title: Pressure-controlled ventilation and intrabronchial pressure during one-lung ventilation.
abstract: BACKGROUND
  Pressure-controlled ventilation (PCV) has been suggested to reduce peak airway pressure (P(peak)) and intrapulmonary shunt during one-lung ventilation (OLV) when compared with volume-controlled ventilation (VCV). At the same tidal volume (V(T)), the apparent difference in P(peak) is mainly related to the presence of a double-lumen tracheal tube. We tested the hypothesis that the decrease in P(peak) observed in the breathing circuit is not necessarily associated with a decrease in the bronchus of the dependent lung.
  
  
  METHODS
  This observational study included 15 consecutive subjects who were ventilated with VCV followed by PCV at constant V(T). Airway pressure was measured simultaneously in the breathing circuit and main bronchus of the dependent lung after 20 min of ventilation.
  
  
  RESULTS
  PCV induced a significant decrease in P(peak) [mean (sd)] measured in the breathing circuit [36 (4) to 26 (3) cm H(2)0, P<0.0001] and in the bronchus [23 (4) to 22 (3) cm H(2)O, P=0.01]. However, the interaction (ventilatory mode x site of measurement) revealed that the decrease in P(peak) was significantly higher in the circuit (P<0.0001). Although the mean percentage decrease in P(peak) was significant at both sites, the decrease was significantly lower in the bronchus [5 (6)% vs 29 (3)%, P<0.0001].
  
  
  CONCLUSIONS
  During PCV for OLV, the decrease in P(peak) is observed mainly in the respiratory circuit and is probably not clinically relevant in the bronchus of the dependent lung. This challenges the common clinical perception that PCV offers an advantage over VCV during OLV by reducing bronchial P(peak).
authors.affiliation: Department of Anaesthesiology and Critical Care, Centre Hospitalier Universitaire (CHU) Bordeaux, Groupe Sud, Pessac, Bordeaux, France. hadrien.roze@chu-bordeaux.fr
authors.forename: H
authors.initials: H
authors.lastname: Rozé
authors.forename: M
authors.initials: M
authors.lastname: Lafargue
authors.forename: H
authors.initials: H
authors.lastname: Batoz
authors.forename: M Q
authors.initials: MQ
authors.lastname: Picat
authors.forename: P
authors.initials: P
authors.lastname: Perez
authors.forename: A
authors.initials: A
authors.lastname: Ouattara
authors.forename: G
authors.initials: G
authors.lastname: Janvier
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000403:Airway Resistance; D001980:Bronchi / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019990:Perioperative Care / Q000379:methods*; D011013:Pneumonectomy / Q000379:methods; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D015656:Respiratory Mechanics / Q000502:physiology; D013908:Thoracotomy / Q000379:methods*; D013990:Tidal Volume / Q000502:physiology; D055815:Young Adult