摘要:

The hazards of hydrogen as used for the detection of shunts has been studied under clinical conditions with the Standard Mine Safety Appliance Explosimeter and under additional simulated circumstances far more extreme than would ever be encountered in a catheterization laboratory. Because of the lightness of the gas and its ready diffusibility, explosive concentrations were transiently identified in small zones that were grossly different from those reportedly associated with “heavier than air” explosive gases. With its use in single inhalations for the identification of an intracardiac shunt and with allowances for a liberal safety factor, no explosive risk exists outside a conical envelope, which may be considered to extend 3 feet above, 6 inches below, and 12 inches laterally in all directions from the patient's mouth. Ordinary electronic apparatus, motor-driven syringes, and x-ray equipment, provided they are commonly grounded and outside this zone, require no explosive safety precautions in their use when hydrogen is used in this manner for shunt detection. Room ventilation is desirable for personal comfort but should not be considered a safety requirement. Release of large quantities of hydrogen has shown that there is no reason to specify a time interval between inhalations for the dispersion of hydrogen.These conclusions are not intended to bemean those measures that are routinely followed to avoid the generation of static electricity.16But were a spark generated, it would be of no significance unless it occurred in the restricted zone described.

ISSN:0009-7322    

出版商:OVID    

年代:1965

数据来源: OVID

摘要:

Cardiac output was determined by the indicator-dilution technic with injection of indicator into the ascending aorta, left ventricle, and pulmonary artery in 13 cases of mitral incompetence and in 15 control cases (normal or mild valvular obstruction). The ascending aortic dye curve is not involved in mitral incompetence in its primary circulation and was used for comparison.In normal subjects, there is no significant difference between the cardiac output obtained by injection of indicator into the ascending aorta and the left ventricle.The cardiac output obtained from indicator-dilution curves affected by mitral regurgitation in its primary circulation is underestimated by approximately 20 per cent.The effects of the coronary recirculated indicator particles on the disappearance slope would best explain the discrepancy. Even in the normal circulation, the inclusion of the coronary recirculated particles leads to a small underestimation of the cardiac output when the indicator is injected into the pulmonary artery.

ISSN:0009-7322    

出版商:OVID    

年代:1965

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1965

数据来源: OVID

摘要:

The hemodynamic changes resulting from injection of radiopaque material into the left heart in a series of patients undergong cineangiographic studies have been reported. The hypertonicity of radiopaque materials appears to be responsible for much of the observed reaction. The mechanism whereby hypertonic solutions produce the observed physiologic changes remains unknown.Changes observed in patients could be reproduced in experimental animals. The combined experimental and clinical data show that left atrial pressure increases, left atrial pulse contour alters, stroke output increases, heart rate is much unchanged, peripheral artery pressure falls, hematocrit level falls, and myocardial contractile force decreases mildly and transiently.The difference between the physiologic effects of injecting hypertonic media into the right and left sides of the circulation is discussed.Because the pressure changes are easy to monitor and parallel the other features of the hemodynamic reaction, it is good to wait until pressures have returned to the pre-angiographic level before proceeding with the injection of more radiopaque material. This usually requires 15 minutes.

ISSN:0009-7322    

出版商:OVID    

年代:1965

数据来源: OVID

摘要:

Circulatory observations have been made on six normal subjects and six hypertensive patients before and after the acute intravenous injection of 5 mg. of phentolamine.The drug caused a prompt reduction in systemic vascular resistance which resulted in a rapid fall in systemic blood pressure in spite of an increase in heart rate and cardiac output.Evidence is presented that the predominant vascular activity of the drug is to cause a direct relaxation of vascular smooth muscle, an effect far more potent than its antagonism of circulating catecholamines or its very much weaker sympathetic-blocking action. This direct depressor effect on vascular smooth muscle unaccompanied by any but slight sympathetic blocking activities endows the drug with theoretically ideal antihypertensive properties.Phentolamine caused a transient but significant reduction in oxygen uptake in the majority of individuals. It is suggested that this may be due to a direct inhibition of cellular oxidative mechanisms.An appraisal of the circulatory activities of the drug with particular regard to its use as a diagnostic test for pheochromocytoma leads to serious doubts, not only with regard to the precision with which the results of such tests can be interpreted, but also to the validity of the use of the drug as a reliable screening test for excessive circulating catecholamines.

ISSN:0009-7322    

出版商:OVID    

年代:1965

数据来源: OVID

摘要:

A patient is described in whomSalmonella schwarzengrundbacteremia was associated with infection of the aorta in the area at which a Hufnagel valve had been implanted 4 years earlier. Despite prolonged and repeated therapy with antimicrobial agents to which the organism was sensitive, an abscess developed in the aortic wall and led to a dissecting aneurysm and death.The role of the Hufnagel valve in altering the anatomy and hemodynamics in the lower aorta and predisposing to local and persistent infection is discussed. It is suggested, on the basis of the course of this patient's illness, that the appearance of bacteremia is especially ominous when such a prosthesis is present, and that antimicrobial therapy should be initiated as early as possible, that the doses used be large, and that the treatment be prolonged, without interruption. If manifestations consistent with aortic tear appear, despite apparent control of the infection, the presence of an abscess in the aortic wall must be suspected and the possibility of removal of the prosthesis and excision of the infected area be given serious consideration.

ISSN:0009-7322    

出版商:OVID    

年代:1965

数据来源: OVID

摘要:

In an infant with severe, multiple, peripheral pulmonary artery stenoses angiography clearly demonstrated enlarged tortuous bronchial arteries, especially in the right lung, where a major tortuosity corresponded closely to the point of maximal intensity of a loud continuous murmur. Increased bronchial circulation may be responsible for continuous murmurs in patients with severe multiple peripheral pulmonary artery stenosis.

ISSN:0009-7322    

出版商:OVID    

年代:1965

数据来源: OVID

摘要:

A case of massive pulmonary arteriovenous fistula, diagnosed and treated in the first week of life is reported. A concept of severely altered intrauterine and neonatal pulmonary blood flow is proposed, with consequent left ventricular overload manifested electrocardiographically by left axis deviation and left ventricular preponderance. Consideration of this malformation in seriously ill cyanotic infantswith a radiographic density and these electrocardiographic changes is essential, since this is a surgically curable lesion.

ISSN:0009-7322    

出版商:OVID    

年代:1965

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1965

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1965

数据来源: OVID