title: Clinical death and the measurement of stressed vascular volume.
abstract: OBJECTIVE
  To measure stressed vascular volume in humans and to review the concepts of stressed and unstressed vascular volume.
  
  
  METHODS
  Observational study during surgical procedure.
  
  
  METHODS
  Operating room at a university hospital.
  
  
  METHODS
  Five patients undergoing hypothermic circulatory arrest for surgery on major vessels.
  
  
  METHODS
  We measured the volume that drained from the patient to the reservoir of the pump when the pump was turned off.
  
  
  RESULTS
  Stressed volume was 20.2+/-1.0 mL/kg, which is 30% of the predicted blood volume of these patients.
  
  
  CONCLUSIONS
  The amount of blood volume that determines vascular filling pressure is only about a quarter of the total predicted volume, which means that there is a large reserve of unstressed volume that can be recruited to maintain vascular filling pressure.
authors.affiliation: Division of Critical Care, Royal Victoria Hospital, McGill University, Montréal, PQ, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Magder
authors.forename: B
authors.initials: B
authors.lastname: De Varennes
mesh_terms: D000818:Animals; D001794:Blood Pressure; D001810:Blood Volume; D006324:Heart Arrest, Induced; D006801:Humans; D013312:Stress, Physiological / Q000503:physiopathology; D018924:Vascular Capacitance; D014656:Vascular Surgical Procedures