title: The approximated cardiovascular reserve index complies with haemorrhage related hemodynamic deterioration pattern: A swine exsanguination model.
abstract: BACKGROUND
  To estimate the cardiovascular reserve we formulated the Cardiovascular Reserve Index (CVRI) based on physiological measurements. The aim of this study was to evaluate the pattern of CVRI in haemorrhage-related haemodynamic deterioration in an animal model simulating combat injury.
  
  
  METHODS
  Data were collected retrospectively from a research database of swine exsanguination model in which serial physiological measurements were made under anesthesia in 12 swine of haemorrhagic injury and 5 controls. We calculated the approximated CVRI (CVRIA). The course of haemodynamic deterioration was defined according to the cumulative blood loss until shock. The ability of heart rate (HR), mean arterial blood pressure (MABP), stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) and the CVRIAto predict haemodynamic deterioration was evaluated according to three criteria: strength of association with the course of haemodynamic deterioration (r2> 0.5); threshold for haemodynamic deterioration detection; and range at which the parameter remained consistently monotonous course of deterioration.
  
  
  RESULTS
  Three parameters met the first criterion for prediction of haemodynamic deterioration: HR (r2= 0.59), SV (r2= 0.57) and CVRIA(r2= 0.66). Results were negative for MABP (r2= 0.27), CO (r2= 0.33) and SVR (r2= 0.02). The detection threshold of the CVRIAwas 200-300 ml blood loss whereas HR, SV and CO showed a delay in detection, MABP and CVRI exhibited a wide indicative range toward shock.
  
  
  CONCLUSIONS
  The CVRIAmet preset criteria of a potential predictor of haemorrhage-related haemodynamic deterioration. Prospective studies are required to evaluate use of the CVRI in combat medicine.
  
  
  METHODS
  Level III.
authors.affiliation: Surgeon General Headquarters, Medical Corps, Israel Defense Forces, Ramat Gan, Israel.
authors.forename: Roy
authors.initials: R
authors.lastname: Nadler
authors.affiliation: Surgeon General Headquarters, Medical Corps, Israel Defense Forces, Ramat Gan, Israel.
authors.forename: Elon
authors.initials: E
authors.lastname: Glassberg
authors.affiliation: Quality Unit, Rabin Medical Center, Beilinson Hospital, Petach Tikva, Israel.
authors.forename: Itay E
authors.initials: IE
authors.lastname: Gabbay
authors.affiliation: Institute for Research in Military Medicine, Faculty of Medicine, Hebrew University, Jerusalem, Israel.
authors.forename: Linn
authors.initials: L
authors.lastname: Wagnert-Avraham
authors.affiliation: Surgeon General Headquarters, Medical Corps, Israel Defense Forces, Ramat Gan, Israel.
authors.forename: Gal
authors.initials: G
authors.lastname: Yaniv
authors.affiliation: Center for Innovative Surgery, Hadassah Medical Center, Jerusalem, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Kushnir
authors.affiliation: Surgeon General Headquarters, Medical Corps, Israel Defense Forces, Ramat Gan, Israel; Institute for Research in Military Medicine, Faculty of Medicine, Hebrew University, Jerusalem, Israel.
authors.forename: Arik
authors.initials: A
authors.lastname: Eisenkraft
authors.affiliation: School of Electrical Engineering - Systems, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Ben-Zion
authors.initials: BZ
authors.lastname: Bobrovsky
authors.affiliation: Quality Unit, Rabin Medical Center, Beilinson Hospital, Petach Tikva, Israel; Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Uri
authors.initials: U
authors.lastname: Gabbay
keywords: Cardio-Vascular Reserve Index (CVRI); Haemodynamic deterioration; Haemorrhage; Shock; Swine model