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RIGID BRONCHOSCOPY IN THE TWENTY-FIRST CENTURY
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FLEXIBLE BRONCHOSCOPY UPDATE
+ .OO
RIGID BRONCHOSCOPY IN THE TWENTY-FIRST CENTURY Michael L. Ayers, MD, and John F. Beamis, Jr, MD
Rigid bronchoscopy is a procedure that truly has stood the test of time-it now has been performed in three centuries. Rigid bronchoscopy was introduced more than 100 years ago and for many years was performed primarily by surgeons for therapeutic interventions such as foreign body removal and dilation of stenoses. The introduction of the flexible bronchoscope in the mid-1960s led to major changes in the field of bronchoscopy; internists, primarily pulmonologists, became interested in and developed expertise in flexible bronchoscopy, resulting in a dramatic decrease in the number of rigid bronchoscopies performed. Since the mid-l980s, there has been a renewed interest in rigid bronchoscopy, in part because of the emerging lung cancer epidemic, the development of new endobronchial therapies, and the evolution of the new specialty of interventional pulmonology. Today, the rigid bronchoscope serves an important conduit to the central airways for those who manage patients with difficult benign and malignant airway disorders. A number of therapies such as laser photoresection, endobronchial stents, balloon dilation, electrocautery, argon beam coagulation, and cryotherapy can be performed safely and effectively with the rigid bronchoscope.
For many decades, rigid bronchoscopy was viewed as a somewhat crude and uncomfortable procedure for the patient. Now, however, it is considered a safe and easily tolerated procedure because of improvements in anesthesia and ventilation techniques. Despite the incredible explosion in medical technology in the latter half of the twentieth century, there have been only minor structural changes to the original rigid bronchoscope. In fact, the rigid bronchoscopes used today do not differ significantly to those used in the earlier part of the twentieth century. It is not clear what the twenty-first century holds for rigid bronchoscopy, but there is little doubt that the rigid instrumentation and procedure are here to stay. HISTORY
Gustav Killian, a German otolaryngologist, performed the first rigid bronchoscopy in 1897. The patient who underwent the first bronchoscopy had aspirated a pork bone into his right main bronchus? Killian successfully removed the foreign body and prevented a tracheotomy, which was the usual method of foreign body removal in the late nineteenth
From the Department of Pulmonary and Critical Care Medicine, Division of Internal Medicine, Lahey Clinic, Burlington, Massachusetts (JFB); and the Department of Pulmonary ana Critical Care, Dartmouth Medical School, Hanover, New Hampshire (MLA); and Veterans Affairs Hospital, White River Junction, Vermont (MLA)
CLINICS IN CHEST MEDICINE VOLUME 22 * NUMBER 2 * JUNE 2001
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define the of modern era of pulmonary medicentury. Killian presented his remarkable cine. Flexible bronchoscopy quickly gained findings at a medical meeting in Heidelberg worldwide acceptance as a diagnostic instruthe following year. Initially, his new procement. By the mid-l970s, flexible bronchosdure was met with a degree of skepticism, copy had replaced rigid bronchoscopy almost but the dramatic successes of this procedure, completely for the diagnosis of bronchopulespecially in the removal of airway foreign monary diseases. bodies, rapidly were appreciated by the mediIn the past two decades, because of the cal community and gained international recincreasing number of patients presenting with ognition for Killian. As he gained experience, he experimented with new bronchoscopes, central airway obstruction from carcinoma of the lung and the dismal prognosis associated developed new and improved techniques, with this condition, there has been increasing and expanded the indications for rigid broncall for local lung cancer management, stimuchoscopy. He held many training courses for lating the development of a number of endophysicians in his institution and throughout bronchial treatment modalities. These modalthe world. Killian therefore is commonly reities, for the most part, are palliative and ferred to as the ”father of broncho~copy.”~ include laser bronchoscopy, placement of enIn America, Chevalier Jackson, a laryngolodobronchial stents, balloon dilation techgist originally from Pittsburgh, PA, also deniques, endobronchial electrocautery and cryoveloped an interest in endoscopy with “open therapy, endobronchial brachytherapy, and tubes” in the late nineteenth century. After argon beam coagulation. Patients requiring graduating from medical school in 1886, he traveled to London to observe Sir Morel1 these treatment modalities often present with MacKensie, a leading English laryng~logist.~ critical airway obstruction caused by bulky vascular tumors. Control of ventilation and After his return to America, he began to develop his own endoscopes with distal illumi- hemorrhage is paramount in the management of these patients. Rigid bronchoscopy has nation. He experimented with foreign body proved to be an excellent tool to provide acremoval in dogs and with inanimate models. cess to the airway for these new therapies. In 1899, Jackson began working with bronJean Francois Dumon, a French pulmonolochoscopes and, in 1907, he published his landgist, has been extremely influential in promotmark book entitled, Trucheobronchoscopy, Esoing the revival of rigid bronchoscopy. Like phugology and Bronchos~opy.~ In his own Killian and Jackson before him, he offered workshop, he designed and built new esotraining courses in bronchoscopic and laser phagoscopes and bronchoscopes and accestechniques and published journal articles and sory instruments. He perfected new techmonographs allowing him to share his experiniques of scope insertion and foreign body removal. He understood the importance of ence and expertise with numerous physicians training programs and gave instructional throughout the world. Today, many interventional pulmonologists, thoracic surgeons, and courses on bronchoesophagology. He firmly otolaryngologists continue to use the rigid believed in the importance of strict safety probronchoscope for the management of difficult tocols; many of the safety techniques that airway obstructions. Jackson popularized are used today. Jackson eventually held separate chairmanships in bronchoesophagology at all five medical THE RIGID BRONCHOSCOPE schools in Philadelphia, PA and is considered ”the father of American bronchoesophagolToday’s rigid bronchoscopes are similar to ~gy.”~ those used in the days of Jackson. They are Until the mid-l960s, rigid bronchoscopy alhollow, straight tubes made of stainless steel most exclusively was performed by surgeons. (Fig. 1). The length and width vary. Adult In 1966, Shigeto Ikeda from the National Canbronchoscopes are usually 40 cm long and cer Center Hospital, Tokyo, Japan, introduced range in diameter from 9 to 13.5 mm. The the flexible bronchoscope, which revolutionbronchoscope barrel wall is 2 to 3 mm thick ized the field of bronchoscopy and helped
RIGID BRONCHOSCOPY IN THE TWENTY-FIRST CENTURY
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Figure 1. A, A typical rigid bronchoscope (middle) with Hopkins rod rigid telescope (fop) and optical biopsy forceps. B, Close view of proximal end of bronchoscope with optical biopsy forceps and telescope in place. Lower large side port accepts anesthesia tubing or is left open for Venturi ventilation. Slanted port for suction catheter or Venturi jet. Upper port (and lower port on telescope) accepts light source.
and the inner, round lumen is uniform throughout. The proximal, or operator, end of the bronchoscope consists of a central opening and several side ports. A rigid telescope and many accessory instruments such as forceps, suction catheters, laser fibers, or silicone stent delivery systems can be placed through the proximal opening. The proximal side ports allow for connection of ventilating tubes and an external light source. The distal end of most bronchoscopes is beveled, which permits atraumatic separation of the vocal cords during passage through the larynx, allows the bronchoscope to be “cork screwed” through tight stenoses, and aids in “coring out” obstructing lesions. Rigid bronchoscopes have slit-like openings in the distal end that serve as ventilating ports; shorter tracheoscopes have no side holes on the barrel and can be used to approach high tracheal lesions with-
out leaking ventilating gases above the vocal cords (Fig. 2). Dumon recently redesigned the rigid bronchoscope (Fig. 3A) and introduced a “universal head” to which multiple bronchoscope barrels of varying lengths and diameters, from pediatric to adult size, can be attached. The universal head has special ports for insertion of suction catheters, laser fibers, and telescopes (Fig. 3B) This bronchoscope also is designed for placement of endobronchial and endotracheal silicone stents (Fig. 4). Standard xenon light sources provide illumination for rigid bronchoscopy. Rigid optical telescopes afford a slightly magnified, clear, wide-angled view of the airway. Zerodegree telescopes are adequate for most procedures. Angled telescopes (30” to 45”) permit visualization of upper lobe bronchi. Chargecoupled device (CCD) chip video cameras can
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Figure 2. Tracheoscope.
Figure 3. A, Dumon Series II rigid bronchoscope: Universal head with two bronchoscope barrels and one tracheoscope barrel. B, Close view of universal head with ports for (from left) suction catheter, telescope, anesthesia connection, and biopsy forceps or Venturi connection.
RIGID BRONCHOSCOPY IN THE TWENTY-FIRST CENTURY
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Figure 4. Silicone stent delivery devices for Dumon rigid bronchoscopes. Original loader and insertion device (bottom). Series II loader and delivery device allow for visualization of stent deployment (top).
be attached to the telescope, allowing the bronchoscopist to share the procedure with other members of the team on video screens and to record the procedure on tape. The internal diameter of most adult bronchoscopes is sufficient to allow passage of a flexible bronchoscope. This measurement often is helpful in dealing with tortuous airways and distal lesions. INDICATIONS The rigid bronchoscope can be used diagnostically and therapeutically in a number of benign and malignant conditions: Massive hemoptysis Foreign body removal Tracheobronchial stenosis Post-traumatic Postinfectious (tuberculosis, histoplasmosis, Herpes virus) Postinflammatory (Wegener 's granuloma) Postintubation or tracheostomy Tracheobronchomalacia Tracheoesophageal fistula Tracheobronchial obstruction Extrinsic compression Esophageal tumor Lymphoma Mediastinal tumors (Thymus, Thyroid,
Germinal cell tumors) Aortic aneurysm Benign Tumors Papillomatosis of the large airways Endobronchial amyloidosis Malignant Tumors Bronchogenic tumors Adenoid cystic carcinoma Mucoepidermoid tumor Carcinoid tumor Metastatic tumors Post lung transplantation Anastomotic stenosis Indications for a rigid bronchoscope include diagnosis of airway disease, foreign body removal, management of massive hemoptysis, clot and mucous plug removal, and a number of therapeutic interventions: Lasers Carbon dioxide Neodymium-yttrium-aluminum-garnet Potassium titanyl phosphate Electrocautery Cryotherapy Argon beam coagulator Stents Silicone Metallic Hybrid "Y Dilating balloons
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For nearly 70 years, the rigid bronchoscope provided the only access to the airways. Since the late 1960s, however, virtually all diagnostic procedures have been performed through the flexible bronchoscope. Today, in adult bronchology, the rigid bronchoscope is reserved for the most difficult diagnostic cases and many therapeutic indications. In pediatric bronchoscopy, the rigid bronchoscope remains both a diagnostic and therapeutic tool, although there is now a general acceptance that even the smallest children can undergo flexible bronchoscopy safely. The enormous growth of medical technology in the latter half of the twentieth century led to a number of advances in therapeutic bronchoscopy, including laser phototherapy (photocoagulation, cutting, and vaporization), endobronchial stent placement (silicon and metallic), electrocautery, cryotherapy, balloon dilatation, and argon beam coagulation. Many times, these interventions must be performed on severely ill patients with acute airway obstruction. The rigid bronchoscope has proved to be well suited for these situations because it allows excellent control for ventilation and provides easy passage for various instruments that aid in the removal of obstructing tissue and foreign bodies. Rigid bronchoscopy remains the preferred technique for removal of large, central foreign bodies. Smaller and more distal foreign bodies often can be removed with a flexible bronchoscope. The rigid bronchoscope continues to play an important role in the management of massive hemoptysis. It can serve as a device to tamponade the source of bleeding, provide excellent suction of obstructing clots and blood, and allow use of tamponading balloons, forceps, or sponges. CONTRAINDICATIONS
Rigid bronchoscopy is a safe procedure. Because it requires general anesthesia, the absolute contraindications are related to comorbid diseases that increase the risk associated with anesthesia. These include an unstable cardiopulmonary status, cardiac arrhythmia, and severe, uncorrectable hypoxic respiratory distress. Other contraindications to rigid bron-
choscopy relate to the patient’s neck and jaw anatomy-unstable cervical spine, oral or maxillofacial trauma, cervical ankylosis, or severe kyphoscoliosis. TECHNIQUE
Patient Preparation
Rigid bronchoscopy typically is performed under general anesthesia in an operating room setting. Proper preoperative assessment therefore is required. This assessment includes a thorough physical examination that pays particular attention to the oral cavity and neck mobility. A minimal number of laboratory tests are necessary. Standard tests include a complete blood count, arterial blood gases or oxygen saturation, a chest radiograph, and an electrocardiogram. Other tests may be necessary, as dictated by the patient’s underlying condition. The anesthesiologist plays an important role in explaining the risk associated with general anesthesia to the patient and assessing the upper airway for ease of intubation. Anesthesia
Modern rigid bronchoscopy often involves the use of lasers, electrocautery, and cryotherapy to treat localized endobronchial obstructions. These procedures are performed best in a controlled setting in which there is minimal movement because of cough or patient discomfort. Rigid bronchoscopy therefore is performed best under general inhalational or intravenous anesthesia. In extremely cooperative patients, the procedure may be performed with topical anesthesia and conscious sedation. The bronchoscopist must work closely with the anesthesiologist and operating room personnel. An ideal anesthetic for rigid bronchoscopy provides quick onset of action and a short half-life to allow the patient to awaken quickly. Today, the combination of propofol, a short-acting intravenous anesthetic with a rapid onset of action, along with intravenous medazolam and fentanyl, provides effective and safe anesthesia, amne-
RIGID BRONCHOSCOPY IN THE TWENTY-FIRST CENTURY
sia, and pain control. Muscle relaxants often are used to promote passage of the bronchoscope through the upper airway and to facilitate controlled ventilation. This combination of medications rapidly and effectively sedates the patient, reverses quickly, and suppresses cough, which is vital for the bronchoscopist to perform precise, delicate maneuvers with the laser or other interventional tools. Patients undergoing rigid bronchoscopy must be monitored closely. Standard operating room monitoring of blood pressure, electrocardiogram, and pulse oximetry usually suffices. Pulmonary artery catheter monitoring and arterial blood pressure monitoring rarely are indicated. Ventilation is assessed with end-tidal carbon dioxide monitoring in closed ventilation systems or chest wall exertion when open systems are employed. Ventilation
A number of ventilation techniques can be used during rigid bronchoscopy. Today, the most common technique is spontaneous assisted ventilation. With this technique, the patient receives general intravenous anesthesia but maintains shallow spontaneous breathing.l0 The anesthesiologist provides frequent assisted breaths (10-20 per minute) and attempts to synchronize breathing with the bronchoscopist’s maneuvers. Venturi jet ventilation is preferred by a number of centers. This technique, as described by Godden et al: is an open ventilation system. One-hundred percent oxygen is injected into one of the proximal ports of the rigid bronchoscope at 50 psi. Room air is entrained through the open end of the bronchoscope. The pressure of the Venturi jet is sufficient to provide thoracic cage exertion. Because the amount of room air entrained varies with lung and chest wall compliance, the fraction of inspired oxygen at the level of the trachea is variable, not measurable, but is usually sufficient to maintain adequate arterial oxygen saturation. Insertion of the Rigid Bronchoscope
Once in the operating theater, the patient is placed in the supine position. After induction
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of anesthesia, the patient’s eyes and teeth are protected with commercially available eye pads and tooth guards or with moist gauze pads. A folded towel is placed under the extended head of the patient. Some bronchoscopists prefer to suspend the patient’s head over the table’s edge and support the head with his or her thigh or an assistant’s hand. The advantage of this technique is that the trachea is forced into a more anterior position, facilitating placement of the bronchoscope. Most patients, however, can be intubated with the rigid bronchoscope while in the supine position with the neck slightly extended. Three classic intubation techniques can be employed, depending on the bronchoscopist’s experience and the patient’s underlying condition. The rigid bronchoscope can be inserted directly, with the aid of a laryngoscope, or guided by an endotracheal tube. In the direct technique, the bronchoscopist looks directly down the open tube or through a rigid telescope placed inside the bronchoscope. The scope then is inserted into the oropharynx with the beveled end in the anterior position. After passing the uvula, the beveled end is used to displace the epiglottis anteriorly. At this point, the vocal cords are visualized. The bronchoscope then is rotated 90” and advanced through the cords. Once the bronchoscope enters the trachea, it is rotated back 90°, keeping the beveled end anteriorly. This insertion technique demands a considerable amount of expertise and is not for the novice. In the second insertion technique, a straight laryngoscope is used to visualize the vocal cords in much the same way as it is used to insert an endotracheal tube. When the vocal cords come into view, the rigid bronchoscope is advanced through the cords and the laryngoscope is removed. Once the rigid bronchoscope is in the proximal trachea, a telescope is inserted down the barrel of the scope and the airway inspection is carried out. At times a patient may be brought to the operating room intubated, receiving oxygen and mechanical ventilation. In this situation, the endotracheal tube must be removed to perform rigid bronchoscopy. The rigid bronchoscope, along with its telescope, is advanced through the mouth anteriorly, or later-
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ally, along the endotracheal tube, until the vocal cords come into view. The anesthesiologist or an assistant then slowly removes the endotracheal tube as the bronchoscopist keeps constant watch of the vocal cords. As the endotracheal tube is pulled above the vocal cords, the rigid bronchoscope is advanced into the trachea as described in the direct technique. Once the bronchoscope is passed into the trachea, the central airways can be visualized. The use of a telescope provides an excellent, slightly magnified view of the large airways, including the trachea, main bronchi, and the openings to the five lobar bronchi. Often, segmental bronchi in the left upper lobe and right upper lobes cannot be visualized with the 0" telescope. To visualize these segments, angled telescopes can be used or a flexible bronchoscope can be passed through the rigid instrument. Several recent references provide a more detailed description of intubation l4 techniques for the rigid bronchoscope.1,2,
COMPLICATIONS
When performed in a controlled setting by an experienced bronchoscopist assisted by an experienced anesthesiologist, the complications of rigid bronchoscopies are rare. The most common complications are the result of improper intubation technique resulting in trauma to the teeth or oropharynx, or perforation of the tracheal or bronchial wall. Massive hemorrhage is extremely rare. In fact, the most dangerous complications associated with rigid bronchoscopy are those related to the use of general anesthesia, especially in patients with compromised pulmonary reserve who readily develop hypoxia and secondary cardiac arrhythmias. Caputi6 has reported only two deaths in more than 11,000 rigid bronchoscopies performed at his center in Italy. Most rigid bronchoscopies can be performed safely on an ambulatory basis. Admission is dictated by the patient's underlying condition and functional status, rather than by the procedure itself.
ADVANTAGES AND DISADVANTAGES
There are many advantages to rigid bronchoscopy. This procedure allows for excellent control of the compromised airway, whether the obstruction is attributable to foreign body, benign stenosis, or malignant tumor. The telescopes used with the rigid bronchoscope provide bright, magnified views of the airway. The lumen of the rigid bronchoscope is sufficient for passage of large biopsy forceps and other accessory instruments. Because rigid bronchoscopy is performed under general anesthesia, often with muscle relaxation, cough is suppressed and the patient remains motionless even during prolonged procedures. In general, interventional procedures are much shorter in duration when performed with a rigid bronchoscope than with a flexible bronchoscope. Therapeutic procedures such as laser therapy, electrocautery, cryotherapy, and endobronchial stent placement can be performed through the rigid bronchoscope. In fact, silicone stents can be placed only with a rigid bronchoscope. The rigid bronchoscope provides an excellent channel for grasping foreign bodies. The barrel of the bronchoscope can serve as a tamponading device in the event of hemorrhage from a central lesion. There are also disadvantages associated with rigid bronchoscopy. Obtaining operating room privileges is often problematic for the pulmonologist. The operating room schedule often is not accommodating to the nonsurgeon. The help of an anesthesiologist and operating room ancillary staff is required. The physiology of patients with upper airway lesions or maxofacial pathology may not be able to accommodate the rigid instrument. Lesions in distal airways might not be accessible to the rigid instrument. For the pulmonologist, a major obstacle to obtaining proficiency in rigid bronchoscopy is the lack of exposure during fellowship training. Extra training outside of a classic pulmonary fellowship usually is required. This training may be in the form of an interventional pulmonology fellowship or may require postgraduate courses n r working closely with a local mentor.
RIGID BRONCHOSCOPY IN THE TWENTY-FIRST CENTURY
FOR THE FUTURE Despite its 100 years of use, its obvious historical importance in the progress of pulmonary medicine, and the ease with which it can be adapted for use with modern endobronchial therapies, the popularity of rigid bronchoscopy continues to decline. In 1999, in a survey sponsored by the American Association of Bronchology, Colt and Prakash7surveyed 2500 members of the American College of Chest Physicians (ACCP) regarding bronchoscopic practices throughout North America. Only 4% of 744 respondents reported that they perform rigid bronchoscopy, compared with 8% of respondents in a 1989 ACCP bronchoscopy survey.ll In many European pulmonary training programs, rigid and flexible bronchoscopy are taught. Bronchoscopic surveys performed in England and The Netherlands have shown that 20% and 9% of bronchoscopists perform rigid bronchoscopy, respectively.13,l5 In the United States, few pulmonary fellowship programs offer training in rigid bronchoscopy. Many fellows therefore must seek training outside of fellowship to achieve experience in rigid bronchoscopy. Unfortunately, postgraduate courses only can provide an introduction to interventional techniques, including rigid bronchoscopy, and do not enable a physician to become competent enough to perform these therapeutic procedures independently. Nevertheless, the rigid bronchoscope will remain an invaluable tool for interventional pulmonologists and thoracic surgeons who manage patients with challenging airway obstruction. Medical technology surely will advance throughout the twenty-first century, and the rigid bronchoscope, although not likely to change in design, surely will be adaptable to these new developments. Anesthetic techniques will improve further, making the procedure safer and more comfortable for patients. It is likely that there will be improvements in stent design and deployment and that the application of current ablative techniques, such as laser, electrocautery, and cryotherapy, will improve. As the field of interventional pulmonology becomes further defined, it is likely that current bronchoscopy
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rooms will become full-service interventional pulmonology suites, where general anesthesia may be administered, avoiding the difficulties with operating room access that many pulmonologists face.l2 Once the rigid bronchoscope is brought from the operating room to the pulmonary procedure room, its acceptance by pulmonologists should improve. Unfortunately, the epidemic of lung cancer is likely to continue well into the twenty-first century. This terrible cancer often impacts on the quality of life of an individual by producing central airway obstruction. As new therapies to relieve this obstruction are developed, it is likely that the safety and effectiveness of their application will be enhanced by the use of the rigid bronchoscope.
SUMMARY
Rigid bronchoscopy, a procedure more than 100 years old, now has been performed in three centuries. The "open tube" bronchoscope provides safe access to the lower airways and has proved to be compatible with newer, more sophisticated therapies as they have been introduced into the practice of bronchology. The twenty-first century surely will provide the bronchoscopist with exciting new diagnostic and therapeutic tools for the management of lung diseases, and it is likely that the rigid bronchoscope will continue to play an important role in delivering these tools to the airways. Pulmonologists need to appreciate the use of this classic instrument and prevent rigid bronchoscopy from becoming a forgotten art.
References 1. Beamis J F Rigid bronchoscopy. In Beamis JF, Mathur PN (eds): Interventional Pulmonology. New York, McGraw-Hill, 1999, pp 17-28 2. Beamis JF: Modem use of rigid bronchoscopy. In Bolliger CT, Mathur PN (eds): Interventional Bronchoscopy. Basil, Karger, p 22-30, 2000 3. Becker HD, Killian G: A biographical sketch. Journal of Bronchology 27743,1995 4. Becker HD, Marsh BR History of the rigid bronchoscope. In Bolliger CT, Mathur PN (eds): Interventional Bronchoscopy. Basil, Karger, p 2-15, 2000
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5. Boyd AD, Jackson C: The father of American bronchoesophagology. Ann Thorac Surg 57502-505,1994 6. Caputi M, Bellissimo U, DiMatteo L, et al: Complications during bronchofiberscopy and rigid bronchoscopy. Panminerva Med 28:271-277,1986 7. Colt HG, Prakash UBS, Offord KF: Bronchoscopy in North America: Survey by the American Association for Bronchology, 1999. Journal of Bronchology 7825,2000 8. Godden DJ, Willey RF, Fergusson RJ, et al: Rigid bronchoscopy under intravenous general anesthesia with oxygen Venturi ventilation. Thorax 37532-534, 1987 9. Jackson C: The life of Chevalier Jackson: An autobiography. New York, MacMillan, 1938 10. Perrin G, Colt HG, Martin C, et al: Safety in interventional rigid bronchoscopy using intravenous anesthe-
sia, and spontaneous assisted ventilation: A prospective study. Chest 1021526-1530, 1992 11. Prakash UBS, Offord KP, Stubbs SE: Bronchoscopy in North America: The ACCP Survey. Chest 100:16681675, 1991 12. Prakash UBS: Bronchoscopy unit expertise, equipment and personnel. In Bolliger CT, Mathur PN (eds): Interventional Bronchoscopy. Basil, Karger, Prog Respir p 31-43, 2000 13. Simpson FG, Arnold AG, Purvis A, et al: Postal survey of bronchoscopic practice by physicians in the United Kingdom. Thorax 41:311-3117, 1986 14. Stradling P: Diagnostic Bronchoscopy: A teaching Manual, ed 5. New York, Churchill Livingstone, 1986 15. Sutjedja T, Festen J, Vanderschueren R, et al: A postal survey of bronchoscopic practice in the Netherlands. Journal of Bronchology 3:17-21, 1996
Address reprint requests to John F. Beamis, Jr, MD Lahey Clinic 41 Mall Road Burlington, MA 01805
FLEXIBLE BRONCHOSCOPY UPDATE
+ .OO
RIGID BRONCHOSCOPY IN THE TWENTY-FIRST CENTURY Michael L. Ayers, MD, and John F. Beamis, Jr, MD
Rigid bronchoscopy is a procedure that truly has stood the test of time-it now has been performed in three centuries. Rigid bronchoscopy was introduced more than 100 years ago and for many years was performed primarily by surgeons for therapeutic interventions such as foreign body removal and dilation of stenoses. The introduction of the flexible bronchoscope in the mid-1960s led to major changes in the field of bronchoscopy; internists, primarily pulmonologists, became interested in and developed expertise in flexible bronchoscopy, resulting in a dramatic decrease in the number of rigid bronchoscopies performed. Since the mid-l980s, there has been a renewed interest in rigid bronchoscopy, in part because of the emerging lung cancer epidemic, the development of new endobronchial therapies, and the evolution of the new specialty of interventional pulmonology. Today, the rigid bronchoscope serves an important conduit to the central airways for those who manage patients with difficult benign and malignant airway disorders. A number of therapies such as laser photoresection, endobronchial stents, balloon dilation, electrocautery, argon beam coagulation, and cryotherapy can be performed safely and effectively with the rigid bronchoscope.
For many decades, rigid bronchoscopy was viewed as a somewhat crude and uncomfortable procedure for the patient. Now, however, it is considered a safe and easily tolerated procedure because of improvements in anesthesia and ventilation techniques. Despite the incredible explosion in medical technology in the latter half of the twentieth century, there have been only minor structural changes to the original rigid bronchoscope. In fact, the rigid bronchoscopes used today do not differ significantly to those used in the earlier part of the twentieth century. It is not clear what the twenty-first century holds for rigid bronchoscopy, but there is little doubt that the rigid instrumentation and procedure are here to stay. HISTORY
Gustav Killian, a German otolaryngologist, performed the first rigid bronchoscopy in 1897. The patient who underwent the first bronchoscopy had aspirated a pork bone into his right main bronchus? Killian successfully removed the foreign body and prevented a tracheotomy, which was the usual method of foreign body removal in the late nineteenth
From the Department of Pulmonary and Critical Care Medicine, Division of Internal Medicine, Lahey Clinic, Burlington, Massachusetts (JFB); and the Department of Pulmonary ana Critical Care, Dartmouth Medical School, Hanover, New Hampshire (MLA); and Veterans Affairs Hospital, White River Junction, Vermont (MLA)
CLINICS IN CHEST MEDICINE VOLUME 22 * NUMBER 2 * JUNE 2001
355
356
AYES & BEAMIS
define the of modern era of pulmonary medicentury. Killian presented his remarkable cine. Flexible bronchoscopy quickly gained findings at a medical meeting in Heidelberg worldwide acceptance as a diagnostic instruthe following year. Initially, his new procement. By the mid-l970s, flexible bronchosdure was met with a degree of skepticism, copy had replaced rigid bronchoscopy almost but the dramatic successes of this procedure, completely for the diagnosis of bronchopulespecially in the removal of airway foreign monary diseases. bodies, rapidly were appreciated by the mediIn the past two decades, because of the cal community and gained international recincreasing number of patients presenting with ognition for Killian. As he gained experience, he experimented with new bronchoscopes, central airway obstruction from carcinoma of the lung and the dismal prognosis associated developed new and improved techniques, with this condition, there has been increasing and expanded the indications for rigid broncall for local lung cancer management, stimuchoscopy. He held many training courses for lating the development of a number of endophysicians in his institution and throughout bronchial treatment modalities. These modalthe world. Killian therefore is commonly reities, for the most part, are palliative and ferred to as the ”father of broncho~copy.”~ include laser bronchoscopy, placement of enIn America, Chevalier Jackson, a laryngolodobronchial stents, balloon dilation techgist originally from Pittsburgh, PA, also deniques, endobronchial electrocautery and cryoveloped an interest in endoscopy with “open therapy, endobronchial brachytherapy, and tubes” in the late nineteenth century. After argon beam coagulation. Patients requiring graduating from medical school in 1886, he traveled to London to observe Sir Morel1 these treatment modalities often present with MacKensie, a leading English laryng~logist.~ critical airway obstruction caused by bulky vascular tumors. Control of ventilation and After his return to America, he began to develop his own endoscopes with distal illumi- hemorrhage is paramount in the management of these patients. Rigid bronchoscopy has nation. He experimented with foreign body proved to be an excellent tool to provide acremoval in dogs and with inanimate models. cess to the airway for these new therapies. In 1899, Jackson began working with bronJean Francois Dumon, a French pulmonolochoscopes and, in 1907, he published his landgist, has been extremely influential in promotmark book entitled, Trucheobronchoscopy, Esoing the revival of rigid bronchoscopy. Like phugology and Bronchos~opy.~ In his own Killian and Jackson before him, he offered workshop, he designed and built new esotraining courses in bronchoscopic and laser phagoscopes and bronchoscopes and accestechniques and published journal articles and sory instruments. He perfected new techmonographs allowing him to share his experiniques of scope insertion and foreign body removal. He understood the importance of ence and expertise with numerous physicians training programs and gave instructional throughout the world. Today, many interventional pulmonologists, thoracic surgeons, and courses on bronchoesophagology. He firmly otolaryngologists continue to use the rigid believed in the importance of strict safety probronchoscope for the management of difficult tocols; many of the safety techniques that airway obstructions. Jackson popularized are used today. Jackson eventually held separate chairmanships in bronchoesophagology at all five medical THE RIGID BRONCHOSCOPE schools in Philadelphia, PA and is considered ”the father of American bronchoesophagolToday’s rigid bronchoscopes are similar to ~gy.”~ those used in the days of Jackson. They are Until the mid-l960s, rigid bronchoscopy alhollow, straight tubes made of stainless steel most exclusively was performed by surgeons. (Fig. 1). The length and width vary. Adult In 1966, Shigeto Ikeda from the National Canbronchoscopes are usually 40 cm long and cer Center Hospital, Tokyo, Japan, introduced range in diameter from 9 to 13.5 mm. The the flexible bronchoscope, which revolutionbronchoscope barrel wall is 2 to 3 mm thick ized the field of bronchoscopy and helped
RIGID BRONCHOSCOPY IN THE TWENTY-FIRST CENTURY
357
Figure 1. A, A typical rigid bronchoscope (middle) with Hopkins rod rigid telescope (fop) and optical biopsy forceps. B, Close view of proximal end of bronchoscope with optical biopsy forceps and telescope in place. Lower large side port accepts anesthesia tubing or is left open for Venturi ventilation. Slanted port for suction catheter or Venturi jet. Upper port (and lower port on telescope) accepts light source.
and the inner, round lumen is uniform throughout. The proximal, or operator, end of the bronchoscope consists of a central opening and several side ports. A rigid telescope and many accessory instruments such as forceps, suction catheters, laser fibers, or silicone stent delivery systems can be placed through the proximal opening. The proximal side ports allow for connection of ventilating tubes and an external light source. The distal end of most bronchoscopes is beveled, which permits atraumatic separation of the vocal cords during passage through the larynx, allows the bronchoscope to be “cork screwed” through tight stenoses, and aids in “coring out” obstructing lesions. Rigid bronchoscopes have slit-like openings in the distal end that serve as ventilating ports; shorter tracheoscopes have no side holes on the barrel and can be used to approach high tracheal lesions with-
out leaking ventilating gases above the vocal cords (Fig. 2). Dumon recently redesigned the rigid bronchoscope (Fig. 3A) and introduced a “universal head” to which multiple bronchoscope barrels of varying lengths and diameters, from pediatric to adult size, can be attached. The universal head has special ports for insertion of suction catheters, laser fibers, and telescopes (Fig. 3B) This bronchoscope also is designed for placement of endobronchial and endotracheal silicone stents (Fig. 4). Standard xenon light sources provide illumination for rigid bronchoscopy. Rigid optical telescopes afford a slightly magnified, clear, wide-angled view of the airway. Zerodegree telescopes are adequate for most procedures. Angled telescopes (30” to 45”) permit visualization of upper lobe bronchi. Chargecoupled device (CCD) chip video cameras can
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Figure 2. Tracheoscope.
Figure 3. A, Dumon Series II rigid bronchoscope: Universal head with two bronchoscope barrels and one tracheoscope barrel. B, Close view of universal head with ports for (from left) suction catheter, telescope, anesthesia connection, and biopsy forceps or Venturi connection.
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Figure 4. Silicone stent delivery devices for Dumon rigid bronchoscopes. Original loader and insertion device (bottom). Series II loader and delivery device allow for visualization of stent deployment (top).
be attached to the telescope, allowing the bronchoscopist to share the procedure with other members of the team on video screens and to record the procedure on tape. The internal diameter of most adult bronchoscopes is sufficient to allow passage of a flexible bronchoscope. This measurement often is helpful in dealing with tortuous airways and distal lesions. INDICATIONS The rigid bronchoscope can be used diagnostically and therapeutically in a number of benign and malignant conditions: Massive hemoptysis Foreign body removal Tracheobronchial stenosis Post-traumatic Postinfectious (tuberculosis, histoplasmosis, Herpes virus) Postinflammatory (Wegener 's granuloma) Postintubation or tracheostomy Tracheobronchomalacia Tracheoesophageal fistula Tracheobronchial obstruction Extrinsic compression Esophageal tumor Lymphoma Mediastinal tumors (Thymus, Thyroid,
Germinal cell tumors) Aortic aneurysm Benign Tumors Papillomatosis of the large airways Endobronchial amyloidosis Malignant Tumors Bronchogenic tumors Adenoid cystic carcinoma Mucoepidermoid tumor Carcinoid tumor Metastatic tumors Post lung transplantation Anastomotic stenosis Indications for a rigid bronchoscope include diagnosis of airway disease, foreign body removal, management of massive hemoptysis, clot and mucous plug removal, and a number of therapeutic interventions: Lasers Carbon dioxide Neodymium-yttrium-aluminum-garnet Potassium titanyl phosphate Electrocautery Cryotherapy Argon beam coagulator Stents Silicone Metallic Hybrid "Y Dilating balloons
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For nearly 70 years, the rigid bronchoscope provided the only access to the airways. Since the late 1960s, however, virtually all diagnostic procedures have been performed through the flexible bronchoscope. Today, in adult bronchology, the rigid bronchoscope is reserved for the most difficult diagnostic cases and many therapeutic indications. In pediatric bronchoscopy, the rigid bronchoscope remains both a diagnostic and therapeutic tool, although there is now a general acceptance that even the smallest children can undergo flexible bronchoscopy safely. The enormous growth of medical technology in the latter half of the twentieth century led to a number of advances in therapeutic bronchoscopy, including laser phototherapy (photocoagulation, cutting, and vaporization), endobronchial stent placement (silicon and metallic), electrocautery, cryotherapy, balloon dilatation, and argon beam coagulation. Many times, these interventions must be performed on severely ill patients with acute airway obstruction. The rigid bronchoscope has proved to be well suited for these situations because it allows excellent control for ventilation and provides easy passage for various instruments that aid in the removal of obstructing tissue and foreign bodies. Rigid bronchoscopy remains the preferred technique for removal of large, central foreign bodies. Smaller and more distal foreign bodies often can be removed with a flexible bronchoscope. The rigid bronchoscope continues to play an important role in the management of massive hemoptysis. It can serve as a device to tamponade the source of bleeding, provide excellent suction of obstructing clots and blood, and allow use of tamponading balloons, forceps, or sponges. CONTRAINDICATIONS
Rigid bronchoscopy is a safe procedure. Because it requires general anesthesia, the absolute contraindications are related to comorbid diseases that increase the risk associated with anesthesia. These include an unstable cardiopulmonary status, cardiac arrhythmia, and severe, uncorrectable hypoxic respiratory distress. Other contraindications to rigid bron-
choscopy relate to the patient’s neck and jaw anatomy-unstable cervical spine, oral or maxillofacial trauma, cervical ankylosis, or severe kyphoscoliosis. TECHNIQUE
Patient Preparation
Rigid bronchoscopy typically is performed under general anesthesia in an operating room setting. Proper preoperative assessment therefore is required. This assessment includes a thorough physical examination that pays particular attention to the oral cavity and neck mobility. A minimal number of laboratory tests are necessary. Standard tests include a complete blood count, arterial blood gases or oxygen saturation, a chest radiograph, and an electrocardiogram. Other tests may be necessary, as dictated by the patient’s underlying condition. The anesthesiologist plays an important role in explaining the risk associated with general anesthesia to the patient and assessing the upper airway for ease of intubation. Anesthesia
Modern rigid bronchoscopy often involves the use of lasers, electrocautery, and cryotherapy to treat localized endobronchial obstructions. These procedures are performed best in a controlled setting in which there is minimal movement because of cough or patient discomfort. Rigid bronchoscopy therefore is performed best under general inhalational or intravenous anesthesia. In extremely cooperative patients, the procedure may be performed with topical anesthesia and conscious sedation. The bronchoscopist must work closely with the anesthesiologist and operating room personnel. An ideal anesthetic for rigid bronchoscopy provides quick onset of action and a short half-life to allow the patient to awaken quickly. Today, the combination of propofol, a short-acting intravenous anesthetic with a rapid onset of action, along with intravenous medazolam and fentanyl, provides effective and safe anesthesia, amne-
RIGID BRONCHOSCOPY IN THE TWENTY-FIRST CENTURY
sia, and pain control. Muscle relaxants often are used to promote passage of the bronchoscope through the upper airway and to facilitate controlled ventilation. This combination of medications rapidly and effectively sedates the patient, reverses quickly, and suppresses cough, which is vital for the bronchoscopist to perform precise, delicate maneuvers with the laser or other interventional tools. Patients undergoing rigid bronchoscopy must be monitored closely. Standard operating room monitoring of blood pressure, electrocardiogram, and pulse oximetry usually suffices. Pulmonary artery catheter monitoring and arterial blood pressure monitoring rarely are indicated. Ventilation is assessed with end-tidal carbon dioxide monitoring in closed ventilation systems or chest wall exertion when open systems are employed. Ventilation
A number of ventilation techniques can be used during rigid bronchoscopy. Today, the most common technique is spontaneous assisted ventilation. With this technique, the patient receives general intravenous anesthesia but maintains shallow spontaneous breathing.l0 The anesthesiologist provides frequent assisted breaths (10-20 per minute) and attempts to synchronize breathing with the bronchoscopist’s maneuvers. Venturi jet ventilation is preferred by a number of centers. This technique, as described by Godden et al: is an open ventilation system. One-hundred percent oxygen is injected into one of the proximal ports of the rigid bronchoscope at 50 psi. Room air is entrained through the open end of the bronchoscope. The pressure of the Venturi jet is sufficient to provide thoracic cage exertion. Because the amount of room air entrained varies with lung and chest wall compliance, the fraction of inspired oxygen at the level of the trachea is variable, not measurable, but is usually sufficient to maintain adequate arterial oxygen saturation. Insertion of the Rigid Bronchoscope
Once in the operating theater, the patient is placed in the supine position. After induction
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of anesthesia, the patient’s eyes and teeth are protected with commercially available eye pads and tooth guards or with moist gauze pads. A folded towel is placed under the extended head of the patient. Some bronchoscopists prefer to suspend the patient’s head over the table’s edge and support the head with his or her thigh or an assistant’s hand. The advantage of this technique is that the trachea is forced into a more anterior position, facilitating placement of the bronchoscope. Most patients, however, can be intubated with the rigid bronchoscope while in the supine position with the neck slightly extended. Three classic intubation techniques can be employed, depending on the bronchoscopist’s experience and the patient’s underlying condition. The rigid bronchoscope can be inserted directly, with the aid of a laryngoscope, or guided by an endotracheal tube. In the direct technique, the bronchoscopist looks directly down the open tube or through a rigid telescope placed inside the bronchoscope. The scope then is inserted into the oropharynx with the beveled end in the anterior position. After passing the uvula, the beveled end is used to displace the epiglottis anteriorly. At this point, the vocal cords are visualized. The bronchoscope then is rotated 90” and advanced through the cords. Once the bronchoscope enters the trachea, it is rotated back 90°, keeping the beveled end anteriorly. This insertion technique demands a considerable amount of expertise and is not for the novice. In the second insertion technique, a straight laryngoscope is used to visualize the vocal cords in much the same way as it is used to insert an endotracheal tube. When the vocal cords come into view, the rigid bronchoscope is advanced through the cords and the laryngoscope is removed. Once the rigid bronchoscope is in the proximal trachea, a telescope is inserted down the barrel of the scope and the airway inspection is carried out. At times a patient may be brought to the operating room intubated, receiving oxygen and mechanical ventilation. In this situation, the endotracheal tube must be removed to perform rigid bronchoscopy. The rigid bronchoscope, along with its telescope, is advanced through the mouth anteriorly, or later-
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ally, along the endotracheal tube, until the vocal cords come into view. The anesthesiologist or an assistant then slowly removes the endotracheal tube as the bronchoscopist keeps constant watch of the vocal cords. As the endotracheal tube is pulled above the vocal cords, the rigid bronchoscope is advanced into the trachea as described in the direct technique. Once the bronchoscope is passed into the trachea, the central airways can be visualized. The use of a telescope provides an excellent, slightly magnified view of the large airways, including the trachea, main bronchi, and the openings to the five lobar bronchi. Often, segmental bronchi in the left upper lobe and right upper lobes cannot be visualized with the 0" telescope. To visualize these segments, angled telescopes can be used or a flexible bronchoscope can be passed through the rigid instrument. Several recent references provide a more detailed description of intubation l4 techniques for the rigid bronchoscope.1,2,
COMPLICATIONS
When performed in a controlled setting by an experienced bronchoscopist assisted by an experienced anesthesiologist, the complications of rigid bronchoscopies are rare. The most common complications are the result of improper intubation technique resulting in trauma to the teeth or oropharynx, or perforation of the tracheal or bronchial wall. Massive hemorrhage is extremely rare. In fact, the most dangerous complications associated with rigid bronchoscopy are those related to the use of general anesthesia, especially in patients with compromised pulmonary reserve who readily develop hypoxia and secondary cardiac arrhythmias. Caputi6 has reported only two deaths in more than 11,000 rigid bronchoscopies performed at his center in Italy. Most rigid bronchoscopies can be performed safely on an ambulatory basis. Admission is dictated by the patient's underlying condition and functional status, rather than by the procedure itself.
ADVANTAGES AND DISADVANTAGES
There are many advantages to rigid bronchoscopy. This procedure allows for excellent control of the compromised airway, whether the obstruction is attributable to foreign body, benign stenosis, or malignant tumor. The telescopes used with the rigid bronchoscope provide bright, magnified views of the airway. The lumen of the rigid bronchoscope is sufficient for passage of large biopsy forceps and other accessory instruments. Because rigid bronchoscopy is performed under general anesthesia, often with muscle relaxation, cough is suppressed and the patient remains motionless even during prolonged procedures. In general, interventional procedures are much shorter in duration when performed with a rigid bronchoscope than with a flexible bronchoscope. Therapeutic procedures such as laser therapy, electrocautery, cryotherapy, and endobronchial stent placement can be performed through the rigid bronchoscope. In fact, silicone stents can be placed only with a rigid bronchoscope. The rigid bronchoscope provides an excellent channel for grasping foreign bodies. The barrel of the bronchoscope can serve as a tamponading device in the event of hemorrhage from a central lesion. There are also disadvantages associated with rigid bronchoscopy. Obtaining operating room privileges is often problematic for the pulmonologist. The operating room schedule often is not accommodating to the nonsurgeon. The help of an anesthesiologist and operating room ancillary staff is required. The physiology of patients with upper airway lesions or maxofacial pathology may not be able to accommodate the rigid instrument. Lesions in distal airways might not be accessible to the rigid instrument. For the pulmonologist, a major obstacle to obtaining proficiency in rigid bronchoscopy is the lack of exposure during fellowship training. Extra training outside of a classic pulmonary fellowship usually is required. This training may be in the form of an interventional pulmonology fellowship or may require postgraduate courses n r working closely with a local mentor.
RIGID BRONCHOSCOPY IN THE TWENTY-FIRST CENTURY
FOR THE FUTURE Despite its 100 years of use, its obvious historical importance in the progress of pulmonary medicine, and the ease with which it can be adapted for use with modern endobronchial therapies, the popularity of rigid bronchoscopy continues to decline. In 1999, in a survey sponsored by the American Association of Bronchology, Colt and Prakash7surveyed 2500 members of the American College of Chest Physicians (ACCP) regarding bronchoscopic practices throughout North America. Only 4% of 744 respondents reported that they perform rigid bronchoscopy, compared with 8% of respondents in a 1989 ACCP bronchoscopy survey.ll In many European pulmonary training programs, rigid and flexible bronchoscopy are taught. Bronchoscopic surveys performed in England and The Netherlands have shown that 20% and 9% of bronchoscopists perform rigid bronchoscopy, respectively.13,l5 In the United States, few pulmonary fellowship programs offer training in rigid bronchoscopy. Many fellows therefore must seek training outside of fellowship to achieve experience in rigid bronchoscopy. Unfortunately, postgraduate courses only can provide an introduction to interventional techniques, including rigid bronchoscopy, and do not enable a physician to become competent enough to perform these therapeutic procedures independently. Nevertheless, the rigid bronchoscope will remain an invaluable tool for interventional pulmonologists and thoracic surgeons who manage patients with challenging airway obstruction. Medical technology surely will advance throughout the twenty-first century, and the rigid bronchoscope, although not likely to change in design, surely will be adaptable to these new developments. Anesthetic techniques will improve further, making the procedure safer and more comfortable for patients. It is likely that there will be improvements in stent design and deployment and that the application of current ablative techniques, such as laser, electrocautery, and cryotherapy, will improve. As the field of interventional pulmonology becomes further defined, it is likely that current bronchoscopy
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rooms will become full-service interventional pulmonology suites, where general anesthesia may be administered, avoiding the difficulties with operating room access that many pulmonologists face.l2 Once the rigid bronchoscope is brought from the operating room to the pulmonary procedure room, its acceptance by pulmonologists should improve. Unfortunately, the epidemic of lung cancer is likely to continue well into the twenty-first century. This terrible cancer often impacts on the quality of life of an individual by producing central airway obstruction. As new therapies to relieve this obstruction are developed, it is likely that the safety and effectiveness of their application will be enhanced by the use of the rigid bronchoscope.
SUMMARY
Rigid bronchoscopy, a procedure more than 100 years old, now has been performed in three centuries. The "open tube" bronchoscope provides safe access to the lower airways and has proved to be compatible with newer, more sophisticated therapies as they have been introduced into the practice of bronchology. The twenty-first century surely will provide the bronchoscopist with exciting new diagnostic and therapeutic tools for the management of lung diseases, and it is likely that the rigid bronchoscope will continue to play an important role in delivering these tools to the airways. Pulmonologists need to appreciate the use of this classic instrument and prevent rigid bronchoscopy from becoming a forgotten art.
References 1. Beamis J F Rigid bronchoscopy. In Beamis JF, Mathur PN (eds): Interventional Pulmonology. New York, McGraw-Hill, 1999, pp 17-28 2. Beamis JF: Modem use of rigid bronchoscopy. In Bolliger CT, Mathur PN (eds): Interventional Bronchoscopy. Basil, Karger, p 22-30, 2000 3. Becker HD, Killian G: A biographical sketch. Journal of Bronchology 27743,1995 4. Becker HD, Marsh BR History of the rigid bronchoscope. In Bolliger CT, Mathur PN (eds): Interventional Bronchoscopy. Basil, Karger, p 2-15, 2000
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5. Boyd AD, Jackson C: The father of American bronchoesophagology. Ann Thorac Surg 57502-505,1994 6. Caputi M, Bellissimo U, DiMatteo L, et al: Complications during bronchofiberscopy and rigid bronchoscopy. Panminerva Med 28:271-277,1986 7. Colt HG, Prakash UBS, Offord KF: Bronchoscopy in North America: Survey by the American Association for Bronchology, 1999. Journal of Bronchology 7825,2000 8. Godden DJ, Willey RF, Fergusson RJ, et al: Rigid bronchoscopy under intravenous general anesthesia with oxygen Venturi ventilation. Thorax 37532-534, 1987 9. Jackson C: The life of Chevalier Jackson: An autobiography. New York, MacMillan, 1938 10. Perrin G, Colt HG, Martin C, et al: Safety in interventional rigid bronchoscopy using intravenous anesthe-
sia, and spontaneous assisted ventilation: A prospective study. Chest 1021526-1530, 1992 11. Prakash UBS, Offord KP, Stubbs SE: Bronchoscopy in North America: The ACCP Survey. Chest 100:16681675, 1991 12. Prakash UBS: Bronchoscopy unit expertise, equipment and personnel. In Bolliger CT, Mathur PN (eds): Interventional Bronchoscopy. Basil, Karger, Prog Respir p 31-43, 2000 13. Simpson FG, Arnold AG, Purvis A, et al: Postal survey of bronchoscopic practice by physicians in the United Kingdom. Thorax 41:311-3117, 1986 14. Stradling P: Diagnostic Bronchoscopy: A teaching Manual, ed 5. New York, Churchill Livingstone, 1986 15. Sutjedja T, Festen J, Vanderschueren R, et al: A postal survey of bronchoscopic practice in the Netherlands. Journal of Bronchology 3:17-21, 1996
Address reprint requests to John F. Beamis, Jr, MD Lahey Clinic 41 Mall Road Burlington, MA 01805