Multiple intraosseous sites versus peripheral intravenous sites in a pig model comparison of drug pharmacokinetics - abstract

The pharmacokinetics of injected sodium bicarbonate and radioactive tracers were studied from various intraosseous (IO) sites and a peripheral intravenous (IV) site. Anaesthetised piglets (12-23kg) were catheterised with peripheral 22-gauge IV catheters and 18-gauge bone marrow needles in the medial malleolar, tibial, femoral and humeral IO sites. Standardised aliquots of NaHCO3, (1meq/kg) and Tc-99m DTPA (600 micro-curies) were injected at randomly selected sites. The initial time and maximal level of CO2 rise after NaHCO3 injected were monitored using an end tidal CO2 monitor. The initial time to reach, and proportion of injected tracer in the central circulation were determined using radioactivity counter measure of carotid blood samples drawn at 1.5 second intervals for 1 minute and at 2, 5, 10, 20, 30, and 40, minutes. The following kinetics were determined: SAS analysis by ANOVA. KINETICS - DTPA time to carotid (sec); Tracer amount/Total dose (percentage total dose; Initial CO2 rise (sec);Maximal CO2 rise (mmHg);- IV - 12.8, .032, 12.8 9.6 respectively; HUMERUS - 12.0, .048, 12.0, 8.4 respectively; FEMUR - 13.5, .035, 12.6, 8.1 respectively; ANKLE - 18.6, .037, 13.6, 7.3 respectively; TIBIA - 17.3, .033, 12.9, 12.9 respectively. There was no statistically significant difference (p>.05) in the following: 1) Time of initial expired CO2 rise, 2) Maximal expired CO2 rise, 3) Time of tracer to reach the central circulation from IO and IV sites. Our study suggests: (1) IO and IV sites are similarly rapid means of injection delivery to the central circulation, (2) adjustments in dosages of medication may not be required to achieve the same IO effects as IV injection (AU)