X-Message-Number: 25200 From: "Aschwin de Wolf" <> Subject: Recent Hypothermia and Resuscitation Publications in Critical Care Medicine Date: Thu, 2 Dec 2004 21:41:37 -0500 Crit Care Med. 2004 Feb;32(2 Suppl):S46-50. Suspended animation for resuscitation from exsanguinating hemorrhage. Tisherman SA. Department of Surgery, Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, USA. In dogs, isotonic saline at 0-4 degrees C, flushed into the aorta at a rate of 1-2 L/min, with drainage of the vena cava, can achieve deep to profound hypothermia of vital organs at a cooling rate of up to 3 degrees C per minute. This achieves preservation of viability of the organism during predictable durations of no flow: cardiac arrest of 15-20 mins at Tty of 30-35 degrees C, cardiac arrest of 30 mins at Tty of 25 degrees C, cardiac arrest of 60 mins at Tty of 15 degrees C, and cardiac arrest of 90 mins at Tty of 10 degrees C. So far, pharmacologic approaches have not resulted in any breakthrough effect on outcome above that achieved with hypothermia, except perhaps the antioxidant tempol. Additional studies of novel drugs and, perhaps, combination therapies remain warranted. The optimal fluids to have in the circulation during circulatory arrest and reperfusions need to be determined. As laboratory studies to optimize suspended animation proceed, clinical trials should be initiated. In addition, devices should be developed to facilitate induction of suspended animation, eventually in the field. Crit Care Med. 2004 Feb;32(2 Suppl):S51-5. Smart aortic arch catheter: moving suspended animation from the laboratory to the field. Yaffe L, Abbott D, Schulte B. Alion Science and Technology, McLean, VA, USA. Crit Care Med. 2003 May;31(5):1592-3. Suvival without brain damage after clinical death of 60-120 mins in dogs using suspended animation by profound hypothermia. Behringer W, Safar P, Wu X, Kentner R, Radovsky A, Kochanek PM, Dixon CE, Tisherman SA. Safar Center for Resuscitation Research, Pittsburgh, PA, USA. OBJECTIVES: This study explored the limits of good outcome of brain and organism achievable after cardiac arrest (no blood flow) of 60-120 mins, with preservation (suspended animation) induced immediately after the start of exsanguination cardiac arrest. DESIGN: Prospective experimental comparison of three arrest times, without randomization. SETTING: University research laboratory. SUBJECTS: Twenty-seven custom-bred hunting dogs (17-25 kg). INTERVENTIONS: Dogs were exsanguinated over 5 mins to cardiac arrest no-flow of 60 mins, 90 mins, or 120 mins. At 2 mins of cardiac arrest, the dogs received, via a balloon-tipped catheter, an aortic flush of isotonic saline at 2 degrees C (at a rate of 1 L/min), until tympanic temperature reached 20 degrees C (for 60 mins of cardiac arrest), 15 degrees C (for 60 mins of cardiac arrest), or 10 degrees C (for 60, 90, or 120 mins of cardiac arrest). Resuscitation was by closed-chest cardiopulmonary bypass, postcardiac arrest mild hypothermia (tympanic temperature 34 degrees C) to 12 hrs, controlled ventilation to 20 hrs, and intensive care to 72 hrs. MEASUREMENTS AND MAIN RESULTS: We assessed overall performance categories (OPC 1, normal; 2, moderate disability; 3, severe disability; 4, coma; 5, death), neurologic deficit scores (NDS 0-10%, normal; 100%, brain death), regional and total brain histologic damage scores at 72 hrs (total HDS >0-40, mild; 40-100, moderate; >100, severe damage), and morphologic damage of extracerebral organs. For 60 mins of cardiac arrest (n = 14), tympanic temperature 20 degrees C (n = 6) was achieved after flush of 3 mins and resulted in two dogs with OPC 1 and four dogs with OPC 2: median NDS, 13% (range 0-27%); and median total HDS, 28 (range, 4-36). Tympanic temperature of 15 degrees C (n = 5) was achieved after flush of 7 mins and resulted in all five dogs with OPC 1, NDS 0% (0-3%), and HDS 8 (0-48). Tympanic temperature 10 degrees C (n = 3) was achieved after flush of 11 mins and resulted in all three dogs with OPC 1, NDS 0%, and HDS 16 (2-18). For 90 mins of cardiac arrest (n = 6), tympanic temperature 10 degrees C was achieved after flush of 15 mins and resulted in all six dogs with OPC 1, NDS 0%, and HDS 8 (0-37). For 120 mins of cardiac arrest (n = 7), three dogs had to be excluded. In the four dogs within protocol, tympanic temperature 10 degrees C was achieved after flush of 15 mins. This resulted in one dog with OPC 1, NDS 0%, and total HDS 14; one with OPC 1, NDS 6%, and total HDS 20; one with OPC 2, NDS 13%, and total HDS 10; and one with OPC 3, NDS 39%, and total HDS 22. CONCLUSIONS: In a systematic series of studies in dogs, the rapid induction of profound cerebral hypothermia (tympanic temperature 10 degrees C) by aortic flush of cold saline immediately after the start of exsanguination cardiac arrest-which rarely can be resuscitated effectively with current methods-can achieve survival without functional or histologic brain damage, after cardiac arrest no-flow of 60 or 90 mins and possibly 120 mins. The use of additional preservation strategies should be pursued in the 120-min arrest model. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=25200