title: Near-fatal pulmonary embolism in an experimental model: hemodynamic, gasometric and capnographic variables.
abstract: BACKGROUND
  Experimental studies on pulmonary embolism (PE) are usually performed under mechanical ventilation. Most patients with suspicion of PE enter the Emergency Services in spontaneous breathing and environmental air. Thus, under these conditions, measurements of hemodynamic, gasometric and capnographic variables contribute largely to a more specific comprehension of cardiopulmonary and gasometric alterations in the acute phase of the disease. Studies which evaluated animals under conditions are lacking.
  
  
  OBJECTIVE
  This study aimed to submit animals under spontaneous ventilation and without supplemental oxygen to PE.
  
  
  METHODS
  PE was induced in six pigs using autologous blood clots, and cardiorespiratory and gasometric records were performed before and after PE. The values of "near fatal" mean pulmonary arterial pressure (MPAP) were previously determined.
  
  
  RESULTS
  The presence of obstructive shock could be evidenced by increased MPAP (from 17.8 ± 3.5 to 41.7 ± 3.3 mmHg) (P<0.0001) and decreased cardiac output (from 4.9 ± 1.0 to 2.7 ± 1.0 L/min) (P<0.003). Consequently, metabolic acidosis occurred (Lac art) (from 2.4 ± 0.6 to 5.7 ± 1.8 mmol/L)(P<0.0001). It was observed hypoxemia (from 73.5 ± 12.7 to 40.3 ± 4.6 mmHg) (P<0.0001); however, PaCO2 did not vary (from 44.9 ± 4.4 to 48.2 ± 6.0 mmHg) (NS). There were significant increases in both P(a-et)CO2 (from 4.8 ± 2.8 to 37.2 ± 5.8 mmHg) and P(A-a)O2 (from 8.2 ± 8.9 to 37.2 ± 10.3 mmHg) (both P<0.0001). There was also a significant increase in the total alveolar minute volume (from 4.0 ± 0.9 to 10.6 ± 2.9 L/min) (P<0.0001).
  
  
  CONCLUSIONS
  In this model, the near fatal MPAP was from 2 to 2.5 times the basal MPAP; and the capnographic variables, associated with arterial and venous gasometry, showed effective in discriminating an acute obstructive profile.
authors.affiliation: Department of Pharmacology, Faculty of Medical Sciences, University of Campinas, Campinas, SP, Brazil.
authors.forename: Daniel José
authors.initials: DJ
authors.lastname: Pereira
authors.forename: Marcos Mello
authors.initials: MM
authors.lastname: Moreira
authors.forename: Ilma Aparecida
authors.initials: IA
authors.lastname: Paschoal
authors.forename: Luiz Cláudio
authors.initials: LC
authors.lastname: Martins
authors.forename: Konradin
authors.initials: K
authors.lastname: Metze
authors.forename: Heitor
authors.initials: H
authors.lastname: Moreno Junior
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002245:Carbon Dioxide / Q000097:blood*; D004195:Disease Models, Animal; D006439:Hemodynamics / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D011655:Pulmonary Embolism / Q000209:etiology / Q000503:physiopathology*; D013552:Swine
chemical_list: D002245:Carbon Dioxide