Postintubation Tracheal Stenosis

Transcription

1 Postintubation Tracheal Stenosis Noel H. Fishman, M.D., Herbert H. Dedo, M.D., William K. Hamilton, M.D., Warren A. Hinchcliffe, M.D., and Benson B. Roe, M.D. D uring the past three years, 12 patients have been treated at the University of California Medical Center, San Francisco, for severe tracheal stenosis that followed prolonged mechanical ventilation. A retrospective analysis of the clinical material was made to determine the role of techniques, underlying disease, and coincident contributory factors in the production of this previously rare complication. The results of treatment were also evaluated. MATERIAL AND METHODS Of the 12 patients in the series, 3 were referred from other hospitals for treatment of tracheal stenosis developing secondary to barbiturate coma, aspiration pneumonitis, and chest trauma. The other 9 patients developed strictures following mechanical ventilation after open-heart surgery on our service. Signs and symptoms of progressive airway obstruction were first recognized one to eight weeks after extubation. The extent of stenosis was investigated by serial bronchoscopic examinations in every patient, contrast tracheography (tantalum) in 6 patients, and operative findings and histological examination of resected specimens from 6 patients. The inflammatory process, which typically was 3 or 4 cm. long, often extended through the tracheal wall into adjacent soft tissue. The normal columnar cells had been replaced with squamous epithelium and granulation tissue. The cartilage, which was in various stages of degeneration, was totally replaced by fibrous tissue at the narrowest point, which was always less than 5 mm. in diameter. Stenosis occurred at the tracheostoma in 3 patients. In the other 9 the stricture corresponded in location and length to the previously inflated balloon. REVIEW OF TECHNIQUES Details of technique and management are difficult to assess from the usual notes in the patient s medical record; however, 9 of the 12 strictures occurred on the Cardio-Thoracic Surgical Service, where techniques have been standardized for several years. On our service, a Portex nasotracheal tube is used for ventilation during the operation and is usually maintained for 12 to 24 hours after cardiac surgical From the Departments of Surgery; Ear, Nose, and Throat; Anesthesia; and Radiology of the University of California School of Medicine, San Francisco, Calif. Presented at the Fifth Annual Meeting of The Society of Thoracic Surgeons, San Diego, Calif., Jan , Address reprint requests to Dr. Fishman, Department of Surgery, University of California School of Medicine, San Francisco, Calif VOL. 8, NO. 1, JULY,

2 FISHMAN ET AL. procedures in adults. Occasionally, a satisfactorily functioning nasotracheal tube may be left in place for a few days longer. is performed as soon as prolonged mechanical ventilation is anticipated. A horizontal skin incision 2 to 3 cm. long is made just above the thyroid isthmus, and a minimal area of trachea is exposed by blunt dissection. A ed 60" metal tube is inserted through a horizontal curved incision through the second cartilaginous ring. Motion and tension at the connection between the tracheostomy and ventilator tubes is minimized by interposition of a flexible rubber tube adaptor. Sterile gloves and catheters are used for aspiration of tracheal secretions, and the nurses are instructed to deflate the every hour for five minutes. The pressure (20 to 45 cm. H,O) at which the ventilating gases are delivered via the Bird respirator is governed by repeated blood-gas and tidal-volume determinations. COMPLICATING FACTORS Severely depressed cardiac output was observed in all the patients. Pathogenic bacteria were discovered in the trachea in only 3 patients. Two patients received corticosteroids for 48 hours for treatment of cerebral air embolism. The small tracheal diameter in 1 patient (Case 8) enabled tracheal stenosis to be predicted. lntubation in the 12 patients varied from 36 hours to five weeks. (See Table 1.) TREATMENT Tracheal dilatation by bronchoscopy was used initially to provide symptomatic relief. (See Table 2.) Four patients obtained long-term freedom from obstruction after one to six dilatations. Two patients (Cases 4, 12) who are now asymptomatic were restudied recently with tantalum tracheography and were found to have a 50% reduction in airway diameter (Fig. 1). Two other patients continue to require periodic dilatations, and operation is anticipated in both. Wedge resection of the anterior portion of one or two tracheal rings was performed in 3 patients (Cases 1, 2, 7), leaving an apparently normal posterior membrane in place. Stenosis recurred within a week in all 3 patients. Circumferential resection was performed in 4 patients. In 1 patient (Case 5) a combined cervical and thoracic approach was used, as described by Grillo [31. The mediastinal trachea was mobilized, the hilar structures were dissected free from pericardial and pleural attachments, and the right inferior pulmonary ligament was divided. Obstruction due to tracheomalacia occurred in one week. A subglottic Silastic T tube stent [5] was inserted to support the trachea until fibrous tissue could form to support it. Upon attempting to remove the stent one year later, complete tracheal obstruction occurred because of the florid granulation tisue response that had developed along its entire length. No further attempt has been made to decannulate the trachea. Three patients had resection of long tracheal segments through a single cervical incision 121. In order to mobilize sufficient trachea for relaxed end-to-end reconstruction, transcervical dissection of the mediastinal trachea and bronchi was combined with release of the larynx [8]. Postoperative management did not include anterior cervical flexion, distal tracheostomy, prophylactic antibiotics, or corticosteroids. All 3 patients are now completely free of airway obstruction. Tantalum tracheograms performed two months after operation in 2 of these patients revealed satisfactory anastomotic lumina without narrowing (Fig. 2). COMMENT STOMAL STRICTURES Etiological factors that have been implicated in the production of stoma1 strictures include removal of excessive amounts of cartilage and 48 THE ANNALS OF THORACIC SURGERY

3 ~ I+ (0 Case No. Age Site Date Technique Stoma Stoma Stoma TABLE 1. POSTINTUBATION TRACHEAL STENOSIS Nasotracheal tube Narotracheal tube Naso tracheal tube Indications for Where Prolonged Mechanical Performed Duration Ventilation Outside hospital Outside hospital Outside hospital 9 days 2 weeks 3 weeks 2 weeks 2 weeks 2 weeks 5 weeks 2 weeks 3 weeks 36 hours 3 days 5 days Lowoutput syndromea Aspiration pneumonitis Cerebral air embolism, low-output syndrome Barbiturate coma Crush chest injury Cerebral air embolus, low-output syndrome After valve replacement or aneurysmectomy. Complicating Factors Large tracheal stoma, shock Pump lung Steroids for 2 days Infection, shock, re tracheostomy Pump lung Pneumonia, atelectasis, shock Small tracheal lumen Infection, steroids for 2 days - -

4 FISHMAN ET AL. TABLE 2. TREATMENT OF POSTINTUBATION TRACHEAL STENOSIS DILATATION ONLY Case No. Dilatations Result 4 6 Asymptomatic; audible turbulence 6 4 Asymptomatic; audible turbulence 9 15 Severely obstructed; awaiting operation 10 5 Asymptomatic; audible turbulence 11 5 Mild obstructive symptoms Severely obstructed; awaiting operation WEDGE RESECTION Preop. Postop. Case No. Dilatations Dilatations Result Asymptomatic; audible turbulence Asymptomatic; audible turbulence Circumferential resection required CIRCUMFERENTIAL RESECTION Preop. Tracheal Case No. Dilatations Resection Result cm." Asymptomatic; no audible turbulence cm.b Obstruction recurred; subglottic stent required cm.8 Asymptomatic; no audible turbulence cm.8 Asymptomatic; no audible turbulence "Single cervical incision [21. Release of larynx and transcervical mobilization of mediastinal trachea. "Grillo's operation [31. Mobilization of cervical and mediastinal trachea, dissection of hilar structures from pleural and pericardial attachments, and division of right inferior pulmonary ligament. mucous membrane during the tracheostomy procedure [S]; destruction of additional tissue by pressure necrosis [l, 71 and infection [I, 4, 91; impairment of blood supply by the operative dissection and interruption of retrograde mucosal blood flow by the inflated distal [9]. One of the three stoma1 strictures that were treated at this institution (Case 3) resulted from upward migration of the metal tube into the narrow cricoid area, a potentially avoidable complication. CUFF-LEVEL STRICTURES The circumstantial evidence presented suggests that the localpressure effect of the inflated balloon is the primary cause of strictures occurring distal to the tracheostoma. Ischemic necrosis is a recognized hazard of pressure, and the danger is increased when tissue perfusion is impaired. Several of our patients had cardiac outputs barely sufficient to supply basal metabolic demands, and the work-sparing ef- 50 THE ANNALS OF THORACIC SURGERY

5 Postintubation Tracheal Stenosis FIG. 1. Tantalum tracheogram taken two years after repeated tracheal dilatation (Case 4). The patient is entirely asymptomatic even though he has a residual 50% narrowing of tracheal diameter. fect of assisted mechanical ventilation [ 101 was essential to their survival. Lengthy periods of balloon deflation could not be tolerated in some patients, who developed cardiac arrhythmias after just a few seconds of interrupted ventilation. It is not possible to rule out the A FIG. 2. (A) Tantalum tracheogram performed two months after resection of 4 em. of trachea through a single cervical incision (Case 7). Note the satisfactory anastomotic lumen at the leuel of the thoracic inlet. (B) Tantalum tracheogram performed two months after circumferential resection of 4 cm. of trachea, including lower half of cricoid cartilage (Case 3). The anastomosis is faintly visible 2 em. below the closed glottis. B VOL. 8, NO. I, JULY,

6 FISHMAN ET AL. mechanical trauma of the tracheostomy procedure or the manipulation of the metal tubes as contributory causes of -level strictures. However, the occurrence of this complication after nasotracheal intubation without tracheostomy (Cases 10, 1 1, 12) demonstrates that local pressure in the presence of reduced systemic tissue blood flow is alone sufficient to cause stricture. During the same three-year period covered by this report, tracheal stenosis was not a complication of any of the other 300 tracheostomies performed in this hospital. RECOGNITION AND LOCALIZATION The diagnosis of tracheal obstruction is usually obvious clinically, but it has been mistaken for other causes of pulmonary and cardiac dysfunction, such as tracheobronchitis or pulmonary edema. Bronchoscopy is essential in determining the degree of stenosis and the activity of the inflammatory process; however, the lack of depth perception through this distant monocular view of the trachea has resulted in erroneous and inconsistent localization of the site of stenosis and inadequate appreciation of the length of the disease process. Contrast tracheography has been extremely helpful in this regard. TREATMENT Tracheal Dilatation. In this series no patient responded to repeated dilatations with permanent benefit unless it was possible to space the treatments at progressively greater intervals, up to a maximum of six dilatations. Significant anatomical stenosis may persist after a successful program of repeated dilatation, suggesting that this is not ideal treatment and should be continued only in the patient who is an extremely poor surgical risk. Wedge Resection. The characteristic postintubation stricture is too long to be satisfactorily removed by this type of partial excision. The recurrent stenosis probably represents contraction of residual scar tissue. Furthermore, angulation produced by wedge resection may impede air flow. circumferential Resection. Complete resection of all diseased tissue with end-to-end anastomosis of normal mucous membrane, performed without tension, is clearly the ideal management. No successful tracheal prosthesis has yet been devised. Indwelling stents are not satisfactory alternatives to resection. Failure to establish an adequate airway in the patient who was operated upon early in our experience with Grillo s technique (Case 5) is attributed in retrospect to inadequate resection. The first two tracheal rings, which contained the tracheostoma, were totally devoid of cartilage anteriorly and should have been removed with the other three diseased rings. Circumferential resection in 52 THE ANNALS OF THORACIC SURGERY

7 Postintubation Tracheal Stenosis the other 3 patients was performed entirely through the neck, because previous mediastinal surgery (Cases 3, 8) and massive chest injury (Case 7) precluded a major thoracic exploration. The observation by Mulliken and Grillo [6] that transcervical mediastinal dissection would yield additional tracheal length was confirmed. We also discovered that releasing the larynx allowed us to develop an additional 3 cm. After removal of up to 4 cm. of trachea, the edges were reanastomosed with minimal tension. SUMMARY Twelve cases of benign tracheal stricture following prolonged mechanical ventilation were analyzed. Nine stenoses were localized to the area of the previously inflated balloon and appeared to be the result of ischemic necrosis. Three of these s had been on nasotracheal tubes. Contrast tracheography was useful in demonstrating the extent of the lesion. Mobilization of sufficient trachea to permit relaxed end-to-end anastomosis after resection of 4 cm. was possible through a single cervical incision. REFERENCES 1. Christensen, K. D., and Duvall, A. J. Tracheal stenosis from the ed tracheotomy tube. Arch. Otolaryng. (Chicago) 87:279, Dedo, H. H., and Fishman, N. H. Laryngeal release and sleeve resection for tracheal stenosis. Ann. Otol. 78:285, Grillo, H. C. Circumferential resection and reconstruction of the mediastinal and cervical trachea. Ann. Surg. 162:374, Johnston, B. J., Wright, J. S., and Hercus, V. Tracheal stenosis following tracheostomy. J. Thorac. Cardiovasc. Surg. 53:206, Montgomery, W. W. T-tube tracheal stent. Arch. Otolaryng. (Chicago) 82: 320, Mulliken, J. B., and Grillo, H. C. The limits of tracheal resection with primary anastomosis: Further anatomical studies in man. J. Thorac. Cardiovasc. Surg. 55:418, Murphy, D. A., MacLean, L. D., and Dobell, A. R. Tracheal stenosis as a complication of tracheostomy. Ann. Thorac. Surg. 2:44, Ogura, J. H., and Roper, C. L. Surgical correction of traumatic stenosis of larynx and pharynx. Laryngoscope 72:468, Pearson, F. G., Goldberg, M., and da Silva, A. J. Tracheal stenosis complicating tracheostomy with ed tubes. Arch. Surg. (Chicago) 97:380, Thung, N. The cost of respiratory effort in postoperative cardiac patients. Circulation 28:552, DISCUSSION DR. KENNETH L. HARDY (Oakland, Calif.): I enjoyed Dr. Fishman s presentation very much, especially the ingenious method of causing relaxation by incision of the hyoid cornu. VOL. 8, NO. 1, JULY,

8 FISHMAN ET AL. I think it is interesting that, excluding the 3 patients with stoma1 strictures attributed to errors in surgical technique, the remaining 12 patients that he presented developed strictures in association with the tube. It is noted that in 3 of these patients the endotracheal tubes were left in position from one to three days, which is done by all of us. I would like to ask Dr. Fishman if these endotracheal s were subjected to the usual routine of deflation and reinflation every 30 minutes or so. The reason for this inquiry is that Dr. Shelley, working with Dr. May and myself, showed in dogs that if inflation volume did not exceed the amount required to prevent leakage around the at 30 cm. mass pressure ventilation, the s could be left constantly inflated for five days and none of the animals would develop strictures. However, if double inflation volume was used, which we term two times minimal occlusion volume, or twice MOV, more than half the animals developed strictures. Since in our clinical cases, and also in Dr. Fishman s, most patients who subsequently developed strictures had been at some phase postoperatively in low cardiac output with periods of low tissue perfusion, Dr. Shelley repeated the above experiments with dogs who were subjected to blood-loss hypotension for a four-hour period. To our surprise, the number that developed strictures did not increase. We are all aware of the fact that the anesthesiologist, in entraining the ed endotracheal tube, very carefully adjusts the MOV, or minimal occluding volume, of the by sensitive control of the rebreathing bag in his hand, which has been trained for this. Although our Intensive Care Unit nurses, and I am sure yours, are carefully instructed regarding MOV reinflation, it has been noted that many will add 1 to 4 cc. more of air to the or balloon just to insure against leaks, especially when busy with the many other duties involved in caring for a critically ill patient. If we could be sure that reinflation was always at the MOV pressure, we might not see so many strictures following tube. We might be better off to leave the tube inflated at the proper pressure, rather than to subject patients to repeated variations in overinflation. The anesthesiologist leaves the tube inflated at the same pressure for many hours and does a great many cases that do not develop late strictures. DR. W. GERALD RAINER (Denver, Colo.): I enjoyed Dr. Fishman s presentation very much, and would concur on practically all the basic principles he has outlined for approaching this particularly difficult problem. When Dr. Fishman mentioned the 30 dilatations required by one of his patients prior to definitive reconstructive surgery, it certainly was reminiscent of a similar case in our series. We attempted every form of dilatation-chemical cautery, electrical cautery, and one timidly attempted resection which was repaired with too much tension-until we finally mobilized widely the entire trachea according to the technique outlined by Dr. Pearson of Toronto. This particular case was a problem of tracheal stenosis occurring at the junction of the cervical and mediastinal trachea following an aortic valve replacement. Through the reopened median sternotomy, the right inferior pulmonary ligament was incised and afforded surprisingly good access to the entire carinal region by opening the posterior pericardium behind the ascending aorta. The lateral and anterior walls of the trachea were totally mobilized throughout its entire length, leaving the posterior wall intact for its blood supply. The resected stricture showed a lumen of 4 mm., even though the patient had undergone dilatation of his stricture 24 hours previously. A macrophotograph of the strictured area showed a relatively normal tracheal wall width underneath the intact mucosa, but where mucosa was missing there was considerable inflammatory scarring to the point of near obliteration of the tracheal lumen. In an attempt to overcome some of the problems of a constantly inflated 54 THE ANNALS OF THORACIC SURGERY

9 Postintubation Tracheal Stenosis, we have inserted a perforated connector tube into the nebulizer line of a Bennett PR-2 respirator. The connector tube has an escape hole that is less than one-half the smallest diameter of the tube itself. With this simple apparatus, one can produce inhation with inspiration and deflation with expiration. Cinefluorography in experimental animals shows that this functions well in vivo and that function is not dependent upon rate or respirator pressure. This has been applied clinically in 5 cases thus far, and we are optimistic that it will be helpful in preventing tracheal strictures secondary to the inherent problems of a constantly inflated tracheostomy tube. DR. EMIL BLAIR (Burlington, Vt.): I should like to dwell briefly on one aspect of Dr. Fishman s very fine presentation. This is the matter of the use of nasotracheal intubation. In our institution this is being used more and more, and the tube is being left in for long periods of time. Of course, the advantages of this procedure in an emergency are well appreciated. Patients in whom the tube is left for prolonged periods of time include individuals with heart-lung disease, those suffering from chest traumas with secondary contusion and pneumonia, and patients with head injuries. We have permitted the tube to remain for up to 12 days. In a small group of individuals, tracheostomy was found to be necessary subsequently. Regarding the problem of complications, the vast majority of patients showed a very minimal amount of difficulty in the larynx. The patients who demonstrated a severe degree of trauma were those who subsequently died, not from the tube but from the primary disease problem. In no instance was there any tracheal stenosis. Many problems, of course, are associated with the matter of trauma, to the larynx and particularly to the trachea. Dr. Hardy s was one that was of particular significance to the trachea, and this is a matter of the pressure within the. It has been a habit, a custom, of our respiratory therapists to take great care in inflating the, such that at peak pressure, usually 30 cm. H20, there is a slight hiss or escape of air. They believe that allowing this slight escape of air insures the integrity of the mucosa and does not in any way impede the efficiency of the respirator. CAPT. MAX J. TRUMMER (San Diego, Calif.): I wish to underscore this increasingly common and potentially lethal iatrogenic complication that you have seen described. In the past nine months we have encountered 5 patients with stenosis following tracheal intubation. Four have required resection. The most severe stenosis occurred in a young Marine who underwent a total thyroidectomy for follicular carcinoma followed by a left radical neck dissection, with sacrifice of the left recurrent laryngeal nerve and injury to the right nerve. A poorly positioned tracheostomy was performed and a ed tube was inserted. The neck wound became infected. The devascularization and infection led to an unrelenting excessive scar through which a patent airway could be maintained only by repeated dilatations ancl an indwelling Portex tube. After six months the strictured area was resected. It extended from the first tracheal ring down to 2 cm. above the carina. The trachea was encased in a dense cicatrix. Microscopic sections revealed squamous metaplasia of the mucosa, which in some places was completely absent. Beneath it there was fibrosis, remnants of cartilage, and extensive heterotopic bone formation. The gap was bridged by a 9 cm. heavy Marlex prosthesis, which functioned beautifully for three days until it eroded the innominate vessel and the patient died. DR. CHARLES P. BAILEY (New York, N.Y.): I cannot truthfully say that I enjoyed hearing Dr. Fishman s paper on this dismal subject, but I am certainly glad I heard it because I have learned so much, even from the discussion. Dr. VOL. 8, NO. 1, JULY,

10 FiSHMAN ET AL. Hardy s explanation of the mechanism of causation is probably the right one in most of these cases. Dr. Rainer has presented an ingenious way of preventing this complication. We have chosen a different method, which may be even more practical in application. During the past 15 months we have been using two separate s on our endotracheal or tracheostomy tubes. These s are inflated alternately for periods of one hour at a time. Thus, even if the tubes are injected under too much tension, it is for only an hour that excessive tension will be applied to a given area of the tracheal lumen. Since we began using this principle we have had no instance of this complication, although seven severe tracheal stenoses had occurred during the previous two years. DR. FISHMAN: I would like to thank the discussants for their kind and informative remarks. The methods suggested by Drs. Rainer, Bailey, and Hardy for the prevention of postintubation tracheal stenosis are all quite ingenious and appear to me to have great merit. In answer to Dr. Hardy s question regarding our method of management, the nurses are instructed to deflate the every hour and to reinflate it to a minimal occluding pressure. Dr. Hardy has intimated that excessive pressures may have been used occasionally during reinflation. This possibility cannot be excluded, of course, in this type of retrospective analysis. I would like to call attention to Dr. Pearson s recent article (Arch. Surg. 97:380, 1968) in which he describes the findings of a prospective study. All patients who had undergone prolonged endotracheal intubation with a ed tube were bronchoscoped. The finding of focal necrosis or subclinical stenosis in the majority of these patients indicates the seriousness of this problem. The use of a single cervical incision for tracheal mobilization was forced upon us by the antecedent thoracic trauma and surgery in these patients. Having demonstrated its effectiveness, we plan to use this approach electively in all patients who have lesions that require resections of the cervical trachea. 56 THE ANNALS OF THORACIC SURGERY