Intraosseous Infusion: Pressure-flow Relationship and Pharmacokinetics

In order to quantitatively investigate the usefulness of intraosseous fluid and drug administration as a resuscitative modality, we studied the infusion flow rates of crystalloid solutions obtainable at varying infusion pressures into the bovine tibial medullary cavity and time to initial as well as 90% of maximal effect of intraosseously administered vasoactive drugs. Mean infusion rates ± SEM (n = 6) at 300, 200, and 100 torr and atmosphere + 81 cm H2O were 41 ± 2, 32 ± 1, 27 ± 2, and 10 ± 1 ml/min, respectively. The mean time (± SEM) to initial effect of intraosseous injections (n = 6) of either 0.5 mg epinephrine or 50 mg ephedrine was 17 ± 3 seconds and mean time to 90% of maximal effect was 45 ± 5 seconds. These results provide a quantitative basis for resuscitation by fluid and drug administration via the tibial malleolar intraosseous route and suggest that when performed in appropriate situations, the technique may have clinical utility.