Interventional bronchoscopy procedures are used to alleviate symptoms caused by stenoses and obstructions in the trachea and main bronchi. The patient may be severely compromised with a life-threatening airway obstruction by the time it has produced significant symptoms. Endoscopic management with laser ablation, stent placement, and other techniques can provide successful symptom relief in many of these patients.1
Interventional bronchoscopic procedures are routinely performed during general anesthesia. The insertion of an airway device and the nature of these procedures often make muscle relaxation and controlled ventilation necessary. In addition to the airway narrowing or obstruction, the airway caliber is compromised by the endoscopic instrumentation, and may be further challenged by clots or tumor fragments. Adequate ventilation and oxygenation can therefore be a challenge in such patients.2
In this article, we report our experience regarding the choice of airway route and ventilation management during interventional bronchoscopy treatment in patients with different types of airway obstruction, with special focus on airway management in patients with critical airway obstruction (CAO).
Interventional bronchoscopic procedures have been performed at The Intervention Centre in Oslo University Hospital, Rikshospitalet, since 1998. The institution is a tertiary medical center and patients with malignant airway obstruction nationwide are referred to us for treatment. All patients referred for interventional bronchoscopy were evaluated on the basis of medical history, clinical examination, and bronchoscopy. All procedures were consecutively registered in the department’s procedural database, and all treated patients in the period from January 1, 1998 to January 1, 2012 were included. The study population consisted of 206 women and 355 men with median age of 63 years (range, 11 to 91 y). Of all patients, 419 (75%) were admitted for malignant disease, and 142 (25%) for nonmalignant disease (Table 1).
Data from the database (patient demography, procedure, disease category, problem codes, procedure duration) and supplemental information from patient medical charts (nature of the problem, attempted solution) for each procedure were collected and analyzed retrospectively. Information on the choice of airway [orotracheal tube, nasotracheal tube, tracheostomy cannula, laryngeal mask airway (LMA), rigid bronchoscope] and ventilation was collected from the database and medical charts. Survival after the first interventional bronchoscopy treatment was registered. Time of death was registered based on the information from the National Population Registry of Norway. The data collection was completed on August 1, 2013.
Bronchoscopy procedures were performed by interventional pulmonologists with a flexible or rigid bronchoscope depending on the location and volume of tumor masses, and on the procedure type. A rigid bronchoscope was chosen if the procedure included placement of silicone stents, debulking of the tumor by use of the scope, or if it was likely that scope debulking or the use of large forceps would be needed. Otherwise, a flexible bronchoscope through the endotracheal tube or LMA was chosen. In some cases, other variants of airway devices were chosen, depending mostly on individual factors; patients who had tracheostomy cannulas or nasotracheal tubes underwent the procedures through these. Lesions with endobronchial growth were treated using Nd-YAG laser or electrocautery. The laser was set to 40 to 45 W and 1-second laser followed by 1-second intervals to avoid tumor overheating and combustion. Laser resection followed by balloon dilation was used in stenotic bronchi. Extrinsic compression from tumors or enlarged lymph nodes was treated with metallic (Ultraflex) or silicone stents (Dumon, Hood). A combination of different techniques was used when required (Table 2).
Anesthesia and Ventilation
The patients were anesthetized by total intravenous anesthesia, using propofol infusion (4 to 8 mg/kg/h) and opioid intermittently or as infusion (remifentanil 0.1 to 0.5 μg/kg/min). Norcuronium or cisatracurium were used for induction of neuromuscular blockade. Repeated doses were administered if prolonged neuromuscular blockade was needed. The patients were ventilated by controlled ventilation using the volume-controlled mode. In patients with ventilation problems, irrespective of the chosen airway, manual ventilation was attempted before the eventual change of airway. The FiO2 in the anesthetic gas mix was 0.3 to 0.9 without using the laser, and 0.35±0.05 during laser ablation. The choice of airway was made according to procedure and location of lesion. The majority of the procedures was performed through the orotracheal tube, LMA, or rigid bronchoscope (Table 3).
CAO was characterized by (1) stridor, (2) narrow tracheal lumen <5 mm on CT scans (Fig. 1), (3) stenosis of both the main bronchi, or (4) events during the procedure that lead to airway obstruction, such as tumor swelling, or tumor fragments or blood clots obstructing trachea and/or both the main bronchi. Ventilation or oxygenation problems were either problem coded in the anesthesia chart or in the procedure description, but most often without quoting any oxygen saturation values or tidal volume values that may have triggered the problem coding. This classification was nevertheless used as a definition of difficult ventilation or oxygenation
Statistics and Ethics
Data are presented as median (interquartile range). Survival analysis was performed using the Kaplan-Meier method. The log-rank test was conducted to compare results between groups. A two-tailed P-value of ≤0.05 was considered as statistically significant. The SPSS program for Windows (version 18.0; SPSS Inc., Chicago, IL) was used for statistical analysis.
The study protocol for the retrospective study was approved by The Regional Committee for Research Ethics (Oslo, Norway). The requirement for written informed consent was waived by the Ethics Committee upon approval from the Norwegian Directorate of Health (16.02.2009, Ref. 08/8013).
Between 1998 and 2012, we performed 902 procedures on 561 patients. Of them, 54 patients (9.6%) underwent 60 procedures where the patients either presented with CAO (n=15), or developed CAO or other ventilation challenges during the procedures (n=45) (Fig. 1). The most common types of obstruction were occluding tumor (n=48) and hemorrhage/clotting (n=7).
A change of the airway device in the CAO group was required in 55 procedures (6%). In the procedures performed in the CAO group, change of the airway device was required in 20 procedures (33%). In 5 of these, the change of airway was motivated by poor ventilation conditions. In 4 procedures, the LMA was changed to the orotracheal tube with the tip placed subglottic or supraglottic (3 and 1, respectively). In 4 patients, the orotracheal tube was withdrawn with a dislodged stent, tumor fragments, or blood clots before reinsertion of a new orotracheal tube. In 1 patient, the tracheostomy cannula was changed to a larger caliber endotracheal tube to give room for instrumentation and improve ventilation. In 10 patients, the LMA or orotracheal tube was replaced with a rigid bronchoscope to enable removal of clots (Fig. 2), or debulking of tumors with forceps or coring of the tumor using the rigid scope. In 1 patient, an orotracheal tube was changed to a 14 Fr airway exchange catheter (Cook Medical Inc., Bloomington, IN), which was used for jet ventilation oxygenation of the left lung while recanalizing the right bronchus. The choice of airway device is shown in Table 3. A difficult procedure was anticipated in all 60 cases.
A higher complication rate was observed in the group with CAO compared with the group without CAO (29.9% vs. 4.3%, respectively, P<0.01, Table 4). Median time per procedure in the cancer patients with critical airway was 87 minutes, compared with 75 minutes in cancer patients without critical stenosis, and 65 minutes in the patients with benign etiology of airway obstruction. In the critical stenosis group, 15 procedures lasted 2 to 4 hours, requiring a combination of laser evaporation with mechanical debulking in 3 of these. Six procedures were defined as ultra long with duration >4 hours.
By the end of the study, 401 patients had died and 160 were alive. Median survival in the patients with malignant disease was 182 days, and in the patients with malignant disease and CAO 100 days (P<0.05). Survival probability at 90 days for patients with malignant disease with and without CAO was 0.65 and 0.51, respectively (P=0.14). Median survival in the patients with benign disease was 2042 days (Fig. 3).
In this retrospective study, we present a single-center experience with patients undergoing interventional bronchoscopy procedures in general anesthesia.
In patients with CAO either detected before or occurring during the procedure, the choice of airway was somewhat different than for the other patients. LMA was used more frequently because of the occurrence of high tracheal lesions requiring high tracheal instrumentation. In some situations, the LMA may provide inadequate airway because of poor fit or high airway pressures. In 1 patient, we changed the LMA to a supraglottic tube because of poor fit of the LMA with a resulting air leak. The patient in this situation had a proximal tumor that precluded the use of an infraglottic endotracheal tube. The LMA fitted poorly because of tumor-induced changes in the hypopharyngeal anatomy, and therefore we changed to a supraglottic tube that gave satisfactory ventilation of the patient, and good working conditions for the bronchoscopist.
In one third of the patients with critical airway stenosis or obstruction, the airway was changed. In some cases, this was because of poor ventilation conditions, but was most often associated with a need for improved operating conditions—changing to a rigid bronchoscope to allow the use of larger forceps or coring, or changing the tracheostomy cannula to a larger tube. In 1 case, the orotracheal tube was changed to an LMA to facilitate a second proximal stent in the immediate subglottic room. The complexity of the procedures, along with the need for a change between treatment and ventilation modalities in patients with CAO, is reflected in increased time consumption and a higher complication rate. All of the ultra-long procedures in our case series were performed on patients with very advanced disease, requiring a combination of laser evaporation, mechanical tumor debulking, and clot removal.
Regardless of airway device, the stenosis in the airways remains a challenge. We regularly use controlled ventilation in our institution as most of the patients are muscle paralyzed in order to insert the airway and suppress coughing in response to the massively irritating stimulus of airway instrumentation. Whether volume-controlled or pressure-controlled ventilation is chosen, the anesthetist has to keep a vigilant eye on the parameter not controlled, that is, high pressure limit or low tidal volume, respectively. Because of the compromised airway conditions when the flexible bronchoscope is manipulated in the endotracheal tube (or the LMA or other airway), we feel most confident that the desired tidal volume is achieved when using a volume-controlled mode. When we had problems with ventilation, we tried manual ventilation before an eventual change of airway. This enabled a tactile assessment of the ventilation, and the possibility of varying the volume and timing of inspiratory versus expiratory phase while observing the excursion of the thorax. Jet ventilation should be a part of the armamentarium during rigid bronchoscopy, although ventilation breaks may be necessary using this ventilation mode as well.
Choice of Airway
The choice of airway will depend on the type and location of the lesion, as well as on the planned procedure. We used a standard orotracheal tube in more than two thirds of our patients. Ventilation with an LMA is an option to endotracheal intubation in patients with proximal tracheal pathology.3 The LMA is placed above the vocal cords, and gives good access for subglottic procedures.4 In addition, the lumen of the LMA is large enough to introduce the bronchoscope without obliterating the ventilating lumen.5 In our case series, LMA was the second most used airway type, used in over 10% of the cases, with few problems. In patients with CAO it was used more frequently, and in these patients we had to change the LMA because of ventilation problems in 4 of the 13 cases where LMA was the initial airway choice.
Rigid bronchoscopy provides safe and effective airway control, and is highlighted as an effective strategy in previous reports.6 The use of rigid scopes provides a ventilation route concurrent with airway assessment, and allow the establishment of airway control distal to obstruction. In our experience, air leak around the rigid scope, or during instrumentation, can be a problem, but is most often solved by use of a tampon in the hypopharynx or by using jet ventilation.
The choice of airway device during general anesthesia normally is made at the anesthesiologists’ discretion, but in patients undergoing interventional bronchoscopy it is necessary to place a large-bore tube above the stenotic lesion to allow instrumentation. The choice of airway device, and the possible change of strategy during the procedure, should be discussed and planned by the bronchoscopist and the anesthesiologist before the procedure.
In the present study, the 90-day survival in the patients with CAO due to malignant disease did not differ significantly from the patients without CAO. This emphasizes that patients with advanced lung cancer with locally treated CAO might have short-term outcomes similar to those without CAO, and should therefore be offered active treatment when possible. Chhajed et al7 have shown that the survival of non–small cell lung carcinoma patients with malignant CAO, who received treatment with therapeutic bronchoscopy in combination with systemic chemotherapy with or without external-beam radiation therapy was similar to those who do not have CAO and are treated only with systemic chemotherapy.
The influence of a single procedure on survival in an advanced disease is difficult to assess. Nevertheless, there is some evidence of its positive effect on general survival in the population with malignant airway disease. Eichenhorn et al8 demonstrated a longer median survival among those who underwent laser treatment and radiation therapy compared with control subjects after radiation therapy alone. The study by Brutinel et al9 showed a higher survival rate in patients treated with endobronchial laser compared with no treatment in the historical group, and yet other studies have demonstrated additional effect from laser therapy, or timely airway stenting on survival in lung cancer patients.10,11 Prevention or delay of malignant CAO complications such as pneumonia, sepsis, and respiratory failure certainly contribute to the improvement in the quality of life as well as survival.12
Limitations of the Study
Most of the evidence supporting the use of interventional techniques has arisen from retrospective reviews and single-center experiences.13 Prospective randomized controlled studies are a gold standard in the assessment of clinical therapies. The effect on survival is not established in such a study, but the effect on symptom relief is demonstrated in several studies. It is difficult to conduct a randomized study, as it is ethically controversial to randomize patients in need of this kind of therapy.
The definition of CAO used in the study was mainly based on clinical presentation rather than a systematic classification.14 This is a typical limitation for almost any retrospective study as the information on the obstruction site, degree, and type was not available in all patients.15 “Ventilation problem” was quite loosely defined; if the operator or the anesthesiologist had experienced problems, this was accepted as a “ventilation problem.” This reflects the actual working conditions; in most of the patients undergoing interventional bronchoscopy, some degree of desaturation or ventilation difficulty is experienced, but at some point the therapeutic team defines the deterioration as a problem. That is really to be understood as “more of a problem than usual, and at the verge of changing operative strategy.” This is far from a universal definition of “ventilation problem,” but makes sense in small teams that are used to work together. Our team has consisted mainly of 2 interventional pulmonologists and 2 anesthetists, and a small group of nurses. Within such a group the concept of “ventilation problems” is meaningful, as there is a common experience and understanding of what this implies.
Ventilation problems are among the main challenges for the anesthetist during interventional bronchoscopy. Close planning between interventional pulmonologists and anesthetists is crucial in patients with CAO, as these patients may require a change of ventilatory and airway strategies during the procedure. Despite various challenges in the management of patients with CAO, the short-term survival of these patients is comparable to that of patients without CAO.
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