During a 3-yr period, 31 adult victims of severe traumatic shock were enrolled in a prospective randomized investigation of the relative effectiveness of dextran 70 vs. Ringer's acetate to treat shock and protect against trauma-induced adult respiratory distress syndrome (ARDS). Fourteen patients were given dextran 70 and Ringer's acetate to compensate for interstitial fluid loss, and whole blood as required; the remaining 17 patients received three to four times the total fluid volume of Ringer's acetate given in the former group, and whole blood as required.Hemodynamics improved significantly more rapidly in the dextran group. In the 7 to 8-day post-trauma period, no patient in the dextran group developed ARDS, compared to five cases of ARDS in the Ringer's acetate group. Also, the cardiac index of dextran patients was significantly higher, and patients challenged with 0.5 L of dextran 70 showed a significantly higher increase in cardiac index than those challenged with 2 L of Ringer's acetate. It is concluded that in the severely traumatized patient, a fluid program based on dextran 70 is superior to Ringer's acetate alone. Furthermore, patients should continue on a fluid program containing dextran 70 to counteract unrecognized, hypovolemia. Our results support the assumption that early aggressive shock treatment with dextran 70, followed by continued dextran administration in the post-trauma period might prevent complications such as ARDS.