title: Selective tracheal gas insufflation during partial liquid ventilation improves lung function in an animal model of unilateral acute lung injury.
abstract: OBJECTIVE
  During unilateral lung injury, we hypothesized that we can improve global lung function by applying selective tracheal gas insufflation (TGI) and partial liquid ventilation (PLV) to the injured lung.
  
  
  METHODS
  Prospective, interventional animal study.
  
  
  METHODS
  Animal laboratory in a university hospital.
  
  
  METHODS
  Adult mixed-breed dogs.
  
  
  METHODS
  In six anesthetized dogs, left saline lung lavage was performed until PaO(2)/FiO(2) fell below 100 torr (13.3 kPa). The dogs were then reintubated with a Univent single-lumen endotracheal tube, which incorporates an internal catheter to provide TGI. In a consecutive manner, we studied 1) the application of 10 cm H(2)O of positive end-expiratory pressure (PEEP); 2) instillation of 10 mL/kg of perflubron (Liquivent) to the left lung at a PEEP level of 10 cm H(2)O (PLV+PEEP 10 initial); 3) application of selective TGI (PLV+TGI) while maintaining end-expiratory lung volume (EELV) constant; 4) PLV+TGI at reduced tidal volume (VT); and 5) PLV+PEEP 10 final.
  
  
  RESULTS
  Application of PLV+PEEP 10 initial did not change gas exchange, lung mechanics, or hemodynamics. PLV+TGI improved PaO(2)/FiO(2) from 189 +/- 13 torr (25.2 +/- 1.7 kPa) to 383 +/- 44 torr (51.1 +/- 5.9 kPa) (p <.01) and decreased PaCO(2) from 55 +/- 5 torr (7.3 +/- 0.7 kPa) to 30 +/- 2 torr (4.0 +/- 0.3 kPa) (p <.01). During ventilation with PLV+TGI, reducing VT from 15 mL/kg to 3.5 mL/kg while keeping EELV constant decreased PaO(2)/FiO(2) to 288 +/- 49 torr (38.4 +/- 6.5 kPa) (not significant) and normalized PaCO(2). At this stage, end-inspiratory plateau pressure decreased from 19.2 +/- 0.7 cm H(2)O to 13.6 +/- 0.7 cm H(2)O (p <.01). At PLV+PEEP 10 final, measurements returned to those observed at previous baseline stage (PLV+PEEP 10 initial).
  
  
  CONCLUSIONS
  During unilateral lung injury, PLV with a moderate PEEP did not improve oxygenation, TGI superimposed on PLV improved gas exchange, and combination of TGI and PLV allowed a 77% reduction in VT without any adverse effect on PaCO(2).
authors.affiliation: Servei de Medicina Intensiva, Hospital de Sabadell, Corporació Parc Tauli, Sabadell, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Blanch
authors.forename: T E
authors.initials: TE
authors.lastname: Van der Kloot
authors.forename: A M
authors.initials: AM
authors.lastname: Youngblood
authors.forename: A B
authors.initials: AB
authors.lastname: Adams
authors.forename: A
authors.initials: A
authors.lastname: Naveira
authors.forename: G
authors.initials: G
authors.lastname: Murias
authors.forename: P V
authors.initials: PV
authors.lastname: Romero
authors.forename: A
authors.initials: A
authors.lastname: Nahum
mesh_terms: D000818:Animals; D004285:Dogs; D006439:Hemodynamics; D007327:Insufflation / Q000379:methods*; D021061:Liquid Ventilation / Q000379:methods*; D011175:Positive-Pressure Respiration / Q000379:methods; D012128:Respiratory Distress Syndrome / Q000628:therapy*; D015656:Respiratory Mechanics; D007507:Therapeutic Irrigation; D014132:Trachea