title: Cerebral Hemodynamics and Metabolism During Cardiac Arrest and Cardiopulmonary Resuscitation Using Hyperspectral Near Infrared Spectroscopy.
abstract: Maintaining cerebral oxygen delivery and metabolism during cardiac arrest (CA) through resuscitation is essential to improve the survival rate while avoiding brain injury. The effect of CA and cardiopulmonary resuscitation (CPR) on cerebral and muscle oxygen delivery and metabolism is not clearly quantified.
  
  
  
  A novel hyperspectral near-infrared spectroscopy (hNIRS) technique was developed and evaluated to measure cerebral oxygen delivery and aerobic metabolism during ventricular fibrillation (VF) CA and CPR in 14 pigs. The hNIRS parameters were measured simultaneously on the dura and skull to investigate the validity of non-invasive hNIRS measurements. In addition, we compared the hNIRS data collected simultaneously on the brain and muscle. Following VF induction, oxygenated hemoglobin (HbO2) declined with a 9.9 s delay and then cytochrome-c-oxidase (Cyt-ox) decreased on average 4.4 s later (P<0.05). CPR improved cerebral metabolism, which was reflected by an average 0.4 μmol/L increase in Cyt-ox, but had no significant effect on HbO2, deoxygenated hemoglobin (HHb) and tissue oxygen saturation (tSO2). Cyt-ox had greater correlation with HHb than HbO2. Muscle metabolism during VF and CPR was significantly different from that of the brain. The total hemoglobin concentration (in the brain only) increased after ~200 s of untreated CA, which is most likely driven by cerebral autoregulation through vasodilation.
  
  
  
  Overall, hNIRS showed consistent measurements of hemodynamics and metabolism during CA and CPR.
authors.affiliation: Department of Physics, Ryerson University.|Medical Physics, Sunnybrook Health Sciences Centre.
authors.forename: Reyhaneh
authors.initials: R
authors.lastname: Nosrati
authors.affiliation: Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital.|Department of Medicine, University of Toronto.
authors.forename: Steve
authors.initials: S
authors.lastname: Lin
authors.affiliation: Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ramadeen
authors.affiliation: Department of Physics, Ryerson University.
authors.forename: Dena
authors.initials: D
authors.lastname: Monjazebi
authors.affiliation: Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital.|Department of Medicine, University of Toronto.
authors.forename: Paul
authors.initials: P
authors.lastname: Dorian
authors.affiliation: Department of Physics, Ryerson University.|Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital.
authors.forename: Vladislav
authors.initials: V
authors.lastname: Toronov
mesh_terms: D000818:Animals; D016887:Cardiopulmonary Resuscitation; D002560:Cerebrovascular Circulation; D003576:Electron Transport Complex IV / Q000097:blood; D005260:Female; D006323:Heart Arrest / Q000097:blood / Q000503:physiopathology / Q000628:therapy; D006454:Hemoglobins / Q000378:metabolism; D010100:Oxygen / Q000097:blood*; D013055:Spectrophotometry, Infrared; D013552:Swine; D014664:Vasodilation; D014693:Ventricular Fibrillation / Q000097:blood / Q000503:physiopathology / Q000628:therapy
chemical_list: D006454:Hemoglobins; D003576:Electron Transport Complex IV; D010100:Oxygen
keywords: Cardiac arrest; Cardiopulmonary resuscitation; Cytochrome-c-oxidase; Metabolism; Near-infrared spectroscopy