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Biomedical subjects

L Sasson

Publications and source records attributed to L Sasson.

9 recordsLinked to original sources
PubMed2006

Impedance cardiography revisited.

UNLABELLED: Previously reported comparisons between cardiac output (CO) results in patients with cardiac conditions measured by thoracic impedance cardiography (TIC) versus thermodilution (TD) reveal upper and lower limits of agreement with two standard deviations (2SD) of approximately +/-2.2 l min(-1), a 44% disparity between the two technologies. We show here that if the electrodes are placed on one wrist and on a contralateral ankle instead of on the chest, a configuration designated as regional impedance cardiography (RIC), the 2SD limit of agreement between RIC and TD is +/-1.0 l min(-1), approximately 20% disparity between the two methods. To compare the performances of the TIC and RIC algorithms, the raw data of peripheral impedance changes yielded by RIC in 43 cardiac patients were used here for software processing and calculating the CO with the TIC algorithm. The 2SD between the TIC and TD was +/-1.7 l min(-1), and after annexing the correcting factors of the RIC formula to the TIC formula, the disparity between TIC and TD further declined to +/-1.25 l min(-1). CONCLUSIONS: (1) in cardiac conditions, the RIC technology is twice as accurate as TIC; (2) the advantage of RIC is the use of peripheral rather than thoracic impedance signals, supported by correcting factors.

Algorithms↗
PubMed2000

Effect of ligation of spleen vessels on left ventricular function and coronary blood flow in dogs injected with scorpion venom.

Scorpion sting may cause myocardial dysfunction in human victims, probably by increased O2 demand and decreased O2 supply. In dog, scorpion venom (SV) causes no myocardial dysfunction. Myocardium is probably protected by "autotransfusion" of blood from the spleen to the circulation, increasing coronary blood flow (CBF) and O2 delivery. We hypothesized that ligation of spleen vessels prior to injection of SV in dogs would prevent the autotransfusion of blood, thereby causing myocardial ischemia due to decreased CBF, simulating the hemodynamic pattern of human envenomation. We studied cardiac output (CO), CBF, left ventricular (LV) O2 delivery and contractility in 11 dogs injected with 0.07 mg/kg of SV (Leiurus quinquestriatus). Ligation of spleen vessels was performed on 6 of the 11 dogs prior to SV injection. 15 min after SV injection CO had increased by 186% in control dogs, while ligation of spleen vessels completely prevented CO elevation (p<0.001). In both groups, however, LV dp/dt increased by 400% and dp/dt/p by 170% (p<0.001). CBF increased by 350% and 550% in the spleen and control groups (p<0.001) respectively. This was associated with elevation of diastolic blood pressure and a decrease in coronary vascular resistance. LV O2 delivery increased (p<0.05) in both groups. At 60 minutes there was a decrease in CO, stroke work, and LV end systolic pressure in both groups, while LV contractility remained above baseline. Scorpion venom injection in dogs causes an initial increase in CO by auto-transfusion of blood from the spleen. Prevention of the autotransfusion does not preclude increases in CBF, O2 delivery and LV contractility.

Animals↗
PubMed2000

Computerised coordinated care system in the RISE project.

It is a fact that elderly peoples' life is characterized by problems such as deteriorating health and physical condition, feelings of loneliness, isolation, and of being dependent on others, in many aspects of their everyday lives. The objective of the RISE project is to provide an efficient vehicle for Health Care Professionals for improving Health Care, quality of life and integration of the elderly and disabled people with society by implementing Information technology applications. In particular, RISE project aims in developing a distributed network of service providers across the European Union, which will provide integrated types of services to the elderly and disabled population. The purpose of this paper is to present the impact of this project concerning the Health Informatics sector. It will describe the issues regarding, the needs for education and training of the professionals that arise by the introduction of this concept, and, the possible ways that such a concept forms an efficient vehicle for Health Professionals in assisting these particular groups of users. The longer perspective seeks to redefine and reshape the Health Care services' larger purpose, i.e. to make those comport with elementary individual needs of the elderly and disabled by introducing new methods of efficient health service provision. To achieve this there is an increased need for the training of the professionals. The outcome of RISE will be a set of specialised software components, tools and training methodologies designed to assist the Health Professionals achieving the aforementioned tasks.

Aged↗
PubMed1996

Effect of systemic vasodilators on internal mammary flow during coronary bypass grafting.

BACKGROUND: The effect of vasodilators on acute flow in the internal mammary (IMA) is unclear. Topical vasodilators show no effect on acute flow when the distal segment of the IMA is resected. The purpose of this study was to evaluate the effect of systemic vasodilators when this segment is resected. METHODS: We studied 60 patients with proximal anterior descending coronary artery lesions in whom the left IMA was harvested for grafting to the left anterior descending coronary artery. The patients were divided into six groups (n = 10), based on which of the following agents were studied: normal saline solution, nitroglycerin, nitroprusside, dobutamine, dopexamine, and amrinone. After harvesting, the IMA was trimmed as proximally as possible (and at least 3 cm proximal to the bifurcation), and free flow was measured before any pharmacologic intervention (flow 1). Systemic infusion of one of the six agents commenced. A mean of 17 +/- 3.4 minutes after infusion began, with a comparable cardiac index, a second measurement of IMA flow was taken (flow 2). Hemodynamic measurements for each flow, including blood pressure, heart rate, and cardiac output, were taken. RESULTS: A significant increase in IMA flow was noted for those patients receiving nitroglycerin (93.5 versus 106.8 mL/min; p = 0.025), and a significant decrease in flow was noted for those receiving nitroprusside (91.0 versus 78.2 mL/min; p = 0.042). The effects remained significant when corrected for cardiac index and compared with the normal saline solution group. No other systemic agents tested significantly affected the IMA flow (dobutamine, 83.8 versus 85.0 mL/min; dopexamine, 101.8 versus 91.4 mL/min; amrinone, 75.4 versus 79 mL/min; normal saline solution, 85.8 versus 84.6 mL/min). CONCLUSIONS: Resection of the distal segment of the IMA and the use of intravenous nitroglycerin optimizes the flow in IMA grafts.

Amrinone↗
PubMed1995

Effect of topical vasodilators on internal mammary arteries.

The internal mammary artery (IMA) is the conduit of choice for grafting the left anterior descending artery. However, arterial spasm and reduced early flow has been a cause of postoperative morbidity. The purpose of this study is to evaluate the effect of vasodilators on IMA flow. Fifty patients who had the IMA harvested in preparation for bypass grafting were studied. The IMA was mobilized from the subclavian vein to below the bifurcation of the IMA. The artery was prepared for grafting at least 3 cm proximal to the bifurcation. The IMA was allowed to bleed freely, and flow was determined (flow 1). The patients were divided into five groups: group I (n = 10) had 10 mL of saline solution applied topically to the IMA; group II had topical papaverine (5 mg/10 mL normal saline solution) applied to the IMA; group III had nitroglycerin (5 mg/10 mL normal saline solution) applied to the IMA, group IV had sodium nitroprusside (2.5 mg/10 mL) applied to the pedicle, and group V had 5 mL of papaverine mixed in 5 mL of saline solution injected into the periarterial tissues of the IMA pedicle. Before cardiopulmonary bypass, the flows were remeasured (flow 2). With each measurement, hemodynamic parameters were recorded. The time between measurements was recorded. There was no difference in blood pressure or pulse at the time of measurement.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1991

Effect of dexamethasone on diaphragmatic and soleus muscle morphology and fatigability.

In spite of the extensive use of corticosteroids, its myopathic effect on respiratory muscle is unknown with relation to the dose and duration of therapy. The present study examined the effects of dexamethasone on the morphology and function of respiratory (diaphragm) as compared to skeletal (soleus) muscle. Control rats were compared to those that received low, high and prolonged doses of dexamethasone. Body mass was reduced proportionally to the dose and duration of therapy. Atrophy of the diaphragm was greater than that of the soleus when normalized to body mass. Absolute tension and tension as a function of cross sectional area was significantly (P less than 0.05) less in the diaphragm and soleus at the high and prolonged dosages. Dexamethasone had no effect on fatigability except in the soleus after prolonged treatment. Furthermore, after prolonged therapy, it had converse effects on the Pt and 1/2RT in the diaphragm as compared to the soleus muscle. Dexamethasone improved the recovery times in the diaphragm alone. Our data suggest that dexamethasone weakens the diaphragm and soleus by reducing its mass and apparently also through some effect on the intrinsic contractile apparatus.

Animals↗