Twenty years of vasoplegic syndrome treatment in heart surgery. Methylene blue revised / Vinte anos de tratamento da síndrome vasoplégica em cirurgia cardíaca. Azul de metileno revisado

Objective: This study was conducted to reassess the concepts established over the past 20 years, in particular in the last 5 years, about the use of methylene blue in the treatment of vasoplegic syndrome in cardiac surgery. Methods: A wide literature review was carried out using the data extracted from: MEDLINE, SCOPUS and ISI WEB OF SCIENCE. Results: The reassessed and reaffirmed concepts were 1) MB is safe in the recommended doses (the lethal dose is 40 mg/kg); 2) MB does not cause endothelial dysfunction; 3) The MB effect appears in cases of NO up-regulation; 4) MB is not a vasoconstrictor, by blocking the cGMP pathway it releases the cAMP pathway, facilitating the norepinephrine vasoconstrictor effect; 5) The most used dosage is 2 mg/kg as IV bolus, followed by the same continuous infusion because plasma concentrations sharply decrease in the first 40 minutes; and 6) There is a possible "window of opportunity" for MB's effectiveness. In the last five years, major challenges were: 1) Observations about side effects; 2) The need for prophylactic and therapeutic guidelines, and; 3) The need for the establishment of the MB therapeutic window in humans. Conclusion: MB action to treat vasoplegic syndrome is time-dependent. Therefore, the great challenge is the need, for the establishment the MB therapeutic window in humans. This would be the first step towards a systematic guideline to be followed by possible multicenter studies. .

Objetivo: O presente estudo foi realizado com a finalidade de reavaliar conceitos estabelecidos em 20 anos, com ênfase nos últimos 5 anos, sobre a utilização do azul de metileno no tratamento da síndrome vasoplégica em cirurgia cardíaca. Métodos: Foram considerados dados da literatura utilizando-se três bases de dados (MEDLINE, SCOPUS e ISI Web of Science). Resultados: Os conceitos reavaliados e reafirmados foram: 1) Nas doses recomendadas o AM é seguro (a dose letal é de 40 mg/kg); 2) O AM não causa disfunção endotelial; 3) O efeito do AM só aparece em caso de supra nivelamento do NO; 4) O AM não é um vasoconstritor, pelo bloqueio da via GMPc ele libera a via do AMPc, facilitando o efeito vasoconstritor da norepinefrina; 5) A dosagem mais utilizada é de 2 mg/kg, como bolus EV, seguida de infusão contínua porque as concentrações plasmáticas decaem fortemente nos primeiros 40 minutos, e; 6) Existe uma "janela de oportunidade" precoce para efetividade do AM. Nos últimos cinco anos, os principais desafios foram: 1) Observações de efeitos colaterais; 2) A necessidade de diretrizes, e; 3) A necessidade da determinação de uma janela terapêutica para o uso do AM em humanos. Conclusão: O efeito do AM no tratamento da SV é dependente do tempo, portanto, o grande desafio atual é a necessidade do estabelecimento da janela terapêutica do AM em humanos. Esse seria o primeiro passo para a sistematização de uma diretriz a ser seguida por possíveis estudos multicêntricos. .

Effects of catecholamines on volemic replacement with saline solution and the impact on heart rate variability in rabbits subjected to hemorrhage. A study by spectral analysis

PURPOSE: To verify the effects of different catecholamines on volemic expansion and on the autonomic nervous system in rabbits that were subjected to hemorrhage. METHODS: Twenty four rabbits subjected to hemorrhage (with a 25% loss of blood volume) and were randomly divided into four experimental groups: 1) HEMO Group underwent replacement with their own blood in an equal volume; 2) SS Group underwent replacement with saline solution (SS) in a volume that corresponded to three times the removed blood volume; 3) ISP Group underwent replacement with SS and isoprenaline; 4) FNL Group underwent replacement with SS and phenylephrine. Spectral Analysis of the heart rate and heart rate variability were performed from the recorded data. Hematocrit was measured throughout the experiment. RESULTS: Replacement with SS and an α- or β-agonist did not produce differences in the intravascular retention compared to replacement with SS alone. An analysis of HRV showed that the FNL group maintained the LF/HF ratio better than ISP and SS. CONCLUSIONS: No difference in vascular retention when α- or β- agonists were added to SS during post-hemorrhagic recovery. The animals in the FNL group maintained the integrity of the autonomic response within normal physiological standards during hemorrhagic stress. .

Avaliação do conhecimento de enfermeiros sobre a importância da infusão contínua de catecolaminas em unidade de terapia intensiva / Evaluacion del conocimiento de los enfermeros sobre la importancia de la infusion continua de catecolaminas en la unidad de cuidados intensivos / Assessment of nurses’ knowledge about the importance of continuous infusion of catecholamines in intensive care unit

O objetivo com este estudo foi avaliar o conhecimento de enfermeiros intensivistas sobre a importância da infusão contínua de catecolaminas. Trata-se de estudo descritivo, exploratório com delineamento transversal, desenvolvido em Unidades de Terapia Intensiva de um Hospital Escola no município de Fortaleza-CE. Foram entrevistados 49enfermeiros. A maioria, 80,4% (40), declarou, ainda, que não tinha o título de especialista em terapia intensiva. Os dispositivos mais utilizados para a infusão contínua de catecolaminas foram bombas infusoras e equipos com injetores laterais (93, 88%). Dado preocupante foi encontrado quando 54,34% dos entrevistados relataram que não obedeciam rigorosamente à infusão contínua. Em relação à investigação do conhecimento dos enfermeiros sobre a importância do conceito farmacológico desse tipo de infusão, 57,14% da amostra demonstrou dominar de forma parcial a importância farmacológica do conceito de infusão contínua. Conclui-se que a elaboração de protocolos especificando a necessidade de troca continuada das soluções possa auxiliar significativamente a assistência de enfermagem.

The aim of this study was to evaluate the nurses’ knowledge about the importance of continuous infusion of catecholamine. This is a descriptive exploratory cross-sectional study conducted in the Intensive Care Unit of a teaching hospital in Fortaleza-Ceará. We interviewed 49 nurses. The majority 80.4% (40) were not specialists in intensive care.The most used device for the continuous infusion of catecholamines were infusion pumps and jet-directed catheter(93. 88%). Worryingly 54.34% of the nurses interviewed stated they do not strictly comply with the continuous infusion.Regarding the investigation of nurses’ knowledge about the importance of the pharmacological concept of that drug infusion 57.14% partially dominate the pharmacological importance of the concept of continuous infusion. In conclusion the development of protocols that specify the need for continuous solutions exchange can help significantly the nursing care assistance.

El objeto de este estudio fue evaluar el conocimiento de los enfermeros sobre la importancia de la infusión continua decatecolaminas. Se trata de un estudio exploratorio descriptivo llevado a cabo en la Unidad de Cuidados Intensivos de un hospital universitario de Fortaleza-Ceará. Se realizaron entrevistas con 49 enfermeras. La mayoría, el 80,4% (40), no era especialista en terapia intensiva. Los dispositivos más utilizados para la infusión de catecolaminas eran la bomba de infusión y el catéter (93, 88%). 54,34% de los entrevistados informó que no seguía estrictamente la infusión continua.En cuanto a la investigación del conocimiento de los enfermeros sobre la importancia del concepto de infusión de medicamentos el 57,14% de la muestra indicó dominar parcialmente la importancia farmacológica del concepto de infusión continua. Se concluye que la elaboración de protocolos especificando la necesidad de cambiar las soluciones podría ayudar significativamente a la atención de enfermería.

Modulation of the caveolin-3 localization to caveolae and STAT3 to mitochondria by catecholamine-induced cardiac hypertrophy in H9c2 cardiomyoblasts

We investigated the effect of phenylephrine (PE)- and isoproterenol (ISO)-induced cardiac hypertrophy on subcellular localization and expression of caveolin-3 and STAT3 in H9c2 cardiomyoblast cells. Caveolin-3 localization to plasma membrane was attenuated and localization of caveolin-3 to caveolae in the plasma membrane was 24.3% reduced by the catecholamine-induced hypertrophy. STAT3 and phospho-STAT3 were up-regulated but verapamil and cyclosporin A synergistically decreased the STAT3 and phospho-STAT3 levels in PE- and ISO-induced hypertrophic cells. Both expression and activation of STAT3 were increased in the nucleus by the hypertrophy. Immunofluorescence analysis revealed that the catecholamine-induced hypertrophy promoted nuclear localization of pY705-STAT3. Of interest, phosphorylation of pS727-STAT3 in mitochondria was significantly reduced by catecholamine-induced hypertrophy. In addition, mitochondrial complexes II and III were greatly down-regulated in the hypertrophic cells. Our data suggest that the alterations in nuclear and mitochondrial activation of STAT3 and caveolae localization of caveolin-3 are related to the development of the catecholamine-induced cardiac hypertrophy.

Modulation of feeding and drinking behaviour by catecholamines injected into nucleus caudatus in rats.

Lesions of nucleus caudatus have been documented to produce adipsia and aphasia in rats. Injection of dopamine into this nucleus has been shown to facilitate water intake in rats. But, reports are not available on the effects of intracerebral injection of epinephrine and norepinephrine on feeding and drinking behaviour in animal models. Therefore, in the present study the effect of adrenaline and noradrenaline injected into nucleus caudatus on food and water intake in rats was assessed. 24 h basal food and water intakes were recorded in Wistar rats and were found to be 12.37 +/- 0.20 g and 22.04 +/- 0.27 ml respectively. Stainless steel cannulae were implanted stereotaxically into the nucleus caudatus. Four different doses (0.1 microgram, 0.5 microgram, 1 microgram, and 2 micrograms) of adrenaline and noradrenaline were injected into the nucleus caudatus through the implanted cannulae in separate groups of animals and their 24 h food and water intakes were recorded following these injections. No change in food and water intake was observed following the administration of different doses of adrenaline. A significant increase in 24 h food intake reaching a maximum of 16.03 +/- 0.15 g at 2 micrograms dose, without change in water intake was observed following administration of different doses of noradrenaline. The noradrenaline-facilitated food intake was blocked when noradrenaline was injected following injection of phentolamine, an alpha-receptor blocker. The bilateral lesions of nucleus caudatus resulted in a significant and sustained inhibition of food (8.98 +/- 0.17 g) and water intake (19.12 +/- 0.16 ml). These observations suggest that nucleus caudatus is involved in regulation of food and water intakes in rats. Noradrenaline-facilitated food intake is mediated by alpha-receptors. Adrenaline does not affect these ingestive behaviours when injected into the nucleus caudatus in rats.

Catecholamine-induced vasoconstriction is sensitive to carbonic anhydrase I activation

We studied the relationship between alpha- and beta-adrenergic agonists and the activity of carbonic anhydrase I and II in erythrocyte, clinical and vessel studies. Kinetic studies were performed. Adrenergic agonists increased erythrocyte carbonic anhydrase as follows: adrenaline by 75 percent, noradrenaline by 68 percent, isoprenaline by 55 percent, and orciprenaline by 62 percent. The kinetic data indicated a non-competitive mechanism of action. In clinical studies carbonic anhydrase I from erythrocytes increased by 87 percent after noradrenaline administration, by 71 percent after orciprenaline and by 82 percent after isoprenaline. The increase in carbonic anhydrase I paralleled the increase in blood pressure. Similar results were obtained in vessel studies on piglet vascular smooth muscle. We believe that adrenergic agonists may have a dual mechanism of action: the first one consists of a catecholamine action on its receptor with the formation of a stimulus-receptor complex. The second mechanism proposed completes the first one. By this second component of the mechanism, the same stimulus directly acts on the carbonic anhydrase I isozyme (that might be functionally coupled with adrenergic receptors), so that its activation ensures an adequate pH for stimulus-receptor coupling for signal transduction into the cell, resulting in vasoconstriction

Efecto de las catecolaminas sobre la perfusión esplácnica en la sepsis / Effects of catecholamines on splanchnic perfusion in sepsis

Splanchnic ischemia is frequent in sepsis and septic shock and is related to impairment in intestinal permeability, derangement in mucosal barrier functions and translocation of proinflammatory mediators. These changes can contribute to the pathogenesis of multiple organ failure. Vasoactive drugs such as dobutamine and dopexamine can improve splanchnic perfusion and gastric intramucosal pH during sepsis. However, contradictory results have been obtained with dopamine and norepinephrine. On the other hand, epinephrine further impairs splanchnic perfusion. In view of the contradictory effects of different vasoactive drugs, gastric tonometry must be measured during their use, to find the optimal drug combination that optimizes splanchnic blood flow

Cefaléia em pacientes com feocromocitoma: influência da hipertensäo arterial / Headache in patients with pheochromocytoma: influence of arterial hypertension

A cefaléia no feocromocitoma é elemento diagnóstico importante, que pode caracterizar uma reaçao do organismo frente a oscilaçoes hormonais patológicas. Após averiguaçao da hipertensao arterial e da cefaléia em 20 pacientes durante os períodos de descompensaçao do feocromocitoma, sugerimos que a hipertensao arterial isolada nao é o único fator desencadenante dos fenômenos álgicos cranianos. A possibilidade das variaçoes nas catecolaminas, adrenomedulina e outras substâncias neuroendócrinas deve ser melhor esclarecida para comprovar esta hipótese.

Efecto de la cocaína y las catecolaminas sobre la quimiotaxis y la quimioluminiscencia de neutrófilos humanos in vitro

El objetivo fue determinar el efecto de la cocaína sola y mezclada con catecolaminas sobre la quimiotaxis y la explosión metabólica de los neutrófilos humanos y evaluar si la cocaína se une a estas células. La quimiotaxis se realizó en un gel de agarosa utilizando el péptido quimiotáctico FMLP. La explosión respiratoria se determino mediante la cuantificación de fotones (quimioluminiscencia) emitidos por las celulas activadas con PMA. Para cada prueba, las celulas se expusieron a concentraciones de cocaína de 1 a 1000ug/m y de catecolaminas 0.001 y 0.001 ug/mL y luego a la mezcla de 1000 ug/mL de cocaina con 0.001 ug/mL de catecolamina. La union de la cocaina a las celulas se evaluó mediante un ensayo de competición, con cocaína tritiada 10 nM y cocaína no radioactiva 500 uM. Los resultados no mostraron efecto de la cocaína quimiotaxis, pero sí aumento estadisticamente significativo (p=0.004), de la quimioluminiscencia de los neutrófilos tratados con 1000ug/mL de cocaína. Los valores de quimioluminiscencia sin cocaína fueron 1.2 x 10 a la 6 ñ 10 a la 4 cuentas por minuto (cpm) y con cocaina 1.7 x 10 a la 6 ñ1 x 10 a la 5 cpm. Las catecolaminas no modificaron los resultados obtenidos con la cocaina sola. La union de la cocaína tritiada a los neutrofilos tuvo un valor de 3.893 ñ 343 cpm, que disminuyó significativamente a 301 ñ 124 cpm en el ensayo de competición (p=0.008). Se demostró un incremento en la actividad metabólica de los neutrofilos inducido por cocaína, al parecer por su union a estas celulas. Estos resultados no son extrapolables a la clínica; sin embargo, el aumento de quimioluminiscencia debe ser tenido en cuenta, puesto que la exposición recurrente a la cocaína podría eventualmente conducir al mismo efecto

Heterogeneity of glomerular perfusion and filtration induced by epinephrine and norepinephrine

The role of catecholamines in the distribution of intrarenal blood flow and in single-nephron glomerular filtration rate (SNGFR) was evaluated in anesthetized Wistar rats by the Hanssen technique. Epinephrine (EPI) and norepinephrine (NOR) were infused to produce elevations of 20-30 mmHg in mean arterial pressure. Superficial and juxtamedullary nephron perfusion and filtration were determined by the presence of Prussian blue dye. In the control group, 100 per cent of the nephrons presented a homogeneous pattern of perfusion and filtration. In contrast, a heterogenous distribution of the dye was found even in the larger arteries (arciform and radial), indicating variable perfusion and filtration in both superficial and juxtamedullary nephrons. The effects of EPI and NOR were also evaluated in the superficial cortex by the micropuncture technique in two additional groups of Munich-Wistar rats. Mean SNGFR was 27 per cent and 54 per cent lower in the EPI-and NOR-treated groups, respectively. No change in mean intraglomerular hydraulic pressure was observed after EPI or NOR infusion in spite of a highly scattered pattern, indicating an important variability in perfusion along the superficial cortex, and/or different sensitivity of the pre-and post-glomerular arterioles. The present data suggest that EPI and NOR may affect intrarenal hemodynamics by modifying perfusion and filtration in both superficial and juxtamedullary glomeruli and not by shifting blood folow from superficial to juxtamedullary nephrons. The heterogenous pattern of perfusion was a consequence of differential vasoconstriction along the intrarenal arteries, probably due to different density and/or sensitivity of the adrenergic receptor subtypes present in the intrarenal vascular tree.

Inhibidores enzimáticos en el tratamiento de la enfermedad de Parkinson / Enzymatic inhibitors in the treatment of Parkinson's disease

La introducción de la L-DOPA en el tratamiento de los pacientes con enfermedad de Parkinson produjo un dramático impacto en la historia natural de esta enfermedad. Sin embargo su empleo crónico se asocia con la aparición de fluctuaciones motoras, describiéndose además una capacidad neurotóxica de la Dopamina. Ambos factores promueven la investigación constante de nuevos fármacos que permitan estabilizar los niveles plasmáticos de la L-DOPA y reducir las dosis útiles necesarias. Los inhibidores de la monoaminooxidasa (MAO) y de la catecol-oxi-metiltransferasa (COMT) permiten disminuir la degradación de la Dopamina contribuyendo a aumentar su biodisponibilidad y reducir las dosis de L-DOPA. Los inhibidores de la COMT aparecen como nuevos adjuvantes seguros y eficaces de la terapia antiparkinsoniana, pudiendo actuar a nivel central y periférico. Estas nuevas herramientas farmacológicas están destinadas a disminuir los efectos deletéreos que a largo plazo acarrea la L-DOPA terapia

Inactivación de la lipoamida deshidrogenasa de miocardio por catecolaminas: protección por captopril y otros tioles / Inactivation of the myocardial lipoamide dehydrogenase by catecholamines: prevention by captopril and other thiol compounds

Inactivation of lipoamide dehydrogenase (LipDH) by the Cu(II)/H2O2 Fenton system (SF-Cu(II): (5.0 microM Cu(II), 3.0 mM H2O2) was enhanced by catecholamines (CAs), namely, epinephrine, levoDOPA (DOPA), DOPAMINE, 6-hydroxyDOPAMINE (OH-DOPAMINE) and related compounds (DOPAC, CATECHOL, etc.). After 5 min incubation with the Cu(II)/H2O2/CA system (0,4 mM CA), the enzyme activity decayed as indicated by the following percentage values (mean +/- S.D.; in parenthesis, number of determinations): SF-Cu(II) alone, 43 +/- 10 (18); SF-Cu(II) + epinephrine, 80 +/- 9 (5); SF-Cu(II)'+ DOPA, 78 +/- 2 (4); SF + Cu(II) + DOPAMINE, 88 +/- 7 (5); SF-Cu(II) + OH-DOPAMINE 87 +/- 6 (7); SF-Cu(II) + DOPAC, 88 +/- 3 (6); SF-Cu(II) + catechol, 85 +/- 6 (5). In all cases P < 0,05, with respect to the SF-Cu(II) control sample. CAs effect was concentration-dependent and at the 0-100 microM concentration range, it varied with the CA structure. Above the 100 MicroM concentration, CAs were equally effective and produced 90-100 percent enzyme, inactivation (Figure 2). In the absence of oxy-radical generation, the enzyme specific activity (mean + S.D.) was 149 +/- 10 (24) micromol NADH/min/mg protein. Assay of HO. production by the Cu(II)/H2O2/CA system in the presence of deoxyribose (TBA assay) yielded values much greater than those obtained omitting CA. Hydroxyl radical production depended on the presence of Cu(II) and H2O2, and significant HO. values were obtained with OH-DOPAMINE, DOPAC, epinephrine, DOPAMINE, DOPA and catecol supplemented systems (Table 2). LipDH (1.0 microM) inhibited 50-80 percent deoxyribose oxidation, the inhibition depending on the CA structure (Table 2). Native catalase (20 microg/ml) and bovine serum albumin (40 microg/ml) effectively prevented LipDH inactivation by the Cu(II)/H2O2/CA system, denaturated catalase, SOD, 0,3 M mannitol, 6,0 mM ethanol and 0,2 M benzoate were less effective or did not protect LipDH (Table 3). Incubation of CAs with the Cu(II)H2O2 system produced a time and Cu(II)-dependent destruction of CAs, the corresponding o-quinone, production as illustrated with epinephrine (figures 6 and 7), as illustrated with epinephrine and DOPAMINE (Table 4). These results support LipDH inactivation by (a) reduction of Cu(II) to Cu(I) by CAs followed by Cu-catalyzed production of HO. from H2O2; (b) CA oxidation followed by the corresponding o-quinone interaction with LipDH. CAPTOPRIL, N-acetylcysteine, mercaptopropionylglycine and penicillamine prevented to various degree LipDH inactivation by the Cu(II)/H2O2/CA systems (Table 1). The former was the most effective and 0,4 mM CAPTOPRIL prevented about 95-100 percent the effect of Cu(II)/H2O2/CA systems supplemented with epinephrine, DOPAMINE and OH-DOPAMINE (Figures 3 and Table 1). LipDH increased and CAPTOPRIL inhibited epinephrine oxidation by Cu(II)/H2O2 (Figures 4 and 5). Since un-physiological concentrations of CAs and Cu(II) may be released in the myocardium after ischemia-reperfusion, the summarized observations may contribute to explain myocardial damage in that condition.

Reanimación cardiopulmonar en pediatría / Cardiopulmonary resuscitation in pediatrics

La reanimación pediátrica (RP) ha experimentado avances, mejorando el conocimiento epidemiológico y fisiopatológico del paro en niños y de los efectos de procedimientos empleados para revertirlo. El paro cardiorrespiratorio en los niños suele ser un evento terminal, secundario a problemas respiratorios y habitualmente en asistolía. La entubación traqueal continúa siendo el método óptimo para asegurar una ventilación efectiva cuando el paro es atendido por personal experimentado. En la RP la utilidad de la toracotomía con masaje directo no ha sido comprobada y el procedimiento se considera peligroso. Después de asegurar la ventilación y el masaje cardíaco efectivos e ininterrumpidos, la prioridad es el rápido acceso venoso. Los equipos de RP deben emplear protocolos para lograr un acceso vascular. Si después de 3 intentos o 90'' no se obtiene una vía venosa, se deberá instalar una intraósea en menores de 6 años, en mayores se intentará cateterizar la vía femoral. Si no es posible, puede emplearse vía endotraqueal en pacientes entubados, recordando aumentar la dosis de adrenalina. Dada la gran letalidad del paro, fuera (90 a 97 por ciento) y dentro del hospital (69 a 95 por ciento), el mejor tratamiento es la prevención y detección precoz de los factores de riesgo. La adrenalina continúa siendo el fármaco de elección entre los empleados en el manejo del paro, por su capacidad para aumentar la presión de perfusión coronaria y cerebral, no habiendo sido superada por otras aminas naturales o sintéticas. Su dosis óptima parece ser mayor que lo establecido antes, recomendándose, en niños sin respuesta a una primera de 0,01 mg x kg, usar 0,1 a 0,2 mg x kg 3 a 5 min. después de la anterior. En el manejo de la acidosis, el empleo de alcalinizantes continúa siendo controvertido. El tratamiento más racional es conseguir ventilación pulmonar efectiva y perfusión tisular óptima con masaje y adrenalina. Atropina y calcio juegan roles menores en la RP y deben ser consideradas sólo en condiciones especiales. En el manejo de la fibrilación ventr y taquicardia ventricular sin pulso, la lidocaína y el bretilio son probablemente útiles y su empleo debe ser considerado en pacientes que no responden a la desfibrilación eléctrica. La adenosina constituye un nuevo medicamento antiarrítmico que ha probado ser efectivo y seguro en revertir la taquicardia supraventricular y debe ser incluido entre los nuevos medicamentos en RP

Control of melanosome movements in isolated skin melanophores of a catfish Clarias batrachus (Linn.).

Adrenergic and cholinergic receptors have been studied in isolated skin melanophores of a catfish Clarias batrachus. Catecholamines induced a strong aggregatory effect on the melanophores. Melanosome aggregation induced by adrenaline and noradrenaline was partially blocked by alpha adrenergic receptor blockers and a beta receptor blocker. Cholinomimetic drugs aroused a significant dispersion of melanophroes. Atropine effectively blocked the dispersal, responses of melanophores to acetylcholine and carbachol, while, hexamethonium blocked the nocotine induced dispersal responses of the melanophores.

El consumo de oxígeno y catecolaminas

En los últimos 10 años, numerosas publicaciones han aparecido enfatizando la relación de dependencia o independencia entre el consumo y el aporte de oxígeno (VO2/DO2) y en la importancia de la intervención terapéutica precoz, la cual ha tenido ingerencia directa en la sobrevida de los pacientes críticos. Han sido utilizadas varias modalidades terapéuticas con el objeto de manipular esta relación. Los fármacos más comúnmente usados han sido las catecolaminas. Pero, son realmente las catecolaminas capaces de producir un cambio hemodinámico favorable en los pacientes y cuáles son los pacientes que más se benefician? La presente revisión trata de encontrar una respuesta a estas preguntas