The ability to deliver large volumes of intravenous (IV) fluids may be critical to the successful prehospital resuscitation of hypovolemic patients. We compared the time required to deliver one liter of crystalloid solution, using an administration set-up consisting of a 16-gauge (g), 1.25 inch, intravenous cannula, a pneumatic pressure bag, and either conventional intravenous tubing (3.2 mm internal diameter [ID]) or large bore (4.4 mm internal diameter [ID]) "shock" tubing. With the fluid bag positioned at 110cm (46 inches) above the level of the cannula, the mean elapsed time to deliver 1,000ml using the conventional tubing set-up was 6.0 minutes, while the same volume could be delivered in only 2.7 minutes with the shock tubing configuration. This time was reduced to 1.8 minutes when the intravenous cannula size was increased to 14g. By attaching a liter of fluid to each arm of the "Y" adapter of the shock tubing, virtually uninterrupted fluid flow may be maintained at this rate. We feel this intravenous configuration could enhance greatly the ability of paramedics to provide fluid resuscitation in the field setting. When such IVs are established en route to a receiving hospital, this technique may prove to be an important adjunct to improving patient outcome from hypovolemic shock.