title: Role of the venous return in critical illness and shock: part II-shock and mechanical ventilation.
abstract: OBJECTIVE
  To provide a conceptual and clinical review of the physiology of the venous system as it is related to cardiac function in health and disease.
  
  
  METHODS
  An integration of venous and cardiac physiology under normal conditions, critical illness, and resuscitation.
  
  
  CONCLUSIONS
  The usual clinical teaching of cardiac physiology focuses on left ventricular pathophysiology and pathology. Due to the wide array of shock states dealt with by intensivists, an integrated approach that takes into account the function of the venous system and its interaction with the right heart may be more useful. In part II of this two-part review, we describe the physiology of venous return and its interaction with the right heart function as it relates to mechanical ventilation and various shock states including hypovolemic, cardiogenic, obstructive, and septic shock. In particular, we demonstrate how these shock states perturb venous return/right heart interactions. We also show how compensatory mechanisms and therapeutic interventions can tend to return venous return and cardiac output to appropriate values.
  
  
  CONCLUSIONS
  An improved understanding of the role of the venous system in pathophysiologic conditions will allow intensivists to better appreciate the complex circulatory physiology of shock and related therapies. This should enable improved hemodynamic management of this disorder.
authors.affiliation: Section of Critical Care Medicine, Department of Medicine, University of Manitoba, Manitoba, Canada.
authors.forename: Duane J
authors.initials: DJ
authors.lastname: Funk
authors.forename: Eric
authors.initials: E
authors.lastname: Jacobsohn
authors.forename: Anand
authors.initials: A
authors.lastname: Kumar
mesh_terms: D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D002316:Cardiotonic Agents / Q000627:therapeutic use; D002395:Catecholamines / Q000378:metabolism; D003326:Coronary Circulation / Q000502:physiology*; D016638:Critical Illness; D016207:Cytokines / Q000378:metabolism; D005440:Fluid Therapy; D006801:Humans; D020896:Hypovolemia / Q000503:physiopathology / Q000628:therapy; D009569:Nitric Oxide / Q000378:metabolism; D011030:Pneumothorax / Q000503:physiopathology; D011175:Positive-Pressure Respiration; D012769:Shock / Q000503:physiopathology* / Q000628:therapy; D013318:Stroke Volume / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000627:therapeutic use; D014665:Vasodilator Agents / Q000627:therapeutic use; D018754:Ventricular Dysfunction / Q000503:physiopathology / Q000628:therapy
chemical_list: D002316:Cardiotonic Agents; D002395:Catecholamines; D016207:Cytokines; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009569:Nitric Oxide