TEMPORAL PATTERNS OF RADIOGRAPHIC INFILTRATION IN SEVERELY TRAUMATIZED PATIENTS WITH AND WITHOUT ADULT-RESPIRATORY-DISTRESS-SYNDROME

We prospectively evaluated the patterns of pulmonary structural and functional changes in 100 consecutive surgical intensive care unit trauma patients who had (1) emergent major surgery, (2) a pelvic fracture, or (3) two or more major long bone fractures. For each patient, arterial blood gas measurements (ABGs), central venous pressure (CVP), pulmonary capillary occlusion pressure (PAOP), thoracic compliance, arterial oxygen tension/fraction of inspired oxygen (PAo2/FIO2), pulmonary venous admixture (Qs/Qt), and portable chest roentgenograms were sequentially tracked. The senior staff radiologist interpreted all chest roentgenograms. Pulmonary infiltration was quantitated in each of six fields using a scale ranging from 0 to 4, with 0 being no infiltration and 4 being the maximum. Adult respiratory distress syndrome (ARDS) was defined as follows: Qs/Qt greater-than-or-equal-to 20%, PAo2/FIO2 < 250 or both; dependence on mechanical ventilation for life support for greater-than-or-equal-to 24 hours; PAOP or CVP or both <20 mm Hg; and thoracic compliance <50 mL/cm H2O. Time zero (T0) the time of onset of ARDS, was defined as the time these criteria were met. Eighty-three of 100 study group patients had penetrating injuries, and 17 were admitted with blunt trauma. Fifty-one of 100 patients developed ARDS: 36 of 51 died. Only 4 of 49 (8%) patients without ARDS died. The injured lungs of patients with and without ARDS had similar amounts of infiltration over most measured time intervals. The noninjured lungs of the ARDS patients, however, had significantly greater infiltration than those without ARDS at T0 and over subsequent time intervals. Before T0, the total infiltration of the injured lungs was significantly greater than that for the noninjured lungs in both the ARDS and nonARDS patient groups (4.5 +/- 0.6 vs. 0.7 +/- 0.2 and 2.4 +/- 0.4 vs. 0.4 +/- 0.3, respectively). The infiltration in the injured and noninjured lungs in both groups converged at T0 and remained similar for several days. We conclude that pulmonary infiltration develops simultaneously with lung dysfunction in trauma patients with evolving ARDS. Densities associated with ARDS are first visible in the upper and middle lung fields.