Background: A trial of a decision-support tool to modify utilization of the coronary care unit (CCU) failed because utilization improved after explanation of the tool but before its actual employment in the trial. We investigated this unexpected phenomenon in light of an emerging theory of decision-making under uncertainty.
Methods: A prospective trial of the decision-support intervention was performed on the Family Practice service at a 100-bed rural hospital. Cards with probability charts from the acute ischemic Heart Disease Predictive Instrument (HDPI) were distributed to residents on the service and withdrawn on alternate weeks. Residents were encouraged to consult the probability charts when making CCU placement decisions. The study decision was between placement in the CCU and in a monitored nursing bed. Analyses included all patients admitted during the intervention trial year for suspected acute cardiac ischemia (n = 89), plus patients admitted in two pretrial periods (n = 108 and 50) and one posttrial period (n = 45).
Results: In the intervention trial, HDPI use did not affect CCU utilization (odds ratio 1.046, P > .5). However, following the description of the instrument at a departmental clinical conference, CCU use markedly declined at least 6 months before the intervention trial (odds ratio 0.165, P < .001). Simply in learning about the instrument. residents achieved sensitivity and specificity equal to the instrument's optimum, whether or not they actually used it.
Conclusions: Physicians introduced to a decision-support tool achieved optimal CCU utilization without actually performing probability estimations. This may have resulted from improved focus on relevant clinical factors identified by the tool. Teaching simple decision-making strategies might effectively reduce unnecessary CCU utilization.