Theodore Rodman

Emergency room assessment and treatment of patients with acute asthma: Adequacy of the conventional approach

Abstract The adequacy of emergency room treatment of patients with acute severe asthma was assessed by analyzing the course of 127 visits to the emergency room by 102 patients. Using conventional clinical criteria as an end point (i.e., disappearance of dyspnea, elimination of labored breathing and reduction or elimination of wheezing) in 85.4 per cent of these episodes the patients responded sufficiently to emergency room treatment to allow their discharge. However, the relief of airway obstruction measured directly (1 second forced expiratory volume, FEV 1 ) was modest (mean FEV 1 on discharge was 57 per cent of the predicted normal value). Approximately one-quarter of those episodes that ended in the patients discharge from the emergency room were followed by equally severe episodes within 10 days (relapse); 6 per cent of the patients initially discharged who returned to the emergency room required hospitalization. Subjects who had a relapse had significantly less improvement in FEV 1 during treatment and lower FEV 1 values at discharge than those who did not have a relapse (p 2 ] or oxygen [PaO 2 ] tension) was sufficiently reliable as an index of the degree of obstruction to substitute for the FEV 1 . We conclude that (1) the success of emergency room treatment depends on the degree of improvement in pulmonary function achieved; and (2) objective measures (e.g., FEV 1 ) of the degree of airway obstruction are helpful in predicting the outcome of emergency room treatment of patients with acute asthma.

THE OXYHEMOGLOBIN DISSOCIATION CURVE IN ANEMIA

Excerpt The primary function of hemoglobin is the transport of oxygen from the lungs to the tissues. Anemia compromises this transport mechanism and exposes the tissues to the dangers of hypoxia. T...

Alveolar hypoventilation due to involvement of the respiratory center by obscure disease of the central nervous system

Abstract In four patients with alveolar hypoventilation secondary to dysfunction of the respiratory center, the clinical picture resembled, respectively, congenital heart disease, primary polycythemia, arteriosclerotic heart disease and narcolepsy. The diagnosis of primary alveolar hypoventilation should be suspected in a polycythemic or cyanotic patient if central nervous system symptoms such as somnolence, headache and easy fatigability are prominent, or if electrocardiographic and roentgenologic evidence of right ventricular enlargement or strain are present in the absence of dsypnea. The diagnosis can be established by demonstrating the arterial blood gas changes to alveolar hypoventilation (elevated carbon dioxide, reduced oxygen saturation, normal or low pH) in the absence of lung disease, extreme obesity or disease of the neuromuscular apparatus of respiration. It is suggested that the syndrome may occur as a complication of many neurologic diseases because of the susceptibility of the medullary respiratory center to noxious agents. Other manifestations of the underlying neurologic disease may be slight or absent, and the clinical picture may be dominated by the sequelae of hypoventilation, anoxemia, hypercapnia, polycythemia, right ventricular hypertrophy, strain and failure. Our experience suggests that the primary hypoventilation syndrome is compatible with prolonged life and that therapy should be directed primarily at maintaining normal blood viscosity and cardiac compensation.

Effect on cardiac output of conversion from atrial fibrillation to normal sinus mechanism

Abstract Hemodynamic studies were performed before and after restoration of a normal sinus rhythm in forty-eight patients with chronic atrial fibrillation. Conversion to a sinus mechanism was achieved in twenty-six patients with quinidine and in twenty-two patients with capacitor discharged direct current. In the quinidine-treated group, who were restudied five to ten days after conversion, the mean cardiac index had risen 22 per cent from 2.40 to 2.93 L., the circulation time had decreased from a mean of 17 to 12 seconds, the mean stroke volume had increased 44 per cent from 55 to 79 ml. and the mean arteriovenous oxygen difference had dropped from 5.4 to 4.3 cc. per 100 ml. In the electrically treated group, who were studied serially for 3 hours after conversion, there was a gradual 12 per cent rise in cardiac index from a preconversion mean of 2.36 to 2.65 L. 180 minutes later, accompanied by commensurate improvement in the other hemodynamic parameters. Our data confirm the experimental studies reported in lower animals and man which indicate that a normally positioned atrial systole contributes importantly to ventricular function since restoration of a normal sinus mechanism in patients with chronic atrial fibrillation is followed by a significant increase in cardiac output. The full hemodynamic benefit, however, may not be evident for several hours or days after the return of normal electrical atrial activity.

The oxyhemoglobin dissociation curve in the common hemoglobinopathies

Abstract The in vivo oxyhemoglobin dissociation curve has been studied in twelve patients whose hemoglobin was entirely or partially abnormal. Five had no normal hemoglobin. Three of these five had pure S hemoglobin and sickle cell anemia; two had hemoglobin C-S disease. Of the other 7 patients, 3 had A-S hemoglobin, three A-C hemoglobin and one S-A hemoglobin and thalassemia. Arterial oxygen unsaturation was present in the five patients who had no normal hemoglobin and the oxyhemoglobin dissociation curve was displaced to the right. The degree of displacement was sufficient to explain the observed arterial oxygen unsaturation. The oxyhemoglobin dissociation curve was normal in patients with A-C and A-S hemoglobin and in the one patient with S-A hemoglobin and thalassemia. It is suggested that displacement of the dissociation curve may be related to reduction of the intracellular pH of the red cell. The clinical implications are briefly discussed. A moderate shift of the curve is beneficial in anemia if cardiopulmonary function is normal. A marked shift, however, or even a moderate shift in the presence of significant cardiopulmonary dysfunction, will aggravate the tissue anoxia of the anemic state.

Medical Aspects of Open-Heart Surgery

IN the ten years since a pump oxygenator was first successfully used during cardiac surgery on a human patient1 the risk involved has been reduced enormously, but complications, many of them life t...

The hemodynamic effects of digitalis in the normal and diseased heart

Abstract Concepts of the hemodynamic action of digitalis have changed greatly during the past 50 years, and recent developments suggest that we may reasonably anticipate further evolution of these ideas. Present experimental and clinical observations can best be reconciled with the hypothesis that digitalis exerts a positive inotropic effect on all types of muscle, smooth and voluntary as well as cardiac. Indirect cardiac effects result from its action on arterial smooth muscle and on venous smooth muscle, primarily of the hepatic veins, by altering blood pressure and cardiac inflow. The direct cardiac action results in increased force of systolic contraction, with a resultant increase in cardiac output. These effects appear to be the same in normal or diseased hearts, although their external effects in terms of cardiac output may differ. The prevalent idea that digitalis is detrimental to the nonfailing heart is not compatible with our present knowledge of its pharmacologic properties. In addition to its therapeutic use in cardiac failure of any etiology, it can, therefore, also be used “prophylactically” in patients about to undergo stress, such as surgery or delivery, if there is any reason to suspect impaired myocardial reserve. It also plays an important role in the prevention and treatment of arrhythmias by virtue of its salutary effect on the functioning of cardiac muscle.

A comparison of laboratory methods for the control of anticoagulant therapy with prothrombinopenic agents: I. The Quick one-stage procedure, the prothrombin and proconvertin test and the one-stage determination of true prothrombin activity

Abstract Several newer, more complex tests of the clotting mechanism have been suggested to replace the relatively simple Quick one-stage test for prothrombin complex activity. In a controlled study of the P and P test, the one-stage determination of true prothrombin activity and the Quick one-stage test using two commercially available tissue thromboplastins, neither of the more complex procedures was shown to be superior to the Quick procedure. Because of the intermediate sensitivity of the Quick test, patients whose prothrombin complex activity values were controlled with it most often had values in the therapeutic range of the other two tests as well. The Quick one-stage procedure, properly performed, appears to be a satisfactory method for the control of anticoagulant therapy in the light of our incomplete knowledge of anticoagulant mechanisms.

II. Problems encountered in the laboratory control of anticoagulant therapy with the one-stage determination of prothrombin complex activity

Abstract An evaluation of the Quick one-stage determination of prothrombin complex activity was undertaken to determine why it has not been entirely satisfactory in clinical practice, and whether its deficiencies can be corrected. Our results indicate that the test is relatively simple, accurate and, except for prolonged exposure of plasma and reagents to water bath temperatures, not seriously affected by common variations in technic. The chief source of error in clinical laboratories appears to be the use of incorrect dilution curves for conversion of plasma clotting time to per cent of normal plasma activity. This difficulty is compounded by the controversy regarding the proper choice of a diluent in making these curves. Until laboratory personnel agree to use the same highly standardized thromboplastin preparation for the test and the same diluent in constructing dilution curves, conversion to per cent of normal plasma activity will not provide a satisfactory basis for comparison of results from different laboratories, and the results are better expressed in seconds. With attention to standardization of technic the one-stage determination of prothrombin, complex activity is a satisfactory method for the control of anticoagulant therapy with coumarin-like agents.

A comparative study of four prothrombinopenic anticoagulant drugs: II. Clinical study

Abstract Four prothrombinopenic anticoagulants were compared under controlled conditions in 287 patients over a LAperiod of fourteen months. Somewhat better control was achieved with bishydroxycoumarin and diphenadione than with phenindione and warfarin. The differences were statistically significant but not great. Satisfactory control was achieved in the majority of patients with all four drugs. There was relatively wide variation in dosage requirements in the same patient from day to day and among patients receiving the same preparation. This variation was less with bishydroxycoumarin and diphenadione than with phenindione and warfarin, but the differences were not sufficient to be clinically useful. An induction schedule which consisted of a large single loading dose followed by a small maintenance dose was found to be desirable and safe. Using such a program the prothrombin activity in the majority of patients (82 per cent) was brought into the therapeutic range within forty hours of the initial dose with all four drugs. This program also facilitated the early establishment of a stable maintenance dose.