title: Evaluation of intraosseous pressure in a hypovolemic animal model.
abstract: BACKGROUND
  In emergent situations, access to the vascular bed is frequently required for fluid and medication administration. Central venous catheter placement is associated with risk and may slow resuscitation in the unstable patient. The purpose of this study was to determine whether intraosseous pressure (IOP) could be consistently recorded and how similar this pressure was to central venous and arterial pressure in a porcine hemorrhagic shock model.
  
  
  METHODS
  After sedation, eight female swine had catheters placed in the femoral vein, aorta via femoral artery, and superior vena cava. IOP lines were placed in the proximal humerus, distal femur, and proximal tibia. Pressure readings were recorded continuously through the five stages of progressive hypovolemia. Pressure data were descriptively summarized, with the percent of change of IOP at each stage compared with arterial pressure using a multilevel mixed effects linear model with log transformation.
  
  
  RESULTS
  The IOP baseline values were between 16 and 18 mm Hg, approximately 22% of baseline arterial pressure. The intraosseous (IO) waveform mostly closely resembled the arterial pressure waveform, including the presence of a dichroitic notch. Pressure variations caused by ventilation (respiratory variability) were also identified in all the tracings. The rate of pressure change in the humeral IO most closely matched the change in arterial pressure rate. IO blood gas analysis showed gas composition to most closely match venous blood.
  
  
  CONCLUSIONS
  IOP was reliably obtained in this porcine model and suggests potential for clinical application in humans.
authors.affiliation: Department of Emergency Medicine, Regions Hospital, St. Paul, MN.
authors.forename: Ralph J
authors.initials: RJ
authors.lastname: Frascone
authors.affiliation: Critical Care Reseach Center, Regions Hospital, St. Paul, MN. Electronic address: Joshua.g.salzman@healthpartners.com.
authors.forename: Joshua G
authors.initials: JG
authors.lastname: Salzman
authors.affiliation: HealthPartners Institute for Education and Research, Bloomington, MN.
authors.forename: Alex B
authors.initials: AB
authors.lastname: Adams
authors.affiliation: Home Healthcare Solutions, Philips Healthcare, Kennesaw, GA.
authors.forename: Peter
authors.initials: P
authors.lastname: Bliss
authors.affiliation: Critical Care Reseach Center, Regions Hospital, St. Paul, MN.
authors.forename: Sandi S
authors.initials: SS
authors.lastname: Wewerka
authors.affiliation: Department of Surgical Services, HealthPartners Medical Group, Bloomington, MN; Department of Surgery, University of Minnesota, Minneapolis, Minnesota.
authors.forename: David J
authors.initials: DJ
authors.lastname: Dries
mesh_terms: D000818:Animals; D001011:Aorta; D001794:Blood Pressure / Q000502:physiology; D002405:Catheterization, Central Venous; D004195:Disease Models, Animal; D005260:Female; D005263:Femoral Artery; D005268:Femoral Vein; D020896:Hypovolemia / Q000503:physiopathology* / Q000628:therapy; D017148:Infusions, Intraosseous; D011312:Pressure; D012151:Resuscitation / Q000379:methods; D012771:Shock, Hemorrhagic / Q000503:physiopathology* / Q000628:therapy; D034421:Sus scrofa; D062666:Vascular Access Devices; D014683:Vena Cava, Superior
keywords: Blood pressure; Central venous catheter; Hemorrhage; Intraosseous; Shock