Articles: critical-illness.
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Comparative Study
Clinical validation of a radionuclide detector to measure ejection fraction in critically ill patients.
The use of a new non-imaging nuclear probe (Cardioscint) capable of continuous online monitoring of left ventricular function is described in critically ill patients undergoing mechanical ventilation. Ejection fraction, measured by the Cardioscint, was compared with that measured by echocardiography. ⋯ Examples of fluid loading and inotropic support showed comparable changes in stroke counts measured by the Cardioscint and stroke index measured by thermodilution. The Cardioscint is a practical bedside method for continuous or repeated measurement of ejection fraction and for assessing the response to therapeutic interventions in critically ill patients.
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Critical care medicine · May 1994
Ventilatory response to high caloric loads in critically ill patients.
To assess the effect of high caloric loads on CO2 metabolism and ventilation. ⋯ Increased CO2 production, exhaled minute ventilation, and deadspace ventilation values in the overfed group and the lack of difference between alveolar ventilation, PaCO2, and measured energy expenditure, along with correlations between CO2 production and alveolar ventilation suggest that carbohydrate loads increase CO2 production which drives alveolar ventilation, thus preventing hypercapnia. When alveolar ventilation does not increase (and PaCO2 increases) or when the spontaneous breathing rate increases to augment alveolar ventilation, the clinical response of increasing mechanical ventilation may increase deadspace ventilation.
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Nutritional support of the seriously ill patient has evolved with time and reflects new developments in the field of critical care. Current information suggests that optimal nutritional support can be provided by supplying at least 80% of energy requirements with at least 70% of the energy given as carbohydrate and the remaining 30% or less administered as fat (with > or = 3% of energy requirements as essential fatty acids). The caloric load may be reduced to 50% of requirements if growth factors (e.g., growth hormone) are utilized and the patient has adequate fat stores. ⋯ Nutrients should be administered early in the catabolic course, especially glucose, sodium, potassium, vitamins, and minerals. Over time (approximately 7 days) amino acids should be added and approximately 50% of caloric support should be provided. Finally, full nutritional support should be provided (by 7 to 10 days) if the catabolic course is expected to continue.
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Overfeeding occurs when the administration of calories and/or specific substrate exceeds the requirements to maintain metabolic homeostasis. These requirements are substantially altered during periods of injury-induced acute metabolic stress. Excess nutritional delivery during this period can further increase the metabolic demands of acute injury and place an added burden on the lungs and liver. ⋯ In these acutely-stressed infants, measured energy expenditure constitutes the total energy requirement, and caloric delivery in excess of this amount should be avoided until metabolic stress parameters indicate resolution of the acute injury state. Enteral delivery should be used in preference to parenteral feeding. Even if total caloric delivery cannot be achieved enterally, the provision of a small amount of the total energy budget via the enteral route is generally possible and is likely advantageous.(ABSTRACT TRUNCATED AT 250 WORDS)