Bronchial Thermoplasty

March 31, 2014
Author: VerLee, Miller

Description: Bronchial Thermoplasty is a novel treatment for asthma in patients who require high dose continuous medical therapy to control symptoms.

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Introduction

Bronchial thermoplasty is a new modality for treating asthma. Airway obstruction from asthma occurs not only at the small airway level, but from smooth muscle constriction of larger airways as well. Bronchial thermoplasty targets airway smooth muscle by delivering a controlled specific amount of thermal energy (radiofrequency ablation) to the airway wall through a dedicated catheter via a flexible bronchoscope. Bronchial thermoplasty is performed via fiberoptic bronchoscopy in 3 separate procedures in which all accessible airways located beyond the mainstem bronchi (average of 3-10 mm in diameter) except for the right middle lobe are treated. The delivery of energy during bronchial thermoplasty uses continuous feedback to tightly control the degree and time of tissue heating to decrease smooth muscle mass without airway perforation or stenosis.

BT Airways
BT-Device

View the Manufacturer's Video describing equipment and procedure

BT Graphic

Indications:

  • Candidates for bronchial thermoplasty include adults with severe persistent asthma who require
    • regular maintenance medications of inhaled corticosteroids (>1000 μg/day beclomethasone or equivalent) and
    • a long- acting beta agonist (≥100 μg/day salmeterol or equivalent).
  • These patients would have received add-on therapies such as
    • leukotriene modifiers (Singulair, Zyflo, Accolate),
    • omalizumab (Xolair), and
    • oral corticosteroids 10 mg/day or less.
  • These patients should
    • be on stable maintenance asthma medications according to accepted guidelines,
    • have a prebronchodilator FEV1 of 60% or more of predicted, and
    • have a stable asthma status:
      • FEV1 within 10% of the best value,
      • no current respiratory tract infection, and
      • no severe asthma exacerbation within the preceding 4 weeks.

Contraindications:

Contraindications to bronchial thermoplasty include the following:

  • The presence of a pacemaker, internal defibrillator, or other implantable electronic device.

  • Known hypersensitivity to drugs used during bronchoscopy

  • Active respiratory infection
  • Asthma exacerbation or changing dose of systemic corticosteroids for asthma (up or down) in the past 14 days
  • Severe comorbid conditions that would increase the risk of adverse events
  • Patients were not considered candidates for bronchial thermoplasty if in the previous year they had
    • 3 or more hospitalizations for asthma,
    • 3 or more lower respiratory tract infections, and
    • 4 or more oral corticosteroids used for asthma.
  • Patients previously treated with the Alair System should not be retreated in the same area(s).
  • Known coagulopathy
  • As with other bronchoscopic procedures, patients should stop taking anticoagulants, antiplatelet agents, aspirin and NSAIDS before the procedure with physician guidance.

Location of Procedure:

The Alair System should only be used in a fully equipped bronchoscopy suite or Operating Room with access to full resuscitation equipment to handle hemoptysis, pneumothorax, and other respiratory complications including acute exacerbation of asthma and respiratory failure requiring intubation.

The Alair System should only be used by clinicians who are experienced in bronchoscopy and have undergone adequate training with the device.

The Alair System should only be used in patients stable enough to undergo bronchoscopy in the judgment of their clinician.


Anesthesia Technique

The first session treats the airways in the right lower lobe of the lungs, the second treats the airways in the left lower lobe, and the third procedure treats the airways in both upper lobes of the lungs.

  • Standard ASA monitors
  • Preoperative sedation is acceptable, if desired
  • DuoNeb treatment preop in ACU
  • Check with pulmonologist and anesthesiologist about a bolus dose of IV steroids (suggested Solumedrol 40mg IV) if the patient did not take his or her oral steroids on the day of the procedure.
  • Glycopyrrolate 0.4 mg IV as an anti-sialogogue pre-induction in ACU or OR (0.2mg not enough)
  • Intravenous induction with propofol and alfentanil. Some anesthetists add ketamine to propofol, 20mg ketamine /200mg propofol.
  • Succinylcholine for intubation, unless contraindicated
  • 8.0 ETT, if possible; Respiratory Therapy has adapter for 'scope and Breathing Circuit
  • Maintenance with sevoflurane and propofol infusion supplemented with IV alfentanil as needed.
        • Return of spontaneous ventilation is important, as positive pressure ventilation is complicated by continuous suction by endoscopist
        • The BTP procedure can make uptake of inhaled agent less predictable, and the propofol plus alfentanil helps maintain anesthesia while also reducing airway reflexes.
        • Further muscle relaxant is not required in most cases.
  • Plan to extubate the trachea at the end of the procedure.

 

There is NO increased risk of airway fire from the ablation catheter in this procedure.

December 23, 2013, updated Mar 8, 2014


References

Manufacturer's Video describing equipment and procedure

FDA Medical Device Approval

J Allergy Clin Immunol. 2013 Aug 30 Bronchial Thermoplasty for Asthma: 5 Year Efficacy Results