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Biomedical subjects

K M Moser

Publications and source records attributed to K M Moser.

At least 127 records · Page 7Linked to original sources
PubMed1983

Patterns of pulmonary perfusion scans in normal subjects. III. The prevalence of abnormal scans in nonsmokers 30 to 49 years of age.

The prevalence of abnormal pulmonary perfusion (Q) scans in persons without cardiopulmonary disease has not been well defined; this prevalence could impact on the current diagnostic approach to those in whom pulmonary embolic disease is suspected. In prior studies, we found that Q scan defects, particularly lobar or segmental defects, are rarely present in normal young smokers and nonsmokers. To determine if normal nonsmokers of an older age group have a higher prevalence of Q defects, we performed 6-view Q scans in 40 subjects 32 to 49 yr of age who had no known cardiopulmonary disease. Each subject had undergone a history, physical examination, electrocardiogram, spirometry, and posteroanterior chest roentgenogram prior to scanning. All Q scans were interpreted blindly and independently by 2 experienced readers. No subject demonstrated a lobar or segmental defect on 2 views. One subject with scoliosis had a subsegmental defect corresponding to a prominent aortic arch on the chest roentgenogram. We conclude that abnormal Q scans are extremely uncommon among normal nonsmokers 30 to 49 yr of age.

Adult↗
PubMed1983

Computer-assisted versus visual lung gallium-67 index in normal subjects and in patients with interstitial lung disorders.

The pulmonary uptake of 87Ga citrate has been proposed as an index that assists clinical decision-making in patients with certain interstitial lung diseases. Such use, however, requires definition of the range of normal values, the range of values in patients with various interstitial diseases, and interobserver and intraobserver variability. We studied 9 normal subjects and 15 patients with interstitial lung diseases. The 87Ga indexes were determined by visual analysis and by a computer-assisted method. We found that the variation among experienced observers in visual index values was substantial in both normal subjects and patients, and that the computer-assisted indexes were less variable. These data suggest that if this approach is to be used in clinical decision-making: (1) the variability of visual indexes, and of normal values, should be recognized; (2) consideration should be given to a less subjective, computer-assisted method of index calculation; (3) each institution should establish standardized methodology and consider determination of its range of variability and normal index values.

Adult↗
PubMed1983

Perfusion lung scans vs pulmonary angiography in evaluation of suspected primary pulmonary hypertension.

A retrospective review of 15 patients with angiographically- or biopsy-documented primary pulmonary hypertension was performed to assess the value of pulmonary perfusion scanning in noninvasively differentiating these patients from those with potentially operable, chronic (large-vessel) thromboembolic pulmonary hypertension. None of the 15 patients with primary pulmonary hypertension demonstrated a segmental or larger perfusion defect whereas such defects have been uniformly present in previous reports of patients with large-vessel thromboembolic pulmonary hypertension. While perfusion scans in primary pulmonary hypertension may show certain abnormalities, the presence of segmental or larger perfusion defects should suggest the diagnosis of potentially correctable, large-vessel thromboembolic pulmonary hypertension rather than small-vessel, obliterative (primary, idiopathic) pulmonary hypertension.

Adolescent↗
PubMed1983

Use of the balloon-tipped pulmonary artery catheter in pulmonary disease.

Use of the balloon-tipped (Swan-Ganz) pulmonary artery catheter has increased in recent years. The device has three fundamental applications: pressure measurement, flow measurement, and blood sampling. Like any invasive procedure, this catheter should be used only after careful assessment of factors that affect its risk/benefit ratio. There must be a well-defined indication for the procedure. Physicians must be aware of the factors that can influence the validity of the measurements. Familiarity with the technical details of the procedure and with potential complications and how to avoid or manage them is essential to minimize risks and increase the likelihood of obtaining useful information.

Arrhythmias, Cardiac↗
PubMed1983

Chronic thrombotic obstruction of major pulmonary arteries. Results of thromboendarterectomy in 15 patients.

Since 1969, 15 patients, ranging in age from 21 to 67 years, with pulmonary hypertension associated with chronic thrombotic obstruction of major pulmonary arteries have had pulmonary thromboendarterectomy. Symptoms compatible with embolism antedated surgery for periods of 8 months to 18 years; several alternative diagnoses were maintained for months to years. Only 2 of 15 were treated for the initial embolic episode. All patients had dyspnea on exertion and were in New York Heart Association class III-IV before surgery. Resting arterial hypoxemia was common. Resting preoperative mean pulmonary artery pressures ranged from 25 to 66 mm Hg; pulmonary vascular resistances, 420 to 1869 dynes/sec X cm-5. Partial or complete thromboendarterectomy was possible in patients using cardiopulmonary bypass with hypothermia and cardioplegia. All patients showed a fall in pulmonary vascular resistance. All developed some degree of "reperfusion" lung edema and arterial hypoxemia that lasted for a few days to several months. Two patients died during hospitalization. The 13 survivors have been followed for 8 to 144 months (mean, 38.3 months). All patients improved after surgery. One patient died of nonembolic causes; none had recurrent embolism.

Adult↗
PubMed1983

Thromboembolic disease in the patient undergoing urologic surgery.

There is no question that a substantial risk of venous thrombosis, pulmonary embolism, and lethal pulmonary embolism exist among patients undergoing urologic surgery. Available prophylactic strategies should sharply reduce this risk. Acceptable treatment options exist for patients who develop thromboembolism despite, or in the absence of, prophylaxis. Accurate diagnosis, however, is essential in order to select the most appropriate option. Finally, it should be noted that in making judgments, the comments provided can offer only general guidelines for patients undergoing urologic surgery. Individual patients may have a particular constellation of circumstances that dictates a rational deviation in decision-making from these general guidelines. However, one pivotal decision from which there should be not deviation without extraordinarily special justification is that some form of prophylaxis for deep venous thrombosis should be offered to all patients undergoing major urologic surgical procedures.

Aminocaproic Acid↗
PubMed1983

Dissociation between hemodynamic and platelet antiaggregant effects of prostacyclin in dogs determined with a rapid platelet isolation technique.

Prostacyclin, a potent vasodilator and inhibitor of platelet aggregation, is being increasingly used in disease states in which platelets may play a pathophysiologic role. A literature review revealed a variable dissociation between the in vitro platelet antiaggregant activity of prostacyclin and both the in vivo hemodynamic and platelet antiaggregant activities. Because widely variable platelet isolation techniques may have contributed to this variability, we investigated the hemodynamic and platelet antiaggregant effects of prostacyclin infusion in the dog, using in vitro techniques limiting the time from blood sampling to aggregometry to 2 1/2 and 10 1/2 min. Using the short technique, we demonstrate complete inhibition of platelet aggregation at a prostacyclin infusion rate that caused only a mild decrease in arterial pressure. In contrast, the longer technique requires an eightfold higher prostacyclin infusion rate to achieve the same degree of antiaggregant activity. The prostacyclin activity apparent half-life was 3 min. Because interspecies differences exist in both the hemodynamic and antiaggregant effects of prostacyclin and in their relationship to each other, we suggest that a closer approximation of in vivo antiaggregant effects may be obtained with in vitro methods that are rapid, thus taking into account the lability of prostacyclin. We conclude that the variable in vitro platelet antiaggregant effects of prostacyclin reported in the literature are due to the variable and longer techniques.

Animals↗
PubMed1982

Coagulative interventions during angiography.

Incident to his routine diagnostic and interventional activities, the angiographer is becoming increasingly involved in the manipulation of blood clotting factors. Since the field of hemostasis generally extends beyond the sphere of conventional angiographic training, an analysis of selected angiographic aspects was undertaken. This paper reviews and summarizes the fundamentals of coagulation, and appropriate methods for manipulating coagulation during angiography, particularly via heparin and protamine sulfate. Basic aspects of platelet activity, and modifications produced by aspirin and dipyridamole, have been emphasized. Finally, the nature of the fibrinolytic system, and the current role of systemic and selective fibrinolytic therapy have been depicted.

Angiography↗
PubMed1982

Right and left ventricular response to subcutaneous terbutaline in patients with chronic obstructive pulmonary disease: radionuclide angiographic assessment of cardiac size and function.

To assess the response of the right and left ventricles to the subcutaneous administration of terbutaline sulfate, a beta-2 selective agonist, we evaluated 14 patients with chronic obstructive pulmonary disease (COPD) with equilibrium radionuclide angiography (RNA). Prior to injection, eight patients (57%) had an abnormal right ventricular ejection fraction (RVEF), four (29%) had a low left ventricular ejection fraction (LVEF), and three (21%) had low ejection fractions of both ventricles. After terbutaline injection, RVEF increased in 13 of 14 patients (93%) by 17 +/- 8% (p less than 0.001) while LVEF increased in all patients by 15 +/- 7% (p less than 0.001). Both left and right ventricular end-diastolic volumes decreased (p less than 0.01), while stroke volume was unchanged. Cardiac output rose by 0.8 +/- 1.3 L/min (p less than 0.05), primarily due to the increase in heart rate (10 bpm, p less than 0.001), since stroke volume did not significantly change. We conclude that in patients with COPD subcutaneous terbutaline has significant beta-1 cardiac effects; it increases the heart rate and decreases cardiac size.

Aged↗
PubMed1982

Indium-111-labeled platelets: effects of heparin on uptake by venous thrombi and relationship to the activated partial thromboplastin time.

The goal of heparin therapy in deep vein thrombosis is to prevent thrombus extension. The relationship between thrombus extension and the results of coagulation tests used to monitor heparin therapy is unclear. To explore this relationship, we studied the effect of several heparin regimens on the accretion of indium-111-labeled platelets on fresh venous thrombi, as detected by gamma imaging, and monitored the activated partial thromboplastin time (APTT). Six dogs were treated with a 300-U/kg bolus of heparin followed by a 90-U/kg/hour heparin infusion, a dose of heparin sufficient to increase the APTT to levels greater than eight times baseline (APTT ratio); platelet accretion (thrombus imaging) occurred only after the heparin effect was reversed with protamine sulfate. Nineteen dogs were treated with a 150-U/kg bolus of heparin followed by a 4-hour, 45-U/kg/hour heparin infusion; a thrombus was demonstrated only after protamine injection in 12 (mean APTT ratio 1.3 +/- 0.19) and before protamine injection in seven. In thirteen of these 19 dogs, 30 minutes separated the platelet injection from heparin therapy, while in six this duration was less than 30 minutes. In four of these six dogs, thrombi were demonstrated before protamine therapy and at APTT ratios greater than 3.0. Finally, 10 dogs were treated with a 100-U/kg bolus followed by a 3-hour, 50-U/kg/hour heparin infusion, after which the APTT was allowed to return to baseline values spontaneously. In all 10 dogs, a thrombus was demonstrated only after cessation of the heparin infusion, and at a mean APTT ratio of 1.4 +/- 0.15 times baseline. These results suggest that, except with very early platelet injection, platelet accretion by thrombi is consistently inhibited by heparin at APTT ratios greater than 2.5. Platelet accretion by venous thrombi occurs within narrow limits of heparin effect as reflected by the APTT.

Animals↗
PubMed1982

Sensitivity, specificity, and risk of diagnostic procedures in a canine model of Streptococcus pneumoniae pneumonia.

A canine model in which unilateral Streptococcus pneumoniae pneumonia was induced was used to evaluate the sensitivity, specificity, and risk of various technics proposed for the diagnosis of pulmonary infection. Control and infected animals were studied during spontaneous and mechanical ventilation. We found that three procedures provided a reasonable degree of combined specificity and sensitivity: transthoracic needle aspiration (TTN), catheter-brush biopsy (CBB), and transbronchial biopsy (TBB). Transtracheal aspiration, although sensitive, was consistently low in specificity, whereas TTN provided the highest sensitivity/specificity. Both CBB and TBB provided almost the same results in intubated animals, but specificity was lower in nonintubated animals. Gram-stained smears obtained by TTN, CBB, and TBB were highly specific, but often negative. The only risk encountered was pneumothorax. The TTN was associated with a 20 to 30% risk of pneumothorax; CBB and TBB did not appear to induce pneumothorax. These studies provide the first animal data regarding the comparative yield/risk of these diagnostic approaches. As such, they may prove useful in the design of future human investigations.

Animals↗