Context Experienced clinicians' gestalt is useful in estimating the pretest
probability for pulmonary embolism and is complementary to diagnostic testing,
such as lung scanning. However, it is unclear whether recently developed clinical
prediction rules, using explicit features of clinical examination, are comparable
with clinicians' gestalt. If so, clinical prediction rules would be powerful
tools because they could be used by less-experienced health care professionals
to simplify the diagnosis of pulmonary embolism. Recent studies have shown
that the combination of a low pretest probability (using a clinical prediction
rule) and a normal result of a D-dimer test reliably excludes pulmonary embolism
without the need for further testing.
Objective To evaluate and demonstrate the accuracy of pretest probability assessment
for pulmonary embolism using clinical gestalt vs clinical prediction rules.
Data Sources The MEDLINE database was searched for relevant articles published between
1966 and March 2003. Bibliographies of pertinent articles also were scanned
for suitable articles.
Study Selection To be included in the analysis, studies were required to have consecutive,
unselected patients enrolled; participating physicians in the studies, blinded
to the results of diagnostic testing, had to estimate pretest probability
of pulmonary embolism; and validated diagnostic methods had to be used to
confirm or exclude pulmonary embolism.
Data Extraction Three reviewers independently scanned titles and abstracts for inclusion
of studies. An initial MEDLINE search identified 1709 studies, of which 16
involving 8306 patients were included in the final analysis.
Data Synthesis A clinical gestalt strategy was used in 7 studies, and in the low, moderate,
and high pretest categories, the rates of pulmonary embolism ranged from 8%
to 19%, 26% to 47%, and 46% to 91%, respectively. Clinical prediction rules
were used in 10 studies, and 3% to 28%, 16% to 46%, and 38% to 98% in the
low, moderate, and high pretest probability groups, respectively, had pulmonary
Conclusions The clinical gestalt of experienced clinicians and the clinical prediction
rules used by physicians of varying experience have shown similar accuracy
in discriminating among patients who have a low, moderate, or high pretest
probability of pulmonary embolism. We advocate the use of a clinical prediction
rule because it has shown to be accurate and can be used by less-experienced