Comparison of vena cava distensibility index and pulse pressure variation for the evaluation of intravascular volume in critically ill children

Abstract Objective: In this study, the authors aimed to evaluate the effectiveness of the vena cava distensibility index and pulse pressure variation as dynamic parameters for estimating intravascular volume in critically ill children. Methods: Patients aged 1 month to 18 years, who were hospitalized in the present study's pediatric intensive care unit, were included in the study. The patients were divided into two groups according to central venous pressure: hypovolemic (< 8mmHg) and non-hypovolemic (central venous pressure ≥ 8 mmHg) groups. In both groups, vena cava distensibility index was measured using bedside ultrasound and pulse pressure variation. Measurements were recorded and evaluated under arterial monitoring. Results: In total, 19 (47.5%) of the 40 subjects included in the study were assigned to the central venous pressure ≥ 8 mmHg group, and 21 (52.5%) to the central venous pressure < 8 mmHg group. A moderate positive correlation was found between pulse pressure variation and vena cava distensibility index (r = 0.475, p < 0.01), while there were strong negative correlations of central venous pressure with pulse pressure variation and vena cava distensibility index (r = -0.628, p < 0.001 and r = -0.760, p < 0.001, respectively). In terms of predicting hypovolemia, the predictive power for vena cava distensibility index was > 16% (sensitivity, 90.5%; specificity, 94.7%) and that for pulse pressure variation was > 14% (sensitivity, 71.4%; specificity, 89.5%). Conclusion: Vena cava distensibility index has higher sensitivity and specificity than pulse pressure variation for estimating intravascular volume, along with the advantage of non-invasive bedside application.

Enfermedad hepática congestiva, las repercusiones hepáticas de un corazón enfermo / Congestive liver disease, the hepatic consequences of a diseased heart

La hepatopatía congestiva comprende el espectro de manifestaciones a nivel del hígado, con injuria inducida como consecuencia de la congestión venosa hepática por una alteración en el flujo venoso del tracto de salida hepático. La etiología más frecuente es la falla cardiaca derecha, que por aumento de la presión venosa central, lleva retrógradamente al aumento de la presión venosa hepática, disminución del flujo hepático y disminución de la saturación de oxígeno, con congestión a nivel sinusoidal y particular compromiso de los hepatocitos de la zona 3. Generalmente tiene una presentación subclínica en cuanto a manifestaciones hepáticas que son enmascaradas por los signos y síntomas de falla cardiaca. El diagnóstico comprende la suma de hallazgos serológicos, imagenológicos e histológicos, luego de una exclusión de otras patologías con posible injuria hepática. El tratamiento se basa en el manejo de la falla cardiaca de base, y el pronóstico a su vez, queda supeditado a la fase de la enfermedad cardiaca de base. Se realizó una búsqueda de la literatura con el fin de construir una revisión de esta entidad, con conceptos actualizados a partir de la evidencia reciente.

Congestive liver disease comprises the spectrum of manifestations secondary to liver injury as a consequence of hepatic venous congestion due to a disturbance in the hepatic venous outflow. The most frequent cause is right heart failure, which, due to an increase in central venous pressure, leads retrogradely to an increase in hepatic venous pressure, a decrease in liver inflow and a decrease in oxygen saturation, with sinusoidal congestion and characteristic compromise of zone 3 hepatocytes. Its presentation is usually subclinical in terms of liver manifestations, masked by the signs and symptoms of heart failure. The diagnosis includes the sum of serological, imaging and histological findings, after exclusion of other entities involving liver injury. Treatment is based on the management of the underlying heart failure and the prognosis is as well dependent on the stage of the underlying heart disease. A literature search was carried out in order to create a review of this entity with updated concepts based on recent evidence.

Pressão arterial central e risco cardiovascular / Central blood pressure and cardiovascular risk

Pressão Central, como o nome indica, é uma medida hemodinâmica semelhante a pressão arterial convencional porém avaliada de forma indireta por equipamento especifico, que avalia estes parâmetros na saída do sangue na raiz da aorta. Esta medida tem uma maior confiabilidade pois prediz de forma mais acurada os riscos de adoecimento e morte cardiovascular. Isto ocorre, pois a a onda de pulso (OP) ao percorrer os trajetos arteriais sofrem ampliações e importantes modificações no seu contorno deformando o valor original. Embora seja mais precisa em valores, ainda não é usado de rotina na pratica clinica por razoes de custos dos seus equipamentos e provavelmente por exigir habilidades maiores que as medidas captadas pelo equipamentos de mensuração periférica

Central pressure, as the name implies, is a hemodynamic measure similar to conventional blood pressure, but indirectly assessed by specific equipment, which evaluates these parameters at the blood outlet at the root of the aorta. This measure has greater confidence because it more accurately predicts the risks of cardiovascular disease and death. This occurs because the pulse wave (OP) when traversing the arterial paths provides enlargements and modifications in its contour, deforming the original value. Although it is more precise in terms of values, it is not yet routinely used in clinical practice for reasons of the cost of its equipment and probably because it requires greater needs than measures captured by peripheral measurement equipment

Caudal vena cava collapsibility index in healthy cats by ultrasonography / [Índice de colapsibilidade da veia cava caudal em gatos domésticos Saudáveis, obtido por meio de ultrassonografia]

The objective of this study was to calculate the collapsibility index (CI) in a group of 15 healthy adult mixed breed cats via right hepatic intercostal ultrasound view. The minimal and the maximal diameters of the caudal vena cava (CVC) were obtained during inspiration and expiration, respectively, then CI was calculated. The mean diameter of the CVC was 0.5cm. The mean CI was 28±3% and CI was not significantly associated with gender. As in human medicine, there is a growing need for less invasive monitoring in small animal practice. The CI enables the assessment of estimated volemia without the need for a central venous catheter. This is the first reported study investigating CI in cats.(AU)

O objetivo deste estudo foi calcular o índice de colapsabilidade (IC) em um grupo de 15 gatos adultos, saudáveis e SRD, por meio da janela ultrassonográfica hepática intercostal direita. Os diâmetros mínimo e máximo da veia cava caudal (VCC) foram obtidos durante a inspiração e a expiração, respectivamente. O IC foi calculado, posteriormente. O diâmetro médio da VCC foi de 0,5cm. O diâmetro médio do IC foi de 28±3%, e o IC não foi significativamente associado ao gênero. Como na medicina humana, há uma necessidade crescente de monitoramento menos invasivo na prática de pequenos animais. O IC possibilita a avaliação da volemia estimada sem a necessidade de um cateter venoso central. Este é o primeiro estudo relatado sobre IC em gatos domésticos.(AU)

Effect of opium addiction on postoperative arrhythmia among patients undergoing cabg operation on cardiopulmonary bypass

Abstract Objectives: Postoperative arrhythmia is an important complication of coronary artery bypass grafting (CABG) surgeries among patients. It seems that opioid usage is implicated in the pathogenesis of this condition due to its impacts on different organ systems, such as the autonomic nervous system. The present study was performed to investigate the effect of opium use on postoperative arrhythmia in patients undergoing CABG surgery. Methods: Study participants were selected via convenience sampling from patients undergoing CABG surgery in a referral hospital. Study variables, including use of inotropic drugs, vital signs monitoring parameters and postoperative arrhythmia were observed and recorded at baseline and at follow-up time after surgery. Results: Sixty-five (14.8%) patients had postoperative arrhythmia, and 104 participants were addicted. Prevalence of postoperative arrhythmia was the same among addict and non-addict patients. According to the regression analysis model, only serum level of epinephrine in operating room, heart rate and central venous pressure at baseline and 48 hours after operation are known as independent predictors of postoperative arrhythmia among study population. Conclusion: This study showed that although opium addiction increased postoperative arrhythmia among patients undergoing CABG surgery, this difference was not significant, and this association is probably mediated by other study variables.

Indicaciones para el uso del catéter venoso central y el tiempo de colocación en los pacientes hospitalizados en el servicio de medicina interna del hospital Dr. Miguel Pérez Carreño / Indications for the use of the central venous catheter and the time of its use in the patients hospitalized in the internal medicine service of the Dr. Miguel Pérez Carreño hospital

La inserción del catéter venoso central (CVC) ha significado un gran avance en la medicina moderna y su uso generalizado ha permitido el desarrollo de nuevas técnicas diagnósticas y tratamientos especializados. En este estudio se dan a conocer las indicaciones presentes al momento de colocar el catéter venoso central y el tiempo de colocación en los pacientes. Métodos: La investigación fue de tipo retrospectivo, descriptivo y de corte transversal, con un diseño de investigación no experimental y tuvo la finalidad de conocer, en forma directa, la realidad de la problemática. Las unidades de observación fueron(188) historias clínicas de los pacientes que ingresaron en el servicio de medicina interna en el hospital Miguel Pérez Carreño en el periodo comprendido entre enero y abril de 2017. Resultados: El 68% de la indicación del catéter venoso central es para la medición de la presión venosa central (PVC) y control de líquidos, mientras que en el 32% la indicación fue por administración de fármacos. El tiempo de colocación tuvo un predominio del 61% de los pacientes que utilizaron el catéter venoso central durante 1 a 3 semanas, en segundo lugar, el 36% utilizo el catéter por unos días, solo un 3% amerito el uso del catéter venoso central durante 1 mes. Conclusiones: La mayoría de los pacientes estudiados tuvieron como principal indicación de CVC para control de líquido y medición de presión venosa central. Con una duración de 1 a 3 semanas(AU)

The insertion of the central venous catheter (CVC) has meant a great advance in modern medicine and its widespread use has allowed the development of new diagnostic techniques and specialized treatments. In this study we present the indications present at the moment of placing the central venous catheter and the time of use in patients. Methods: The research was of a retrospective, descriptive and cross-sectional type, with a non-experimental research design and aimed to know, in a direct way, the reality of the problem. The units of observation were (188) clinical records of patients admitted to the internal medicine service in the hospital Miguel Pérez Carreño in the period between January and April 2017. Results: 68% of the indication of the central venous catheter is for the measurement of central venous pressure (CVP) and fluid control, while in 32% the indication was for drug administration. The time of use had a predominance of 61% of patients who used the central venous catheter for 1 to 3 weeks, secondly, 36% used the catheter for a few days, only 3% required the use of the central venous catheter for 1 month. Conclusions: The majority of patients studied had CVC as main indication for fluid control and central venous pressure measurement. With a duration of 1 to 3 weeks(AU)

Índice de colapsabilidad de la vena cava inferior como predictor de hipotensión intraoperatoria / Inferior vena cava collapsibility index of the as a predictor of intraoperative hypotension

OBJECTIVE: To evaluate the lower vena cava Collapse Index (CI) as a predictor parameter of hypotensive episodes after general anesthesia induction in ASA I and II patients who were scheduled for elective surgery. MATERIALS AND METHODS: A prospective, observational and simple blind study was designed. A sample of 80 patients was recruited. In the preoperative stage, they underwent protocolarized sedation and CI was obtained. Prior to induction, the baseline values ​​of heart rate, non-invasive mean arterial pressure and continuous electrocardiographic tracing in DII were noted. In the post-orotracheal intubation stage, the aforementioned hemodynamic monitoring variables were recorded manually for 10 minutes. RESULTS: The data of 78 individuals are presented. After anesthetic induction, 8 (10.3%) patients developed hypotension. The adjustment of the univariate logistic regression model for CI shows a good diagnostic capacity, with the area under the ROC curve equal to 0.76. The chance of presenting hypotension is increased by 62% by increasing the CI by 5 points (p = 0.003). Regarding the negative predictive value, we found that with values ​​corresponding to the cutoff points between 39% and 46%, a probability of at least 93.1% of not presenting hypotension was obtained. The optimal cutoff point of the CI to predict hypotension is estimated at 43%, with a sensitivity of 62.5% and a specificity of 92.9%. CONCLUSION: A lower IC was associated with a lower probability of developing intraoperative hypotension. The use of this tool could be useful to anticipate which patients will be prone to intra-surgical hypotension.

OBJETIVO: Evaluar el índice de colapsabilidad (IC) de la vena cava inferior (VCI) como predictor de episodios hipotensivos posinducción de anestesia general en cirugía electiva de pacientes ASA I y II. MATERIALES Y MÉTODOS: Se diseñó un estudio prospectivo, observacional y simple ciego. Se reclutó una muestra de 80 pacientes. En etapa preoperatoria fueron sometidos a una sedación protocolizada y se obtuvo el IC. Previo a la inducción, se anotaron los valores basales de la frecuencia cardíaca, la presión arterial media y el trazado electrocardiográfico continuo en DII. Posintubación orotraqueal, se registraron manualmente las variables hemodinámicas mencionadas durante 10 minutos. RESULTADOS: Se presentan datos de 78 individuos. Luego de la inducción, 8 (10,3%) pacientes desarrollaron hipotensión. El ajuste del modelo de regresión logística univariado para IC muestra una buena capacidad diagnóstica, siendo el área bajo la curva ROC igual a 0,76. La chance de presentar hipotensión se incrementa en un 62% al aumentar el IC en 5 puntos (p = 0,003). En cuanto al valor predictivo negativo, encontramos que con valores correspondientes a los puntos de corte entre 39% y 46%, se obtenía una probabilidad de 93,1% de no presentar hipotensión. El punto de corte óptimo del IC para predecir hipotensión se estima en 43%, con una sensibilidad del 62,5% y una especificidad del 92,9%. CONCLUSIÓN: Un menor IC se asoció con una menor probabilidad de desarrollar hipotensión intraoperatoria. El uso de esta herramienta podría ser de utilidad para anticipar qué pacientes serán propensos a hipotensión intraquirúrgica.

Práticas relacionadas ao uso do garrote durante a punção venosa periférica: uma revisão de escopo / Health professionals' practices related with tourniquet use during peripheral venipuncture: a scoping review / Prácticas relacionadas al uso del garrote durante la punción venosa periférica: una revisión de alcance

Objetivos durante a punção venosa periférica, recomenda-se o uso de um garrote acima do local da punção para potencializar a distensão venosa. Dadas as suas características e o uso em ambientes clínicos, os garrotes podem representar uma fonte de disseminação de micro-organismos. Entretanto, os resultados de estudos científicos nessa área estão dispersos na literatura. Esta revisão de escopo tem como objetivo mapear as evidências disponíveis a respeito das práticas dos profissionais de saúde no que concerne ao uso do garrote durante a punção venosa periférica e à contaminação microbiológica associada. Método revisão de escopo de acordo com a metodologia do Instituto Joanna Briggs. Dois revisores independentes analisaram a relevância dos estudos, extraíram e sintetizaram dados. Resultados quinze estudos foram incluídos na revisão. Em geral, os garrotes foram reutilizados sem processos de descontaminação recorrentes. Verificou-se que os profissionais compartilham esses dispositivos entre si e os usaram continuamente por períodos entre duas semanas e sete anos e meio. Conclusão as práticas de enfermagem relacionadas ao uso do garrote durante a punção venosa periférica não são uniformes. A reutilização de garrotes pode colocar em risco a segurança do paciente se o reprocessamento (limpeza e desinfecção/esterilização) não for adequado, dado o tipo de material do garrote e a microbiota encontrada. Novos estudos são necessários para avaliar o impacto de vários tipos de práticas de reprocessamento na descontaminação de garrotes e na segurança do paciente.

Objectives during peripheral venipuncture, health professionals are recommended to use a tourniquet above the puncture site in order to potentiate venous distension. Given its characteristics and use in clinical settings, tourniquets may represent a source of microorganism dissemination. However, the results of scientific studies in this area are scattered in the literature. This scoping review aims to map the available evidence on health professionals' practices related with tourniquet use during peripheral venipuncture and associated microbiological contamination. Methods scoping review following the Joanna Briggs Institute methodology. Two independent reviewers analyzed the relevance of the studies, extracted and synthesized data. Results fifteen studies were included in the review. Overall, tourniquets were reused without being subject to recurring decontamination processes. It has been found that practitioners share these devices among themselves and use them successively for periods between two weeks and seven and half years. Conclusion nursing practices related to tourniquet use during peripheral venipuncture are not standard. Reuse of tourniquets may jeopardize the patient's safety if reprocessing (cleaning and disinfection/sterilization) is not adequate, given the type of tourniquet material and microbiota found. New studies are needed to assess the impact of various types of reprocessing practices on tourniquet decontamination and patient safety.

Objetivos durante la punción venosa periférica, se recomienda el uso de un garrote arriba del sitio de la punción para potenciar la distensión venosa. Dadas sus características y uso en ambientes clínicos, los garrotes pueden representar una fuente de diseminación de microorganismos. Sin embargo, los resultados de estudios científicos en esta área están dispersos en la literatura. Esta revisión de alcance tiene como objetivo mapear las evidencias disponibles acerca de las prácticas de los profesionales de salud en lo que concierne al uso del garrote durante la punción venosa periférica y la contaminación microbiológica asociada. Método revisión de alcance de acuerdo con la metodología del Instituto Joanna Briggs. Dos revisores independientes analizaron la relevancia de los estudios, extrajeron y sintetizaron datos. Resultados quince estudios se incluyeron en la revisión. En general, los garrotes fueron reutilizados sin procesos de descontaminación recurrentes. Se verificó que los profesionales comparten estos dispositivos entre sí y los utilizaron continuamente por períodos entre dos semanas y siete años y medio. Conclusión las prácticas de enfermería relacionadas al uso del garrote durante la punción venosa periférica no son uniformes. La reutilización de garrotes puede poner en riesgo la seguridad del paciente si el reprocesamiento (limpieza y desinfección/esterilización) no es adecuado, dado el tipo de material del garrote y la microbiota encontrada. Nuevos estudios son necesarios para evaluar el impacto de varios tipos de prácticas de reprocesamiento en la descontaminación de garrotes y en la seguridad del paciente.

Hemodinámica funcional: ¿Qué significa "ser respondedor"? / Functional hemodynamics: "Be responsive, what does this mean"?

The conventional analysis and approach to the physiology of the fluid responsiveness has traditionally been focused mainly on the physiology of heart-lung interactions, and on reviews of the technical, methodological, and epidemiological aspects of the dynamic parameters, which are translated into simple algorithms to assess fluid responsiveness and to guide fluid therapy.However, fundamental features of the dynamics of the peripheral circulation, heart-vasculature interaction, and blood volume distribution, are overlooked and sometimes not accounted for, motivating misconceptions about the cardiovascular system's response to fluid administration and fluid management, such as equating fluid loading with cardiac preload, a predictable interpretation whenever Starling's ventricular function curve is analyzed in isolation. This paper reexamines fluid responsiveness' rationale offering a broadened perspective on the circulatory phenomena involved in the physiological interaction between BV, cardiac preload and output, and stroke volume variation. Finally, implications relevant in physiological and clinical terms are discussed.

El análisis convencional y abordaje actual de la fisiología de la "respuesta a fluidos" (RF) ha estado focalizada principalmente sobre la fisiología de la interacción cardiopulmonar, y sobre aspectos técnicos, metodológicos y, epidemiológicos de los parámetros dinámicos, los cuales son traducidos en algoritmos simplificados para evaluar la RF y guiar la fluidoterapia. Sin embargo, aspectos fundamentales de la dinámica de la circulación periférica, el acoplamiento entre el corazón y la vasculatura, y la distribución del volumen sanguíneo son frecuentemente omitidos, motivando mal interpretaciones sobre la respuesta del sistema cardiovascular a la administración de fluidos, tal como equiparar la carga de fluidos con la precarga ventricular, una consecuencia predecible al interpretar la curva de función ventricular (Starling) de forma aislada. Así, esta revisión reexamina la rationale de la RF, ofreciendo una perspectiva ampliada sobre aquellos fenómenos circulatorios implicados en la interacción entre el volumen sanguíneo, la precarga ventricular, el gasto cardíaco y la variación del volumen sistólico. Finalmente, se analizarán las implicancias prácticas y conceptuales.

Disminución de la presión venosa central: efecto sobre el gasto cardíaco / Reduction of central venous pressure: effect on cardiac output

Introducción: La disminución de la presión venosa central (PVC) a menos de 5mmHg ha sido recomendada para disminuir el sangrado durante la cirugía hepática. No se conoce el efecto de esto en el llenado ventricular e índice cardíaco (IC). Objetivo: Medir el efecto en el volumen de fin de diástole del ventrículo izquierdo indexado (VFDVII) e IC de la disminución a 3-4mmHg de la PVC. Método: Se estudiaron pacientes sometidos a cirugía general en los cuales se monitorizó presión arterial directa, PVC, y ecocardiografía transesofágica (ETE). Posterior a la inducción anestésica, y después de 5min de estabilidad hemodinámica, se midieron VFDVII e IC, los cuales se repitieron 5 min después de disminuir la PVC a 3-4 mmHg. Resultados: Se estudiaron 32 pacientes; 12 cumplían criterios de disfunción diastólica (DD). Los valores basales y posteriores a la reducción de la PVC de VFDVII e IC fueron respectivamente 49,4 ± 13 y 40,1 ±13 ml/m², y 2,8 ± 0,56 y 2,5 ± 0,7 l/m² (ambos p < 0,01). Todas las variaciones fueron mayores en los pacientes con DD. Conclusiones: La disminución de la PVC a los niveles recomendados para disminuir el sangrado produce una moderada pero significativa reducción del IC. Esto debe ser considerado en pacientes con condiciones que pudieran hacer más importante el efecto de la disminución de la PVC.

Introduction: The reduction of central venous pressure (CVP) below 5mmHg has been recommended to decrease bleeding during hepatic surgery. The effect of this practice on cardiac function has not been quantified. Objective: To measure the repercussion of the decrease of CVP on left ventricular end diastolic volume (LVEDV) and cardiac index (CI). Method: Patients undergoing general anaesthesia for major surgery were studied. Monitoring included direct arterial pressure, CVP, and transesophageal echocardiography (TEE). During a stable period of anaesthesia, all of these parameters were measured before and after lowering CVP to 3-4mmHg. Results: Thirty-two patients were studied. Twelve patients met TEE diagnostic criteria for diastolic dysfunction (DD). Basal and post CVP reduction values of LVEDVI and CI were 49.4 ± 13 and 40.1 ±13ml/m², 2.8±0.56 and 2.5±0.7l/m² respectively (both P< .01). All these variations were greater in patients with DD. Conclusions: Reduction of CVP produced a moderate but significant decrease in LVEDV and CI This should be considered in patients with conditions that may increase the effect of decreasing the CVP.

Comparison of Two Central Venous Pressure Control Strategies to Prevent Atrial Fibrillation After Coronary Artery Bypass Grafting / Comparação de Duas Estratégias de Controle de Pressão Venosa Central na Prevenção de Fibrilação Atrial em Pós-Operatório de Revascularização do Miocárdio

Abstract Background: Atrial fibrillation (AF) takes place in 10-40% of patients undergoing coronary artery bypass grafting (CABG), and increases cardiovascular mortality. Enlargement of atrial chambers is associated with increased AF incidence, so patients with higher central venous pressure (CVP) are expected to have larger atrial distension, which increases AF incidence. Objective: To compare post-CABG AF incidence, following two CVP control strategies. Methods: Interventional, randomized, controlled clinical study. The sample comprised 140 patients undergoing CABG between 2011 and 2015. They were randomized into two groups, G15 and G20, with CVP maintained ≤ 15 cmH2O and ≤ 20 cmH2O, respectively. Results: 70 patients were included in each group. The AF incidence in G15 was 8.57%, and in G20, 22.86%, with absolute risk reduction of 14.28%, and number needed to treat (NNT) of 7 (p = 0.03). Mortality (G15 = 5.71%; G20 = 11.42%; p = 0.07), hospital length of stay (G15 = 7.14 days; G20 = 8.21 days; p = 0.36), number of grafts (median: G15 = 3, G2 = 2; p = 0.22) and cardiopulmonary bypass use (G15 = 67.10%; G20 = 55.70%; p = 0.22) were statistically similar. Age (p = 0.04) and hospital length of stay (p = 0.001) were significantly higher in patients who developed AF in both groups. Conclusion: Keeping CVP low in the first 72 post-CABG hours reduces the relative risk of AF, and may be useful to prevent AF after CABG.

Resumo Fundamento: A fibrilação atrial (FA) ocorre em 10-40% dos pacientes submetidos a cirurgia de revascularização miocárdica (RM), e eleva a mortalidade cardiovascular. Como o aumento dos átrios está associado ao aumento da incidência de FA, espera-se que pacientes com pressão venosa central (PVC) mais alta tenham maior distensão atrial, o que eleva a incidência dessa arritmia. Objetivo: Comparar a incidência de FA em pós-operatório de RM, seguindo duas estratégias de controle de PVC. Métodos: Estudo clínico randomizado controlado intervencionista. A amostra foi composta por 140 pacientes submetidos a RM entre 2011 e 2015. Os pacientes foram randomizados em dois grupos, G15 e G20, mantidos com PVC máxima de 15 cmH2O e 20 cmH2O, respectivamente. Resultados: Foram incluídos 70 pacientes em cada grupo. A incidência da arritmia em G15 foi de 8,57% e, no G20, de 22,86%, com redução de risco absoluto de 14,28% e número necessário para tratar (NNT) de 7 (p = 0,03). Mortalidade (G15 = 5,71%; G20 = 11,42%; p = 0,07), tempo de internamento (G15 = 7,14 dias; G20 = 8,21 dias; p = 0,36), número de enxertos (medianas: G15 = 3, G2 = 2; p = 0,22) e uso de circulação extracorpórea (G15 = 67,10%; G20 = 55,70%; p = 0,22) mostraram-se estatisticamente semelhantes. A idade (p = 0,04) e o tempo de internamento (p = 0,001) foram significativamente maiores nos pacientes que desenvolveram FA nos dois grupos. Conclusão: Manter a PVC com valores mais baixos nas primeiras 72h após a cirurgia de RM reduz o risco relativo de FA e pode ser uma ferramenta útil na prevenção da FA após RM.

Methylene blue to treat protamine-induced anaphylaxis reactions. An experimental study in pigs

ABSTRACT Objective: To examine if methylene blue (MB) can counteract or prevent protamine (P) cardiovascular effects. Methods: The protocol included five heparinized pig groups: Group Sham -without any drug; Group MB - MB 3 mg/kg infusion; Group P - protamine; Group P/MB - MB after protamine; Group MB/P - MB before protamine. Nitric oxide levels were obtained by the nitric oxide/ozone chemiluminescence method, performed using the Nitric Oxide Analizer 280i (Sievers, Boulder, CO, USA). Malondialdehyde plasma levels were estimated using the thiobarbiturate technique. Results: 1) Groups Sham and MB presented unchanged parameters; 2) Group P - a) Intravenous protamine infusion caused mean arterial pressure decrease and recovery trend after 25-30 minutes, b) Cardiac output decreased and remained stable until the end of protamine injection, and c) Sustained systemic vascular resistance increased until the end of protamine injection; 3) Methylene blue infusion after protamine (Group P/MB) - a) Marked mean arterial pressure decreased after protamine, but recovery after methylene blue injection, b) Cardiac output decreased after protamine infusion, recovering after methylene blue infusion, and c) Sustained systemic vascular resistance increased after protamine infusion and methylene blue injections; 4) Methylene blue infusion before protamine (Group MB/P) - a) Mean arterial pressure decrease was less severe with rapid recovery, b) After methylene blue, there was a progressive cardiac output increase up to protamine injection, when cardiac output decreased, and c) Sustained systemic vascular resistance decreased after protamine, followed by immediate Sustained systemic vascular resistance increase; 5) Plasma nitrite/nitrate and malondialdehyde values did not differ among the experimental groups. Conclusion: Reviewing these experimental results and our clinical experience, we suggest methylene blue safely prevents and treats hemodynamic protamine complications, from the endothelium function point of view.

Medida da pressão venosa central com o paciente em diferentes angulações / Central venous pressure measurement with patient at different angles / Medición de la presión venosa central con el paciente en diferentes ángulos

Objetivo: identificar se existe diferença nos valores da pressão venosa central com a cabeceira do leito do paciente elevada. Método: estudo longitudinal, analítico e de abordagem quantitativa, realizado em quatro unidades de terapia intensiva de um hospital de grande porte do noroeste paulista, de agosto a novembro de 2013. A pressão venosa central foi mensurada em 156 pacientes, em quatro angulações diferentes, totalizando 624 medidas. Os dados são apresentados em números absolutos e percentuais, as variáveis analisadas pelo Teste de Mann-Whitney e Wilcoxon e associação entre as medidas pela análise do coeficiente de correlação de Pearson (r). Conclusão: a mensuração pode ser realizada com acurácia a 0° e 30°, pois apresentaram correlação positiva entre as medidas, porém a 0° e 45° a correlação é fraca, demonstrando pouca associação entre as variáveis.

Objective: to investigate whether central venous pressure values differ with patient bed inclination. Method: this quantitative, analytical, longitudinal study was conducted from November to August 2013 at four intensive care units at a large hospital in northwest São Paulo. Central venous pressure was measured in 156 patients at four different bed inclinations each, totaling 624 measurements. The data are expressed in absolute and percentage values, variables were analyzed using the Mann-Whitney and Wilcoxon tests, and associations between measurements were tested by Pearson's correlation coefficient (r). Conclusion: measurements were found to be accurate at 0° and 30° (a positive correlation between measurements), but a weak correlation at 0° and 45° (revealing little association between the variables).

Objetivo: identificar si existen diferencias de valores de la presión venosa central dependiendo de la altura de la cabecera de la cama del paciente. Método: el estudio es cuantitativo, analítico y longitudinal, realizado en cuatro unidades de cuidados intensivos de un hospital de gran porte, ubicado en el Noroeste del São Paulo entre agosto y noviembre de 2013. Se midió la presión venosa central en 156 pacientes, desde cuatro ángulos diferentes, totalizando 624 mediciones. Los datos se presentan en números absolutos y en porcentajes; las variables fueron analizadas mediante la Prueba de Mann­Whitney­Wilcoxon y la asociación entre las medidas se hizo a través del análisis del coeficiente de correlación de Pearson (r). Conclusión: la medición pudo realizarse con exactitud a 0° y 30° grados, ya que presentan una correlación positiva entre las medidas. Sin embargo, a 0° y a 45° grados, la correlación fue débil mostrando poca asociación entre las variables.

Current concepts on hemodynamic support and therapy in septic shock / Conceitos atuais sobre suporte hemodinâmico e terapia em choque séptico

ABSTRACTSevere sepsis and septic shock represent a major healthcare challenge. Much of the improvement in mortality associated with septic shock is related to early recognition combined with timely fluid resuscitation and adequate antibiotics administration. The main goals of septic shock resuscitation include intravascular replenishment, maintenance of adequate perfusion pressure and oxygen delivery to tissues. To achieve those goals, fluid responsiveness evaluation and complementary interventions - i.e. vasopressors, inotropes and blood transfusion - may be necessary. This article is a literature review of the available evidence on the initial hemodynamic support of the septic shock patients presenting to the emergency room or to the intensive care unit and the main interventions available to reach those targets, focusing on fluid and vasopressor therapy, blood transfusion and inotrope administration.

RESUMOA sepse grave e o choque séptico são um grande desafio para a assistência médica. Grande parte da melhoria na taxa de mortalidade associada ao choque séptico está relacionada ao reconhecimento precoce em combinação com a reposição volêmica oportuna e a administração adequada de antibióticos. Os principais objetivos da reanimação do choque séptico incluem reposição intravascular, manutenção adequada da pressão de perfusão e fornecimento de oxigênio para os tecidos. Para atingir esses objetivos, a avaliação da responsividade do volume e das intervenções complementares (vasopressores, inotrópicos e transfusão de sangue) pode ser necessária. Este artigo é uma revisão da literatura para identificar as evidências disponíveis do suporte hemodinâmico inicial aos pacientes com choque séptico admitidos em sala de emergência ou unidade de terapia intensiva e as principais intervenções disponíveis para atingir essas metas, com foco em terapia com reposição de líquidos e vasopressores, transfusão de sangue e administração de inotrópicos.

Efeito do controle da pressão venosa central na ocorrência de fibrilação atrial após revascularização do miocárdio: estudo caso-controle / Effect of central venous pressure control on the occurrence of atrial fibrillation after coronary artery bypass grafting: case-control study

Introdução: Este estudo teve como objetivo comparar a incidência de fibrilação atrial apósrevascularização do miocárdio entre pacientes que tiveram a pressão venosa central rigorosamente controladanas primeiras 48-72 horas de pós-operatório e pacientes que não tiveram controle rigoroso. Método: Estudoobservacional, do tipo caso-controle, realizado na Santa Casa de Misericórdia de Ponta Grossa. O caso foicomposto por 80 pacientes avaliados prospectivamente submetidos a revascularização miocárdica entre 2012e 2014, os quais tiveram a pressão venosa central avaliada de duas em duas horas, nas primeiras 72 horas depós-operatório, sendo administrada uma ampola de furosemida cada vez que a pressão atingiu o ponto de cortepreestabelecido de forma randomizada em 15 cmH2O ou 20 cmH2O. Já o controle foi composto por 184 pacientesavaliados retrospectivamente submetidos a revascularização miocárdica entre 2009 e 2012, antes do início darandomização, nos quais o controle da pressão venosa central foi menos rigoroso, ficando a necessidade de usode diurético a critério dos intensivistas. Avaliou-se a incidência de fibrilação atrial nas primeiras 72 horas depós-operatório nos dois grupos. Resultados: A incidência de fibrilação atrial foi menor no grupo caso (11,25%, 9em 80), comparativamente ao grupo controle (23,35%, 43 em 184) (P = 0,03). Outras variáveis estudadas foramsemelhantes entre os grupos, exceto o clearance de creatinina, que foi maior no grupo controle. Conclusão: Opresente estudo demonstra que o controle da pressão venosa central nas primeiras 72 horas de pós-operatório écapaz de reduzir a incidência de fibrilação atrial após revascularização do miocárdio.

Background: This study was aimed at comparing the incidence of atrial fibrillation after coronaryartery bypass grafting among patients who have had central venous pressure strictly controlled within thefirst 48-72 hours after surgery and patients who did not have a strict control. Method: Observational, casecontrolstudy, performed at Santa Casa de Misericórdia de Ponta Grossa. The case included 80 prospectivelyevaluated patients submitted to myocardial revascularization between 2012 and 2014, who had central venouspressure evaluated every two hours, in the first 72 hours after surgery. Patients received a vial of furosemide everytime the pressure reached the pre-established cutoff randomly set as 15 or 20 cmH2O. The control included 184retrospectively evaluated patients undergoing myocardial revascularization between 2009 and 2011 prior to thebeginning of randomization; in this group central venous pressure control was less rigorous, requiring use ofdiuretics at the discretion of the intensivists. The incidence of atrial fibrillation in the first 72 hours after surgerywas evaluated in both groups. Results: The incidence of atrial fibrillation was lower in the case group (11.25%,9 in 80) than in the control group, (23.35%, 43 in 184) (P = 0.03). Other studied variables were similar betweenthe groups except for the creatinine clearance, which was higher in the control group. Conclusion: The presentstudy demonstrates that the central venous pressure control within the first 72 hours after surgery reduces theincidence of atrial fibrillation after coronary artery bypass grafting.

Aplicativo multimídia em plataforma móvel para o ensino da mensuração da pressão venosa central / Multimedia application in mobile platform for teaching the measurement of central venous pressure / Aplicación multimedia en la plataforma móvil para la enseñanza de la medición de la presión venosa central

O objetivo do estudo foi desenvolver e avaliar um aplicativo multimídia em plataforma móvel para o ensino da Mensuração da Pressão Venosa Central (PVC). A pesquisa foi desenvolvida em três fases (Levantamento das necessidades; Metodologia de desenvolvimento do aplicativo multimídia e Avaliação do aplicativo multimídia). A multimídia foi o método escolhido por favorecer um ambiente motivador e dinâmico, integrar imagens e textos num aplicativo disponível para celulares, constituindo-se um meio móvel e autônomo de aprendizagem. Os resultados permitem demonstrar a viabilidade do desenvolvimento da ferramenta para subsidiar a prática pedagógica e abrem perspectivas para acreditar que, na educação em Enfermagem, a tecnologia disponível pode descortinar novos modos de aprender significativamente.

This study aimed to develop and assess an application software for the teaching of the procedure Manual Measurement of the Central Venous Pressure which can be used in mobile devices. The research was conducted in three phases (Survey of needs; Methodology for multimedia application development and evaluation of the multimedia application).The multimedia was the method chosen because it favors an encouraging and dynamic environment, as it integrates images and texts into an application software available for cell phones, constituting a mobile and autonomous means for learning. The research allowed to demonstrate the feasibility of the development from this pedagogical tool and open up prospects for believing that, in Nursing education, the technology available can uncover new ways of learning in a meaningful manner.

El objetivo del estudio fue desarrollar y evaluar una aplicación multimedia en la plataforma móvil para la enseñanza Medición de la Presión Venosa Central (PVC). La investigación se llevó a cabo en tres fases (estudio de las necesidades, metodología para el desarrollo de aplicaciones multimedia y evaluación de la aplicación multimedia). Multimedia fue el método elegido para proponer un ambiente dinámico y motivador, la integración de imágenes y texto en una aplicación disponible en los teléfonos móviles, convirtiendo-se en un medio de aprendizaje móvil y autónomo. Los resultados nos permiten demostrar la viabilidad de desarrollar una herramienta para apoyar la práctica docente y abrir perspectivas para creer que la educación en Enfermería, la tecnología disponible puede descubrir nuevas formas de aprendizaje de manera significativa.

Effects of arterial oxygen tension and cardiac output on venous saturation: a mathematical modeling approach

OBJECTIVES: Hemodynamic support is aimed at providing adequate O2 delivery to the tissues; most interventions target O2 delivery increase. Mixed venous O2 saturation is a frequently used parameter to evaluate the adequacy of O2 delivery. METHODS: We describe a mathematical model to compare the effects of increasing O2 delivery on venous oxygen saturation through increases in the inspired O2 fraction versus increases in cardiac output. The model was created based on the lungs, which were divided into shunted and non-shunted areas, and on seven peripheral compartments, each with normal values of perfusion, optimal oxygen consumption, and critical O2 extraction rate. O2 delivery was increased by changing the inspired fraction of oxygen from 0.21 to 1.0 in steps of 0.1 under conditions of low (2.0 L.min-1) or normal (6.5 L.min-1) cardiac output. The same O2 delivery values were also obtained by maintaining a fixed O2 inspired fraction value of 0.21 while changing cardiac output. RESULTS: Venous oxygen saturation was higher when produced through increases in inspired O2 fraction versus increases in cardiac output, even at the same O2 delivery and consumption values. Specifically, at high inspired O2 fractions, the measured O2 saturation values failed to detect conditions of low oxygen supply. CONCLUSIONS: The mode of O2 delivery optimization, specifically increases in the fraction of inspired oxygen versus increases in cardiac output, can compromise the capability of the "venous O2 saturation" parameter to measure the adequacy of oxygen supply. Consequently, venous saturation at high inspired O2 fractions should be interpreted with caution.

Presión aórtica central y parámetros de reflexión de onda. Importancia clínica y análisis de consistencias y discrepancias con niveles de presión periférica / Central aortic pressure wave reflection parameters. Clinical significance and analysis of consistencies and discrepancies with peripheral pressure levels

Introducción: se presenta un trabajo de revisión sobre las diferencias entre la presión aórtica central (PAC) y la presión arterial periférica (PAP), y sobre la importancia biomédica de la PAC. Adicionalmente, se presenta un trabajo de investigación original que permitió determinar curvas por edad para la PAC de una población uruguaya y determinar los porcentajes de individuos (discriminando por edad, sexo y nivel de PAP) que presentan niveles de PAC hipertensivos. Material y método: en 785 uruguayos (edad: 6-79 años), sin enfermedad cardiovascular, hipertensión arterial, diabetes e insuficiencia renal, y sin empleo de fármacos vasoactivos, se midió la PAC y parámetros de reflexión de onda (índice de aumento, presión de aumento aórtica) mediante tonometría de aplanamiento radial y aplicación de una función transferencia generalizada. Resultados: se obtuvieron las tendencias por edad esperables de encontrar para los parámetros de PAC y reflexiones de onda. El 3% y 24% de personas con PAP normal/normal alta, respectivamente, presentaron PAC sistólica mayor del valor deseado. El 32% de personas con PAP clasificable como HTA 1 no presentarían PAC hipertensiva. El 11%-17% de las personas con niveles de PAP óptimos presentaron presión de pulso (PP) aórticas hipertensivas. El 22% y 35% de las personas con PAP normal/normal alta, respectivamente, presentaron PP aórtica hipertensivas. El 43% de personas con niveles de PAP clasificable como HTA 1 no presentaron PP aórtica hipertensiva. Conclusión: medir la PAC contribuiría en la evaluación y clasificación de estados hipertensivos, la valoración de la respuesta al tratamiento y en la determinación del riesgo vascular del paciente.

Should we stop using the determination of central venous pressure as a way to estimate cardiac preload? / Debemos abandonar la determinacion de la presion venosa central como medida de estimacionde la precarga cardiaca?

The determination of the values of central venous pressure has long been used as a guideline for volumetric therapy in the resuscitation of the critical patient, but the performance of such parameter is currently being questioned as an effective measurement of cardiac preload. This has aroused great interest in the search for more accurate parameters to determine cardiac preload and a patient’s blood volume.Goals and Methodology: Based on literature currently available, we aim to discuss the performance of central venous pressure as an effective parameter to determine cardiac preload.Results and Conclusion: Estimating variables such as end-diastolic ventricular area and global end-diastolic volume have a better performance than central venous pressure in determining cardiac preload. Despite the best performance of these devices, central venous pressure is still considered in our setting as the most practical and most commonly available way to assess the patient’s preload.Only dynamic variables such as pulse pressure change are superior in determining an individual’s blood volume