Anesthesia and anesthesiologist concerns for bronchial thermoplasty.

Bronchial thermoplasty (BT) is an upcoming treatment for patients with asthma refractory to traditional pharmacotherapy. BT is an invasive procedure which carries a risk of coughing, wheezing, bronchospasm, and laryngospasm during and after the procedure. Some of these complications can be minimized using better anesthetic techniques during BT. We hereby report a case of a 63-year-old female with poorly controlled asthma posted for BT done under general anesthesia (GA) with supraglottic device. GA provides better working conditions for pulmonologists when compared with sedation. But still there is no consensus on what would be the ideal anesthetic technique for BT procedure. Till the time, considering anesthesiologist and pulmonologist's prospective, GA (total intravenous anesthesia) using supraglottic device would be a preferred choice for a safe and effective anesthetic strategy in BT.

Background

Bronchial thermoplasty (BT) is an upcoming treatment for patients with asthma refractory to traditional pharmacotherapy.[1] In BT, controlled radiofrequency energy is applied to the bronchial wall to reduce the airway smooth muscle mass.[2] BT is an invasive procedure performed in patients with severe asthma, and it carries a risk of coughing, wheezing, bronchospasm, and desaturation during the procedure. In the postprocedural period, coughing with laryngospasm and bronchospasm are the common causes of morbidity[3] leading to increased hospital stay. Some of these complications can be minimized using better anesthetic techniques during BT. But still there is no consensus on what would be the ideal anesthetic technique for BT procedure.

We share our experience of a case of BT done under general anesthesia (GA) with supraglottic device.

Case Report

A 63-year-old female having diabetes and hypothyroidism, controlled on medications, presented in the pulmonary medicine outpatient department with complaints of dyspnea (NYHA grade 4) and B/L wheeze in chest. Her pulmonary function test showed severe restrictive abnormality (FEV1 = 55%, FVC = 60%, FEV1/FVC = 99%). She was diagnosed with asthma 5 years ago and her symptoms were poorly controlled on multiple medications. She was on tab. Wysolone (prednisolone) 50 mg OD, MDI Foracort (budesonide + formoterol), and MDI Tiova (tiotropium) puffs in the preprocedure period. Considering her long history with poorly controlled symptoms of asthma, she was planned to undergo BT.

After taking informed written consent, she was premedicated with 0.5 mg of alprazolam PO in the night before BT to allay her anxiety and advised to take her usual medications of asthma till the morning of the procedure. After taking the patient to the table, appropriate monitors were applied including three-lead electrocardiogram, continuous pulse oximetry (SpO2), and noninvasive blood pressure. Her baseline heart rate (HR) was 94 beats/min, SPO2 97%, and blood pressure 149/84 mmHg. A 20-G IV line was secured. Inj. glycopyrrolate was given in the doses of 0.2 mg intravenously and patient was nebulized with duolin (salbutamol and ipratropium) before starting the procedure.

She was preoxygented with 100% oxygen for 3 min. Induction was done with IV fentanyl 100 μg, propofol 120 mg, and atracurium 30 mg. Once the adequacy on ventilation was confirmed, supraglottic device (i-gel 3#) was inserted and ventilation was resumed. Balanced anesthesia was maintained with O2/air mixture with FiO2 0.3 and propofol infusion keeping BiSpectral Index values between 40 and 60 with intermittent boluses of inj. fentanyl (1 μg/kg) and inj. atracurium. A flexible bronchoscope was placed through the supraglottic device and a bronchial thermoplasty catheter was placed through the bronchoscope to perform thermoplasty of the right lower lobe [Figure 1]. The entire procedure was uneventful with FiO2 of 0.3, except for one episode of desaturation with SPO2 dropping down to 82% and tachycardia, and HR reaching up to 180/min. The episode of desaturation and tachycardia was observed during the first activation of thermoplasty catheter [Figure 2]. This was immediately informed to the pulmonologists and it settled down once the activation was stopped. The procedure lasted for about 45 min. After completion of the procedure, muscle relaxation was reversed with neostigmine and gylcopyrrolate. i-gel was removed after the patient was fully awake and following commands. She was shifted to the intensive care unit on supplemental oxygen via face mask and monitored for postprocedural complications. The patient was followed up to 1 week after procedure and she did not develop any respiratory complications.

Figure 1

Flexible bronchoscope through the supraglottic device with bronchial thermoplasty catheter (white in color)

Figure 2

Bronchoscopic view of thermoplasty catheter in right lower lobe of bronchus

Discussion

The challenge in any procedure that involves sharing the airway is the ability to provide adequate ventilation and oxygenation. First, BT procedures require high precision and last longer than diagnostic bronchoscopies. Second, they are performed in patients with highly reactive airways which involve an increased risk of developing laryngospasm and bronchospasm during the procedure. Every single activation during a BT represents a strong mechanical manipulation of the bronchial mucosal wall that contributes to an increased risk of adverse events[4] and hemodynamic alterations. In this case, we too assume that during activation of the catheter there was strong mechanical stimulation leading to tachycardia.

In our case, GA was used with Supraglottic device SGD (i-gel) and produced better procedural conditions compared with moderate and deep sedation. It has been found that procedural conditions were occasionally suboptimal in moderate to deep sedation due to episodes of hypoventilation and/or airway obstruction requiring jaw thrusts and either oral or nasal airways to maintain the patency of the upper airway.[5] The decision to use an SGD (i-gel) over an Endotracheal tube (ETT) was based on several factors. SGD (i-gel) placement is less stimulating than ETT placement, which may reduce the risk of bronchospasm triggered by endotracheal intubation.[6] Also, SGD (i-gel) insertion is easier when compared with intubation. However, the use of endotracheal tube may be considered in patients with high aspiration risk and in anticipation of severe bronchospasm with high peak airway pressures.

These patients’ population are more prone to gas trapping which can be precipitated by coughing during procedure, hence controlled ventilation is preferred.[7] Finally, during BT delivery, extreme heat is being delivered to airway muscle which under high inspired oxygen concentration carries a risk of airway fire. Under controlled ventilation, the inspired oxygen concentration can be lowered down to a safe limit rapidly when compared with spontaneous ventilation. Therefore, we used O2/air mixture with FiO2 0.3.

The existing literature supports BT as an effective procedure with low incidence of adverse events such as asthma exacerbations or atelectasis.[8] In our case also, the patient did not develop any postprocedural complications such as dyspnea, wheezing, and coughing till discharge.

BT is a rapidly emerging bronchoscopic treatment for patients with severe asthma. GA provides better working conditions for pulmonologists when compared with sedation. It not only provides an immobile patient but also requires fewer interruptions during the procedure. In addition, patient satisfaction is better as periprocedural complications are less during GA. The debate still continues on what would be the ideal form of anesthesia for BT. Few properly conducted randomized trials can give us a better answer to it. Till the time, considering anesthesiologist and pulmonologist's prospective, GA (total intravenous anesthesia) using supraglottic device would be a preferred choice for a safe and effective anesthetic strategy in BT.

Ethical Approval/Patient consent

Patient consent was taken.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.