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W J Gibbons

Publications and source records attributed to W J Gibbons.

15 recordsLinked to original sources
PubMed2001

Co-existing granular cell tumor and adenocarcinoma of the lung: a case report and review of the literature.

Granular cell tumor (GCT) of the lung is a rare tumor, constituting less than 10% of all GCTs. It is a multicentric tumor and infiltrates into adjoining tissue, but malignant GCT of the lung has not been reported. Diagnosis is usually obtained with bronchoscopic biopsy. Treatment options include bronchoscopic extirpation, laser therapy, and sleeve resection. We present a case of GCT co-existing with adenocarcinoma of the lung and review the literature.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1999

Maximal exercise testing for the selection of heart transplantation candidates: limitation of peak oxygen consumption.

BACKGROUND: Peak exercise oxygen consumption (peak VO2), which is considered an indicator of prognosis in advanced heart failure, is currently being used as a major criterion in many centers for the selection of candidates for heart transplantation. Available studies suggest that patients with peak VO2 < 14 mL/min/kg have improved survival and significant functional benefit with transplantation. Since patients may terminate symptom-limited exercise tests for a variety of reasons, peak VO2 does not necessarily reflect maximal VO2, leading to the possibility of inappropriate selection for transplantation. Therefore, we investigated the proportion of transplant candidates referred for exercise testing considered to have achieved maximal results from studies. METHODS: Fifty-five patients with heart failure, aged 51+/-9 years, (mean +/- SD) underwent maximum symptom-limited exercise tests on a cycle ergometer utilizing a Jones stage 1 incremental protocol. Tests were considered maximal if subjects achieved peak heart rate (HR) > 85% predicted ("cardiocirculatory limitation") or peak minute ventilation (VE) > 85% predicted ("ventilatory limitation"), and achieved an anaerobic threshold (AT) by noninvasive measures. RESULTS: Seven tests were terminated because of chest pain, ST-segment abnormalities, or ventricular arrhythmias. Of the remaining 48 studies, the reasons for stopping exercise were leg fatigue in 52%, dyspnea in 16%, and both symptoms in 23%. Sixteen of the 48 patients (33%) had peak VO2 < 14 mL/min/kg. In 8 of these 16 patients, both peak HR and VE were < 85% predicted. Of these eight without apparent HR or ventilatory limitation, none had oxygen desaturation below 90% or fall in BP, two were in atrial fibrillation, and only three had evidence that an AT was achieved. CONCLUSIONS: Among the patients with peak VO2 < 14 mL/min/kg, there were no objective signs of a cardiocirculatory or a respiratory limitation to exercise in half of them, and 31% did not achieve an AT either, thus not meeting any criteria to support evidence of maximal exercise. Exercise tests without objective evidence of cardiocirculatory or ventilatory limitation may not represent maximal performance. Consequently, peak VO2 may misclassify an appreciable proportion of candidates if the test results are submaximal. CLINICAL IMPLICATIONS: Clinical exercise studies indicating low peak VO2 must be interpreted in the context of whether a defined objective exercise limitation is evident to avoid biasing the selection of heart transplant candidates.

Adult↗
PubMed1996

Detection of excessive bronchoconstriction in asthma.

Airway hyperresponsiveness is easily assessed by measuring the concentration or dose of an inhaled agonist that produces a defined response, e.g., PC20 or PD20. However, this measure does not assess excessive bronchoconstriction. We report the results of analyzing bronchial dose-response curves by measuring percent fall in vital capacity (delta FVC%) as the response rather than the PC20. In our analysis, delta FVC% was measured at the PC20, and therefore it was the dependent variable, whereas the concentration of agonist was the independent variable, in contrast to the usual bronchoprovocation tests in which the response is the independent variable and the dose is the dependent variable. We reasoned that a dose-dependent increase in gas trapping with histamine would detect excessive bronchoconstriction as a decrease in FVC; in contrast, PC20 measures only the ease of bronchoconstriction. In 10 patients with mild asthma the reproducibility of delta FVC% when FEV1 fell by 20%, i.e., at the PC20 concentration of histamine, taken from a greater than 6-s FVC on an otherwise standard histamine challenge test was comparable to that of PC20. In 10 healthy asymptomatic subjects there were only trivial falls (0.3%) in FVC to as much as 16 mg/ml histamine. In a retrospective study of 146 patients with mild asthma, the delta FVC% was normally distributed (13.2 +/- 5.5 SD%) and did not correlate with the number of beta 2-agonist prescriptions or the PC20, but it did correlate with the number of prescriptions written per month for oral prednisone (r = 0.55, p < 0.02). We conclude that delta FVC% when FEV1 falls by 20% is a safe method of detecting excessive bronchoconstriction, and it reveals that different asthmatics react in fundamentally different ways to the same agonist. This may be useful in detecting the asthmatic at risk for serious disease.

Adult↗
PubMed1993

Graft position and pulmonary function after single lung transplantation for obstructive lung disease.

Single lung transplantation (SLT) has become a therapeutic option for the treatment of end-stage obstructive lung disease. Between January 1989 and June 1990, there were 14 patients with end-stage obstructive lung disease who underwent SLT. Eleven of these patients were surviving at 1 year following transplantation. Three of the patients had received left-sided SLT, and eight had received right-sided SLT. In the patients receiving left-sided SLT, the native right lung radiographically appeared to compress the left lung graft. In the patients receiving right-sided SLT, the native left lung did not appear to compress the right lung graft. We hypothesized that right SLT may provide a functional advantage over left SLT for patients with obstructive lung disease. We compared pulmonary function test results before and after transplantation (approximately 3 and 12 months) and compared quantitative ventilation-perfusion lung scan results between the patients with left SLT and those with right SLT. Additionally, we compared graded-exercise test results at 3 and 12 months after transplant between the two groups. Our data revealed no statistical difference in pulmonary function test results or graded-exercise test results between the two groups, although patients undergoing right SLT showed greater increases in FEV1 and forced vital capacity than those undergoing left SLT. Quantitative ventilation and perfusion were greater to the graft in patients receiving right-sided SLT than in patients receiving left-sided SLT, most likely due to the larger size of the right lung. We conclude that there is no functional difference between patients undergoing left or right SLT for end-stage obstructive lung disease.

Adult↗
PubMed1993

Relationship of resting lung mechanics and exercise pattern of breathing in patients with chronic obstructive lung disease.

To investigate the influence of resting pulmonary mechanics on the pattern of breathing during exercise in chronic obstructive pulmonary disease (COPD), we studied 29 patients with moderate to severe COPD (FEV1 50 +/- 20 percent predicted), and 10 normal subjects. Lung mechanics were studied using esophageal balloon technique and body-box. Incremental exercise testing was performed to exhaustion. As minute ventilation (VE) increases, COPD patients with the highest pulmonary resistance (RI) or lowest elastic recoil pressure (PL), used a greater tidal volume/vital capacity ratio (VT/VC) than the COPD patients with more normal RL or lowest PL. To describe the breathing pattern during exercise, an exponential constant (K) describes the rates of increase in VT/VC ratio with increasing VE, calculated according to the equation VT = VC(1-e-KVE). The K values achieved by COPD patients were higher than in normal subjects. In addition, K value correlated negatively with the resting FEV1 and FVC of COPD patients. When COPD patients were grouped according to their K values, it was revealed that patients with high K values generated greater VT/VC ratio and also have the most abnormal resting lung mechanics. These results suggest that the exercise breathing pattern in COPD patients is significantly influenced by the degree of impairment of resting lung mechanics.

Adult↗
PubMed1992

Resistive breathing activates the glutathione redox cycle and impairs performance of rat diaphragm.

Free radical activation and lipid peroxidation have been described in skeletal muscle during strenuous exercise. We hypothesized that oxygen radicals could also be formed in the diaphragm muscle during strenuous resistive breathing and that these radicals might affect diaphragm function. Seven control and 12 experimental male Sprague-Dawley rats were studied. Six experimental animals were subjected to resistive breathing (RB) alone and six animals received 15 min of mechanical ventilatory support (MV) after the resistive breathing period. Inspiratory resistance was adjusted to maintain airway opening pressure at 70% maximum in both groups until exhaustion. Diaphragm samples were obtained for analysis of thiobarbituric acid-reactive substances (TBAR), reduced glutathione (GSH), and glutathione disulfide (GSSG). In vitro isometric contraction times, twitch (Pt) tension and maximum tetanic (Po) tension, force-frequency curves, fatigue index, and recovery index were measured. In RB and MV compared with controls, there were significant decreases in Pt and Po. Diaphragm TBAR concentrations were increased in MV compared with controls or RB. GSSG-to-total glutathione ratio was increased in RB and MV compared with controls. Production of free radicals during RB and MV may represent an important mechanism of diaphragmatic injury that could contribute to the decline in contractility.

Airway Resistance↗
PubMed1992

Ventilation-perfusion inequalities during graft rejection in patients undergoing single lung transplantation for primary pulmonary hypertension.

We report herein data on single lung transplant (SLT) recipients with primary pulmonary hypertension (PPH). One patient did well following surgery but died on the 30th postoperative day due to cytomegalovirus pneumonia. The remaining two patients initially did well with unlimited exercise tolerance following transplantation, but then developed marked dyspnea on exertion and hypoxemia on postoperative days 144 and 120, respectively. Pulmonary function testing showed marked deterioration of function and transbronchial lung biopsy specimens revealed acute graft rejection in one patient and evidence of chronic graft rejection in the second patient. Quantitative ventilation-perfusion lung scanning demonstrated a marked decrease in ventilation to the transplanted lung in both cases associated with only a mild decrease in perfusion. This V/Q mismatch resulted in markedly decreased arterial oxygen saturations, widened alveolar-arterial oxygen gradients, and clinically debilitating dyspnea. We conclude that rejection may result in significant V/Q mismatch and hypoxemia in PPH patients undergoing SLT, which may limit the use of this specific type of surgery for PPH.

Female↗
PubMed1991

Cardiopulmonary exercise responses after single lung transplantation for severe obstructive lung disease.

The purpose of this study was to characterize cardiovascular and ventilatory responses to exercise in single lung transplantation (SLT) recipients with nonseptic, severe obstructive lung disease (SLT-OB). We also investigated whether the hyperinflated native lung in SLT-OB recipients could limit normal increases in tidal volume by mechanically constraining the transplanted lung, resulting in ventilation-perfusion imbalance in the lung graft. Data from six SLT-OB recipients (five women, one man) and six age-matched SLT recipients (two women, four men) with severe interstitial lung disease (SLT-IN) were compared. Resting arterial O2 and CO2 tensions were normal and comparable between the SLT groups. Spirometry results were reduced but comparable between SLT groups. Total lung capacity was significantly larger in patients with SLT-OB than in patients with SLT-IN. Diffusion capacity was not different between SLT groups when differences in alveolar volume were accounted for. Quantitative perfusion to the lung graft was comparable between the SLT groups, but quantitative ventilation was greater in patients with SLT-OB than in patients with SLT-IN. Maximum exercise capacity following SLT-OB was decreased, but was comparable to that of SLT-IN recipients. None of the SLT-OB recipients reached predicted maximum minute ventilation and only one experienced mild arterial O2 desaturation, suggesting peripheral muscle abnormalities from corticosteroid use and deconditioning as limiting factors rather than a ventilatory limitation. Tidal volumes at end exercise in the SLT-OB recipients were normal. Our quantitative lung scan and exercise testing data suggest that ventilation-perfusion imbalance and resulting gas exchange abnormalities from lung graft constraint and compression do not occur at rest or with exercise after SLT for obstructive lung disease.

Anaerobic Threshold↗
PubMed1991

Subclinical cardiac dysfunction in sarcoidosis.

Clinically apparent myocardial disease is infrequent in sarcoidosis. However, autopsy data show myocardial involvement in up to 30 percent of patients. Unexplained exertional symptomatology is a common complaint in patients with sarcoidosis. In this study, we investigated whether abnormal cardiac function might limit exercise performance in patients with sarcoidosis without overt cardiac involvement. We studied exercise responses in 35 patients with sarcoidosis and compared them with 28 untrained controls. Seventy-seven percent of the patients were symptomatic. Pulmonary function test results were lower in the group with sarcoidosis than normal controls, but they were within normal range. Only one patient had evidence of ventilatory limitation to exercise. Sixteen (46 percent) patients had abnormally increased heart rates (HRs) at rest prior to exercise testing and/or with exercise. Rapid HRs were confirmed during daily activities by continuous ambulatory electrocardiographic (ECG) monitoring. Left ventricular ejection fraction (LVEF) was measured to determine if systolic dysfunction could account for abnormal HR responses. Of patients with abnormally increased HRs, five had LVEFs less than 50 percent, and eight had normal LVEFs, of whom 75 percent had tachycardia at rest. Retrospective comparison of HR responses and LVEF between patients who did or did not receive corticosteroids revealed no significant differences between groups. We conclude that abnormal HR responses in patients without evident cardiac sarcoidosis are common and exertional symptoms in this population are often associated with chronotropic abnormalities. The exact mechanisms underlying the chronotropic abnormalities are unclear, but they likely include ventricular systolic dysfunction, sinus node dysfunction from granulomatous infiltration, or combinations of the two.

Adult↗
PubMed1991

Single lung transplantation. Alternative indications and technique.

Twenty-two patients have undergone 23 single lung transplants between March 1980 and April 1990 at the University of Texas Health Science Center at San Antonio. The actuarial survival rate is 77.27% at 12 months and 72.73% at 24 months. There have been no instances of bronchial dehiscence or stenosis, even though 13 of the patients were on a program of preoperative prednisone, every patient had high-dose perioperative methylprednisolone, and omental wraps were not used on any bronchial anastomosis. Of particular interest is the fact that three patients had primary pulmonary hypertension, three had secondary pulmonary hypertension, and 10 patients had chronic obstructive pulmonary disease, due in five cases to an alpha 1-antitrypsin deficiency. Each of these entities was previously thought to contraindicate single lung transplantation. Donor selection was based on an oxygen tension/inspired oxygen concentration ratio greater than 300, donor/recipient chest circumference within 3 inches, clear chest x-ray film, negative sputum Gram stain, and less than 6-hour estimated ischemic time. Harvest technique included donor prostaglandin E1 500 micrograms, topical slush, and pulmonoplegia with cold Euro-Collins solution. The heart and lung were separated in situ rather than the heart lung block being removed. A telescoping bronchial anastomosis was performed with 4-0 Prolene (not absorbable) sutures. We conclude that single lung transplantation has evolved into a simple operation, necessitating meticulous preoperative and postoperative care, which can be performed on a wide spectrum of critically ill patients with an acceptable mortality rate.

Adult↗
PubMed1990

Single lung transplantation for primary pulmonary hypertension.

Single lung transplantation has become a therapeutic option for end-stage interstitial lung disease and obstructive lung disease. Our group recently extended this treatment to three patients with primary pulmonary hypertension. All patients had marked decreases in pulmonary artery pressures and pulmonary vascular resistance and increases in cardiac output following single lung transplantation. Spirometry, lung volumes, and diffusion capacity were not different in comparison to preoperative studies. Quantitative ventilation-perfusion scans revealed the majority of perfusion distributed to the transplanted lung, with ventilation approximately equally divided between the native and the transplanted lung. Despite ventilation-perfusion imbalance, there was no resting hypoxemia and there was no arterial oxygen desaturation with exercise. One patient expired on the 30th postoperative day due to cytomegalovirus infection of the lungs. In the remaining two patients, maximum exercise capacity following transplantation was near normal in one recipient and reduced in the second recipient. Of note, there was no evidence of ventilatory limitation or impaired oxygenation during exercise in these two recipients. Although an exaggerated exercise ventilatory response was present, this did not limit exercise performance. This report supports the use of single lung transplantation for the treatment of primary pulmonary hypertension.

Adult↗
PubMedDate not supplied

Reference values for a multiple repetition 6-minute walk test in healthy adults older than 20 years.

PURPOSE: To (1) identify greatest 6-minute walk distance (6MWD) from among several repetitions (best 6MWD) in a wide age range of healthy volunteers to develop reference values for the multiple repetition 6MWD, and (2) investigate the influence of demographics, anthropometrics, and habitual exercise activity on best 6MWD. METHODS: Four 6MWD were performed on the same day in a 20-meter corridor by 41 male and 38 female healthy volunteers ranging in age from 20 to 80 years. The greatest 6MWD by each subject from among four 6MWDs was the primary outcome measure. RESULTS: Eighty-six percent had their best 6MWD after the first walk; an average increase of 43 meters was observed from first to best 6MWD (P < 0.003). Best 6MWD averaged 698 +/- 96 meters and was inversely related to age (P < 0.001), directly to height (P < 0.001), and was greater in men than women (P < 0.0002). A regression model accounted for 41% of between-subject variability in best 6MWD (P < 0.00000001). In a subset of older subjects, predicted 6MWD significantly underestimated measured best 6MWD when reference values were used from another study where test familiarization was not provided, but this difference disappeared when value were used from the present and a third study where test familiarization was provided. CONCLUSIONS: The present study is the first to provide predicted 6MWD values performed with multiple repetitions and for subjects in the 20-40-year-old age range. Selection of appropriate predicted 6MWD values for interpretation of performance should be guided by subject age and degree of test familiarization provided.

Adult↗
PubMedDate not supplied

Exercise performance after lung transplantation.

Heart-lung, double lung, and single lung transplantation have been shown to be effective in the treatment of patients with advanced cardiopulmonary disorders. An overlap in indications occurs for the different procedures, and in many situations the factors that are important in selecting the best operation for a given patient have not been clearly elucidated. To determine whether the anticipated exercise capacity should be an important consideration in the selection of the optimal procedure for a given patient, we compared exercise performance in patients who had undergone the different lung transplantation procedures in the preceding year and were otherwise well. Eleven heart-lung, six double lung, and 16 single lung recipients and 28 control subjects underwent maximal symptom-limited incremental exercise tests using a cycle ergometer. At peak exercise, transplant recipients reached maximum oxygen uptakes in the range of 40% to 60% of predicted values; no significant differences existed between the means of the different transplant groups. Ventilatory factors did not appear to limit exercise in any group. The exercise responses in the transplant subjects were characterized by reduced aerobic capacity and diminished oxygen pulse, factors indicating abnormal cardiovascular performance. Our data indicate that moderate levels of exercise can be anticipated early after heart-lung, double lung, and single lung transplantation. In the absence of substantial differences in exercise capacity, other considerations would appear to be more important in guiding the selection of the optimal lung replacement procedure for an individual patient.

Adult↗