title: Effects of Progressive Hypoventilation on Left Ventricular Appearance: An Alternative Etiology of Acute Sonographic Short-Axis D-Shaping.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effects of progressive hypoventilation on echocardiographic measures of the left ventricular (LV) appearance in a porcine model.
  
  
  METHODS
  Ten piglets were included in the experimental group, and 5 served as controls. The experimental group underwent 3 interventions of progressive hypoventilation (baseline: tidal volume, 240 mL; respiratory frequency, 16 minutes-1; first intervention: tidal volume, 240 mL; respiratory frequency, 8 minutes-1; second intervention: tidal volume, 240 mL; respiratory frequency, 4 minutes-1; and third intervention: tidal volume, 120 mL; respiratory frequency, 4 minutes-1). Respiratory resuscitation was initiated if the MAP decreased to 50% of the baseline level or at the end of the third intervention. Transthoracic sonography and invasive measurements were obtained throughout. The primary end point was the LV end-diastolic eccentricity index, a measure of LV D-shaping.
  
  
  RESULTS
  The median LV end-diastolic eccentricity index increased from 1.1 (interquartile range, 1.0-1.1) at baseline to 1.4 (1.3-1.4) 3 minutes after the third intervention (P < .001) and returned to baseline after resuscitation (P = .093). The MAP declined from 87 mm Hg (81-92 mm Hg) to 50 mmHg (33-66 mm Hg) after initiation of the third intervention (P < .001). The mean pulmonary arterial pressure increased from 20 mm Hg (15-21 mm Hg) to 39 mm Hg (38-40 mm Hg) during the second intervention (P < .001).
  
  
  CONCLUSIONS
  Progressive hypoventilation led to a marked D-configuration of the LV and a sharp decrease in systemic blood pressure. After respiratory resuscitation, sonographic measures normalized. These findings were explainable by the pressure changes observed within the left and right ventricles.
authors.affiliation: Department of Anesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark.|Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Viktor Kromann
authors.initials: VK
authors.lastname: Ringgård
authors.affiliation: Department of Anesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark.|Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Anders Høyer
authors.initials: AH
authors.lastname: Sørensen
authors.affiliation: Department of Anesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark.|Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Kristian Borup
authors.initials: KB
authors.lastname: Wemmelund
authors.affiliation: Department of Anesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark.|Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Erik
authors.initials: E
authors.lastname: Sloth
authors.affiliation: Department of Anesthesiology, Randers Regional Hospital, Randers, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Juhl-Olsen
mesh_terms: D000208:Acute Disease; D000818:Animals; D001794:Blood Pressure; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D007040:Hypoventilation / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology*
keywords: emergency medicine; hypoventilation; point-of-care sonography; pulmonary embolism; right ventricle; sonography