Context: Measurement of pulsus paradoxus (PP) is one of
several measures previously advocated in the National Heart, Lung, and
Blood Institute asthma management guidelines: a pulsus of > 12 mm Hg
warranted hospital admission. It is one of only a few measures that is
not effort dependent and therefore important in the evaluation of
patients with asthma.
Objective: Determination of
physician accuracy in measuring PP.
Design: A model of
induced PP in a trained healthy subject without respiratory disease was
constructed with a fixed inspiratory resistance with measurement of
inspiratory air pressure and beat-to-beat BP noninvasively.
Attending physicians from emergency medicine and critical care
disciplines who served as consecutive examiners of the trained
reference subject generating known PP.
A total of 19 attending physicians were assessed for ability in
measuring PP by sphygmomanometry and by palpation. The reference
subject generated 4° of PP sequentially, with each examiner blinded
to the value of negative inspiratory pressure and PP. Examiners first
assessed PP qualitatively by palpation, followed by its measurement
within 2 min.
Main outcome measure: Proximity of
physician-measured PP (PPm) to true PP (PPt).
Results: At inspiratory pressures of − 10, − 15,−
20, and − 25 mm Hg, PPt was 13.7, 16.2, 19.1, and 20.7 mm Hg,
respectively (F = 14.8, p < 0.0001; analysis of variance[
ANOVA]). At the same pressures, PPm was 13.1, 17.5, 17.7, and 18.0
mm Hg (p > 0.10; ANOVA). Linear regression of PPm against PPt for
each examiner revealed a slope (SE) of 0.53 (0.23), and not a 1:1
Conclusions: Past and present guidelines
do not account for the challenges in measuring PP, especially in
tachypneic patients. Sphygmomanometric determination of PP should be
augmented by new aids developed through technological