Nd YAG Laser Surgery for severe Tracheal Stenosis Physiologically and Clinically Masked by severe Diffuse Obstructive Pulmonary Disease*

Transcription

1 Nd YAG Laser Surgery for severe Tracheal Stenosis Physiologically and Clinically Masked by severe Diffuse Obstructive Pulmonary Disease* Arthur F. Gelb, M.D.; F.G.G.P.; Donald P. Tashkin, M.D., F.G.G.P.; Joel D. Epstein, M.D., F.G.G.P.; and Noe Zamel, M.D., F.G.G.P. Nd-YAG laser surgery was performed on six patients with tracheal stenosis complicating severe diffuse intrathoracic airways obstruction due to emphysema, chronic obstructive bronchitis and/or asthma. Tracheal stenosis was extrathoracic in four patients and both extrathoracic and intrathoracic in two patients. Results suggest that patients with severe chronic obstructive pulmonary disease and asthma have maximal expiratory and inspiratory Row volume patterns that may completely mask extrathoracic and intrathoracic tracheal stenosis. Following reliefof tracheal obstruction with laser therapy, substantial improvement can occur both clinically and physiologically, as rerected by symptomatic relief and large increases in Vmax0I and FVC. We report our experience in six patients with chronic airways obstruction who developed severe tracheal stenosis as a result of previous endotracheal intubation and/or tracheostomy required for the management of acute episodes of respiratory failure. Four patients developed extrathoracic tracheal obstruction, and two patients had a combination of extrathoracic and intrathoracic tracheal stenosis. On clinical grounds, persistent dyspnea, cough, and/or wheezing in each patient was attributed to the underlying chronic airways obstruction. Physiologically, lung function studies in these patientsfailed to demonstrate flow limitation profiles characteristic of tracheal stenosis. However, bronchoscopy after subsequent bouts of acute respiratory failure demonstrated previously unsuspected severe tracheal stenosis. Following treatment with the Nd-YAG laser, significant clinical and physiologic relief was obtained in five of six patients. MATERIALS AND METHODS Our therapeutic techniques using the Nd-YAG laser (Medilas, MBB, Endo-lase, Inc. New York, NY) have previously been reported.' :' The laser treatment was used for patients with severe tracheal stenosis who were symptomatic and had not improved with bronchoseopic mechanical dilatation or previous surgical excision and/or were felt to be too dyspneic to unde rgo surgery. Detailed informed consent wasobtained from each patient in accordance with the guidelines of the manufacturer, the United States Foodand Drug Administration, the California Patients' Bill of Rights and local From the Departments of Medicine, Pulmonary Divisions, Doctors Hospital of Lakewoodand Rieder Laser Center-Long Beach Memorial Medicine Center, Long Beach, California; University of Toronto. Canada; and UCLA School of Medicine, Los Angeles. Manuscript received June 2; revision accepted August 12. Reprint requests : Dr. Gelh,.36.0 East South Street, Suite 308. Lakewood. Califomia hospital institutional review committees. Palliative improvement was considered to have occurred if the stenotic opening of a previously obstructed trachea was enlarged with relief of dyspnea, cough and/or wheezing and physiologicallydemonstrated reduction in airflow obstruction. Maximal expiratory and inspiratory How volume loops(collinsspirometer, Braintree, MA)were performedin each patient before and at least three weeks after laser therapy; results were compared with previously published standards.'? Predicted Vmax0(Usee) for inspiration was assumed to be equivalent to l.l times the predicted value for Vmax0 expiration.' Following laser therapy, Vmax0during expiration and inspiration was calculated at the same lung volume as that used to calculate the maximal How rates at 0 percent of the vital capacity before laser surgery. In four patients we also obtained maximal expiratory How volume loops after the breathing of a mixture of 20 percent oxygen-so percent helium, according to the method of Despas et ai.8 The normal response to breathinghelium isan increase in How rate at 0 percent of the vital capacity (AVmax0 H.) of greater than 20 percent after forced inspiration and expiration. RESULTS We studied six patients; one had severe chronic asthmatic bronchitis (case 1), three had severe emphysema (cases 2, 3, ) and two had asthma (cases, 6).9 All patients had required endotracheal intubation and/or tracheostomy from four to 60 months prior to study for management of respiratory failure associated with bronchitis, emphysema (cases 1-3, ), asthma and drug overdose (case ), and asthma and chest injury (case 6). All patients had dyspnea and cough with inspiratory and expiratory rhonchi and wheezing on a chronic basis. Isolated inspiratory stridor was not observed. Serial bouts of acute respiratory insufficiency were attributedclinically and physiologically to the underlying bronchitis, emphysema and/or asthma. However, eventual bronchoscopic evaluation performed during a bout of acute respiratory failure either to improve Nd VAGLaser for SevereTrachealStenosis (Gelb et aj)

2 II) u, E (1) E 3 / ~ O '..... ~ 1../ ~3 2..._ V O L U M E ( ~ ) _Pre Laser. Post Laser.. Pre Surg. Resect 3 2 E II) 1 ~ _ -., ~ - r _ -., ~ ~ ~3 u, V O L U M E ( ~ ) C f'-, 6 I '\/ "'''' 12",,,, I I \ I \ I,../,..-_... _ Pre Laser. Post Laser. Pre Surg. Resect FIGURE 1. Maximum inspiratory and expiratory flow-volume loops are described before and after laser treatment in six patients with severe obstructive lung disease with superimposed extrathoracic tracheal stenosis (cases 1-)and two patients with combined extra- and intrathoracic tracheal stenosis (cases, 6). In each patient the size of the stenosed tracheal diameter before and after laser therapy is given. In cases 1- with extrathoracictracheal stenosis there was no inspiratory flowlimiting plateau and VmaxSOI > VmaxSOE. In cases, 6 with combined extra- and intrathoracic tracheal stenosis there was no expiratory or inspiratory flow limiting plateau and VmaxSOI > VmaxSOE. FoUowing laser therapy there was significant clinical improvement in cases 1-3,, 6 and significant increase in forced vital capacity and Vmax(h. Table I-LungfUnction Studies Pre- and Post-Imler Tfl1atment in Patients with E:rtrathoracic (Cases 1-) and Combined E:rtrathoracic and Intrathoracic Tracheal Stenosis (Cases,6) u\ maxso Dca PF FEV, FVC VmaxSOI \-'maxsoi:: (%) \ 'maxsoi::! Case Sex Age Dx (mvminlmmhg) (Usec) (L) (L) (U see) (U see) E I \ 'maxsoi M 78 Bronchitis pre 18 (78) 1.6 (19) 1.1 (39) 3.0 (72) 1.6 (2) 0. (13) 0 0.:31 post 2.8 (33) 1.7 (61).2 (100) 2.0 (3) 1. (36) F 6 Emphysema pre 1.0 (19) 0. (18) 1.0 (37) 0.9 (27) 0.1 (3).09 post 1.8 (3) 0. (23) 1.0 (37) 1. () 0.3 (9).20 3 M 68 Emphysema pre 2. (30) 0.8 (2) 1.9 () 2.7 (6.) 0. (12).19 post 3.0 (36) 1.1 (32) 2.7 (6) 2.6 (63) 0.6 (18).19 F 23 Asthma pre 1. (23) 1.1 (3) 3.2 (82) 3.3 (79) 0.8 (19) post 1. (23) 1.1 (3) 3. (87) 3.6 (86) 0.8 (19) F 63 Emphysema pre" 1.2 (22) 0.8 (32) 2.2 (71) 0.9 (27) 0. (1) pre 0.9 (1) 0. (20) 1.7 (3) 0.7 (21) 0.1 (3) post 1.3 (2) 0.7 (28) 2.2 (71) 1. (2) 0. (1) 6 M 3 Asthma pre 31 (106) 2.7 (32) 1.2 (3) 2.0 (8) 2.0 (7) 0.7 (16) post.0 (8) 1. (1) 2. (.7) 3. (83) 1.0 (23) Before surgical resection of tracheal stenosis. ( )=percent predicted; Dco =single breath diffusing capacity forcarbon monoxide; PF =peak expiratory flow: FEV, =forced expiratory volume in 1 second; FVC =forced vital capacity; VmaxSOI = maximal flowat 0% forced inspiratory volume (flowstudies post laser are measured at the same volume as pre laser); VmaxSOE - maximal Bowat 0% forced expiratory volume (Bowstudies post laser are measured at the same volume as pre laser); AVmaxSO =increase flow at 0% FVC with 20% oxygen-8o% helium mixture : E =expiratory I =inspiratory. CHEST I 91 I 2 I FEBRUARY

3 pulmonary toilet or for diagnostic purposes demonstrated clinically unsuspected severe extrathoracic tracheal stenosis in each patient. Subsequent radiographic studies, including xerograms, CAT scans and tomography of the trachea, further delineated the extent of the lesion. Surgical excision of the stenotic area with removal of at least two cartilage rings was attempted in two patients (cases, 6). However, surgery was subsequently complicated by re-stenosis at the anastomotic site (case ) or by narrowing of the lumen by tissue granulomas (case 6). As a consequence, in each of these two cases, combined extrathoracic and intrathoracictracheal stenosis developed. At the time of study, in all six patients the site of the tracheal stenosis extended from cm below the vocal cords distally for an additional em. In no instance was there obvious necrosis of the remaining cartilaginous rings. Tracheal diameter of the stenotic area before and after laser treatment is shown in Figure 1. All patients had concentric tracheal stenosis. Results of pulmonary function studies before and. after laser treatment are reported in Table 1. Before laser therapy, lung function studies demonstrated severe airflow limitation on expiration in all cases, as well as on inspiration in all but case. The ratio of VmaxSOENmaxSOI was low in all patients and failed to identify the four patients with isolated extrathoracic tracheal stenosis (cases 1-) or to distinguish between lower airway or parenchymal obstructive lung disease and superimposed combined intrathoracic and extrathoracic tracheal stenosis in cases and 6;!:iVmax0 expiration was reduced in three of the four patients in whom it was performed and!:ivmaxso inspiration was reduced in all four patients and failed to identify the patients with extrathoracic tracheal stenosis. Maximal expiratory and inspiratory flow volume loops did not demonstrate flow-limiting plateaus or profiles characteristic of extrathoracic and/or central intrathoracic obstruction (Fig 1). In three of the four patients with extrathoracic tracheal stenosis, laser treatment was followed by improvement in most functional indices, as well as symptomatic amelioration. Symptomatic relief following a single laser treatment persisted for up to nine months in two patients, while one patient succumbed to his underlying emphysema one month after laser treatment. In the two patients with combined extra- and intrathoracic tracheal stenosis, clinical and physiologic improvement developed following a single laser treatment. Relief persisted for up to one year in one patient; in the other patient, re-stenosis occurred one month following laser surgery and a permanent tracheostomy was required. 188 DISCUSSION We studied six patients with asthma, emphysema and chronic asthmatic bronchitis who developed severe central upper airways obstruction; four had extrathoracic tracheal stenosis and two had combined extrathoraeic and intrathoracic tracheal stenosis. In all six patients the superimposed tracheal stenosis was masked both clinically and physiologically. Maximum expiratory and inspiratory flowvolume curves failed to demonstrate the characteristic flow-limiting plateaus. However, after diagnosis of the tracheal stenosis, laser therapy resulted in clinical and physiologic improvement in five of the six patients. In the one patient without clinical or physiologic improvement, laser therapy did cause an increase in the diameter of the tracheal lumen from.0 to 9.0 mm; we presume that flow limitation in this patient was due primarily to the underlying severe asthma. In four of the five patients with symptomatic relief following laser therapy, VmaxSO inspiratory flow rate increased substantially (by 21 to 100 percent, mean 33. percent); this functional change probably refleeted improvement in the extrathoracic component of the tracheal stenosis. Forced vital capacity increased by 0 to 2 percent (mean 2.0 percent); this improvement may have been due to less inspiratory and expiratory tracheal resistance. Because of these substantial increases in FVC, isovolume comparisons of the forced expiratory and inspiratory flow rates before and after tracheal dilation, as used in this study, are necessary to avoid underestimating improvement in the forced flow rates. Previous investigators have discussed the physiologic mechanisms of obstructing lesions of the trachea.'?" Noncompliant tracheal lesions that do not respond to transmural forces result in a fixed obstruction; in these cases it is not possible to distinguish between intrathoracic or extrathoracic tracheal stenoses.p:" Destruction of the tracheal cartilage increases the compliance of the affected part of the narrowed trachea producing variable extra- and/or intrathoracic obstruction. These tracheal lesions are responsive to transmural changes that alterthe caliber of the normal airway and either magnify or diminish the gradient at the narowed site of the stenosed trachea.p''' In addition, the Venturi effect should further magnify the gradient at the compliant narrowed site. Recently, Brown et al" have demonstrated that extraluminal pressures are not different between cervical and thoracic segments of the trachea so that the posterior membrane of the trachea is, in fact, exposed to an extraluminal pressure which approximates pleural pressure. These authors argue that changes in the luminal diameter of the cervical and thoracic Nd-VAG Laser lor S8YenI Tracheal Stenosis(Ge/b et ai)

4 segments of the trachea due to changes in the transmural pressures should be similar, since the most compliant component is the posterior membrane. The pattern of isolated (or relatively more severe) limitation in maximal inspiratory Bow with an inspiratory flow plateau that is characteristically found in variable extrathoracic tracheal obstructiori.p'" can be accounted for by the Venturi effect at the level of the tracheal stenosis. Miller and Hyatt" and Gamsu et al" have previously addressed the issue of the nondiagnostic, atypical or false negative Bow volume loops in patients with combined upper airway obstruction and diffuse intrathoracic obstructive pulmonary disease such as emphysema, asthma and/or bronchitis. In such patients, when Bow rates due to the underlying diffuse obstructive pulmonary disease are too low to produce limiting plateaus, the associated central airway lesion cannot be detected physiologically and is thus masked by the underlying obstructive pulmonary disease. On the other hand, as shown in the present study, subsequent increases in tracheal diameter can result in significant clinical and physiologic improvement. Lavelle et al 1 suggested that central airways obstruction in the presence of underlying peripheral obstruction could be detected by noting large increases in Bow after breathing a helium-oxygen mixture. However, significant density-dependence of maximal expiratory Bow was noted in. only one of four patients in the present study and that patient had asthma which alone could account for the density-dependence.v" Empey" noted that the FEV I (ml)/pefr(umin) ratio was greater than 10 in all patients he examined with clinically significant upper airway obstruction, but less than 10 in most normal subjects and patients with lower airways obstruction due to asthma or chronic bronchitis. In contrast, four of our six patients with combined central and diffuse airways obstruction had FE:V/PEFR ratios less than 10. Moreover, in the two patients (Nos 1 and ) with a.ratio greater than 10, the latter could be attributed to severe underlying diffuse airways obstruction, as was noted in some of Empey's patients." Consequently, this index is not helpful in detecting upper airway obstruction when severe diffuse airways obstruction is also present. The experience gained in the treatment of the six patients herein described fosters two conclusions. First, it is important to identify those patients with severe obstructive pulmonary disease who have previously required endotracheal intubation and/or tracheostomy and subsequently develop significant tracheal stenosis, because the superimposed tracheal stenosis may contribute to their Bow limitation. Often the symptoms related to the tracheal stenosis itselfare similar to those caused by diffuse intrathoracic obstructive lung disease, and the physiologic changes of inspiratory airflow limitation may be masked. Once the clinical suspicion of superimposed tracheal ste nosis develops, noninvasive radiographic studies such as xerograms, routine tomograms and/orcr scans of the trachea should be diagnostic. Bronchoscopic confirmation is required before considering the potential therapeutic alternatives. The second major conclusion from this study is that in selected patients, the use of the Nd-YAG laser may be an acceptable therapeutic alternative to traditional surgical methods when used either initially or after surgery when re-stenosis occurs at the surgical anastomotic site. Our results in this study confirm the findings from our earlier investigation of the use of the YAG laser in tracheal stenosis' and e x t the ~ n use d of the YAG laser beyond endotracheal and endobronchial malignancy.ll.3 is.lli In patients with advanced tracheal stenosis including collapse, previous investigators'v'" have reported a success rate from 33 to 0 percent using eitherthe Nd-YAG or carbon dioxide laser. Some patients may eventually require permanent tracheostomy, a Montgomery tube for tracheal stabilization or a sleeve resection. Optimal results may ultimately require additional surgical procedures, but the initial goal is to provide an adequately patent trachea for ventilation. 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5 13 Gamsu G, Borson DB, Webb WR, Cunningham JH. Structure and function in tracheal stenosis. Am Rev Respir Dis 1980; 121: Brown IG, McClean PA, Webster PM, Holfstein V, Zamel N. Lung volume dependence of esophageal pressure in the neck. J Appl Physiol (in press) 1 Lavelle TF, Rotman HH, Weg JG. Isoflow-volume curves in the diagnosis of upper airway obstruction. Am Rev Respir Dis 1978; 117: Antic R, Macklem PT. The in8uence of clinical factors on site of airway obstruction in asthma. Am Rev Respir Dis 1976; 11: Empey DW: Assessment of upper airways obstruction. Br Med J 1972; 3: Toty L, Personne C, Colchen A, Vourc'h G. Bronchoscopic management of tracheal lesions using the neodymium-yttriumaluminum-garnet laser. Thorax 1981; 36: Dumon JF, Reboud E, Garbe L, Aucomte F, Meric B. Treatment of tracheobronchial lesions by laser photo resection. Chest 1982; 81: Simpson GT, Strong MS, Shapshay SM, Healy GB, Vaughan CW: Predictive factors of success or failure in the endoscopic management oflaryngeal and tracheal stenosis. Ann Otol Rhinol Laryngoll982; 91:38-88 National Association of Medical Directors of Respiratory Care The Annual meeting of the NAMDRC will be held March 13 and 1 at the Willard Hotel, Washington, D.C. Topics will include new frontiers in ventilator management, exercise testing and evaluation of pulmonary impairment, and the medical director and home care. For information, write to NAMDRC, PO Box 7011, Arlington, Virginia (703: ). Cardiology: Clinical Evaluation and Decision Making The spring Auscultation Session of the Texas Heart Institute will be held March in Houston. For information, contact Officeof the Medical Director, TexasHeart Institute, PO Box 20269, Houston 7722 (713: ). 170 Nd VAGLaser lor Severe TrachealStenosis(Gelb at 8/)