T Ohta

Shimane University, Matsu, Shimane Prefecture, Japan

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Publications (4)11.13 Total impact

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    ABSTRACT: A 62-year-old man with liver cirrhosis and hypoxemia was admitted to evaluate the etiology of hypoxemia. The patient had noticed exertional dyspnea for three years. Physical examination, laboratory tests, ultrasonography and liver scintigraphy revealed liver cirrhosis. The arterial blood gas test showed hypoxemia (PO2 46.3 mmHg). Chest roentgenogram showed old pulmonary tuberculosis and the pulmonary function test demonstrated decreased FEV 1.0% and %DLco, which did not account for the marked hypoxemia. Contrast echocardiography was performed by injecting hand-agitated saline into the antecubital vein. Three seconds after the right ventricle was opacified, the contrast echoes appeared in the left atrium and then the left ventricle. Pulmonary arteriography revealed no pulmonary arteriovenous fistula. Hemodynamic data showed low pulmonary vascular resistance. Contrast echocardiography by injecting hand-agitated saline from the catheter tip was performed at both pulmonary arteries and the left atrium was opacified by each injection. The hypoxemia was mainly attributed to a intrapulmonary arteriovenous shunt. Although the etiology of hypoxemia in liver cirrhosis seems to be multifactorial, the intrapulmonary arteriovenous shunt is the most important factor. Contrast echocardiography was useful for detecting this shunt.
    No preview · Article · Jan 1994 · Journal of Cardiology
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    ABSTRACT: A case of cardiac tamponade showing the characteristic flow pattern in the superior vena cava is reported. An 80-year-old man was admitted to our hospital complaining of anorexia and general fatigue. We observed a paradoxical pulse of 25 mmHg, dilatation of the jugular vein, and marked cardiomegaly on chest radiography. A two-dimensional echocardiogram demonstrated a massive pericardial effusion and collapse of the right atrial and right ventricular walls. On the basis of his echocardiograms and clinical signs, we diagnosed his condition as cardiac tamponade. Pulsed Doppler echocardiograms showed two-peaked flow in the superior vena cava in systole. To assess the diagnostic significance of this characteristic flow pattern, the superior vena cava flow was recorded simultaneously with the intrapericardial pressure and the right atrial pressure. The intrapericardial pressure was higher than the right atrial pressure in early systole. After pericardial drainage, these pressures became reversed and the two-peaked flow disappeared. The two-peaked flow is attributed to collapse of the right atrial wall caused by the higher intrapericardial pressure than the right atrial pressure. The superior vena cava flow represents the right heart filling dynamics in cardiac tamponade.
    No preview · Article · Feb 1993 · Journal of Cardiology
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    ABSTRACT: Pulsed Doppler echocardiography was used for investigation of respiratory changes of superior vena caval flow in chronic pulmonary disease to analyze the mode of venous return and its regulating factors. The subjects consisted of 55 patients with various pulmonary diseases and 44 healthy controls. 1. In the controls, the velocities of the S and D waves increased during the inspiratory phase. 2. Patients with pulmonary diseases were categorized into 2 groups. One with the mode of the healthy subjects (normal pattern), and the other with disappearance of the D wave or both the S and D waves (abnormal pattern) in the expiratory phase. All patients with restricted ventilation exhibited the normal patterns, while the abnormal patterns were observed in some of the patients with obstructive ventilation, and most of the patients with combined ventilation. 3. The respiratory patterns of the pressure gradients between the right atrium and subclavian vein reflected patterns of the superior vena caval flow well. In cases with abnormal patterns, the right atrial pressure exceeded the subclavian vein pressure in the expiratory phase. 4. The velocity of the A wave at the expiratory phase correlated significantly with pulmonary vascular resistance and with the mean pulmonary artery pressure. In conclusion, the mode of venous return in patients with pulmonary disease varies depending on the mode of the ventilation disturbance and the presence of right ventricular pressure overload, which is most likely caused by the intrathoracic pressure and by right ventricular filling abnormalities.
    No preview · Article · Feb 1991 · Journal of Cardiology
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    ABSTRACT: Characteristics of venous return and its determining factors were observed using pulsed Doppler echocardiography. Superior vena caval (SVC) flow was regarded as representing venous return. Ten healthy subjects and 23 patients with chronic pulmonary disease were studied. 1. In the healthy subjects, the forward flow was biphasic with dominant systolic (S) wave. Among 23 patients, 18 had normal SVC flow patterns (Group I), while in the remaining 5, SVC flow showed disappearance of the diastolic (D) wave, or both the D and S waves (Group II). 2. The healthy subjects and Group I patients had negative pleural pressures during inspiration and expiration. Consistent findings in Group II patients included positive pleural pressures during expiration and reduction in FEV1.0%. In the normal subjects and Group I patients, right atrial (RA) pressure was less than the pressure of the subclavian vein (ScV) during an entire respiratory phase. However, in Group II, RA pressure was equal to or greater than ScV pressure during expiration, resulting in disappearance or reversal of the S and D waves. 3. Respiratory variation in pleural pressure correlated significantly with that of the S wave (r = 0.77) (p < 0.005), D wave (r = 0.80) (p < 0.005), x descent of RA pressure (r = 0.77) (p < 0.005), and y descent of RA pressure (r = 0.82) (p < 0.005). The present study clearly confirmed that the superior vena caval flow patterns were closely correlated with right heart hemodynamics and truly reflected the effects of pleural pressure.
    No preview · Article · Jan 1991 · Journal of Cardiology

Publication Stats

2 Citations
11.13 Total Impact Points

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  • 1991
    • Shimane University
      • Department of Internal Medicine
      Matsu, Shimane Prefecture, Japan