Bronchial Thermoplasty: A Novel Therapeutic Approach to Severe Asthma

The overall goal of this procedure. Bronchial thermoplasty or BT, is a non-drug procedure for severe persistent asthma that delivers thermal energy to the airway wall in a precisely controlled manner to reduce excessive airway, smooth muscle, reducing the amount of airway, smooth muscle decreases the ability of the airways to constrict, thereby reducing the frequency of asthma attacks. During bronchial thermoplasty, a small flexible tube is advanced into the airway through a standard flexible bronchoscope placed through the mouth or nose.

No incision is required. The allaire device has an expandable wire electrode array at the tip, and when it is expanded, the forearms of the electrode array come in contact with and fit snugly against the airway wall. The expanded electrode array will then deliver controlled radio frequency energy for about 10 seconds to heat the airway smooth muscle.

About one third of the targeted lung areas are treated during a single procedure. A total of three procedures are currently needed for complete treatment. Once the procedure is completed, the device and the bronchoscope are removed.

The controlled energy delivered during bronchial thermoplasty creates mild heat within the airway wall that is designed to reduce the amount of airway smooth muscle. By reducing the amount of airway smooth muscle, the procedure reduces the ability of the airway walls to contract and narrow during an asthma attack. Bronchial thermoplasty is a novel procedure-based therapy for severe asthma.

A main advantage this technique has over conventional pharmacologic therapy is that medications must be taken regularly, multiple times daily, sometimes having side effects. Bronchial thermoplasty has been proven to improve asthma control and have long lasting benefits. The implications of this new procedure are extremely encouraging for those with severe adult asthma.

This represents a new non-pharmaceutical therapy for the treatment of severe asthma. A pulmonologist demonstrating exper expertise in bronchoscopy will be able to perform this procedure after the appropriate training. Careful attention to patient selection, effective patient management and a systematic approach to the procedure allow for best possible outcomes.

So thinking about bronchial thermoplasty and the proper patient to refer for treatment, a typical patient would be someone with asthma who would be classified as severe and persistent despite proper controller medications, including inhaled corticosteroids and long-acting beta agonists. Symptoms they may suffer from would include cough, shortness of breath, chest tightness, mucus production, despite the use of usual standard pharmacologic measures, including the anti-inflammatories, inhaled corticosteroids, and long-acting beta agonists. Despite having severe and persistent asthma, their clinical status should be stable for approximately two weeks before undergoing bronchial thermoplasty.

They should have no active respiratory infections and be stable to perform bronchoscopy as per usual hospital procedures. The treatment plan is to administer bronchial thermoplasty in three treatment sessions. Each session treats a specific region of the lung.

The first session focuses on one lower lobe. The second session focuses on the second lower lobe. The final session focuses on both upper lobes.

Each treatment is scheduled approximately three weeks apart. Bronchial thermoplasty is indicated for the treatment of severe persistent asthma. In adults, the patient must be 18 years and older with asthma that is not well controlled.

Using daily inhaled corticosteroids and long-acting beta agonists, patients should be able to safely undergo bronchoscopy per hospital guidelines. Patients with the following conditions should not be treated with bronchial thermoplasty, presence of a pacemaker, internal defibrillator, or other implantable electronic device. Known sensitivity to medications required to perform bronchoscopy, including lidocaine, atropine, and benzodiazepines.

Patients that have previously been treated with the allaire system should not be retreated in the same areas. No clinical data are available. Studying the safety and effectiveness of repeat treatments.

Patients should not be treated while the following conditions are present. Active respiratory infection, asthma attack, or changing dose of systemic corticosteroids in the past 14 days, known bleeding disorder. As with other bronchoscopic procedures, patients should stop taking anticoagulants, anti-platelet agents, aspirin or nonsteroidal anti-inflammatory medications before the procedure.

With physician guidance on the day of the procedure, the bronchoscopist needs to reevaluate the patient and ensure that the patient's asthma status is stable and that they remain a good candidate for bronchial thermoplasty. Under moderate sedation, the patient should not have any current respiratory tract infections and no severe asthma exacerbations within the last two weeks. Pre-procedure spirometry should be performed and FEV one value should be within 10%of patient's normal value.

Peri procedure preparation includes prophylactic administration of 50 milligrams per day of oral corticosteroids for five days. These include the three days before the procedure, the day of the procedure, and the day after the procedure. Steroids minimize post-procedure inflammation additionally to help dilate the airways.

An inhaled bronchodilators such as albuterol can be administered at least 30 minutes prior to the procedure if needed, based on pre-procedure spirometry results in the period immediately following bronchial thermoplasty. Typically, there is an expected transient increase in the frequency and worsening of respiratory related symptoms, which are of the type expected following bronchoscopy. In patients with asthma, these events typically occur within a day of the procedure and resolved on average within seven days.

With standard care in the long term, fewer bronchial thermoplasty treated patients report adverse respiratory events. The bronchoscopist reviews the lung map and plans the order in which the airway segments are to be assessed and treated. Treated treatment planning is crucial to the thoroughness and ultimately to the success of bronchial thermoplasty, helping to avoid under or overtreatment of the airways to help suppress airway secretions and anticholinergic such as glycopyrrolate is administered at least 30 minutes prior to initiation of the procedure.

Properly treating the patient with an effective drying agent, such as glycopyrrolate is important in bronchial thermoplasty as it reduces the amount of airway secretions and may improve visibility through the bronchoscope. After the patient's chart is reviewed, the patient is prepped and a peripheral intravenous line is placed. Patient is given supplemental oxygen via oral or nasal cannula and is placed on appropriate monitoring.

For sedation, the patient is monitored with continuous electrical cardiac or EKG monitoring, continuous pulse oximetry and continuous intermittent noninvasive blood pressure. A gel type return electrode is placed on the patient and connected to the allaire RF controller for proper functioning of the allaire system. Once the patient is prepared, the sedation is typically accomplished with IV midazolam and fentanyl.

Additionally, judicious application of topical anesthesia such as lidocaine is used during the procedure to control the airway reactivity. The patient's nasal passage, posterior pharynx, focal cords, and bronchial tree are anesthetized. Bronchial thermoplasty is performed using the alaris system, connect the foot switch to the ALLAIRE RF controller.

The single use disposable allaire catheter is removed from the package and connected to the allaire RF controller. The controller is turned on, a self-test is automatically performed, and a green light signals that the controller is functional. A standard commercially available flexible bronchoscope is placed either via the nasal or oral approach.

Liberal topical anesthesia is applied as needed to advance the bronchoscope without difficulty or airway reactivity. As the bronchoscope is passed down the airways, additional local anesthetics are used as necessary. The tip of the bronchoscope is navigated to the region of the lung to be treated.

In this example, the left lower lobe will be treated. All targeted airways are inspected before treatment begins. The bronchoscopist plans the order in which the airway segments are to be assessed and treated, assisted by a map of the airways.

Here, the treatment plan begins in the anterior, then the lateral posterior, and finishing in the superior airway segment. Typically, the most distal airway in the targeted lobe is treated first. Once the site is selected, the allaire catheter is introduced through the working channel of the bronchoscope and positioned at the desired location in the airway at the proper site.

The electrode array at the tip of the catheter is expanded under direct visualization to contact the airway wall. The bronchoscopist activates the radio frequency controller by stepping on the foot switch to deliver RF energy to the tissue. Under direct visualization, the RF controller delivers low power, temperature controlled RF energy to the airway and automatically terminates the energy delivery.

Upon completion of the cycle, a long audible tone by the controller signals the end of RF energy delivery and that the treatment cycle is complete. A single activation of the catheter delivers RF energy over a distance of approximately five millimeters. The length of the exposed electrodes within the electrode array, the bronchoscopist must maintain contact of the electrode array with the airway wall, even while airways remain in motion from tidal breathing, the temperature set point, power limit and delivery time are configured in the RF controller software and are not user adjustable.

The cumulative number of activations is recorded on the allaire controller activation counter Throughout the procedure following the proposed treatment plan, the electrode array is collapsed and the tip of the catheter is moved approximately five millimeters. To repeat the RF activation, five millimeter marker bands at the distal end of the catheter facilitate repositioning of the catheter. This process is repeated and subsequent activations are positioned five millimeters proximally and adjacent to, but not overlapping.

The previous activation site segments that have been treated should be recorded on a procedure form. A systematic approach from distal to proximal working methodically from airway to airway across the region of the lung being treated is recommended to ensure that all accessible airways are carefully identified and treated only once, depending on patient size and anatomy, a range of approximately 40 to 80 activations or energy delivery cycles are performed. This technique is used in all accessible airways distal to the main stem bronchi, and greater than three millimeters in diameter.

Bronchial thermoplasty for the upper lobes requires additional time for the treatment, as these regions are typically treated within one treatment session covering both upper lobes. The procedure performed is identical to that described above, but requires additional time because it involves navigating the tortuous anatomy of the upper airways, and additionally, it covers more area than either lower lobe. Depending on patient size and anatomy.

A range of approximately 60 to 100 activations is performed in the upper lobes. Following the completion of the bronchial thermoplasty procedure, the patient is awakened and begins recovery period. The patient is observed in the recovery room until lung function returns to a satisfactory level, which usually takes two to four hours following each treatment session.

Spirometry, breath sounds and vital signs such as heart rate, blood pressure, temperature, respiratory rate, and pulse oximetry are checked and stabilized before discharge, the patient is discharged from the recovery room when the post bronchodilator FEV one after the bronchial thermoplasty procedure is greater than 80%of the pre-procedure value, and the patient is feeling well, the patient is reminded to use the prednisone or equivalent oral corticosteroids for one day following each bronchial thermoplasty procedure. Patient is called one day, two days, and seven days following the procedure to assess post-procedure status. Office visits are scheduled at two to three weeks following bronchial thermoplasty to assess pulmonary function and patient stability for the next procedure, and to schedule subsequent bronchial thermoplasty procedures as needed.

Follow-up visits for long-term monitoring of improvement of asthma status are scheduled as needed. After watching this video, you should have a good understanding of how to perform bronchial thermoplasty, the experience of the bronchoscopist, a detailed procedural plan. Effective patient management during the procedure and appropriate post-procedure follow-up are all necessary components to achieve the best possible outcomes.

When performing this technique, it is important to remember that proper patient selection ensures safety. Broncho thermoplasty is indicated for severe asthma patients who remain symptomatic despite medications, but whose disease status is stable enough to safely undergo bronchoscopy as per hospital guidelines.