Bruce A. Staats

Exercise tolerance and cardiorespiratory response to exercise after the fontan operation for tricuspid atresia or functional single ventricle

To determine the impact of the Fontan operation on exercise tolerance and on the cardiorespiratory response to exercise, we compared the results of graded exercise to maximal effort of 81 patients with tricuspid atresia or single functional ventricle studied preoperatively with those of 29 patients studied postoperatively. Postoperatively, the values for total work performed, duration of exercise and maximal oxygen uptake increased significantly. Regardless of operative status, the maximal heart rate during exercise was reduced. The cardiac output and stroke volume response to exercise were subnormal after operation. Systemic arterial blood oxygen saturation was reduced markedly preoperatively both at rest and during exercise; postoperatively, it was significantly greater than the preoperative value but it remained slightly abnormal. The ventilatory response to exercise (respiratory rate, minute ventilation and ventilatory equivalent for oxygen) decreased toward normal after operation. Exercise tolerance and the cardiorespiratory responses to exercise improve after the Fontan operation. Formal exercise testing is essential to quantitate the degree of improvement.

The Cushing Syndrome Induced by Bronchial Carcinoid Tumors

OBJECTIVES To define the clinical spectrum of bronchial carcinoid tumors in patients presenting with the Cushing syndrome, to evaluate the role of chest radiographs and computed tomography in their diagnosis, to review the characteristic histologic features, and to determine patient outcome. DESIGN Retrospective analysis of consecutive patients. SETTING A referral-based medical center. PATIENTS Fifteen consecutive patients with the Cushing syndrome evaluated at the Mayo Clinic with histologically proven bronchial carcinoid tumors. MEASUREMENTS Clinical, radiographic, and histologic features. RESULTS The Cushing syndrome was the initial clinical presentation, and bronchial carcinoid tumors were found later in all 15 patients. The diagnosis of carcinoid tumor was proved histologically in all cases. Ten biopsies showed typical carcinoid tumors, three were histologically atypical, and three were metastatic. Corticotropin was detected by immunostaining in seven of these tumors. Biochemical analysis showed marked elevations of circulating corticotropin with a mean serum value of 156 +/- 58 pmol/L (normal, 4 to 22 pmol/L). Additional clinical features included hypokalemia in six patients and glucocorticoid response to either high-dose dexamethasone or metyrapone in 6 of 13. These hormonally active carcinoid tumors were frequently radiographically occult, with 10 of 15 patients initially having normal chest radiographs. Computed tomography was successful in locating carcinoid tumors in five patients with negative chest radiographs evaluated after 1980. All five remaining patients with normal chest radiographs evaluated before 1980 eventually developed nodular lesions on standard chest radiography from 1 to 10 years later. Ten patients achieved complete remission and two patients, partial remission of the Cushing syndrome after surgical resection. Three patients continued to have symptomatic glucocorticoid excess due to metastatic disease. CONCLUSIONS Although uncommon, the Cushing syndrome may be the initial clinical manifestation of an otherwise indolent bronchial carcinoid tumor. Radiographic imaging of occult lesions can be successfully accomplished with computed tomography. Surgical resection is curative in most patients with this disorder.

Obstructive Sleep Apnea-Hypopnea Syndrome

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is characterized by repetitive episodes of airflow reduction (hypopnea) or cessation (apnea) due to upper airway collapse during sleep. Increasing recognition and a greater understanding of the scope of this condition have substantially affected the practices of many clinicians. This review provides practical information for physicians assessing patients with OSAHS. It discusses complications, clinical recognition, the polysomnographic report, and treatment of OSAHS, including strategies for troubleshooting problems associated with continuous positive airway pressure therapy.

Exercise Limitation and Pulmonary Rehabilitation in Chronic Obstructive Pulmonary Disease

Impairment of exercise tolerance is a common problem in patients with severe chronic obstructive pulmonary disease. The cause of exercise intolerance in patients with severe chronic obstructive pulmonary disease is multifactorial and includes impaired lung mechanics, fatigue of inspiratory muscles, impaired gas exchange, right ventricular dysfunction, malnutrition, occult cardiac disease, deconditioning, and psychologic problems; however, impaired lung mechanics and gas exchange abnormalities seem to be the major limiting factors. Recently, the approach to management of pulmonary rehabilitation in patients with chronic obstructive pulmonary disease has changed because improvement in exercise tolerance has been demonstrated after pulmonary rehabilitation. Other adjunctive measures that have been shown to contribute to the observed improvement in exercise tolerance include administration of oxygen, nutritional support, cessation of smoking, and psychosocial support. The roles of ventilatory muscle endurance training, respiratory muscle rest therapy, nasally administered continuous positive airway pressure, and training of the muscles of the upper extremities are less clearly defined.

Chyloptysis in Adults: Presentation, Recognition, and Differential Diagnosis

Chyloptysis is a rare finding, and the accompanying respiratory symptoms are usually nonspecific. The recognition of the chylous nature of the sputum is requisite for proper diagnosis, especially if chyloptysis is not accompanied by chylous pleural effusion. The key to the differential diagnosis of chyloptysis is to consider illnesses that can induce reflux of chyle into the bronchial tree. There are two mechanisms postulated: the first requires the presence of an abnormal communication between the bronchial tree and the lymphatic channels, and the second requires a bronchopleural fistula in the context of a chylous pleural effusion. Chyloptysis in adults should prompt assessment for evidence of lymphatic obstruction from trauma, radiation, and malignancy, and to exclude diseases with known association with chyloptysis, ie, lymphangioleiomyomatosis, yellow nail syndrome, or thoracic lymphangiectasis. A lymphangiogram is recommended to define the abnormality. In the case of lymphangiectasis, patients respond to either dietary modification and/or ligation of the thoracic duct.

Selected ReportsChyloptysis in Adults: Presentation, Recognition, and Differential Diagnosis

Chyloptysis is a rare finding, and the accompanying respiratory symptoms are usually nonspecific. The recognition of the chylous nature of the sputum is requisite for proper diagnosis, especially if chyloptysis is not accompanied by chylous pleural effusion. The key to the differential diagnosis of chyloptysis is to consider illnesses that can induce reflux of chyle into the bronchial tree. There are two mechanisms postulated: the first requires the presence of an abnormal communication between the bronchial tree and the lymphatic channels, and the second requires a bronchopleural fistula in the context of a chylous pleural effusion. Chyloptysis in adults should prompt assessment for evidence of lymphatic obstruction from trauma, radiation, and malignancy, and to exclude diseases with known association with chyloptysis, ie, lymphangioleiomyomatosis, yellow nail syndrome, or thoracic lymphangiectasis. A lymphangiogram is recommended to define the abnormality. In the case of lymphangiectasis, patients respond to either dietary modification and/or ligation of the thoracic duct.

The prevalence of acute response to bronchodilator in pulmonary lymphangioleiomyomatosis

Objective:  The objective of this study was to evaluate the prevalence of acute bronchodilator responses in patients who were evaluated for pulmonary lymphangioleiomyomatosis.

Long-Term Clinical Experience With Transtracheal Oxygen Catheters

OBJECTIVE To evaluate and discuss the use of transtracheal oxygen catheters for the treatment of chronic hypoxemia and to discuss the complications associated with the placement and care of these devices. DESIGN We conducted a retrospective study at a tertiary medical center and reviewed the pertinent literature. MATERIAL AND METHODS The medical records of 56 patients who received a transtracheal oxygen catheter between January 1987 and June 1992 at our institution were reviewed for demographic data, diagnosis leading to catheter placement, complications related to catheter use, reason for catheter removal, and duration of use. Follow-up results were established by documentation in the medical records or telephone interview. RESULTS During the study period, 39 men and 17 women received a transtracheal catheter. More than half the patients (52%) had chronic obstructive pulmonary disease. The duration of use of the catheter ranged from 2 days to more than 6 years, and the most frequent cause for removal of the catheter was death. Of the 56 patients, 42 died with the catheter in place, 24 within the first year after placement. Complications ranged from mucous plugging (38 % of patients) to pneumothorax (4%), and no patient died of a catheter-related complication. Overall, 55% of patients had their catheter for less than 1 year after placement. CONCLUSION In patients with transtracheal oxygen catheters, problems related to mucous plugging are common, but severe complications such as pneumothorax and pneumomediastinum are uncommon. Although selection factors that would identify ideal candidates for transtracheal oxygen therapy have not been established, such a catheter is best placed in highly motivated patients who can physically manage the daily care of this device.

Carbon Monoxide Diffusing Capacity of the Lungs Determined by Single-Breath and Steady-State Exercise Methods

We measured carbon monoxide diffusing capacity of the lungs (DL,CO) by both the resting single-breath (SB) and steady-state (SS) exercise methods in 95 patients referred for pulmonary function testing. A 10-second breath-holding method was used for the SB test. DL,CO (SS) was measured during the last minute of a 3-minute exercise test on a 9-inch step. Results of the two methods showed good agreement, the SB-SS difference averaging -0.70 (SD, 3.39) ml/min per mm Hg. The difference between the two methods was not correlated with other measurements of pulmonary function except minute ventilation during the exercise performed in the DL,CO (SS) procedure. In a separate study of laboratory personnel, the day-to-day variabilities of the two tests were similar (SD, 1.4 ml/min per mm Hg). Alveolar volume obtained by helium dilution during the SB test was comparable to total lung capacity (TLC) estimated by multiple-breath nitrogen washout in patients without severe airway obstruction. In severe airway obstruction, the mean SB alveolar volume was 13.8% less than the TLC by nitrogen washout, a difference that may be useful as an indicator of inefficiency of gas mixing in the lungs. We conclude that the SB and SS exercise methods provide similar estimates of DL,CO in patients referred to a pulmonary function laboratory.

Successful Treatment of Obstructive Sleep Apnea With Use of Nasal Continuous Positive Airway Pressure in Three Patients With Mucosal Hemangiomas of the Oral Cavity

Cysts and benign tumors are uncommon causes of obstructive sleep apnea (OSA), and surgical removal is usually favored. In patients in whom an operation poses a high risk, however, nasal continuous positive airway pressure (CPAP) may prove beneficial. We describe three patients with hemangiomas of the oral cavity in whom polysomnography revealed moderate to severe OSA. In all three patients, nasal CPAP effectively decreased sleep-related disordered breathing events and dramatically improved their sleep. To our knowledge, this is the first report of OSA associated with hemangiomas involving the upper airway. Our experience suggests that nasal CPAP therapy is effective and well tolerated in such patients.