title: Different effects of propofol and dexmedetomidine on preload dependency in endotoxemic shock with norepinephrine infusion.
abstract: BACKGROUND
  To clarify whether propofol (PROP) and dexmedetomidine (DEX) differentially affect preload dependency in an endotoxemic model based on evaluations of the systemic vascular system and cardiac function.
  
  
  METHODS
  Animals were prepared under PiCCO monitoring (BL), and endotoxemic shock was induced using an intravenous bolus of lipopolysaccharide (055:B5) in 16 New Zealand ketamine-anesthetized rabbits. After fluid resuscitation and norepinephrine infusion (SD0), the animals were randomized to PROP (n = 8) or DEX (n = 8) sedation at two incremental doses (SD1 and SD2). The mean arterial pressure and the central venous pressure were monitored. Pulse pressure variation (PPV) was assessed to evaluate preload dependency. Global end-diastolic volume, vascular resistance, mean systemic filling pressure, and cardiac function index were assessed at each time point.
  
  
  RESULTS
  PPV progressively and significantly increased with increasing infusion rates of PROP (SD1 versus SD0, P < 0.01; SD2 versus SD0, P < 0.001; and SD2 versus SD1, P = 0.024) but not DEX. PPV was higher at SD1 and SD2 in the PROP group than in the DEX group (P < 0.001). PROP increased the heart rate without affecting cardiac contractility or vascular resistance. In contrast, DEX decreased heart contractility and increased vascular resistance at the highest dose. However, neither drug affected mean arterial pressure, central venous pressure, mean systemic filling pressure, global end-diastolic volume, or venous return.
  
  
  CONCLUSIONS
  PROP more effectively increased PPV than DEX in an endotoxemic shock model after fluid resuscitation during norepinephrine infusion. DEX, but not PROP, at the highest dose influenced vascular resistance and heart contractility.
authors.affiliation: Department of Critical Care Medicine, Nanjing Zhongda Hospital, Southeast University School of Medicine, Nanjing, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
authors.affiliation: Department of Critical Care Medicine, Nanjing Zhongda Hospital, Southeast University School of Medicine, Nanjing, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Critical Care Medicine, Nanjing Zhongda Hospital, Southeast University School of Medicine, Nanjing, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Critical Care Medicine, Nanjing Zhongda Hospital, Southeast University School of Medicine, Nanjing, China.
authors.forename: Fengmei
authors.initials: F
authors.lastname: Guo
authors.affiliation: Department of Critical Care Medicine, Nanjing Zhongda Hospital, Southeast University School of Medicine, Nanjing, China; Anesthesia and Intensive Care, Department of Translational Medicine, Eastern Piedmont University "A. Avogadro", Novara, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Longhini
authors.affiliation: Department of Critical Care Medicine, Nanjing Zhongda Hospital, Southeast University School of Medicine, Nanjing, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Critical Care Medicine, Nanjing Zhongda Hospital, Southeast University School of Medicine, Nanjing, China. Electronic address: haiboq2000@gmail.com.
authors.forename: Haibo
authors.initials: H
authors.lastname: Qiu
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D020927:Dexmedetomidine / Q000627:therapeutic use*; D019446:Endotoxemia / Q000188:drug therapy* / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D009638:Norepinephrine / Q000008:administration & dosage*; D015742:Propofol / Q000627:therapeutic use*; D011817:Rabbits; D012772:Shock, Septic / Q000188:drug therapy* / Q000503:physiopathology; D013599:Systole / Q000187:drug effects
chemical_list: D020927:Dexmedetomidine; D009638:Norepinephrine; D015742:Propofol
keywords: Cardiac function; Cardiac output; Dexmedetomidine; Endotoxemic shock; Mean systemic filling pressure; Norepinephrine; Preload dependency; Propofol