Which of the following is a postoperative complication of a bronchoscopy?

Introduction

The art of bronchoscopy was introduced in the late 1890s by Gustav Killian with the use of a modified esophagoscope []. With practice on cadavers and continued development, the first foreign body was removed from the airway using a rigid laryngoscope which lead to the era of rigid bronchoscopy. From this foundation, considerable advances have been made to allow the rigid bronchoscope to be used alone and in conjunction with the flexible bronchoscope to complete complex airway procedures.

The rigid bronchoscope

Many varieties of rigid bronchoscopes exist today with slight differences in the assembly and multifunctional head. The main components however remain the same which include: the barrel, multifunctional head, light source and optics seen on .

Figure 1 Left—various rigid barrels [tracheal and bronchial]; right [top to bottom]—multifunctional head, anesthesia connector, metallic obturator cap for double accessory, silastic caps.

Figure 2 Rigid bronchoscope set up with telescope.

The rigid barrel has a beveled tip which is available in two lengths 33 centimeters [tracheal] and 43 centimeters [bronchial] with outer diameters ranging from 6 to 14 mm. The bronchial barrel has fenestrations at the distal end to allow for contralateral ventilation if the barrel is selectively intubated into the right or left mainstem. The tracheal barrel does not include side fenestrations as the length only allows this barrel to reach the mid to distal trachea. The choice depends on the location of the obstruction or lesion as well as goals of the procedure.

The multifunctional head varies in the number of ports available and allows for various instruments to be used during the procedure, including but not limited to: suction catheters, balloons, and biopsy/stent forceps. Connected to this is the anesthesia port comes which is available in two types depending on the mode used for ventilation: jet or volume control.

The light source and optics allow for visualization during the intubation and the procedure. The barrel can be inserted with direct visualization or with the use of a telescope and camera limiting damage to the airway. The typical telescope used is 0° direct visualization and the length is a few centimeters longer than the chosen barrel.

After the airway is secured, the operator can utilize a variety of different instruments depending on the underlying condition and desired procedure. The instruments, when compared to the flexible bronchoscope, are designed to be larger and stiffer, but even with the rigid barrel the flexible scope is used in conjunction in a majority of cases.

Presurgical testing

During the presurgical evaluation in the office or in the intensive care unit, chest imaging, laboratory values [including, but not limited to: complete blood count, PT/INR, type and screen, basic metabolic panel], EKG and any other imaging or testing at the discretion of the anesthetist or proceduralist are reviewed.

During the physical exam, special attention should be given to mouth opening, teeth or lack thereof, neck extension and history of prior facial, neck trauma/surgeries, other oral obstructions.

Increased procedural risks occur in those with limited oxygen reserve, poor neck mobility, hemodynamic instability and higher propensity to bleed: inherently or iatrogenically due to medications which should be discontinued if possible.

Contraindications

Very few contraindications exist for rigid bronchoscopy and, with experienced hands, most of these can be overcome. Relative contraindications include coagulopathy or anticoagulation medication and higher ventilatory requirements. The main absolute contraindication is patients with an unstable cervical spine [e.g., patients with previous radiation, rheumatoid arthritis with neck involvement] risking further damage due to the neck extension which is required for intubation. During the presurgical testing these risks should be addressed with anesthesia and corrected if possible. In all cases, the risk and benefit need to be weighed and discussed with the patient and or power of attorney, as well as, alternative treatments. If the benefit is possible or an alternative is unavailable, then rigid bronchoscopy should be performed.

Anesthesia

Intubation of the patient requires deep sedation and, in most instances, paralytic, to prevent injury to teeth, posterior oropharynx, vocal folds and trachea. The rigid bronchoscope needs to be in very experienced hands for those patients in which a paralytic is not utilized.

Medication recommendations include a combination of hypnotic, narcotic and a paralytic. Common induction agents include propofol, ketamine, and etomidate complemented with a narcotic [fentanyl, remifentanil or alfentanil] []. Remifentanil has been shown to have a faster recovery compared fentanyl in patients during spontaneous assistant ventilation []. For maintenance, the preferred and most commonly used medication is propofol and the paralytic choice depends on the patient’s co-morbid conditions, anesthetist and procedural comfort level, and case length. The common paralytics used include succinylcholine, vecuronium or cisatracurium and rocuronium.

Use of gaseous anesthetics should be avoided due to lack of complete closure of the circuit, as well as, addition and removal of instruments multiple times throughout the case generating larger leaks for short periods of time.

Intubation

Intubation requires teamwork with anesthesia, procedural nurses, and proceduralist. Patient positioning on the bed is of utmost importance to allow proper neck extension for easier intubation. Utilization of an operating room table allows for extension of the neck. The shoulders must be positioned slightly above the breakdown crease to permit proper extension. The anesthetist will then induce the patient and after confirming proper ventilation using bag mask technique a paralytic is given. Next, the neck is extended, a tooth guard is placed on the upper teeth and the scope is handled with the right hand while the mouth is opened with the left. The rigid scope inserted perpendicular to the mouth with the bevel on top just passing the tongue. The index finger acts as a lever as it sits inside the patient’s mouth while the thumb rests on the lips/teeth to prevent injury. Upon passing the tongue the scope lowered to near parallel to the patient’s chest. Once at the level of the epiglottis, it is lifted up and the vocal cords are visualized. The barrel is then rotated 90° and the bevel is used to push one of the vocal cords to the side. As the barrel is introduced through the cords, it is again rotated 90°, in the same direction placing the bevel is at the posterior portion of the larynx. The index finger of the left hand is used to maintain lift on the barrel and bevel to prevent injury the posterior membrane while advancing the scope. Once the barrel is at the desired location, usually distal trachea, the ventilator tubing is connected to the anesthesia port of the rigid bronchoscope.

Modes of ventilation

The particular mode of ventilation will depend on the entire team—their experience and expertise with the different methods, as well as, the available options in the hospital system. Three common techniques are described below.

Spontaneous assisted ventilation is a mode in which intravenous anesthesia is delivered to a level at which the patient is spontaneously breathing. In this technique, paralytic agents are avoided which may prevent post-operative complications such as re-intubation. Complications from this mode of ventilation, in a study by Perrin and colleagues, occurred in about 18% of patients which included: post-operative hypoxemia, bronchospasm and laryngospasm [].

On the other hand, if a combination of paralytic or inhaled anesthetic plus intravenous sedation is used, positive pressure ventilation is required. This mode of ventilation is considered controlled ventilation and special attention to prevention of ventilator and inhaled anesthetic leak is necessary. The prevention of leak is overcome by packing the mouth, and using silastic caps on the ends of the rigid bronchoscope ports. The patient’s end-tidal CO2 is monitored along with the tidal volumes and adjusted per anesthesia. Inhaled anesthetic is typically avoided due to unavoidable small leaks in the system and exposure to the operating room staff [].

Jet ventilation uses high pressured gas delivered in short bursts into an open rigid bronchoscope. Given the open system inhaled anesthetic is contraindicated due to large leaks. Monitoring in these patients requires special attention to chest rise and oxygen saturation, but partial pressure of carbon dioxide is monitored only by serial arterial blood gasses or transcutaneous capnographic monitoring.

Indications for rigid bronchoscopy

The use of rigid bronchoscopy waned after the development of the flexible bronchoscope, but has come back into favor for specific indications which include placement of silicone stents. This article will focus on the therapeutic interventions using the rigid bronchoscope which include tumor excision, stent placement, repair of airway stenosis, and control of hemoptysis.

Airway disease exists in multiple forms which include intrinsic, extrinsic or a combination of both. They are also further differentiated into malignant or benign. Depending on the mixture of the above will guide the proceduralist to the therapeutic options available.

Tumor excision

Various mechanisms can be used for debulking tumors which are usually used in combination with one another including: mechanical, thermal therapy and cryotherapy.

Mechanical debulking can be accomplished using the beveled end of the rigid barrel in a coring technique, forceps whether rigid or flexible, or a microdebrider. When using the rigid barrel, careful attention must be made to the angle of the beveled edge, amount of pressure used and anatomical location of the obstruction. This type of debulking, typically referred to as apple-coring, can easily cause unwanted trauma including: mucosal tears, hemoptysis, and airway obstruction. As the rigid barrel is advanced, it is also rotated about 90–180° to allow the bevel to slice through the tumor. shows an example of pre and post apple coring. Simultaneously, lateral pressure is also applied at the stalk to maintain hemostasis as the barrel is advanced. After passing through the obstruction, the large debulking forceps are used to remove the excised tumor all while keeping constant pressure on the wall from which the tumor was excised. Once the tumor is cleared and visualization is restored, the pressure is slowly released to determine if hemoptysis occurs or hemostasis is achieved.

Figure 3 Malignant right mainstem obstruction. [A,B] Tumor arising from the right upper lobe; [C] right mainstem post rigid coring.

Thermal therapy includes laser [light amplification by stimulated emissions of radiation], electrocautery and argon plasma coagulation [APC]. The particular modality chosen is dependent on the proceduralist’s experience, location and appearance of the tumor, and depth of penetration desired. The largest limitation of thermal therapy is the required drop in fraction of inspired oxygen [FiO2] to less than 0.40 to prevent airway fires.

Laser therapy is best utilized in those tumors which are central, short [