title: Near-infrared spectroscopy-guided closed-loop resuscitation of hemorrhage.
abstract: BACKGROUND
  Endpoint resuscitation has been suggested as a better means to resuscitate penetrating injury. We performed computer-controlled closed-loop resuscitation using invasive cardiac output (CO) or noninvasive skeletal muscle oxygen saturation (SkMusSO(2)) via near infrared spectroscopy (NIRS).
  
  
  METHODS
  Conscious sheep received a 4.0-mm aortotomy and uncontrolled hemorrhage at t = 0 min (T0) while resuscitation started at T20 using lactated Ringer's solution.
  
  
  RESULTS
  The aortotomy rapidly decreased the mean arterial pressure (MAP) to approximately 30 mm Hg and CO to 20% to 30% of baseline. The SkMusSO(2) endpoint group required only half as much fluid through 4 hours of resuscitation as the CO endpoint group (34.9 +/- 8.4 mL/kg vs. 63.1 +/- 9.4 mL/kg). CO and MAP were lower in the SkMusSO(2) group after T60. Mean infusion volumes were 180% and 100% of the bled volume collected at autopsy in the CO and SkMusSO(2) groups. Brain and muscle oxygenation and base excess were as high or higher in the CO endpoint group.
  
  
  CONCLUSIONS
  Closed-loop resuscitation with either CO or SkMusSO(2) endpoints effectively performs fluid resuscitation of severe uncontrolled hemorrhagic shock. Limited resuscitation may achieve favorable clinical results with volumes less than recommended by Advanced Trauma Life Support guidelines.
authors.affiliation: Resuscitation Research Laboratory, Department of Anesthesiology and Physiology, University of Texas Medical Branch, Galveston 77555-0801, USA.
authors.forename: Neal F
authors.initials: NF
authors.lastname: Chaisson
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kirschner
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Deyo
authors.forename: J Abraham
authors.initials: JA
authors.lastname: Lopez
authors.forename: Donald S
authors.initials: DS
authors.lastname: Prough
authors.forename: George C
authors.initials: GC
authors.lastname: Kramer
mesh_terms: D000818:Animals; D002302:Cardiac Output / Q000502:physiology; D004195:Disease Models, Animal; D005440:Fluid Therapy; D006470:Hemorrhage / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy*; D007552:Isotonic Solutions / Q000627:therapeutic use*; D018482:Muscle, Skeletal / Q000503:physiopathology; D010100:Oxygen / Q000032:analysis; D012151:Resuscitation; D000077331:Ringer's Solution; D012756:Sheep; D019265:Spectroscopy, Near-Infrared; D013813:Therapy, Computer-Assisted; D014950:Wounds, Penetrating / Q000150:complications* / Q000503:physiopathology / Q000628:therapy*
chemical_list: D007552:Isotonic Solutions; D000077331:Ringer's Solution; D010100:Oxygen