Changes in the Bronchial Cuff Pressure of Left-Sided Double-Lumen Endotracheal Tube by Lateral Positioning: A Prospective Observational Study

Proper bronchial cuff pressure (BCP) is important when using a double-lumen endotracheal tube (DLT), especially in thoracic surgery. As positional change during endotracheal tube placement could alter cuff pressure, we aim to evaluate the change in BCP of DLT from the supine to the lateral decubitus position during thoracic surgery. A total of 69 patients aged 18–70 years who underwent elective lung surgery were recruited. BCP was measured at a series of time points in the supine and lateral decubitus positions after confirming the DLT placement. The primary outcome was change in the initial established BCP (BCPi), which is the maximum pressure at which the BCP did not exceed 40 cmH2O without air leak in the supine position, after lateral decubitus positioning. As the primary outcome, the BCPi increased from 25.4 ± 9.0 cmH2O in the supine position to 29.1 ± 12.2 cmH2O in the lateral decubitus position (p < 0.001). Out of the 69 participants, 43 and 26 patients underwent surgery in the left-lateral decubitus position (LLD group) and the right-lateral decubitus position (RLD group) respectively. In the LLD group, the BCPi increased significantly (p < 0.001) after lateral positioning and the beginning of surgery and the difference value, ∆BCPi, from supine to lateral position was significantly higher in the LLD group than in the RLD group (p = 0.034). Positional change from supine to lateral decubitus could increase the BCPi of DLT and the increase was significantly greater in LLD that in RLD.

Effect of lateral positioning on the bronchial cuff pressure of a left-sided double-lumen endotracheal tube during thoracic surgery: study protocol for a prospective observational study

IntroductionCorrect pressure is important when using a double-lumen endotracheal tube (DLT), especially in thoracic surgery. An inadequate bronchial cuff pressure (BCP) can cause air leak and interfere with visualisation of the surgical field, whereas an excessive pressure BCP can lead to cuff-related complications. Based on several reports that cuff pressure could alter after a positional change when using an endotracheal tube, we hypothesise that a change from the supine position to the lateral decubitus position, which is essential for thoracic surgery, would affect the BCP of the DLT.Methods and analysisThis prospective, single-centre, observational study will enrol 74 patients aged 18–70 years undergoing elective lung surgery from September 2018 to April 2019. The primary outcome will be the change in the ‘initially established BCP’ (maximum BCP not exceeding 40 cm H2O with no air leak in the supine position) after lateral decubitus positioning. BCP and air leak will be assessed in each patient position during inflation of the cuff with air in 0.5 mL increments from 0 to 3 mL. Secondary outcomes will include the incidence of BCP exceeding 40 cm H2O after the initial established value and that of a change in the smallest bronchial cuff volume without air leak after a change to the lateral position. The relationship between the change in BCP and airway pressure, compliance and body mass index after lateral positioning will be investigated.Ethics and disseminationThe study will be conducted in accordance with the Declaration of Helsinki and supervised by the Daegu Catholic University Medical Center institutional review board (study approval number CR-18–111). All patients will receive information about the study and will need to provide written informed consent before enrolment. The results will be presented at an international meeting and published in a peer-reviewed journal.Trial registration numberNCT03656406; Pre-results.

Dimensions of Double-Lumen Tracheobronchial Tubes

The diameter of the left main bronchus is the determining dimension when selecting the size of a left tracheobronchial (double-lumen) tube for lung separation. However, this information is not given by any manufacturer, either on the tube or in the package insert. This paper describes the lengths and diameters of the deflated bronchial cuff segment of left tracheobronchial tubes in common use. One hundred and seventy-one left tracheobronchial tubes ranging in size from 28 to 41 nominal French gauge from four manufacturers were measured. There was wide variation between tubes of the same nominal size from the same manufacturer. For tubes of the same size from the same manufacturer, the diameter of the segment with the deflated bronchial cuff varied by more than 1 mm in diameter in some instances.The diameter of the bronchial cuff segment did not consistently decrease as the nominal size decreased even for the same manufacturer. There was major overlap in diameters of the bronchial segments between Fr 41, Fr 39, and Fr 37 tubes from most manufacturers, so that some of the Fr 39 tubes have a bronchial cuff segment diameter as much as 0.5 mm larger than the Fr 41 tube. It is concluded that the current French gauge markings on left tracheobronchial tubes are of very limited value in determining the appropriate size to be selected for a patient. More accurate and consistent dimensions of tracheobronchial tubes are required to improve clinical selection.