Am. J. Respir. Crit. Care Med.,
Volume 160, Number 6, December 1999, 2067-2071
Synchronization of Radiograph Film Exposure
with the Inspiratory Pause
Effect on the Appearance of Bedside Chest Radiographs in
Mechanically Ventilated Patients
PAUL B.
LANGEVIN,
VASHTI
HELLEIN,
SUSAN M.
HARMS,
WILLIAM K.
THARP,
C.
CHEUNG-SEEKIT,
and
S.
LAMPOTANG
The Departments of Anesthesiology and Electrical and Computer Engineering, University of Florida Colleges of Medicine
and Engineering, The Brain Institute, University of Florida, and The Veterans Affairs Medical Center, Gainesville, Florida; and
The University of Waterloo, Waterloo, Ontario, Canada
The appearance of portable chest radiographs (CXRs) may be affected by changes in ventilation,
particularly when patients are mechanically ventilated. Synchronization of the CXR with the ventilatory cycle should limit the influence of respiratory variation on the appearance of the CXR. This study
evaluates the effect of synchronizing the CXR film exposure with ventilation on the appearance of
the radiograph. Twenty-five patients who remained intubated postoperatively, were mechanically
ventilated, and required a CXR were enrolled in this triple-blind, randomized prospective study. Each
patient received one radiograph using conventional techniques and another using the interface. The
sequence of the two films was randomized, and the two films were taken on the same patient within
a few minutes of each other. Hence, each patient served as his own control and the position of the
patient, source-film distance, intensity (Kvp), and duration of the exposure (mAs) were identical for
the two films. Five board-certified radiologists were then asked to compare paired films for clarity of
lines and tubes, definition of the pulmonary vasculature, visibility of the mediastinum, definition of
the diaphragm, and degree of lung inflation. Radiologists were also asked to choose which films they
preferred. A majority of board certified radiologists preferred CXRs taken with the interface in 21 of
25 patients (p < 0.0001). Furthermore, four of the five criteria evaluated were improved (p < 0.05)
on synchronized CXRs. Synchronization of the bedside CXR with the end of inspiration ensures that
they are always obtained at maximal inflation, which improves the appearance of a majority of radiographs by at least one of five criteria. Langevin PB, Hellein V, Harms SM, Tharp WK, Cheung-Seekit C, Lampotang S. Synchronization of radiograph film exposure with the inspiratory
pause: effect on the appearance of bedside chest radiographs in mechanically ventilated patients.
