title: Development and testing of portable pump for the induction of profound hypothermia in a Swine model of lethal vascular injuries.
abstract: Rapid induction of a profound hypothermic state (suspended animation) can maintain viability of key organs during repair of lethal injuries. Conventional cardiopulmonary bypass equipment (roller pump) used to induce and reverse hypothermia is expensive, bulky, requires standard electricity, and is not transportable. Development of a small, portable, battery operated, disposable, pump can logistically facilitate induction and maintenance of hypothermia. In this experiment, a portable prototype pump was tested and its performance was compared with the regular roller pump in a swine model of lethal vascular injuries.
  
  
  METHODS
  Uncontrolled hemorrhage was induced in 16 swine (80-120 lbs) by creating an iliac artery and vein injury (nonlethal). After 30 minutes of pulseless shock, the descending thoracic aorta was lacerated (lethal injury). Through a left thoracotomy approach, a catheter was placed in the aorta and cold organ preservation solution was infused to rapidly (2 degrees C/min) induce hypothermia (10 degrees C) for 60 minutes. The performance of the prototype pump was initially tested in a nonsurvival experiment (four animals). Then, 12 animals were cooled either with (n = 6/group) (1) conventional roller pump or (2) small prototype pump. The injuries were repaired during hypothermic arrest and the animals were re-warmed (0.5 degrees C/min). Whole blood was infused during resuscitation on cardiopulmonary bypass. Surviving animals were closely monitored for 3 weeks for postoperative complications, neurologic deficits, and organ dysfunction.
  
  
  RESULTS
  The flow rates and the time needed to induce and reverse profound hypothermia were no different between the prototype and the conventional roller pumps. Three-week survival rates were 83% in both groups. Only a transient increase in liver enzymes, and markers of cellular injury (creatine kinase, lactate dehydrogenase) was noted (no meaningful difference between groups), with no long-term organ dysfunction.
  
  
  CONCLUSIONS
  In this large animal model of lethal vascular injuries, a portable, battery operated, disposable, rotary pump performed as well as the conventional roller pump. The logistical advantages of this system make it an attractive choice for inducing hypothermia in emergency departments and austere settings, and for maintaining hypothermia during transport.
authors.affiliation: Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, USA. hbalam@partners.org
authors.forename: Hasan B
authors.initials: HB
authors.lastname: Alam
authors.forename: Fernando
authors.initials: F
authors.lastname: Casas
authors.forename: Zhang
authors.initials: Z
authors.lastname: Chen
authors.forename: William A
authors.initials: WA
authors.lastname: Smith
authors.forename: Andrew
authors.initials: A
authors.lastname: Reeves
authors.forename: George
authors.initials: G
authors.lastname: Velmahos
authors.forename: Marc
authors.initials: M
authors.lastname: de Moya
authors.forename: Peter
authors.initials: P
authors.lastname: Rhee
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000293:injuries*; D002314:Cardioplegic Solutions / Q000008:administration & dosage*; D004195:Disease Models, Animal; D004867:Equipment Design; D005112:Extracorporeal Circulation / Q000295:instrumentation*; D005260:Female; D007036:Hypothermia, Induced / Q000295:instrumentation*; D019188:Organ Preservation Solutions / Q000008:administration & dosage*; D012771:Shock, Hemorrhagic / Q000209:etiology / Q000628:therapy*; D013552:Swine; D014950:Wounds, Penetrating / Q000150:complications / Q000628:therapy
chemical_list: D002314:Cardioplegic Solutions; D019188:Organ Preservation Solutions