Biomedical subjects
Publications and source records attributed to J F Beamis.
Fiberoptic bronchoscopy is an excellent tool for the evaluation of the airways and lung parenchyma. The history of flexible bronchoscopy, anesthesia, technique, indications, contraindications, and complications in using the bronchoscopy are reviewed.
Although the evolution from low dose rate to high dose rate brachytherapy for malignant endobronchial malignancies was primarily based on economy, patient convenience, and radiation protection, the difference in therapeutic index, if any, between these two modalities must be kept in mind. Our experience with both methods permits assessment of the feasibility of replacing low dose rate brachytherapy with high dose rate brachytherapy. Results with our first 110 patients (group 1) treated with low dose rate brachytherapy (133 procedures) were compared with results with our initial 59 consecutive patients (group 2) treated with high dose rate brachytherapy (161 procedures). In group 1, patients were treated with one or two sessions of 30-60 Gy each calculated at a 1 cm radius. In patients in group 2, we aimed at three weekly sessions of 7 Gy each calculated at a 1 cm radius. External beam irradiation therapy had previously been given to 88% of patients in group 1 and to 85% of patients in group 2. Laser bronchoscopy was performed in 36% of patients in group 1 and in 24% of patients in group 2 before brachytherapy. Clinical or bronchoscopic improvement was noted in 72% of patients in group 1 and in 85% of patients in group 2 (p > 0.05). Complication rates were low and comparable. Survival was similar in both groups (median < 6 months). Although both low dose rate and high dose rate brachytherapy appear equally effective in palliation for malignant endobronchial obstruction, we are now practicing the latter exclusively.
The worldwide epidemic of cancer of the lung has stimulated the development of therapies to relieve endobronchial obstruction. Table 3 lists a number of endobronchial therapies that might be used to treat malignant central airway obstruction. With over 15 years of worldwide experience, the Nd:YAG laser has proven to be the most important of these tools. Laser bronchoscopy can be performed with rigid or flexible instruments and produces a rapid recanalization of the airway with associated relief of symptoms. The treatment is repeatable and has acceptable immediate complications and infrequent delayed complications. To be effective, laser bronchoscopy can only be used for the treatment of intraluminal obstructions. Obstruction by submucosal infiltration and external compression require other endobronchial therapies. The performance of laser bronchoscopy requires an extra commitment by the bronchoscopist. A thorough understanding of airway and mediastinal anatomy is mandatory along with an appreciation of laser physics and tissue interaction. Attendance at specialized training courses may be required to satisfy local credentialing bodies. In the past 15 years, thousands of patients have benefited from the development of laser bronchoscopy techniques. No longer a therapy of last resort, laser bronchoscopy has proven to be an excellent tool to relieve the symptoms of central airway obstruction.
Intraluminal endobronchial brachytherapy is a technique in which an encapsulated radioactive source is placed near a tumor for localized irradiation. It is effective, with or without other treatment modalities, in palliating problems caused by endobronchial malignancies, such as dyspnea, hemoptysis, cough, atelectasis, and postobstructive pneumonia. This article describes the different techniques and dosage schemes for brachytherapy, indications and contraindications, reported rates of efficacy and complications, and limitations of the technique.
BACKGROUND: A study was undertaken to compare the efficacy of short term tube thoracostomy drainage with standard tube thoracostomy drainage before instillation of tetracycline for sclerotherapy of malignant pleural effusions. METHODS: The study consisted of a randomised clinical trial in a sequential sample of 25 patients with malignant pleural effusions documented cytopathologically. Fifteen patients were randomly assigned to group 1 (standard protocol) and 10 to group 2 (short term protocol). Patients in group 1 had tube thoracostomy suction drainage until radiological evidence of lung re-expansion was obtained and the amount of fluid drained was < 150 ml/day, before tetracycline (1.5 g) was instilled. The chest tube was removed when the amount of fluid drained after instillation was < 150 ml/day. Patients in group 2 also had suction drainage, but the tetracycline (1.5 g) was instilled when the chest radiograph showed the lung to be re-expanded and the effusion drained, which was usually within 24 hours. The chest tube was removed the next day. RESULTS: The response to tetracycline sclerotherapy in the two groups was the same (80%) but the duration of chest tube drainage was significantly shorter for patients in group 2 (median two days) than for those in group 1 (median seven days). CONCLUSIONS: The duration of chest tube drainage before sclerotherapy for malignant pleural effusions need not be influenced by the amount of fluid drained daily but by radiographic evidence of fluid evacuation and lung re-expansion. Shorter duration of drainage will reduce the length of hospital stay without sacrificing the efficacy of pleurodesis.
The evaluation of dyspnea is problematic when a cause is inapparent after initial diagnostic studies. We examined the results and role of cardiopulmonary exercise testing (CPET) in 50 patients with a mean 23 months of dyspnea and normal FEV1 and FVC. The CPET studies were interpreted by a panel and a consensus reached. Subsequent tests ordered by the primary physician were reviewed, and a final diagnosis was agreed on by the panel. Seven of 50 patients had cardiac limitation, 17 of 50 had pulmonary limitation, 14 of 50 had obesity and/or deconditioning, 1 of 50 had gastroesophageal reflux, and 16 of 50 had either psychogenic dyspnea or no identifiable disease. Five patients had more than one clinical diagnosis accounting for 55 diagnoses in the 50 patients. Those with a normal CPET had a higher VO2max and O2 pulse than those with cardiac disease, deconditioning, or hyperactive airways disease (HAD) (p < 0.05). Electrocardiographic changes identified cardiac disease while studies demonstrating ventilatory limitation identified a pulmonary process. In 24, deconditioning could not be distinguished from cardiac limitation. Of these, 14 responded to exercise training and/or weight loss, whereas 3 had cardiac disease, 7 had HAD, and 4 had psychogenic dyspnea (4 had more than one clinical diagnosis). In the 13 patients with normal CPET results, one had gastroesophageal reflux, two had HAD, four had psychogenic dyspnea, and six had no identifiable disease. We conclude that a diagnosis can be made in most patients with chronic dyspnea; however, further studies including bronchoprovocation are often required. Cardiopulmonary exercise testing is useful in identifying a cardiac or pulmonary process, but it is insensitive in distinguishing cardiac disease from deconditioning.
OBJECTIVES: To examine a hygroscopic condenser after clinical use and to describe the interaction of a hygroscopic condenser and a closed circuit suction system used simultaneously. DESIGN: Prospective evaluation of hygroscopic condensers used clinically, and laboratory investigation of a hygroscopic condenser used with a closed circuit suction system. SETTING: Tertiary referral centers. MEASUREMENTS AND MAIN RESULTS: The hygroscopic condenser used during mechanical ventilation was removed and peak inflation pressure was measured by delivering a standard tidal volume and inspiratory flow across the isolated hygroscopic condenser while recording the peak inflation pressure. In the laboratory, four 10-mL aliquots of saline were instilled via closed circuit suction system into a test lung with fresh hygroscopic condensers (n = 15) inline. At baseline and after each instillation, the hygroscopic condenser was weighed and the peak inflation pressure was measured while in five condensers, peak expiratory flow rate was also measured. In these five devices, hygroscopic condenser resistance was measured with 100 L/min of constant gas flow while measuring the pressure drop across the hygroscopic condenser. In 11 hygroscopic condensers used for 27.5 +/- 11.9 hrs with no closed circuit suction system, the peak inflation pressure was 3.74 +/- 0.58 cm H2O. In the laboratory, instillation of saline via closed circuit suction system was associated with an increase in hygroscopic condenser weight. Peak inflation pressure increased in a quadratic fashion with the increase in hygroscopic condenser weight, while peak expiratory flow rate decreased in a linear fashion. After four saline instillations, hygroscopic condenser resistance increased from 5.66 +/- 0.31 to 13.9 +/- 2.42 cm H2O/L/sec. CONCLUSIONS: Clinical use of a hygroscopic condenser alone is not associated with a significant increase in peak inflation pressure. We caution the use of a hygroscopic condenser and a closed circuit suction system simultaneously, as an increase in hygroscopic condenser resistance may develop and may be poorly tolerated in patients with marginal ventilatory reserve.
OBJECTIVE: To examine the value of laser bronchoscopy in patients with inoperable carcinoma of the lung who required ventilatory assistance for acute respiratory failure. DESIGN: Retrospective review of the medical records of all patients undergoing laser bronchoscopy. SETTING: The Lahey Clinic Medical Center, a tertiary referral center. PATIENTS: The medical records of 311 patients undergoing laser bronchoscopy at the Lahey Clinic Medical Center between 1982 and 1990 were reviewed. The 17 patients who required mechanical ventilation at the time of laser surgery formed the study group. INTERVENTIONS: All patients underwent neodymium:yttrium-aluminum-garnet laser bronchoscopy through a rigid bronchoscope in the operating room with use of jet ventilation and general anesthesia throughout the procedure. Postoperative care was directed by the same physician for all patients. MEASUREMENTS AND MAIN RESULTS: The following data were extracted from medical records: age and sex of patient, cell type and location of tumor, length of time between diagnosis and laser therapy, treatment before and after laser therapy, number of days receiving mechanical ventilation before and after laser therapy, medical and operative complications, survival, and cause of death. The patients were divided into two groups on the basis of clinical improvement that permitted elective discontinuation of mechanical ventilation. Group 1 included patients who experienced clinical improvement permitting endotracheal extubation. Group 2 was composed of patients who died while still receiving mechanical ventilatory support or who were extubated before institution of comfort measures. The two groups were compared using nonparametric tests of significance, including the Mann-Whitney test. No significant differences were apparent between groups 1 and 2 regarding clinical characteristics before laser treatment. Patients in group 1 had significantly (p = .03) shorter requirements for mechanical ventilation after laser treatment than patients in group 2 (1 vs. 6 days). Similarly, patients in group 1 were more likely to receive additional treatment after laser therapy than patients in group 2 (seven of nine patients vs. two of eight patients; p = .048). Patients in group 1 had significantly (p = .0038) longer survival than patients in group 2 (98 vs. 8.5 days). A greater endobronchial component to airway obstruction appeared to exist in patients in group 1 (nine of nine patients) vs. patients in group 2 (three of eight patients; p = .009). Extrinsic compression and submucosal tumor were more commonly seen in patients in group 2. In addition, patients in group 2 appeared to have a greater number of postoperative medical complications than patients in group 1. Operative complications were minor in both groups. CONCLUSIONS: In nine of 17 patients, laser bronchoscopy appeared to improve the clinical status, permitting removal of mechanical ventilation and extubation and provided the opportunity for further treatment modalities in seven of the nine patients. Survival was improved in this subgroup, and requirement for mechanical ventilatory support was shortened. The improved outcome after laser therapy was related to the presence of obstructing endobronchial tumor as the cause of the respiratory insufficiency. Patients with inoperable carcinoma of the lung and respiratory failure should be evaluated for the presence of an endobronchial lesion that might be responsive to laser bronchoscopy.
OBJECTIVE: Compare unsupported (UAEx) vs supported (SAEx) arm exercise in training of patients with severe chronic airflow obstruction (CAO). DESIGN: Randomized trial of UAEx vs SAEx training added to a 10-week outpatient program of lower extremity (LE) exercise training, respiratory muscle training, breathing retraining, psychological support, and teaching. SETTING: The Lahey Clinic Medical Center, a tertiary referral center. PATIENTS: Forty patients with CAO entered the rehabilitation program with 32 completing training and testing. INTERVENTIONS: All underwent progressive bicycle ergometer and treadmill training and respiratory muscle training using a threshold inspiratory pressure trainer. Patients were randomized to progressive SAEx training (arm cycle ergometer, n = 17) or UAEx training (raising weighted dowel, n = 18). MAIN OUTCOME MEASURES AND RESULTS: There was no significant difference in disease severity or exercise capacity between the two groups. Twelve-min walk test, bicycle ergometer power output, and respiratory muscle function improved with no significant difference in improvement between the two groups. Both groups showed similar improvements in arm ergometer testing while those trained with UAEx showed greater improvement in dowel testing (UAEx > SAEx, p = 0.002). In 17 patients VO2isotime (time at which patient performed pre-training and post-training tests) was measured during dowel testing. Only those trained with UAEx showed decreases in VO2isotime (UAEx trained, p = 0.02; SAEx, p = 0.18). VO2 during the last minute of a 2-min period of simple arm elevation was also measured in 17 patients. Only those trained with UAEx showed decreases in VO2 (UAEx, p = 0.02; SAEx, p = 0.20). CONCLUSION: We confirm that a pulmonary rehabilitation program incorporating exercise training improves LE and respiratory muscle function. Arm exercise training improved arm activity with greater increases in unsupported arm activity seen in those trained with unsupported arm training. Metabolic cost of UAEx decreased only in those trained with UAEx. As UAEx is typical of activities of daily living in patients with CAO, the changes seen with UAEx training may be of greater clinical significance. Arm training should be incorporated in exercise training and a simple program of UAEx appears the optimal format.
From October 1985 through October 1989, 87 patients underwent 105 intraluminal brachytherapy treatments for endobronchial or endotracheal malignant tumors. Low-dose rate iridium-192 seeds were used. Of the 60 patients treated for primary lung carcinoma, 52 patients (87%) had previously received full-course external beam radiotherapy to the tumor sites. Ten patients were treated for symptomatic metastatic disease, and one patient had extension of tumor into the trachea from carcinoma of the cervical esophagus. Clinical or bronchoscopic improvement was noted in 42 patients (59%). No significant difference in the response rate was observed between various types of tumor. Patients who were treated with a radiation dose larger than 2500 cGy at a 2 cm radius had a significantly greater response rate (77%) than patients treated with a dose less than 2500 cGy (38%) (p = 0.001). A trend toward better results was apparent in patients who had undergone Nd:YAG laser bronchoscopy in the 2 weeks before brachytherapy. The treatments were well tolerated, and the incidence of serious complications was low and acceptable.
Tracheobronchial obstruction resulting from esophageal carcinoma is uncommon. Patients with advanced esophageal carcinoma with tracheobronchial obstruction usually present with severe dyspnea or hemoptysis or both and may die of suffocation. The Lahey Clinic experience using laser bronchoscopy for the palliation of symptoms of airway obstruction in patients with esophageal carcinoma is presented. From 1982 to 1990, nine patients were treated in 13 procedures using the neodymium: yttrium-aluminum-garnet laser. Of the patients, seven had undergone previous treatment of the primary tumor. Tumors were located in the trachea in seven patients and in the main stem bronchi in three patients. Improvement of the airway caliber was achieved in all patients with relief of the dyspnea. The mean hospital stay was 2 days. One patient lived 4 years after laser treatment with no recurrence of tumor, and one patient died 1 week after treatment as a result of his poor general condition. The rest of the patients lived 3 to 41 weeks, with a median survival of 35 weeks. No complications were related to the procedures, and in particular, no tracheoesophageal fistulas developed. Our experience indicates that bronchoscopic application of this laser in conjunction with other treatment modalities can improve the quality and duration of life in selected patients with esophageal carcinoma that invades and obstructs the trachea.
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The Lahey Clinic experience using laser bronchoscopy for relief of obstructive tracheobronchial lesions during a 7-year period from 1982 to 1989 involves 269 patients treated with 400 procedures. The carbon dioxide (CO2) laser was used for tracheal stenosis and granulation tissue. The neodymium:yttrium-aluminum-garnet (Nd:YAG) laser was used for all obstructing endobronchial neoplasms. Indications for therapy included severe dyspnea, hemoptysis, and postobstructive pneumonitis. All patients had relatively central lesions. A rigid bronchoscope was used to treat 88% of patients, and 12% of patients were treated with a flexible bronchoscope. One death occurred during the intraoperative period. Eleven deaths occurred within 1 week of therapy and were related to the presence of extensive malignant lesions or to coronary artery disease. Our experience indicates that bronchoscopic application of the CO2 or Nd:YAG laser affords effective palliation for patients with obstructive tracheobronchial lesions. The Nd:YAG laser is recommended for patients with bulky vascular endobronchial neoplasms, and the CO2 laser is best reserved for patients with benign tracheal stenosis and granulation tissue.
Twelve patients with total cervical tracheal stenosis were treated by endoscopic laser excision (neodymium:yttrium aluminum garnet or carbon dioxide laser), bronchoscopic dilation, and prolonged stenting with a silicone T-tube. All patients had previous traumatic or prolonged endotracheal intubation requiring a tracheotomy and presented with aphonia as the major complaint. Multiple laser and dilation treatments were necessary in ten patients. Average duration of T-tube placement was 6 months. Excellent results (decannulation and good voice) were achieved in eight patients with a follow-up of 9 months to 6 years. Persistent granulation tissue and some degree of fibrosis were the most common complications (eight of 12 patients). Two patients died of medical complications. A high success rate with this endoscopic technique justifies this approach as our initial therapy, with open surgical techniques reserved for failure.
A number of groups have demonstrated the efficacy of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser bronchoscopy for treatment of patients with selected tracheobronchial disorders. This therapy involves a new technology, the laser, and new adaptations of conventional rigid and flexible bronchoscopy that are unfamiliar to many bronchoscopists. We describe two teaching models for laser bronchoscopy that have been employed successfully in our laser courses. Using these models, bronchoscopists can become familiar with laser bronchoscopic equipment and appreciate the interaction of laser and soft tissue in a controlled setting in the laboratory before applying this therapy to patients.
A new fiberoptic rigid bronchoscope system, designed especially for laser fiber delivery, provides the endoscopist with an excellent conduit for application of the flexible fiberoptic bronchoscope, while still allowing maintenance of adequate ventilation. This system is designed for treatment of benign and malignant obstructing tumors in the trachea and mainstem bronchi. The bronchoscope will be available in sizes ranging from 6 mm to 10 mm in diameter.
The application of the neodymium-yttrium aluminum garnet (Nd-YAG) laser in bronchoscopy originated in Europe in 1981 and is now widespread in the United States. Transmissible through flexible fiberoptic quartz fibers and an efficient coagulator of tissue, the Nd-YAG laser deeply penetrates tissue not readily predictable by the endoscopist. Dangers associated with the Nd-YAG laser include complications secondary to inadvertent exposure to normal tissues or structures, tracheobronchial accidents (perforation, hemorrhage, fire), and complications related to anesthetic technique (respiratory depression). Hypoxemia related to persistent hemorrhage, accumulation of secretions or debris or both, or anesthesia-induced respiratory depression is the common denominator of most intraoperative and postoperative complications. Careful selection of patients, intraoperative monitoring of ventilation and blood gases, and techniques of rigid bronchoscopy are stressed to avoid complications.