title: [Measurement of the Minimum Pressure in the Bronchial Cuff during One-lung Ventilation Using a Capnometer].
abstract: BACKGROUND
  It is recommended to avoid overinflation of the bronchial cuff, leading to ischemic pressure damages to the respiratory mucosa and bronchial rupture. We investigated the minimum bronchial cuff pressure of 35 Fr double lumen tubes (DLTs) during one lung ventilation using a capnometer.
  
  
  METHODS
  We studied 50 patients who were scheduled to undergo thoracic surgery. General anesthesia was induced and the patients were intubated with 35 Fr left DLT. With a fiberoptic bronchoscope, the DLT was positioned appropriately. The bronchial cuff was inflated first with air 3-3.5 ml. Lung isolation was confirmed by auscultation. Measurements were performed with the patient in the lateral position. Ventilating one lung isolatedly for 5 minutes, we confirmed non ventilated condition with a capnometer displaying flat line. The bronchial cuff was deflated 0.5-ml steps just before displaying the respiratory pattern by the capnogram. The bronchial cuff pressure and volume were recorded at this point
  
  
  RESULTS
  The minimum pressures of bronchial cuff (volume) for one lung ventilation are for male 5.46 ± 0.6 cmH2O (2.33?0.1 ml) and for female 1.5?0.5 cmH20 (1.09 ± 0.3 ml). These values are smaller than the recommended value (< 25 cmH2O). There was no case in which the collapse of the operated lung was insufficient.
  
  
  CONCLUSIONS
  In this study, the bronchial pressure higher than 12 cmH2O was not necessary for one lung ventilation. If high intracuff pressure is necessary to seal the bronchus, there are possibilities of the incompatibility of the size of DLT and the herniation of the bronchial cuff to the proximal side. The method of confirmation of OLV using a capnometer can display the non ventilated condition on the monitor objectively. We can thus decrease troubles during operations.
authors.forename: Haruka
authors.initials: H
authors.lastname: Okubo
authors.forename: Takashi
authors.initials: T
authors.lastname: Kawasaki
authors.forename: Aiko
authors.initials: A
authors.lastname: Shibayama
authors.forename: Takeyoshi
authors.initials: T
authors.lastname: Sata
mesh_terms: D000367:Age Factors; D000368:Aged; D000768:Anesthesia, General / Q000295:instrumentation*; D001980:Bronchi; D019296:Capnography; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D061810:One-Lung Ventilation; D011312:Pressure; D012727:Sex Characteristics