Impact of noninvasive studies to distinguish volume overload from ARDS in acutely III patients with pulmonary edema: Analysis of the medical literature from 1966 to 1998

Study objective: To assess the impact of substituting noninvasive diagnostic studies for Swan-Ganz catheter (SGC) placement in the evaluation of acutely ill patients. Design: Modified decision analysis. Methods: Using published studies that define effectiveness of clinical examination, echocardiography, and SGC placement to diagnose pulmonary edema, an analysis of the impact of substituting three diagnostic approaches using (1) clinical assessment (CA), (2) M-mode two-dimensional transthoracic echocardiography (EC), or (3) CA then EC if necessary for SGC placement was considered. Study population: Patients with acute respiratory distress and radiographic findings of pulmonary edema, and ICU patients with hypotension and/or pulmonary edema without acute cardiac ischemia. Interventions: Three approaches using noninvasive studies were substituted for placement of SGC in the initial evaluation of pulmonary edema. Measurements and results: The number of SGCs placed, the number of tests needed to diagnose (NTND) all eases of volume overload, and the total number of procedure-related adverse events were calculated for each diagnostic approach and compared to SGC placement. EC, and CA then EC approaches produced fewer procedure-related serious complications and deaths, compared to the SGC approach; however, these approaches also produced a higher NTND and total procedures performed than did the SGC or CA approaches. The CA approach led to reduced NTND and procedure-related adverse events. Conclusions: Substituting noninvasive studies for SGC placement in the initial evaluation of acutely ill patients may slightly reduce procedure-related adverse events, but it may also increase the number of procedures performed. Studies of SGC use are warranted and need to include a clinical assessment control group and an analysis of resource utilization.