title: Effects of expiratory tracheal gas insufflation in patients with severe head trauma and acute lung injury.
abstract: OBJECTIVE
  This study analyzed the effect of phasic tracheal gas insufflation at mid- to end-expiration in patients with severe head trauma and acute lung injury (ALI)/acute respiratory distress syndrome (ARDS).
  
  
  METHODS
  A prospective interventional study in a 16-bed intensive care unit.
  
  
  METHODS
  Seven patients with severe head trauma (Glasgow Coma Scale <9) and ALI/ARDS.
  
  
  METHODS
  Patients were ventilated in assist/control mode with a ventilatory strategy providing adequate oxygenation (PaO(2) >70 mmHg) and normocapnia (PaCO(2) between 35-40 mmHg). Mid to end expiratory tracheal gas insufflation at 8 l/min flow rate was delivered for 90 min while normocapnia was maintained by simultaneous reductions in tidal volume. We measured (hemodynamics, oxygenation, lung mechanics, and cerebral parameters) in basal situation and during and after tracheal insufflation.
  
  
  RESULTS
  Tracheal gas insufflation allowed a significant decrease in tidal volume from 9.1 to 7.2 ml/kg, with associated reduction in driving pressure (plateau pressure minus positive end-expiratory pressure, PEEP) from 18.1 to 13.2 cm H(2)O. Total PEEP increased from 9.3 to 12.7 cm H(2)O due to the generation of lung hyperinflation. Oxygenation improved slightly during tracheal gas insufflation, and this improvement remained after stopping tracheal insufflation. No changes in hemodynamic or cerebral parameters were observed during the study.
  
  
  CONCLUSIONS
  In patients with severe head trauma and ALI receiving mechanical ventilation, expiratory tracheal gas insufflation allowed the targeted arterial PCO(2) level to be maintained together with a substantial reduction in tidal volume.
authors.affiliation: Critical Care Center, Hospital de Sabadell, Corporació Parc Taulí, Institut Universitari Fundació Parc Taulí, Universitat Autonoma de Barcelona [corrected] 08206 Sabadell, Spain. Mmartinez@CSPT.es
authors.forename: Melcior
authors.initials: M
authors.lastname: Martínez-Pérez
authors.forename: Francesca
authors.initials: F
authors.lastname: Bernabé
authors.forename: Rocío
authors.initials: R
authors.lastname: Peña
authors.forename: Rafael
authors.initials: R
authors.lastname: Fernández
authors.forename: Avi
authors.initials: A
authors.lastname: Nahum
authors.forename: Lluís
authors.initials: L
authors.lastname: Blanch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006259:Craniocerebral Trauma / Q000628:therapy*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007327:Insufflation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D012121:Respiration, Artificial / Q000379:methods*; D012128:Respiratory Distress Syndrome / Q000628:therapy*; D018709:Statistics, Nonparametric; D014132:Trachea