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Biomedical subjects

S K Koerner

Publications and source records attributed to S K Koerner.

At least 37 records · Page 2Linked to original sources
PubMed1988

Relationship between oxygen uptake and oxygen delivery in patients with pulmonary hypertension.

Dependency of oxygen consumption (VO2) on oxygen delivery (DO2) in patients with adult respiratory distress syndrome and with congestive heart failure has been reported previously. We evaluated this relationship in 11 patients with pulmonary hypertension, 8 with primary pulmonary hypertension (PPH), and 3 with pulmonary hypertension secondary to chronic obstructive lung disease (SPH) at baseline and during treatment with vasodilating calcium channel antagonists. The mean baseline DO2 and VO2 were 11.0 +/- 4.2 and 3.9 +/- 1.1 ml/min/kg, respectively. After increasing cardiac output via vasodilators, we obtained an average of 3 additional data points per patient. We found a significant relationship between changes in VO2 and changes in DO2 (delta VO2 = -0.19 +/- 0.27 x delta DO2; r = 0.88, n = 37). In 4 patients, VO2 was determined both by respired gas analysis and by calculation from thermodilution cardiac output and measured arteriovenous oxygen gradient; results by the 2 methods were virtually identical. There was no significant relationship between cardiac output and mixed venous oxygen content or mixed venous oxygen tension (r = 0.20 and 0.47, respectively). Mean baseline oxygen extraction ratio was 36.7 +/- 6.4% and did not increase significantly after vasodilator therapy. We conclude that in patients with pulmonary hypertension, changes in oxygen consumption appear to be dependent on changes in oxygen delivery. This may represent evidence of tissue hypoxemia, which is otherwise not apparent. This dependency may support the use of vasodilators in these patients.

Biological Availability↗
PubMed1988

Physiologic assessment of lung function in patients undergoing laser photoresection of tracheobronchial tumors.

We performed YAG laser photoresection in 11 patients with tracheal or mainstem bronchial obstruction due to malignant or benign disorders. We used maximal inspiratory-expiratory flow-volume loops and expiratory volume-time plots to assess air flow limitation. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF) and iso-volume maximal flows at 50 percent of forced inspiratory and expiratory volume were calculated. Spirograms and flow-volume loops were repeated within 12 to 72 hours of laser resection. All patients had flattened expiratory limbs on their flow-volume loops. All spirometric parameters increased significantly following laser photoresection. In particular, peak flow improved in all patients, and FEV1 improved in nine of 11 patients, even though four patients had moderate to severe obstructive ventilatory defects which persisted after resection and were probably due to longstanding chronic obstructive pulmonary disease. We conclude that flow-volume loops and spirometry are helpful in assessing the site and nature of malignant large airway obstructive processes and, moreover, provide reliable information for evaluating the efficacy of laser photoresection. Serial physiologic studies indicate changes in the caliber of the upper airways and can be used as a simple means of following these patients.

Adult↗
PubMed1988

Pulmonary hypertension: etiology and clinical evaluation.

Elevation of pulmonary arterial pressure may be secondary to many diseases of the lungs, chest wall, and heart. From a pathophysiologic viewpoint, pulmonary hypertension is secondary to vascular obstruction, vasoactivity, increased circulation, and passive forces. Clinically, the entities that result in secondary pulmonary hypertension present with a picture that identifies the primary disease. Patients with primary pulmonary hypertension may be difficult to identify. Pulmonary hypertension may present early with dyspnea and fatigue, while syncope and hemoptysis are late symptoms. In many instances, pulmonary hypertension can be diagnosed utilizing physical examination and noninvasive tests. Eventually, right heart catheterization is necessary to confirm the diagnosis and to monitor trials of therapy with vasodilators. Treatment may be specific (closure of a septal defect, thromboendarterectomy) or generic (vasodilators). These have been used recently for both secondary and primary pulmonary hypertension in an effort to reduce pulmonary vascular resistance, thereby decreasing right ventricular afterload and improving cardiac output and oxygen delivery. The success of these treatments has not been demonstrated.

Adult↗
PubMed1987

Cost-benefit comparison of aerosol bronchodilator delivery methods in hospitalized patients.

We compared two modes of aerosol bronchodilator delivery in 34 patients hospitalized with obstructive airways diseases. The standard mode, therapist-administered up-draft nebulization (UDN), is labor-intensive and therefore relatively costly. The alternative mode, self-administration by a metered dose inhaler (MDI), is less costly, but its efficacy over an entire hospitalization has heretofore not been established. Patients were enrolled after transfer to the pulmonary ward from the emergency room or intensive care units (ICU). We then randomized them to receive metaproterenol q4h either via MDI or UDN. Daily spirometry revealed that MDI and UDN were associated with equivalent bronchodilation initially and equivalent improvement at discharge. The duration of hospitalization for the two groups was also the same. Thus, the two delivery methods were equally effective. We could not attribute this equivalence to pretreatment intergroup differences or to differences in concomitant therapy with steroids, theophylline, other bronchodilators, or antibiotics. Routine use of MDI rather than UDN in all non-ICU adult patients would save $253,487 per year at our institution alone.

Aerosols↗
PubMed1987

Dependence of oxygen consumption on oxygen delivery in patients with chronic congestive heart failure.

We previously have shown that in patients with adult respiratory distress syndrome (ARDS) oxygen consumption (VO2) is linearly related to oxygen delivery (DO2) below a threshold DO2 of 21 ml/min/kg. To evaluate this relationship in chronic congestive heart failure (CHF), we studied eight patients with chronic CHF at baseline and during treatment with nitroglycerin. The resting DO2 and VO2 were 10.7 +/- 2.3 ml/min/kg and 3.8 +/- 0.87 ml/min/kg, respectively. In our eight patients, we found a significant relationship between changes in VO2 and in DO2 (delta VO2 = 0.16 + 0.34 X delta DO2, r = 0.84, n = 29). There was no significant relationship between DO2 and mixed venous oxygen tension (PvO2, r = 0.16), nor was there a significant relationship between cardiac output (Qt) and PvO2 (r = 0.21). We conclude that in patients with chronic CHF, changes in VO2 appear to be dependent on changes in DO2. This may represent an adaptive tissue response to chronically reduced systemic oxygen transport.

Blood Gas Analysis↗
PubMed1987

Prostaglandin E1 as a screening vasodilator in primary pulmonary hypertension.

Pulmonary vasodilators are variably efficacious in primary pulmonary hypertension (PPH). None has consistently improved hemodynamics enough to obviate the need for complex and potentially hazardous testing of several vasodilators. Prostaglandin E1 (PGE1), a potent, short-acting pulmonary vasodilator, was administered to seven patients with PPH in order to determine whether PGE1 could accurately predict the hemodynamic and gas exchange effects of other commonly used vasodilators. Prostaglandin E1, nifedipine and hydralazine were administered to the patients while measuring pulmonary and systemic hemodynamics and arterial blood gases. Prostaglandin E1 was easily titrated but was inconsistent as a predictor of the effects of the other vasodilators with respect to pulmonary artery pressure, cardiac output and adverse effects on arterial oxygenation. This study suggests that patients with PPH must still receive carefully monitored trials of several vasodilators to determine whether there is a beneficial response and to select the appropriate treatment.

Adult↗
PubMed1987

Primary pulmonary hypertension. A national prospective study.

A national registry was begun in 1981 to collect data from 32 centers on patients diagnosed by uniform criteria as having primary pulmonary hypertension. Entered into the registry were 187 patients with a mean age (+/- SD) of 36 +/- 15 years (range, 1 to 81), and a female-to-male ratio of 1.7:1 overall. The mean interval from onset of symptoms to diagnosis was 2 years. The most frequent presenting symptoms included dyspnea (60%), fatigue (19%), and syncope (or near syncope) (13%). Raynaud phenomenon was present in 10% (95% of whom were female) and a positive antinuclear antibody test, in 29% (69% female). Pulmonary function studies showed mild restriction (forced vital capacity [FVC], 82% of predicted) with a reduced diffusing capacity for carbon monoxide (DLCO), and hypoxemia with hypocapnia. The mean (+/- SD) right atrial pressure was 9.7 +/- 6 mm Hg; mean pulmonary artery pressure, 60 +/- 18 mm Hg; cardiac index, 2.3 +/- 0.9 L/min X m2; and pulmonary vascular resistance index, 26 +/- 14 mm Hg/L/min X m2 for the group. Although no deaths or sustained morbid events occurred during the diagnostic evaluation of the patients, the typically long interval from initial symptoms to diagnosis emphasizes the need to develop strategies to make the diagnosis earlier.

Adolescent↗
PubMed1986

Asbestos and airflow limitation.

To assess the effect of asbestos on the airways, researchers studied 45 shipyard workers who were lifelong nonsmokers and had asbestos-related abnormalities seen on their chest roentgenograms. Patients with interstitial lung disease, bronchial asthma prior to asbestos exposure, recurrent pneumonias, or significant cardiovascular disease were excluded from the study. In addition to chest films, they had spirometry performed before and after bronchodilator inhalation, lung volumes, diffusing capacity, and arterial blood gases. Forced vital capacity and forced expired volume in one second were normal in all patients. Maximum midexpiratory flow rates (MMFR) were abnormal (MMFR less than 75% of predicted) in 13 patients (29%). Therefore, 29% of lifetime nonsmokers with asbestos exposure exhibited evidence of small airways dysfunction. An abnormal MMFR in these workers may be due, in part, to asbestos exposure and could conceivably indicate a population at risk for pulmonary fibrosis and/or obstructive airways disease.

Asbestos↗
PubMed1985

Effect of breathing pattern on dead space ventilation VD/VT during exercise.

In order to assess the effect of breathing pattern on measurements of dead space ventilation (VD/VT) during exercise, we studied 6 patients with the complaint of exertional dyspnea. They had essentially normal resting pulmonary function studies and the only abnormality noted during an initial exercise study was an elevated VD/VT associated with a rapid respiratory rate. A second exercise study was then performed during which they were coached to breathe at a slower rate and larger tidal volume. During the exercise study with coaching, the VD/VT response was normal. We conclude that breathing pattern during exercise influences VD/VT and that an increase in total minute ventilation which is accomplished by a preferential increase in respiratory rate may result in an abnormally high VD/VT.

Aged↗
PubMed1985

Changes in distribution of lung perfusion and ventilation at rest and during maximal exercise.

A new method for evaluation of changes in the distribution of pulmonary perfusion and ventilation during exercise was applied to normal male volunteers. Ventilation and perfusion scans were done with the subjects seated on a bicycle ergometer. The resting studies utilized krypton 81 (81mKr) for ventilation and technetium 99m (99mTc) macroaggregate albumin intravenously for perfusion. Exercise studies were done when 80 percent of maximum predicted heart rate was maintained for five minutes and utilized 81mKr for ventilation and a tenfold dose of 99mTc for perfusion. Higher dose of 99mTc would minimize the effect of radioactivity left over from the resting study. This method allowed us to assess changes in ventilation and perfusion in normal subjects induced by exercise, but may also be applicable in a variety of cardiopulmonary conditions that affect pulmonary ventilation and perfusion or both.

Adult↗
PubMed1985

Mechanical vibration and conventional chest physiotherapy in outpatients with stable chronic obstructive lung disease.

To assess the effect of conventional chest physiotherapy and mechanical chest vibration on arterial blood gas levels, spirometry, and sputum production, we studied 20 stable outpatients with chronic obstructive lung disease. All patients had severe obstructive ventilatory defects with a mean FEV1/FVC ratio of 30 percent and all produced moderate amounts of sputum. Patients were randomized and received chest physiotherapy or mechanical vibration for 20 minutes. Arterial blood gas levels and spirometry obtained 20 minutes and 40 minutes after completion of the treatment did not show any significant change compared to the baseline. We conclude that neither chest physiotherapy nor chest mechanical vibration improved gas exchange, flow rates, or clearance of secretions in stable outpatients with severe chronic obstructive lung disease.

Adult↗
PubMed1984

Gallium scintigraphy in bronchogenic carcinoma. The effect of tumor location on sensitivity and specificity.

Fifty-one patients with primary lung cancer were evaluated using 67Ga citrate scintigraphy with respect to detection of peripheral primary, hilar metastasis, and mediastinal metastasis. The results demonstrated the necessity for an understanding of the criteria used in considering the gallium scintigram as either positive or negative, as well as the instrumentation employed in performing the test before any meaningful sensitivity and specificity figures can be derived within a given institution. Only with this understanding can actual strategy for instituting invasive procedures be achieved.

Carcinoma, Bronchogenic↗
PubMed1983

Sensitive indices of improvement in a pulmonary rehabilitation program.

It is often difficult to demonstrate objective evidence of physiologic improvement following a pulmonary rehabilitation program, despite subjective increases in exercise tolerance. In an attempt to identify sensitive indices of improvement, we studied resting and exercise lung function extensively in 15 patients (age range 45 to 73) with severe chronic obstructive lung disease before and after a pulmonary rehabilitation program. The six-week outpatient rehabilitation program consisted of exercise at 70 percent of the maximum predicted heart rate and diaphragmatic breathing for 20 minutes three times weekly. There were no significant changes in resting pulmonary function following exercise training. Exercise measurements were unchanged after completion of the program, with the exception of two parameters: heart rate and arterial lactate levels. The observed small but significant reductions in exercise heart rate and blood lactate levels following training may be due to conditioning of skeletal muscles, although respiratory muscle conditioning may be a contributing factor. Measurements of blood lactate may be a useful marker of conditioning in patients with chronic obstructive pulmonary disease who complete a pulmonary rehabilitation program.

Exercise Test↗
PubMed1982

Role of exercise testing in assessing functional respiratory impairment due to asbestos exposure.

To evaluate the complaint of exertional dyspnea in asbestos-exposed shipyard workers, pulmonary function tests were performed at rest and during exercise on 90 subjects with pleural plaques. We divided the subjects into four groups based on resting pulmonary function studies. Group I subjects (eight) had a restrictive defect; group II subjects (30) had an obstructive defect; group III subjects (six) had an isolated reduction in diffusing capacity; and group IV subjects (46) had a normal study. Subjects with a restrictive defect demonstrated minor physiologic abnormalities during exercise. Subjects with an obstructive defect demonstrated abnormalities consistent with their obstructive defect. Subjects in groups III and IV demonstrated an abnormally elevated wasted ventilation fraction, which may be an early indicator of interstitial disease due to asbestos exposure. We believe exercise testing was a useful tool in excluding the presence of significant functional exercise limitation due to asbestos exposure in the majority of subjects and also in disclosing some physiologic abnormalities in some of the subjects in our study.

Adult↗
PubMed1982

Abnormal wasted ventilation fraction and normal pulmonary hemodynamics during exercise in patients with exertional dyspnea.

We have previously reported a drop on wasted ventilation fraction (VD/VT) during exercise in patients with pulmonary vaso-occlusive diseases associated with collagen vascular disorders, despite an abnormally high mean pulmonary artery pressure and pulmonary vascular resistance at rest and during exercise. To further evaluate the diagnostic value of VD/VT measurements, we studied 8 subjects with normal spirometry, lung volumes and single-breath diffusing capacity who had previously demonstrated a high VD/VT at rest and during exercise. We found normal pulmonary hemodynamics in these subjects despite an abnormal rest and exercise VD/VT. Our findings effectively exclude hemodynamically significant pulmonary vascular obstruction, and do not support the use of VD/VT as a screening method for detecting diffuse pulmonary vaso-occlusive diseases.

Aged↗
PubMed1979

Effect of donor bronchial length on healing: a canine model to evaluate bronchial anastomotic problems in lung transplantation.

Bronchial anastomotic complications in lung transplantation in man remain a major cause of failure. To study this problem in a canine model, we varied the length of the distal bronchial component in three groups of dogs that underwent hilar stripping, bronchial transection, and reanastomosis, The distal bronchial component was thus analogous to the donor in a transplanted lung. Anastomoses were performed, respectively, at the level of the main carina (long single anastomosis), at the midpoint between the main carina and the bifurcation of the left main-stem bronchus (short single anastomosis), and just distal to the bifurcation of the left main-stem bronchus (lobar anastomosis). Bronchial anastomotic damage and necrosis were evaluated by periodic examination with a fiberoptic bronchoscope and by gross and microscopic examination at sacrifice on the seventh postoperative day. The long single anastomoses demonstrated the most necrosis, and the labor anastomoses showed the least. The short single anastomoses showed an intermediate degree of damage. These findings support the hypothesis that shortening the distal or donor bronchial component reduces anastomotic damage, probably because of better pulmonary-to-bronchial collateral blood supply. This study provides a canine model by which to examine bronchial anastomotic complicatons and demonstrates the feasibility of performing labor anastomoses as a means for decreasing bronchial anastomotic problems in lung transplantation.

Animals↗