title: Microcirculation during cardiac arrest and resuscitation.
abstract: OBJECTIVE
  Direct observations of the microcirculation using orthogonal polarization spectral imaging have attracted attention and revealed that, especially in cardiogenic and distributive shock, there is discordance between the macrocirculation and the microcirculation. We evaluated serial changes and the effects of epinephrine on microcirculatory blood flow in the most severe form of circulatory failure, namely, cardiac arrest.
  
  
  METHODS
  : Controlled laboratory animal study.
  
  
  METHODS
  A total of 15 pigs were subjected to 5 mins of ventricular fibrillation and 5 mins of precordial compression before electrical defibrillation was attempted. In a subset, six animals received 1 mg of epinephrine after 1 min of precordial compression.
  
  
  RESULTS
  Microcirculatory blood flow was visualized in the sublingual mucosa at baseline and 0.5, 1, and 5 mins of ventricular fibrillation, at 1 and 5 mins of precordial compression, and at 1 and 5 mins after return of spontaneous circulation. In addition, coronary perfusion pressure was recorded. Microcirculatory blood flow decreased dramatically in the 0.5 min after the onset of ventricular fibrillation. Precordial compression partially restored microcirculatory blood flow in each animal but to a significantly greater extent in animals that achieved return of spontaneous circulation. These changes were paralleled by similar changes in coronary perfusion pressure. Both variables were highly correlated. Administration of epinephrine resulted in a massive reduction of microcirculatory blood flow that lasted for >/=5 mins.
  
  
  CONCLUSIONS
  In this model, microcirculatory blood flow was highly correlated with macrocirculatory hemodynamics, including coronary perfusion pressure in distinction with septic shock. Administration of epinephrine dramatically decreased microcirculatory blood flow.
authors.affiliation: Weil Institute of Critical Care Medicine, Rancho Mirage, California, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Fries
authors.forename: Max Harry
authors.initials: MH
authors.lastname: Weil
authors.forename: Yun-Te
authors.initials: YT
authors.lastname: Chang
authors.forename: Carlos
authors.initials: C
authors.lastname: Castillo
authors.forename: Wanchun
authors.initials: W
authors.lastname: Tang
mesh_terms: D000818:Animals; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D004554:Electric Countershock; D004837:Epinephrine / Q000494:pharmacology; D006323:Heart Arrest / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008833:Microcirculation; D009060:Mouth Floor; D009061:Mouth Mucosa / Q000098:blood supply*; D013552:Swine; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014693:Ventricular Fibrillation / Q000150:complications / Q000503:physiopathology / Q000628:therapy
chemical_list: D014662:Vasoconstrictor Agents; D004837:Epinephrine