title: Pharmacokinetics from multiple intraosseous and peripheral intravenous site injections in normovolemic and hypovolemic pigs.
abstract: OBJECTIVE
  To examine: a) the rate and extent of delivery of radioactive tracers to the central circulation from the tibial, medial malleolar, distal femoral, and humeral intraosseous sites, as well as from a peripheral intravenous site; and b) the end-tidal CO2 response to injected sodium bicarbonate at these sites.
  
  
  METHODS
  Prospective, descriptive study.
  
  
  METHODS
  Animal laboratory at a university medical center.
  
  
  METHODS
  Twenty anesthetized and mechanically ventilated piglets were cannulated with 18-gauge bone marrow needles at intraosseous sites and 22-gauge Teflon catheters in peripheral veins. A 22-gauge angiocath was placed in the right carotid artery of each subject. Drug kinetics were studied in the normovolemic and hypovolemic (acute bleeding of 25 mL/kg) states.
  
  
  METHODS
  Sodium bicarbonate (1 mEq/kg) was injected into each of the three intraosseous and one intravenous sites with simultaneous monitoring of end-tidal CO2. A 10-min period for stabilization was allowed between injections. Aliquots of 99mtechnetium were injected at randomly selected sites and blood samples were obtained at 1.5-sec intervals via carotid artery for radioactive counts. Experiments were repeated after withdrawal of 25 mL/kg of blood.
  
  
  RESULTS
  Assessment by end-tidal CO2 monitoring after 1-mEq/kg injections of bicarbonate demonstrated a mean initial end-tidal CO2 increase at 12.8 secs and a mean maximal end-tidal CO2 increase of 8 torr (1.06 kPa), with no significant site differences noted. Radioactive tracer injections were detected in the carotid artery after 15.4 secs in normovolemic animals and after 21.4 secs in hypovolemic animals, with no significant site differences detected. The proportion of injected tracer at 2, 5, 10, 20, 30, and 40 mins identified no significant differences between various intraosseous and intravenous sites.
  
  
  CONCLUSIONS
  Our study demonstrated similar rapid transit and proportion of bicarbonate and radioactive tracers, reaching the central circulation from multiple intraosseous sites and a peripheral intravenous site. This finding suggests that adjustments in drug dosage may not be required, using various intraosseous locations as an alternative to peripheral intravenous drug therapy.
authors.affiliation: Department of Pediatrics, University of Western Ontario, London, Canada.
authors.forename: D W
authors.initials: DW
authors.lastname: Warren
authors.forename: N
authors.initials: N
authors.lastname: Kissoon
authors.forename: A
authors.initials: A
authors.lastname: Mattar
authors.forename: G
authors.initials: G
authors.lastname: Morrissey
authors.forename: D
authors.initials: D
authors.lastname: Gravelle
authors.forename: M J
authors.initials: MJ
authors.lastname: Rieder
mesh_terms: D000818:Animals; D001775:Blood Circulation; D001944:Breath Tests; D002245:Carbon Dioxide / Q000032:analysis*; D002406:Catheterization, Peripheral; D005069:Evaluation Studies as Topic; D007205:Indium Radioisotopes / Q000097:blood / Q000493:pharmacokinetics*; D017148:Infusions, Intraosseous / Q000379:methods*; D007262:Infusions, Intravenous / Q000379:methods*; D012769:Shock / Q000097:blood / Q000503:physiopathology* / Q000628:therapy*; D017693:Sodium Bicarbonate / Q000097:blood / Q000493:pharmacokinetics*; D013552:Swine; D013556:Swine, Miniature; D016284:Technetium Tc 99m Pentetate / Q000097:blood / Q000493:pharmacokinetics*; D013990:Tidal Volume; D013997:Time Factors
chemical_list: D007205:Indium Radioisotopes; D002245:Carbon Dioxide; D017693:Sodium Bicarbonate; D016284:Technetium Tc 99m Pentetate