating the risk of pneumonia as a chest X-ray film or the result of a blood test. Thus, the efficacy of each question or sign in the differential diagnosis should be investigat ed to know precisely which questions are to be asked and which signs are to be examined. Unfortunately, the current health insurance system in Japan employs a per item payment policy and thus the length of time used in the interview or in the physical examination is not evaluated at all.This payment system leads physicians to order unnecessary tests and drugs, instead of allowing them to spend more time for hhistory taking or physical exam.The authoris afraid that physicians, who uses a battery of test results rather than the answers and signs, might forget the skill of constructing the most valuable algorithm.