Techniques for Lung Deflation With Arndt® Blocker
Condition: Spontaneous Pneumothorax
MeSH terms: Pneumothorax
Study type: Interventional
Phase: Phase 2

Summary: 
      The use of wire-guided Arndt® endobronchial blocker does not gain widespread acceptance
      during video-assisted thoracoscopy (VATS) because it takes longer time to collapse the
      operative lung especially in patients with chronic obstructive lung disease (COPD). The use
      of a disconnection technique for deflation of Arndt® blocker had a comparable degree of lung
      collapse with the use of double-lumen tubes. However, it carries a risk of blood or infected
      secretions contaminating the dependent lung.

      We hypothesise that the use bronchial suction of through a barrel part of a 1-mL insulin
      syringe attached to the suction port of the bronchial blocker would be associated with
      comparable time to optimum lung collapse with the disconnection technique.

      After ethical approval, 58 patients with spontaneous pneumothorax scheduled for elective VATS
      using Arndt blocker® for lung separation will be included in this prospective, randomized,
      double-blind study.

      Patients will be randomly assigned to deflate the blocker with either disconnecting the
      endotracheal tube from the ventilator for 60 s. prior to inflation of the bronchial blocker
      allowing both lungs to collapse, or attaching -20 cm H2O of suction to the suction port of
      the blocker through the barrel part of a 1-mL insulin syringe (n = 29 for each group).
    

Detailed description: 
      Most Middle Eastern and British thoracic anesthesiologists (100% and 98%, respectively) are
      using a double-lumen endobronchial tube (DLT) as the first-choice lung separation technique,
      1-2 although the intubation with a single lumen tube (SLT) could be easier. However, the use
      of a bronchial blocker has a special concern as it takes longer time to collapse the
      operative lung,3 which precludes its widespread acceptance for video-assisted thoracoscopic
      (VATS) procedures because of delayed insertion of the trocars.

      The wire-guided Arndt® endobronchial blocker (Cook® Critical Care, Bloomington, IN) takes
      longer time for lung collapse than the Univent® tube (approximately, 26 min vs. 19 min,
      respectively; P<0.006),3 that may be due to its narrower inner lumen (1.4 mm vs. 2.0 mm,
      respectively).

      There are different techniques described to speed of lung collapse during the use of Arndt®
      endobronchial blocker. These include the disconnecting of the SLT from the ventilator and
      allowing both lungs to collapse before inflation of the bronchial blocker cuff, 4-5 or
      bronchial suction either through the fiberoptic bronchoscope after deflation of the bronchial
      cuff and cessation of ventilation before re-inflation of the bronchial cuff, or through a
      barrel part of a 3-mL syringe attached to the suction port of the bronchial blocker.3 The use
      of a modified disconnection technique for deflation of Arndt® endobronchial blocker had a
      comparable degree of lung collapse with the use of DLT during VATS procedures in patients
      presented with pneumothorax.5 However, compared with the bronchial suction, the disconnection
      technique may carry a risk of blood or infected secretions contaminating the dependent lung.6

      To the best of our knowledge, the comparison of the efficacy of disconnection and bronchial
      suction techniques to facilitate the deflation of Arndt® blocker during thoracoscopic surgery
      has not yet been studied.

      In all patients, standard monitors and state and response entropy (SE and RE, respectively)
      based-depth of anaesthesia will be applied. The radial artery will be catheterized.

      Anesthetic technique is standardized in all studied patients. The experienced attending
      anesthesiologist (>10 yrs.), who will give the anesthetic and places the Arndt® blocker will
      not be blinded to group assignment and will not be involved in the collection of outcome
      data.

      After preoxygenation, anesthesia will be induced using propofol 1.5-3 mg/kg and
      target-controlled infusion (TCI) of remifentanil at an effect-site concentration (Ce) of 4
      ng/mL, to achieve the SE values below 50 and the difference between RE and SE below 10.

      Cisatracurium (0.2 mg/kg) will be given to facilitate the tracheal intubation with a SLT,
      size 8.0 mm for women and 8.5 mm for men. Then a 9.0 F, 78-cm Arndt® blocker will be advanced
      through the blocker port of its multiport adapter and the wire loop will be coupled with a
      pediatric fiberoptic bronchoscope (FOB) that has been introduced through the fiberoptic port.
      The Arndt® blocker will be introduced to the targeted bronchus. The correct position of the
      Arndt® blocker wil be confirmed with a FOB.

      Anesthesia will be maintained with 0.7-1.5 minimum alveolar concentration (MAC) of
      sevoflurane and remifentanil Ce of 2-4 ng/ml to maintain the SE values below 50, the
      difference between RE and SE below 10 and the mean arterial blood pressure (MA) and heart
      rate <20% of baseline values. Cisatracurium increments will be used to maintain surgical
      relaxation.

      Patients' two lungs (TLV) will be mechanically ventilated with fraction of inspired oxygen
      (FiO2) of 0.4 in air, tidal volume (VT) of 8 mL/kg, inspiratory to expiratory (I: E) ratio of
      1:2.5 and PEEP of 5 cm H2O, and respiratory rate will be adjusted to achieve a PaCO2 of 35-45
      mm Hg.

      After the positioning of the patient in the lateral decubitus position, the position of the
      blocker will be reconfirmed, the blocker cuff will be inflated with a titrated amount of air
      to create a seal under direct visualization of FOB and the wire loop will be removed.

      All surgical procedures will be performed by the same surgeons who are blinded for the lung
      collapse technique and who are absent from the operating room during placement of the BB and
      deflation of the lung.

      The VATS procedure begins with the exploration of the pleural cavity using a 30° video
      thoracoscopic camera through a 1.5 cm single skin incision with the use of 1-3 trocars which
      enabled the thoracoscopic instruments to move the lung.
    

Intervention name(s): Disconnection group; Bronchial Suction group
Intervention type(s): Other; Other
Intervention description(s): The blocker cuff was deflated, the single lumen tube was disconnected from the ventilator for 60 s allowing the surgical lung to collapse, then the cuff was re-inflated with the same amount of air as determined previously and the ventilator was reconnected to the single lumen tube; The barrel part of a 1-mL insulin syringe was attached to the suction port of the bronchial blocker, and connected to -30 cm H2O of suction.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Thoracic surgery; Arndt® blocker; lung deflation; Disconnection technique; Continuous suction; Elective video-assisted thoracoscopic