Advances in Medical Nutrition Therapy: Parenteral Nutrition.

Parenteral nutrition has evolved tremendously, with parenteral formulas now safer and more accessible than ever. "All-in-one" admixtures are now available, which simplify parenteral nutrition usage and decrease line infection rates alongside other methods of infectious control. Recently published data on the benefits of parenteral nutrition versus enteral nutrition together with the widespread use of indirect calorimetry solve many safety issues that have emerged over the years. All these advances, alongside a better understanding of glycemic control and lipid and protein formulation improvements, make parenteral nutrition a safe alternative to enteral nutrition.

Concordancia entre calorimetría indirecta y modelos predictivos en una población sana española / Agreement between indirect calorimetry and predictive equations in a sample of Spanish healthy adults

Objetivo: estudiar la concordancia entre el gasto energético en reposo (GER) obtenido mediante calorimetría indirecta (CI), y las ecuaciones de estimación más utilizadas en población adulta sana española. Métodos: estudio transversal en el que se determinó el GER en 95 sujetos sanos con normopeso mediante calorimetría indirecta y modelos predictivos (se seleccionaron 45 fórmulas desarrolladas en adultos de características similares a la muestra estudiada que incluían peso, talla, sexo y/o composición corporal). La concordancia entre ambos métodos se analizó mediante el Coeficiente de Correlación Intraclase (CCI) y la prueba de Bland-Altman. La significación se alcanzó con p< 0,05. Resultados: la edad media fue de 42 años (rango: 23,0– 63,2). El GER medio estimado por CI en la muestra fue de 1589 (312) kcal/día [1822,3 (224,3) kcal/día en varones y 1379,3 (216,1) kcal/día en mujeres; p< 0,05]. Las fórmulas que mejor se ajustaron a la muestra fueron las de De-Lorenzo, Harris-Benedict, Schofield y, especialmente, Korth. Conclusiones: existen grandes variaciones en la estimación del gasto energético en reposo en función de la ecuación predictiva utilizada. Las fórmulas de De-Lorenzo, Harris-Benedic y Schofield se comportan adecuadamente en la muestra evaluada; sin embargo, la de Korth demostró ser la más apta. Los modelos que incluyen peso y/o talla obtuvieron mejores resultados que los que contienen variables de composición corporal (AU)

Objective: the aim of this study was to analyze the agreement between the resting energy expenditure (REE) obtained by indirect calorimetry (IC) and that obtained by prediction equations in a sample of healthy adults from Spain. Méthods: a descriptive cross-sectional study was conducted in 95 healthy, normal-weight adults. REE was determined by IC and 45 population-specific prediction equations which were based on weight, height, sex and/or body composition (BC). The Intraclass Correlation Coefficient (ICC) and Bland-Alman plots were used to analyze the agreement between the REE obtained by IC and that obtained by prediction equations. The level of signification was reached at p< 0,05. Results: mean age was 42 years (range: 23.0–63.2). Mean REE determined by CI was 1589 (312) kcal/d [1822.3 (224.3) kcal/d in men and 1379.3 (216.1) kcal/d in women; p< 0.05]. The De-Lorenzo, Harris-Benedict, Schofield, and especially the Korth equations showed the greatest level of agreement with respect to IC. Conclusions: there is high variability in the estimates of REE depending on the prediction equation used. The De Lorenzo, Harris-Benedict, and the Schofield equations showed a good level of agreement in our sample; however, the Korth equation was the most appropriate. Equations based on weight and/or height were more accurate than those which included body composition variables (AU)

The power of feeder-mask respirometry as a method for examining hummingbird energetics.

Many birds spend important portions of their time and energy flying. For this reason, quantification of metabolic rates during flight is of crucial importance to understanding avian energy balance. Measurement of organismal gas exchange rates using a mask enclosing the whole head or respiratory orifices has served as an important tool for studying animal energetics because it can free the rest of the body, permitting movement. Application of so-called "mask respirometry" to the study of avian forward flight energetics presents unique challenges because birds must be tethered to gas analysis equipment thus typically necessitating use of a wind tunnel. Resulting potential alterations to a study organism's behaviour, physiology, and aerodynamics have made interpretation of such studies contentious. In contrast, the study of hovering flight energetics in hummingbirds using a specialized form of mask respirometry is comparatively easy and can be done without a wind tunnel. Small size, hovering flight, and a nectarivorous diet are characteristics shared by all hummingbird species that make these birds ideally suited for this approach. Specifically, nectar feeders are modified to function as respirometry masks hummingbirds voluntarily respire into when hover-feeding. Feeder-mask based respirometry has revealed some of the highest vertebrate metabolic rates in hovering hummingbirds. In this review I discuss techniques for the successful measurement of metabolic rate using feeder-mask respirometry. I also emphasize how this technique has been used to address fundamental questions regarding avian flight energetics such as capacities for fuel use and mechanisms by which ecology, behaviour and energy balance are linked.

Novel portable device measures preoperative patient metabolic gas exchange.

BACKGROUND: Indirect calorimetry (IC), the measurement of airway CO2 elimination (VCO2), O2 [corrected] uptake (VO2) [corrected], and respiratory exchange ratio (RER = VCO2/VO2), is a noninvasive modality for the assessment of body metabolism. In anesthesia, IC can signal critical events and onset of acute metabolic derangements. We have previously demonstrated the accuracy and precision of a new IC measurement system designed for mechanically ventilated patients, comprised of a new clinical bymixer, fast response humidity and temperature sensor, and a flowmeter. However, measurement of IC during spontaneous breathing is challenging because of unstable tidal volume, frequency, and functional residual capacity (FRC). METHODS: A new device for IC measurements, designed specifically for spontaneous breathing, was validated against a metabolic lung simulator bench setup. In a second study, the same device was used to conduct preoperative measurements of VCO2 and VO2 in 15 patients. RESULTS: Our measurements showed excellent correlation and agreement with metabolic lung simulator values: The average (+/-SD) percent error for airway VCO2 was -4.7% +/- 3.31%; the average (+/-SD) percent error for airway VO2 was -0.30% +/- 5.25%. Average values of VCO2 and VO2 in the patient study (3.01 +/- 0.56 and 3.44 +/- 0.69 mL x kg(-1) x min(-1), respectively) were in agreement with previously reported values. CONCLUSION: We have shown that the new, portable bymixer-flow device, using a bymixer and a fast response humidity sensor, provided accurate and convenient bedside measurement of VCO2 and VO2. We believe that it can contribute in the future to preoperative assessment and baseline reference value for perioperative management.

Calorimetría indirecta: diez años de experiencia en el hospital Español

Introducción: los requerimientos energéticos en el enfermo se precisan bien por medio de la calorimetría indirecta. La magnitud del catabolismo puede deducirse mediante la escala metabólica de Cerra (EMC) y el índice catabólico de Bistrian (IC). El consumo de oxígeno, la producción de CO2 y la excreción de nitrógeno determinan el coeficiente respiratorio no proteico (QRnoP) para deducir la proporción de grasa y glucosa utilizada como sustrato energético. Material y métodos: en los últimos 10 años se estudiaron 710 sujetos, con diferentes patologías. Los análisis efectuados fueron: 1. Relación entre GBE medido y edad. 2. Relación entre GBE obtenido mediante calorimetría indirecta y la fórmula de Harris-Benedict. 3. Coeficiente respiratorio no proteico en los diversos grupos. 4. Cambios del GBE, QRnop y utilización energética de proteínas en función del grado de estrés. 5. Correlación entre el APACHE II, FBE y QRnoP. Resultados: El GBE mostró una progresiva disminución con la edad. Hubo un incremento moderado en el postoperatorio inmediato de 172 kcl. El GBE de 24 horas fue de 936 kcal en cirugía mayor por sólo 813 kcal en cirugí menor. En los 710 enfermos se observó que la fórmula de Harris-Benedict sobreestimó el GBE> El QRnop se acerca a uno en enfermos neurológicos, sépticos y pancréaticos. Hubo una correlación entre el grado de estrés, el GBE, el QRnoP y el porcentaje de proteínas utilizadas como energético. Esto fue más notable en enfermos con APACHE II mayor de 15 puntos. Sin embargo, por arriba de 20 puntos el GBE disminuye. Comentarios: la calorimetría indirecta es un método útil para precisar el GBE. En nuestro estudio hubo una buena correlación entre el estrés y el GBE. Dar requerimientos energéticos por debajo de lo necesario, no produce resultados satisfactorios; y dar de más genera alteracines y aumenta el costo.