The power of suggestion.

Broadly speaking, clinical decision support has always existed in medicine through tools clinicians create that help them make accurate, reliable, and efficient decisions. In the modern era, a clinical decision support system (CDSS) refers to “any electronic system designed to aid directly in clinical decision making, in which characteristics of individual patients are used to generate patientspecific assessments or recommendations that are then presented to clinicians for consideration.”1 In this issue of RESPIRATORY CARE, Bagga et al2 report on their use of a computerized prompt given to physicians entering ventilator orders for patients receiving volume controlled mechanical ventilation, and the impact that this intervention may have had on initial tidal volumes (VT) set by respiratory therapists at a tertiary care academic medical center. The intervention was a CDSS prompt (an on screen pop-up window) that appeared anytime a physician entered orders for mechanical ventilation. The prompt displayed the patient’s height, actual weight, and ideal body weight; 3 statements about the average, initial, and ideal VT for patients with/without acute lung injury; and 2 calculated VT values for 6 and 8 mL/kg of ideal body weight. Physicians entering orders were required to acknowledge the information provided by clicking on an OK button, which closed the window. The ordering provider could then order any VT of his choosing. The authors retrospectively compared 240 subjects before and after implementation of their tool. Twenty subjects were selected from respiratory care records that equally represented 6 adult ICUs in the before/after periods. ICUs were medically or surgically focused with general, cardiac, or neurologic patient populations. In their review, Bagga et al2 found a significant decrease in the initial delivered VT for subjects in two thirds of the individual ICUs and in their combined cohort (average decrease of 0.84 mL/kg of ideal body weight, P .001). They also found a significant decrease in the number of subjects ventilated at 10 mL/kg of ideal body weight in all of the ICUs following the introduction of this tool (20% vs 4%, P .003). Finally, they observed a reduction in variance of the delivered VT in two thirds of the ICUs. Unfortunately, it is impossible to tell from the retrospective study design and data provided if the intervention played any role in the observed reduction in VT. The authors did not provide evidence that the VT ordered by the physician was the same as the VT set by the respiratory therapist or that these changes occurred at the same time as implementation of the new CDSS. Without these data, a direct effect of the CDSS on ventilator VT has not been proven. The data presented reflect only an association between CDSS implementation and a change in clinical practice.