Effect of the Minimum Bronchial Cuff Volume of Left-sided Double-lumen Endotracheal Tube for One-lung Ventilation on the Change of the Bronchial Cuff Pressure During Lateral Positioning in Thoracic Surgery
Condition: Lung Cancer; Pneumothorax
MeSH terms: Pneumothorax
Study type: Observational

Summary: 
      Over-inflation of the bronchial cuff of the double-lumen tube (DLT) can cause damage to the
      airway mucosa and misplacement of the tube, and under-inflation may cause incomplete collapse
      of the non-ventilated lung and incomplete ventilation of the lung that should be ventilated.
      Appropriate cuff pressure is generally known to be ranged 20-30 cmH₂O, but in the study of
      Okubo et al., who observed the minimum bronchial cuff volume and pressure that did not cause
      air leakage using the method of confirming by capnography, it was possible to obtain the
      result that OLV was possible without air leakage even at a pressure lower than 25 cmH₂O (the
      generally recommended tube cuff pressure) in both men and women. In a recent study of Yamada
      et al., when using the capnography waveform-guided method to inflate the bronchial cuff by
      checking for air leakage using the capnography waveform, the bronchial cuff volume (BCV) that
      satisfies the air-tight seal was significantly smaller compared with a pressure-guided method
      to inflate the bronchial cuff with 20 cmH₂O.

      The minimum bronchial cuff volume (BCVmin) at which such air leakage does not occur may vary
      from individual to individual. It is presumed that this is because the diameter of the left
      main bronchus (LMB) differs from individual to individual, which causes the variation of the
      gap between the diameter of the LMB and the outer diameter of the DLT mounted thereon.
      Moreover, the previous study revealed that the lateral positioning could increase the
      pressure of the bronchial cuff mounted on the LMB due to the gravity-induced morphological
      and conformational change of the trachea. Considering these factors, the researchers
      hypothesized that the change in the bronchial cuff pressure (BCP) due to a positional change
      might vary depending on whether the bronchial cuff was inflated, that is, the initially
      established BCVmin.

      Therefore, in this study, the researchers tried to investigate the effect of BCVmin on the
      change of minimum bronchial cuff pressure (BCPmin) due to the positional change from the
      supine to lateral decubitus, by dividing the groups whose BCVmin is 0 ml or exceeds 0 ml.
    


Intervention name(s): Lateral positioning; Cuff pressure measurement
Intervention type(s): Behavioral; Device
Intervention description(s): After the DLT intubation, the patient is placed in lateral decubitus position; The pressure of the bronchial cuff should be measured with cuff-manometer in supine position, and then measurement should be repeated after lateral positioning
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The researcher contacts patients who are potential candidates for the study at the time of
        their preoperative visit. The participants are being enrolled in the study at the tertiary
        university hospital in Daegu, South Korea, from October 2021 to December 2021
      
Keywords: Cuff pressure; Double lumen endotracheal tube; Lateral positioning