Low-Dose Heparin Anticoagulation During Extracorporeal Life Support for Acute Respiratory Distress Syndrome in Conscious Sheep.
BACKGROUND
Over 32% of burned battlefield causalities develop trauma-induced hypoxic respiratory failure, also known as acute respiratory distress syndrome (ARDS). Recently, 9 out of 10 US combat soldiers' survived life-threatening trauma-induced ARDS supported with extracorporeal membrane oxygenation (ECMO), a portable form of cardiopulmonary bypass. Unfortunately, the size, incidence of coagulation complications, and the need for systematic anticoagulation for traditional ECMO devices have prevented widespread use of this lifesaving technology. Therefore, a compact, mobile, ECMO system using minimal anticoagulation may be the solution to reduce ARDS in critically ill military and civilian patients.


METHODS
We conducted a prospective cohort laboratory investigation to evaluate the coagulation function in an ovine model of oleic acid induced ARDS supported with veno-venous ECMO. The experimental design approximated the time needed to transport from a battlefield setting to an advanced facility and compared bolus versus standard heparin anticoagulation therapy.


RESULTS
Comprehensive coagulation and hemostasis assays did not show any difference because of ECMO support over 10 h between the two groups but did show changes because of injury. Platelet count and function did decrease with support on ECMO, but there was no significant bleeding or clot formation during the entire experiment.


CONCLUSIONS
A bolus heparin injection is sufficient to maintain ECMO support for up to 10 h in an ovine model of ARDS. With a reduced need for systematic anticoagulation, ECMO use for battlefield trauma could reduce significant morbidity and mortality from ventilator-induced lung injury and ARDS. Future studies will investigate the mechanisms and therapies to support patients for longer periods on ECMO without coagulation complications.


METHODS
V--therapeutic animal experiment.
*French Armed Forces Institute of Biomedical Research (IRBA), Paris, France †Division of Pediatric Critical Care, Department of Pediatrics, University of Texas Health Science Center, San Antonio, Texas ‡Department of Anesthesia, Intensive Care Medicine, Emergency and Urgency, Fondazione IRCCS Ca'Granda-Ospedale Maggiore Policlinico, Milan, Italy §Coagulation and Blood Research ||Comprehensive Intensive Care Research, U.S. Army Institute of Surgical Research (USAISR), Ft. Sam Houston, Texas.
Nicolas J
NJ
Prat
Andrew D
AD
Meyer
Thomas
T
Langer
Robbie K
RK
Montgomery
Bijaya K
BK
Parida
Andriy I
AI
Batchinsky
Andrew P
AP
Cap
D000818:Animals; D000925:Anticoagulants / Q000627:therapeutic use; D001772:Blood Cell Count; D002315:Cardiopulmonary Bypass; D015331:Cohort Studies; D016638:Critical Illness; D004195:Disease Models, Animal; D015199:Extracorporeal Membrane Oxygenation / Q000379:methods*; D005260:Female; D005434:Flow Cytometry; D006487:Hemostasis; D006493:Heparin / Q000627:therapeutic use; D000860:Hypoxia; D019301:Oleic Acid / Q000009:adverse effects*; D010974:Platelet Aggregation; D010976:Platelet Count; D011897:Random Allocation; D012121:Respiration, Artificial / Q000379:methods*; D012128:Respiratory Distress Syndrome / Q000628:therapy*; D012756:Sheep; D013916:Thrombelastography; D055397:Ventilator-Induced Lung Injury / Q000628:therapy
D000925:Anticoagulants; D019301:Oleic Acid; D006493:Heparin