Evaluación de un novedoso prototipo diseñado para el apoyo y la sujeción cefálica en pacientes con asistencia respiratoria mecánica / Evaluation of a novelty prototype designed for Support and cephalic support in patients with assistance mechanical respiratory

Objetivos: 1) Fabricar un prototipo de almohada para apoyo y sujeción cefálica para pacientes críticos con asistencia respiratoria mecánica, 2) comparar su eficacia con la de los métodos alternativos de apoyo y sujeción, 3) monitorizar la formación de escaras en contacto con el prototipo, 4) relevar la opinión del personal de enfermería. Diseño: Ensayo clínico con distribución aleatoria. Ámbito: Unidad de Cuidados Intensivos de un hospital privado. Pacientes: 52 hombres y mujeres con asistencia respiratoria mecánica, de entre 31 y 91 años de edad, reunidos en dos grupos: uno de 23 pacientes, que usaron métodos alternativos, y otro de 29 que utilizaron el prototipo. Intervenciones: Se registró la posición de la cabeza en los 52 pacientes por un lapso de entre 1 y 7 días corridos, 3 veces por día; y el desplazamiento del tubo endotraqueal se registró una vez por día. Catorce enfermeros/as respondieron un cuestionario. Variables de interés principales: Posición de la cabeza y desplazamiento del tubo endotraqueal. Resultados: La cabeza se mantuvo centrada en el 56,9% (métodos alternativos) y en el 87,3% (prototipo) (p <0,0001). El tubo endotraqueal no estaba desplazado en un 59,5% (métodos alternativos) y en un 61,9% (prototipo) (p >0,9). Doce de los 14 enfermeros/as encuestados prefirieron el prototipo a los métodos alternativos. Conclusiones: El prototipo resultó significativamente más eficaz que los mé- todos alternativos para mantener la cabeza centrada, mientras que no así para prevenir el desplazamiento del tubo endotraqueal. La mayoría del personal de enfermería prefirió el prototipo a los métodos alternativos.(AU)

Objectives: 1) To build a prototype of a pillow for cephalic holding and restraint for patients under mechanical ventilation. 2) To compare its efficiency against that of alternative methods. 3) To monitor bed sore formation in contact with the prototype. 4) To assess nursery personnel input on the usefullness and convenience of the prototype. Design: Randomized clinical trial. Setting: Intensive Care Unit of a private hospital. Patients and Participants: 52 patients under mechanical ventilation, men and women aged between 31 and 91 years old, randomly gathered in two groups: one of 23 in which alternative methods were used; and one of 29 in which the prototype was used. Interventions: The head position was registered in the 52 patients during a period of between 1 and 7 consecutive days, 3 times a day; the endotracheal tube displacement was recorded once a day. Fourteen nurses responded a questionnaire on the prototype usefulness. Main variables of interest: Head position and endotracheal tube displacement. Results: The head was centered in 56,9% of the records for the alternative methods group, and in 87.3% for the prototype group (p<0.0001). The endotracheal tube was not displaced in 59.5% (alternative methods) and 61.9% (prototype) of the records (p>0.9). Twelve of 14 nurses that answered the questionnaire preferred the prototype to the alternative methods. Conclusions: The prototype turned out more effective (with statistical significance) than the alternative methods to maintain the head centered, but not to prevent the displacement of the endotracheal tube. Most of the nurses preferred the prototype. (AU)

Effect of pulmonary perfusion on the slopes of single-breath test of CO2.

The objective of this study was to evaluate the effects of lung perfusion on the slopes of phases II (S(II)) and III (S(III)) of a single-breath test of CO(2) (SBT-CO(2)). Fourteen patients submitted to cardiac surgery were studied during weaning from cardiopulmonary bypass (CPB). Pump flow was decreased in 20% steps, from 100% (total CPB = 2.5 l.min(-1).m(-2)) to 0%. This maneuver resulted in a progressive and opposite increase in pulmonary blood flow (PBF) while maintaining ventilator settings constant. SBT-CO(2), respiratory, and hemodynamic variables remained unchanged before and after CPB, reflecting a constant condition at those stages. S(III) was similar before and after CPB (19.6 +/- 2.8 and 18.7 +/- 2.1 mmHg/l, respectively). S(III) was lowest during 20% PBF (8.6 +/- 1.9 mmHg/l) and increased in proportion to PBF until exit from CPB (15.6 +/- 2.2 mmHg/l; P < 0.05). Similarly, S(II) and the CO(2) area under the curve increased from 163 +/- 41 mmHg/l and 4.7 +/- 0.6 ml, respectively, at 20% PBF to 313 +/- 32 mmHg/l and 7.9 +/- 0.6 ml (P < 0.05) at CPB end. When S(II) and S(III) were normalized by the mean percent expired CO(2), they remained unchanged during the protocol. In summary, the changes in PBF affect the slopes of the SBT-CO(2). Normalizing S(II) and S(III) eliminated the effect of changes in the magnitude of PBF on the shape of the SBT-CO(2) curve.

[Effects of the alveolar recruitment manoeuver and PEEP on arterial oxygenation in anesthetized obese patients]. / Efectos de la maniobra de reclutamiento alveolar y la PEEP sobre la oxigenación arterial en pacientes obesos anestesiados.

BACKGROUND: Diminished functional residual capacity and pulmonary collapse during general anesthesia lead to alterations in respiratory mechanics and gas exchange. Such phenomena are more pronounced in obese patients. We recently demonstrated the beneficial effects of the alveolar recruitment strategy on oxygenation in anesthetized patients of normal body mass index (BMI). The aim of the present study was to evaluate whether obese patients also benefit from the alveolar recruitment strategy and to determine the level of positive end-expiratory pressure (PEEP) that prevents recollapse in obese patients. METHODS: Three groups of 30 patients each were studied: patients with normal BMI (control group) and obese patients to whom we applied PEEP at 5 and 10 cm H2O (obese-5 and obese-10 groups, respectively) after the recruitment maneuver. We studied respiratory mechanics (respiratory distensibility, airway pressures and flow volume) and arterial oxygenation (PaO2) before and after the recruitment. RESULTS: PaO2 at baseline was higher in the control group (174 +/- 44 mm Hg) than in either the obese-5 or obese-10 group (108 +/- 24 and 114 +/- 22 mm Hg, respectively, p < 0.001). Oxygenation improved in all groups after recruitment (p < 0.001), and PaO2 in the obese-10 group was similar to that of the control group (218 +/- 25 mm Hg and 259 +/- 80 mm Hg, respectively, p > 0.05). Oxygenation in the obese-5 group, however, was worse (153 +/- 41 mm Hg) than that of either of the other groups (p < 0.001). CONCLUSIONS: We conclude that the alveolar recruitment strategy was effective for increasing PaO2 in anesthetized patients, regardless of body mass. The oxygenation of obese patients receiving the higher level of PEEP was similar to that of non-obese patients.

Mejoría de la función respiratoria con una técnica de apertura pulmonar (AP) / Improvement of respiratory function with a technique of open lung

Objetivo: La ventilación mecánica (VM) ha demostrado ser una terapeútica útil en pacientes con compromiso de la función respiratoria. Son múltiples las complicaciones asociadas a los modos convencionales de VM. Están en desarrollo técnicas para disminuir la incidencia de efectos adversos. El objetivo del trabajo es evaluar la técnica ventilatoria denominada APERTURA PULMONAR (AP). (Open Lung Concept. Intens Care Med. 18:319-321, 1992). Pacientes y métodos: Se incorporaron en forma prospectiva y randomizada los pacientes que requirieron VM. Se usaron Siemmens Servo 300 y 900C. Se utilizaron tres modos ventilatorios: Presión Control (PC), Volumen Control (VC), y AP (con parámetros iniciales VT 7-10 ml/kg, PEEP/Presión Inspiratoria Pico (PIP) de 5/25, e incrementos progresivos de 5 cm H20 hasta alcanzar 15/60 e inmediato descenso, posteriormente éste grupo fue ventilado en modo PC con los parámetros de PEEP/PIP de 5-10/25-30, VT 7-10 ml/kg, I:E de 1:1.3, con frec. resp. entre 10-15. La AP se repitió según criterio del equipo médico. Se usó la escala de Murray al ingreso para estratificar las muestras. Se efectuaron registros seriados de monitoreo respiratorio y gasométrico. Se compararon los valores de Pao2/Fio2 entre los diferentes modos ventilatorios. Resultados: Ingresaron 42 pacientes. Se efectuaron 505 monitoreos. En la tabla se observan las comparaciones de los valores de las Pao2/Fio2 generales entre los grupos y las Pao2/Fio2 según horas de VM y según valor de Murray. Conclusiones: el modo AP tuvo mejores índices de oxigenación, siendo más evidente con el transcurso del tiempo y en los pacientes con mayor injuria pulmonar

Age-related changes in essential fatty acid metabolism in cultured rat heart myocytes.

We previously demonstrated that cultured neonatal rat myocytes have the capacity to desaturate/elongate essential fatty acids, alpha-linolenic acid conversion being higher than linoleic acid conversion. The whole process of highly unsaturated fatty acid formation from linoleic and alpha-linolenic acids slows with aging. In this study we grew heart myocytes in culture for different periods of time, and we observed a decrease in the desaturating/elongating activities for both substrates as the cells aged in culture. Alpha-linolenic acid conversion into highly unsaturated fatty acids was less impaired by aging than linoleic acid conversion. These modifications are correlated to the age-dependent alterations observed in the total lipid fatty acid composition, which caused a decrease in the unsaturation index. Changes in the lipid composition that occur in aging cultures parallel those reported for several tissues upon aging in the whole animal. The data herein reported may suggest the possibility of counteracting the effects of aging on lipid metabolism by supplementing cultures with appropriate amounts of highly unsaturated fatty acids.

Essential fatty acids: the effects of dietary supplementation among children with recurrent respiratory infections.

The impact of dietary supplementation with essential fatty acids (EFA) on recurrent respiratory infections (RRI) in children was evaluated by means of a randomized cross-over double-blind study. Linoleic acid (596 mg/day) and alpha-linolenic acid [855 mg/day] as a commercial preparation or placebo (olive oil) were administered for two consecutive winter seasons (November to February, T0-T120) to 20 children affected by RRI, aged between 36 and 49 months. Plasma levels of n-3 and n-6 metabolites increased after the administration of EFA. The number of infective episodes, days' fever and days' absence from school were reduced significantly during the observation period (extended from T120 to T180) in children receiving EFA supplementation. Our results suggest that n-3 and n-6 polyunsaturated fatty acids may play a favourable role in the defence mechanism of these subjects.

Effect of cholesterol-5 alpha,6 alpha-epoxide supplementation to cultured cardiomyocytes.

In order to evaluate the effect of one of the main oxysterols derived from cholesterol oxidation, cholesterol-5 alpha,6 alpha-epoxide (epox), on cardiac cells, we have supplemented the culture medium of neonatal rat cardiomyocytes with scalar concentrations of epox (0.1-100 microM). While 0.1 microM epox supplementation was ineffective, epox supplementation in the range 1-100 microM determined a reduction in cellular protein level, without affecting cell viability, and a dose-dependent epox incorporation into cardiomyocyte lipids. Furthermore, in the same concentration range of epox supplementation, a gas chromatographic peak unambiguously identified by gas chromatography-mass spectrometry as cholestane-3 beta,5 alpha,6 beta-triol, an hydrolytic metabolite of epox, was detected. The mechanism of cytotoxicity of epox to cardiomyocytes could be due to the insertion of epox itself into cellular lipids, and to its metabolization to the more toxic triol.

The effect of dietary lipid changes on the fatty acid composition and function of liver, heart and brain mitochondria in the rat at different ages.

A correlation between dietary lipids and cellular enzyme activities is a problem that has only been partially addressed by nutritionists. Therefore, changes in the fatty acid composition and the activities of some key metabolic enzymes (ubiquinol-2-cytochrome c reductase (EC 1.10.2.2), cytochrome oxidase (EC 1.9.3.1) and ATPase (EC 3.6.1.3)) in the mitochondria of liver, heart and brain of rats fed on diets differing extensively in their polyunsaturated fatty acid compositions have been investigated. The results showed that fatty acid compositional changes brought about by the dietary differences were associated with extensive changes in the activities of these key enzymes in the mitochondria. The extent of the influence differed considerably with the period over which the diets were fed. The role of dietary lipids to effect changes through the preservation of membrane structural integrity is discussed.

Effects of prolonged ingestion of graded doses of licorice by healthy volunteers.

Licorice can induce a hypermineralocorticoid syndrome. Current literature usually refers to the effects of sweets containing glycyrrhizin, but little is known about the consequences of a prolonged intake of "pure licorice". We administered graded daily doses of dried, aqueous extract of licorice root, containing 108, 217, 380 and 814 mg of glycyrrhizin, to 4 groups of 6 healthy volunteers of both sexes for 4 weeks. No significant effects occurred in groups 1 and 2. After 2 weeks, side effects leading to withdrawal from the protocol occurred in a female in group 3 (headache), a male with a family history of hypertension in group 4 (arterial hypertension), and a female also taking oral contraceptives in group 4 (hypertension, hypokalaemia and peripheral edema). In group 4, transient reduction in kalaemia and increase in body weight were found after 1 and 2 weeks, respectively. A depression of plasma renin activity occurred in groups 3 and 4. In healthy subjects, only the highest doses of licorice led to untoward effects. These were favoured by subclinical disease or oral contraceptives, and were less common and pronounced than what has been reported after the intake of glycyrrhizin taken as such or as a flavouring agent in confectionery products.

Oxisterol determination in selected coffees.

The main aim of green-coffee processing techniques, such as decaffeination and roasting, is always to maintain a very high level of quality in taste and flavor, the beverage's most important characteristics to consumers. Oxidative alterations of coffee lipids, which can occur in roasting, exert a very marked influence on these quality traits. Determining the extent of oxidation thus can provide an indication of the product's potential shelf-life and reveal traces of any newly-formed oxidative products that might prove nutritionally unsafe. Yet, while much attention has recently been focused on certain by-products induced by cholesterol oxidation and their proven toxicity as risk factors in atherosclerosis and cancer, oxidated phytosterols have largely gone unnoticed, being considered along with beta-sitosterol as not very dangerous in that neither is absorbed by the intestinal tract. The present study investigates the substances derived from phytosterol oxidation (oxisterols) in samples of regular and decaffeinated commercial coffees. The findings show that oxisterols were absent in some samples and that the traces of oxidate phytosterols detected in others were well below the threshold considered as toxicologically active.

Evidence for a detectable delta-6-desaturase activity in rat heart microsomes: aging influence on enzyme activity.

This study represents the first report indicating that rat heart microsomes contain a measurable delta-6-desaturase activity. The aging process affects delta-6-desaturase activity in the heart to a lesser extent than in the liver, supporting the hypothesis that the regulation of the individual desaturase enzymes may differ in these two tissues. Although decreased desaturase activity, considered alone, may be expected to lower polyunsaturated fatty acid levels, in old animals no modifications in heart microsome fatty acid composition were observed. Probably other metabolic changes may offset this effect, leading to the maintenance of arachidonic acid level in the heart.

Diacylglycerol fatty acid composition is related to activation of protein kinase C in cultured cardiomyocytes.

Using cultures of beating neonatal rat cardiomyocytes we have studied the fatty acid composition of the diacylglycerol produced after different stimulation times with an alpha 1-agonist (phenylephrine) and we have related it to the previously reported time course of the activation of particulate protein kinase C, in control cells and in cells grown in a medium supplemented with docosahexaenoic acid. Gas chromatography of the diacylglycerol produced after stimulation revealed significant differences between control cells and cells treated with docosahexanoic acid. In the cells treated with docosahexanoic acid, the more persistent activation of the membrane-bound protein kinase C might be sustained by an enrichment of diacylglycerol with docosahexanoic acid. The modification of the fatty acid composition of diacylglycerol can cause an alteration in the response of the cells to alpha 1-adrenoceptor stimulation.

[The correlation between the acidic composition of diacylglycerol and protein kinase C activation in cultures of rat cardiomyocytes]. / Correlazione tra composizione acidica del diacilglicerolo e attivazione della proteina cinasi C in colture di cardiomiociti di ratto.

We have studied the fatty acid composition of the diacylglycerol produced after different stimulation times with an alpha 1-agonist (phenylephrine) in cultures of beating neonatal rat cardiomyocytes, and we have related the acidic pattern to the time course of the translocation of protein kinase C from cytosol to the membrane, both in control cells and in cells grown in a medium supplemented with docosahexaenoic acid. Gas chromatography of the diacylglycerol produced after stimulation revealed significant differences between control cells and cells grown in the docosahexaenoic acid supplemented medium. In the control cells, in the early stimulation times, the higher protein kinase C activity was due to a higher relative molar content of arachidonic acid in the diacylglycerol; in the docosahexaenoic acid treated cells the lower but more persistent activation of the membrane-bound protein kinase C might be sustained by an enrichment of diacylglycerol with docosahexaenoic acid. The modification of the fatty acid composition of diacylglycerol can cause an alteration in the response of the cells to alpha 1-adrenoceptor stimulation.

Protein kinase C activity in neonatal cultured rat cardiomyocytes supplemented with docosahexaenoic acid.

In vitro studies have indicated that the 1-stearoyl, 2-arachidonyl diacylglycerol (DAG) is the most effective one for the activation of protein kinase C, although many other DAGs having a different fatty acid composition are active, but to a different extent. Using cultures of neonatal rat ventricular cells, grown in a medium enriched in docosahexaenoic acid (DHA), we previously obtained a cell population that, after alpha 1-adrenoceptor stimulation, produced a DHA enriched DAG. In this study, we have tested the "in vivo" ability of this modified DAG as protein kinase C activator, demonstrating a lower but more persistent translocation of the enzyme from cytosol to particulate fraction in the DHA treated cells. The differences in the PKC activation pattern could be explained by a different metabolism of the DHA enriched DAG by DAG kinase.

Mitochondrial and microsomal cholesterol mobilization after oxidative stress induced by adriamycin in rats fed with dietary olive and corn oil.

The influence of three different dietary fats (8%) and of endogenous lipid peroxidation with regard to cholesterol concentrations in liver mitochondria and microsomes and in serum has been investigated in the rat. Although the different diet fat used did not produce any effect on serum cholesterol, it was possible to show that each experimental diet differently influenced the microsomal and mitochondrial levels of cholesterol. The highest mitochondrial and microsomal cholesterol content was found in case of diet supplemented with virgin olive oil and the lowest with rectified olive oil. An endogenous oxidative stress induced by adriamycin was able to produce a clear decrease in microsomal and mitochondrial cholesterol level and a sharp increase in serum concentration in all three groups. However, dietary fats and adriamycin had no effect on the microsomal and mitochondrial membrane viscosity as detected by fluorescence polarization. These results are consistent with the hypothesis that mitochondrial and microsomal cholesterol can exchange with exogenous pools when phospholipid peroxidation occurs.