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Biomedical subjects

A L Ries

Publications and source records attributed to A L Ries.

At least 19 recordsLinked to original sources
PubMed1992

Effect of posture on arterial oxygenation in patients with chronic obstructive pulmonary disease.

We studied 117 patients with chronic obstructive pulmonary disease (COPD) to evaluate (1) the frequency and magnitude of postural changes in resting arterial oxygenation and (2) the relationship of these changes to other measures of pulmonary function and exercise arterial blood gases. Compared to the supine measurement, room air PaO2 measured while standing increased more than 3 mm Hg in 28 patients (group 1), did not change (+/- 3 mm Hg) in 57 patients (group 2), and decreased more than 3 mm Hg in 32 patients (group 3) (range = 31 mm Hg increase to 20 mm Hg decrease). Patients in group 1 had significantly less severe disease than patients in the other two groups. There were no significant pulmonary function differences between groups 2 and 3. Supine PaO2 was similar for all groups, suggesting that standing PaO2 accounted for the postural change in PaO2. Because of unpredictable postural changes in PaO2 in patients with COPD, we believe that body position should be noted for arterial blood gas measurements and should be kept constant for valid comparison of serial measurements. These findings may also be important for other diffuse lung diseases.

Arteries↗
PubMed1992

Laser resection of granulation tissue secondary to transtracheal oxygen catheter.

Oxygen therapy through a transtracheal catheter has been used increasingly for the long-term delivery of continuous oxygen. Compared to nasal cannula it results in significant reduction in oxygen flow requirements. This form of therapy has gained patient acceptance because of several advantages including improved convenience, aesthetics, compliance, and mobility. Reported complications generally have been minor, including subcutaneous emphysema, cough, "mucous ball" formation and mild hemoptysis. In this report, we describe a case of granulation tissue formation at the transtracheal catheter puncture site which was treated with Nd:YAG laser bronchoscopy to reestablish patency of the upper airway. No recurrence was noted after two years of follow-up.

Bronchoscopy↗
PubMed1991

Use of factor analysis to consolidate multiple outcome measures in chronic obstructive pulmonary disease.

Multiple outcome measures are often used in clinical research and practice. However, the use of multiple measures inflates the probability of a type I error. In this paper, we used factor analysis techniques to reduce multiple outcome measures to a lesser number of orthogonal dimensions. The data were obtained from 119 patients with chronic obstructive pulmonary disease. Each patient had measurements made of 28 variables, including multiple parameters of pulmonary function, exercise tolerance and gas exchange. Factor analysis using a maximum likelihood iterative solution was performed. The factors were then rotated to a varimax solution. The analysis yielded four meaningful factors: exercise tolerance, disease severity, lung volumes and flow rates. Exercise tolerance and disease severity were the most important factors accounting, respectively, for 44 and 13% of the common variance. For further analyses, these composite factors could be used or a representative clinical measure from each factor might be chosen. We conclude that many physiologic measures provide highly correlated information about chronic obstructive pulmonary disease patients. Factor analysis may help reduce these measures into a smaller number of reliable composites.

Aged↗
PubMed1991

Prediction of maximum exercise tolerance in patients with COPD.

Exercise tolerance in patients with COPD is difficult to predict from measurements of lung function. We examined multiple physiologic and psychosocial variables in an attempt to predict exercise performance in a group of patients with COPD enrolled in a clinical trial of pulmonary rehabilitation. A total of 119 patients (FEV1 = 1.41 +/- 0.64 L) were divided randomly into either a study group (group A, n = 58) or validation group (group B, n = 61). Stepwise multiple regression in group A revealed that peak oxygen uptake (peak VO2) was predicted best by the following equation: Peak VO2 (L/min) = (0.0327 x DCO) + (0.0040 x MVV)-(0.0156 x peak-exercise VD/VT) + (0.0259 x resting VE) + 0.848; r = 0.90; SE = 0.233 L/min. This equation was then cross-validated in group B. It demonstrated excellent validity: measured peak VO2 (L/min) = (1.13 x predicted peak VO2)-0.0891; r = 0.90; SE = 0.239 L/min. We conclude that exercise tolerance was predicted reasonably well from measurements of lung function and gas exchange in this group of patients with COPD. However, the variability of the prediction would limit its usefulness in individual patients.

Carbon Dioxide↗
PubMed1991

Maximum intensity exercise training in patients with chronic obstructive pulmonary disease.

We studied high intensity, symptom-limited, endurance exercise training in 52 patients with COPD participating in a pulmonary rehabilitation program. The patients had moderate to severe airway obstruction and reduced exercise tolerance with ventilatory limitation. The target workload for endurance exercise testing was 95 percent of the baseline maximum treadmill work load. At training weeks 1, 4 and 8, they were training at 85, 84, and 86 percent respectively, of baseline maximum. After rehabilitation, there was an increase in maximal treadmill work load, VO2max, and endurance exercise time, and a decrease in perceived symptoms. Patients who did not reach anaerobic threshold (group 2) were able to train at a higher percentage of maximum exercise tolerance than patients who reached anaerobic threshold (group 1). The increase in exercise performance of both groups, however, was similar. We conclude that patients with moderate to severe COPD can perform exercise training successfully at intensity targets which represent higher percentages of maximum than typically recommended in normal individuals or other patients.

Anaerobic Threshold↗
PubMed1990

Experimental evaluation of rehabilitation in chronic obstructive pulmonary disease: short-term effects on exercise endurance and health status.

Randomly assigned 119 adults with chronic obstructive pulmonary disease to an 8-week comprehensive rehabilitation program or to an 8-week education control program. Comprehensive pulmonary rehabilitation included education, physical and respiratory therapy instruction, psychosocial support, and supervised exercise training; education control included biweekly classroom instruction and discussions on respiratory therapy, medical aspects of lung disease, clinical pharmacology, and diet, but no exercise training. Both groups received extensive physiological and psychosocial evaluation before and after the intervention. Six months after enrollment, patients randomly assigned to the rehabilitation program showed significant increases in exercise endurance, whereas patients randomly assigned to control program showed nonsignificant increases. Improvement in self-efficacy was correlated with improvements in exercise endurance.

Combined Modality Therapy↗
PubMed1989

Skin color and ear oximetry.

Measurements of arterial blood oxygen saturation from two ear oximeters were compared with 655 simultaneously drawn arterial blood samples in 187 patients grouped by skin color quantified by the Munsell color system. Technical problems including warning lights and messages with the two ear oximeters were recorded. There were significantly more technical problems in patients with the darkest skin color associated with inability to obtain a reading or warning message indicating poor tissue penetration of the signal (18 and 15 percent vs 1 percent). When readings could be obtained, the ear oximetry readings were found to be slightly less accurate in the darker patient groups. These findings suggest that dark skin color may affect the performance and accuracy of ear oximeters, including the newer type of pulse oximeters.

Blood Gas Monitoring, Transcutaneous↗
PubMed1989

Measurement of lung volumes.

Measurements of lung volume play an integral role in the laboratory evaluation of patients with known or suspected lung disease. Several techniques are available to measure absolute lung volumes (containing residual volume). It should be noted that these techniques measure different theoretical volumes and may produce different results in patients with lung disease. Lung volume measurements are typically elevated in obstructive diseases and reduced in restrictive diseases, making them useful tests in diagnosing and distinguishing these two general classes of disease.

Humans↗
PubMed1988

Pulmonary function tests cannot predict exercise-induced hypoxemia in chronic obstructive pulmonary disease.

We studied 40 patients with chronic obstructive pulmonary disease (COPD) to determine whether measurements of pulmonary function could predict a fall in arterial oxygen pressure (PaO2) with exercise. The PaO2 fell more than 3 mm Hg in 21 patients (group 1), did not change (+/- 3 mm Hg) in nine patients (group 2), and increased more than 3 mm Hg in ten patients (group 3). Group 3 had significantly less severe expiratory obstruction than groups 1 and 2. The most significant variables in predicting a change in PaO2 with exercise were the ratio of the forced expiratory volume in one second over the forced vital capacity (FEV1/FVC) and the single-breath carbon monoxide diffusing capacity (Dsb). Measurements of FEV1/FVC of 0.50 or more and Dsb of 20 ml/min/mm Hg or more were 100 percent predictive in excluding a fall in PaO2 with exercise. Measurements below these thresholds could not be used reliably to predict which patients would develop worsening hypoxemia with exercise. Because of wide variability in reference values from eight different published studies for diffusing capacity, recommended criteria based on the percent predicted Dsb should be used with caution. We conclude that pulmonary function measurements cannot be used to predict exercise-induced hypoxemia in patients with COPD; however, the measurements may be useful in identifying patients whose condition is less severe who are unlikely to develop worsening hypoxemia with exercise.

Carbon Dioxide↗
PubMed1988

Upper extremity exercise training in chronic obstructive pulmonary disease.

Many patients with chronic obstructive pulmonary disease (COPD) report greater limitation for activities involving the upper extremities than the lower extremities. Exercise training has generally emphasized lower-extremity exercise. We designed and evaluated two simple, practical, and widely applicable upper-extremity training programs in 45 patients with COPD participating concurrently in a comprehensive, multidisciplinary pulmonary rehabilitation program. Patients were randomly assigned to one of the following three groups: (1) gravity-resistance (GR) upper-extremity training; (2) modified proprioceptive neuromuscular facilitation (PNF) upper-extremity training; or (3) no upper-extremity training (control). Patients were evaluated before and after at least six weeks of uninterrupted training. Twenty-eight patients completed the study. Compared to controls, both GR and PNF patients demonstrated improved performance on tests specific to the training performed (upper-extremity performance test, maximal level and endurance on isokinetic arm cycle). There were no significant changes on isotonic arm cycle, ventilatory muscle endurance, or simulated activities of daily-living tests. Ratings of perceived breathlessness and fatigue decreased significantly in all groups for several tests. We conclude that specific upper-extremity training may be beneficial in the rehabilitation of patients with COPD and warrants further investigation.

Activities of Daily Living↗
PubMed1988

The use of cutaneous oximetry in the prescription of long-term oxygen therapy.

Using current Medicare guidelines for the prescription of long-term oxygen therapy, we studied the impact on decision-making of substituting cutaneous oxyhemoglobin saturation measurements (SaO2) for direct arterial oxygen tension measurements (PaO2). Fifty-five patients with chronic lung disease and resting hypoxemia were studied. More than 80 percent of patients with a resting PaO2 of 7.33 kPa (55 mm Hg) or less had a cutaneous oximetry SaO2 greater than 85 percent. These patients would not have met the guidelines for long-term oxygen therapy if the cutaneous oximetry measurements were used instead of direct PaO2 measurements. Substituting a threshold criterion of 88 percent instead of 85 percent resulted in fewer patients being denied oxygen therapy but also included patients with PaO2 values greater than 7.33 kPa (55 mm Hg). We conclude that cutaneous oximetry cannot be substituted equivalently for PaO2 measurements in prescribing long-term oxygen therapy.

Adolescent↗
PubMed1988

Restricted pulmonary function in cystic fibrosis.

Some patients with cystic fibrosis have reduced pulmonary volumes, indicating a restrictive pattern of pulmonary disease. We identified ten patients with pulmonary functional evidence of restriction among 158 patients with cystic fibrosis followed at the University of California San Diego Medical Center in 1984 and 1985. We characterized the radiographic, pulmonary functional, and clinical characteristics of these restricted patients compared to matched nonrestricted patients. Pulmonary volumes were measured by three different techniques: plethysmography; nitrogen washout; and radiography. Except for plethysmographic pulmonary volumes, there were no significant differences between the matched restricted and nonrestricted patients. Radiographic pulmonary volume tended to overestimate gas volume measured by the other techniques. Differences among these techniques (thought to represent air-space filling) correlated best with radiographic evidence of air trapping and bronchial markings and not with parenchymal lesions. Serial pulmonary function tests demonstrated changes in pulmonary volume in several patients and a trend toward improvement in pulmonary volume in the restricted patients over time. We conclude that restricted pulmonary function does not necessarily indicate more severe disease in patients with cystic fibrosis and may be reversible in some. The mechanism of restriction may be related more to radiographic evidence of airway disease than to parenchymal abnormalities.

Adult↗
PubMed1987

The role of exercise testing in pulmonary diagnosis.

Exercise stresses the body's functional reserves that allow for the increased metabolic work and gas transport necessary for the efficient production of energy with physical activity or stress. Disease that reduces reserve in the gas transport organs will produce exertional symptoms not present at rest. Exercise testing has been well established in the evaluation of healthy persons and cardiac patients who are limited by cardiac or peripheral muscle function. For patients with lung disease, however, whose exercise performance is limited by reduced ventilatory capacity and disordered gas exchange, principles of exercise testing (and training) are different. In the evaluation of pulmonary patients, exercise testing can be used to measure exercise tolerance, assess the limitation to exercise in patients with unexplained dyspnea, evaluate patients for respiratory disability, assess blood gas changes with exercise, and detect exercise-induced asthma. Nevertheless, our understanding of the role of exercise in pulmonary diagnosis is at an early stage of development and much needs to be learned about the practical applications of exercise testing in the diagnosis, staging, and serial evaluation of pulmonary diseases.

Asthma, Exercise-Induced↗
PubMed1986

Pulmonary function tests in the detection of left heart failure: correlation with pulmonary artery wedge pressure.

Standard pulmonary function tests, including lung volumes measured by three fundamentally different techniques, were performed in 40 patients undergoing cardiac catheterization. These were compared with clinical and radiologic evaluations in detecting left heart failure (LHF). Patients with elevation in mean pulmonary artery wedge pressure (PAWM) greater than or equal to 20 mm Hg had significant restrictive changes with reduction in vital capacity (VC), forced expiratory volume in 1 s (FEV1.0), and total lung capacity (TLC) measured by helium dilution and body plethysmography. Radiographic TLC was not reduced in these patients or correlated with PAWM. Obstructive changes were not present. Radiologic gradings by 5 different observers were reasonably accurate in detecting LHF but varied between observers. VC and TLC measured by helium dilution and body plethysmography were slightly less sensitive but more specific in detecting PAWM elevation. Clinical classification was sensitive but nonspecific; in addition, clinical signs were not reliable indicators of elevated PAWM. We conclude that pulmonary function testing may provide objective, accurate, and useful information in the evaluation of cardiac patients for LHF. However, radiographic measurement of thoracic cage volume does not reflect the changes in lung gas volume measured by gas dilution or plethysmographic techniques in patients with chronic congestive heart failure.

Adult↗
PubMed1986

Comparison of isocapnic hyperventilation and walking exercise training at home in pulmonary rehabilitation.

Eighteen COPD patients enrolled in a comprehensive, multidisciplinary pulmonary rehabilitation program were randomly assigned to perform either: 1) walking, or 2) ventilatory muscle exercise training (VMT) using a prototype, portable device for isocapnic hyperventilation training. Both groups performed exercise training at home. Twelve patients completed the study and follow-up evaluation (five VMT, seven walkers). Pulmonary function did not change in either group. For the VMT patients, there were modest increases in ventilatory muscle endurance and exercise performance. VO2max and VEmax increased significantly. For the walkers, only walking endurance time increased significantly. These results indicate that isocapnic hyperventilation exercise training can be performed successfully by COPD patients in an unsupervised home setting and can lead to improvement in both ventilatory muscle endurance and exercise performance. Walking exercise training did not improve ventilatory muscle endurance.

Aged↗
PubMed1986

Reproductive hormone increases in response to acute exercise in men.

The increase in serum testosterone levels generally observed with intense, short-term exercise remains unexplained since most investigators have not reported any increase in the levels of luteinizing hormone, the pituitary glycoprotein most responsible for testicular steroidogenesis. Hemoconcentration and decreased metabolic clearance have been suggested as mechanisms to explain the exercise-associated testosterone increase. Such non-specific mechanisms should apply to other steroid hormones as well as to testosterone. To investigate whether the exercise-induced changes in other steroid hormones were similar to that of testosterone, we measured serum levels of testosterone, androstenedione, dehydroepiandrosterone, and cortisol as well as gonadotropins, luteinizing hormone and follicle-stimulating hormone, and prolactin at 5-15 min intervals throughout progressive maximal intensity exercise on a cycle ergometer. Significant increases were observed with all hormones with exercise. The increase in serum testosterone began prior to exercise, peaked at 20 min after the beginning of exercise, and fell to baseline within 10 min. The serum luteinizing hormone increase was synchronous with that of testosterone, suggesting that gonadotropin stimulation was not responsible for the testosterone increment. The increments in serum cortisol, androstenedione, dehydroepiandrosterone, and prolactin levels were simultaneous but began 25-30 min after that of testosterone in all subjects. These findings, therefore, suggest that, contrary to previous evidence, the exercise-associated increase in serum testosterone results predominantly from a specific mechanism, presumably involving increased testicular production without gonadotropin stimulation.

Adult↗