title: Spontaneous breathing during airway pressure release ventilation in experimental lung injury: effects on hepatic blood flow.
abstract: OBJECTIVE
  Positive pressure ventilation can affect systemic haemodynamics and regional blood flow distribution with negative effects on hepatic blood flow. We hypothesized that spontaneous breathing (SB) with airway pressure release ventilation (APRV) provides better systemic and hepatic blood flow than APRV without SB.
  
  
  METHODS
  Animal study with a randomized cross-over design.
  
  
  METHODS
  Animal laboratory of Bonn University Hospital.
  
  
  METHODS
  Twelve pigs with oleic-acid-induced lung injury.
  
  
  METHODS
  APRV with or without SB in random order. Without SB, either the upper airway pressure limit or the ventilator rate was increased to maintain constant pH and PaCO2.
  
  
  RESULTS
  Systemic haemodynamics were determined by double-indicator dilution, organ blood flow by coloured microspheres. Systemic blood flow was best during APRV with SB. During APRV with SB blood flow (ml g(-1) min(-1)) was 0.91+/-0.26 (hepatic arterial), 0.29+/-0.05 (stomach), 0.64+/-0.08 (duodenum), 0.62+/-0.10 (jejunum), 0.53+/-0.07 (ileum), 0.53+/-0.07 (colon), 0.46+/-0.09 (pancreas) and 3.59+/-0.55 (spleen). During APRV without SB applying high P(aw) it decreased to 0.13+/-0.01 (stomach), 0.37+/-0.03 (duodenum), 0.29+/-0.03 (jejunum), 0.31+/-0.05 (ileum), 0.32+/-0.03 (colon) and 0.23+/-0.04 (pancreas) p<0.01, respectively. During APRV without SB applying same Paw limits it decreased to 0.18+/-0.03 (stomach, p<0.01), 0.47+/-0.06 (duodenum, p<0.05), 0.38+/-0.05 (jejunum, p<0.01), 0.36+/-0.03 (ileum, p<0.05), 0.39+/-0.05 (colon, p<0.05), and 0.27+/-0.04 (pancreas, p<0.01). Arterial liver blood flow did not change significantly when SB was abolished (0.55+/-0.11 and 0.63+/-0.11, respectively).
  
  
  CONCLUSIONS
  Maintaining SB during APRV was associated with better systemic and pre-portal organ blood flow. Improvement in hepatic arterial blood flow was not significant.
authors: Department of Anaesthesiology and Critical Care Medicine, Bonn University Hospital, Bonn, Germany. Rudolf.Hering@ukb.uni-bonn.de
authors: Rudolf
authors: R
authors: Hering
authors: Jens Christopher
authors: JC
authors: Bolten
authors: Stefan
authors: S
authors: Kreyer
authors: Andreas
authors: A
authors: Berg
authors: Hermann
authors: H
authors: Wrigge
authors: Jörg
authors: J
authors: Zinserling
authors: Christian
authors: C
authors: Putensen
mesh_terms: D000818:Animals; D002302:Cardiac Output / Q000502:physiology; D045422:Continuous Positive Airway Pressure; D018592:Cross-Over Studies; D008099:Liver / Q000098:blood supply*; D008102:Liver Circulation / Q000502:physiology; D019301:Oleic Acid; D010100:Oxygen / Q000097:blood; D012119:Respiration; D012128:Respiratory Distress Syndrome / Q000139:chemically induced / Q000503:physiopathology / Q000628:therapy*; D013552:Swine
chemical_list: D019301:Oleic Acid; D010100:Oxygen