RESUMO
OBJECTIVE: The effectiveness of the intraosseous (IO) route for fluid resuscitation remains uncertain. This study compares IO infusion rates and estimated volume expansion using clinically relevant infusion pressures with lactated Ringer's (LR) and hetastarch (HES). METHODS: IO needles were placed in the sternum or tibia for infusion of HES and LR in 8 Yorkshire pigs. Pressures were recorded at variable flow rates and linear regression used to identify flow rates at 100 and 400 mm Hg. Volume expansion was calculated for a 10-minute infusion. RESULTS: Mean LR flow rates (mL x min(-1)) were 24/111 (tibia--100/400 mm Hg) and 8/34 (sternum--100/400 mm Hg). The HES flow rates (mL x min(-1)) of 10/44 (tibia--100/400 mm Hg) and 6/26 (sternum--100/400 mm Hg) were significantly lower or -40% (p < 0.01) of the LR flow rates into the tibia and -70% (p < 0.05) into the sternum. Mean volume expansion (mL) for a 10-min infusion of LR was estimated to be 80/369 (tibia--100/400 mm Hg) and 27/112 (sternum--100/400 mm Hg). In comparison, HES volume expansion was -20% higher for the tibia (p > 0.05) and 110% to 120% higher for the sternum (p < 0.05). CONCLUSION: HES flow rates are lower than LR flow rates in the sternum and tibia of swine. Sternal infusion of HES is likely to provide greater estimated intravascular volume expansion than LR despite the lower infusion rates.
