Physiology and technology hand in hand for clinical imaging of the microcirculation

Given the growing interest in the study of microcirculation, we believe that an editorial comment about our article should be welcome. Unfortunately, we feel that the editorialists failed to understand our findings. Drs. Takala and Jakob raise some specific issues. First, they emphasize the high susceptibility ofthe model to hemorrhage, already addressed in the manuscript. Unfortunately, they fail to realize that reductions of 24% in cardiac output (CO) only marginally increased lactate (1.6 ± 0.3 to 2.4 ± 0.6 mmol/l) and had no effects on systemic and intestinal oxygen consumptions, blood pressure or base excess, while provoking clear microcirculatory changes. These, however, could be tracked non-invasively in the sublingual mucosa, rendering it a potential area for the clinical monitoring of hypoperfusion.Facultad de Ciencias Médica

Improving acid-base evaluation: The proper use of the old tools

This reply refers to the comment "Reply to Dubin".Facultad de Ciencias Médica

Microcirculation in the intensive care unit

A manutenção da oxigenação tissular é um objetivo primordial no tratamento de pacientes criticamente enfermos. Lamentavelmente não existe um padrão-ouro para seu monitoramento. Há muitos anos a pesquisa tem se focalizado no comportamento dos parâmetros derivados do oxigênio sistêmico. Assim sendo, um grande número de estudo buscou tratar do significado de diferentes relacionamentos entre o transporte de oxigênio (DO2) e seu consumo (VO2). A sepse se caracteriza por anormalidades na extração de oxigênio, mas a relevância de um platô de VO2 ou um relacionamento linear VO2/DO2 (a assim chamada dependência patológica) continua desconhecida.(1) Além do mais, pode ser evidenciada hipoperfusão tissular grave mesmo sob condições normais ou aumentadas de VO2 sistêmico ou intestinal. Por outro lado, alterações paralelas de VO2 e DO2 podem não ser fenômenos patológicos, mas apenas reflexo de um comportamento fisiológico do sistema, no qual o débito cardíaco e DO2 são modificados para satisfazer as modificações na demanda de oxigênio. Na verdade, estes parâmetros podem ser enganosos por causa de desvantagens metodológicas relacionadas a suas mensurações e cálculos. Exames para substituição de VO2/DO2 como saturações venosa central ou venosa mista de oxigênio são geralmente normais nos pacientes de UTI.(2) Consequentemente, sua utilidade, se alguma, parece ser apenas relacionada a pacientes que não receberam ressuscitação.(3) O desenvolvimento de tonometria gastrintestinal e a subsequente introdução de diferentes formas de capnometria tissular foram fases relevantes no monitoramento da perfusão tissular. A tonometria gastrintestinal rapidamente se tornou uma ferramenta útil em pesquisa básica. Além disto, pela primeira vez foi usado um parâmetro regional para detectar e tratar hipoperfusão no paciente crítico.(4) Apesar do relevante corpo de evidência que demostra seu valor, a tonometria gástrica e a capnografia sublingual não são mais utilizadas. Diferentes problemas metodológicos e questões comerciais podem explicar este fato.Facultad de Ciencias Médica

Current use of vasopressors in septic shock

Background: Vasopressors are commonly applied to restore and maintain blood pressure in patients with sepsis. We aimed to evaluate the current practice and therapeutic goals regarding vasopressor use in septic shock as a basis for future studies and to provide some recommendations on their use. Methods: From November 2016 to April 2017, an anonymous web-based survey on the use of vasoactive drugs was accessible to members of the European Society of Intensive Care Medicine (ESICM). A total of 17 questions focused on the profle of respondents, triggering factors, frst choice agent, dosing, timing, targets, additional treatments, and efects of vasopressors. We investigated whether the answers complied with current guidelines. In addition, a group of 34 international ESICM experts was asked to formulate recommendations for the use of vasopressors based on 6 questions with sub-questions (total 14). Results: A total of 839 physicians from 82 countries (65% main specialty/activity intensive care) responded. The main trigger for vasopressor use was an insufcient mean arterial pressure (MAP) response to initial fuid resuscitation (83%). The frst-line vasopressor was norepinephrine (97%), targeting predominantly a MAP>60–65 mmHg (70%), with higher targets in patients with chronic arterial hypertension (79%). The experts agreed on 10 recommendations, 9 of which were based on unanimous or strong (≥80%) agreement. They recommended not to delay vasopressor treatment until fuid resuscitation is completed but rather to start with norepinephrine early to achieve a target MAP of≥65 mmHg. Conclusion: Reported vasopressor use in septic shock is compliant with contemporary guidelines. Future studies should focus on individualized treatment targets including earlier use of vasopressors.La lista completa de autores puede verse en el archivo asociado.Facultad de Ciencias Médica

Physiology and technology hand in hand for clinical imaging of the microcirculation

Given the growing interest in the study of microcirculation, we believe that an editorial comment about our article should be welcome. Unfortunately, we feel that the editorialists failed to understand our findings. Drs. Takala and Jakob raise some specific issues. First, they emphasize the high susceptibility ofthe model to hemorrhage, already addressed in the manuscript. Unfortunately, they fail to realize that reductions of 24% in cardiac output (CO) only marginally increased lactate (1.6 ± 0.3 to 2.4 ± 0.6 mmol/l) and had no effects on systemic and intestinal oxygen consumptions, blood pressure or base excess, while provoking clear microcirculatory changes. These, however, could be tracked non-invasively in the sublingual mucosa, rendering it a potential area for the clinical monitoring of hypoperfusion.Facultad de Ciencias Médica

Current use of inotropes in circulatory shock

Background: Treatment decisions on critically ill patients with circulatory shock lack consensus. In an international survey, we aimed to evaluate the indications, current practice, and therapeutic goals of inotrope therapy in the treatment of patients with circulatory shock. Methods: From November 2016 to April 2017, an anonymous web-based survey on the use of cardiovascular drugs was accessible to members of the European Society of Intensive Care Medicine (ESICM). A total of 14 questions focused on the profile of respondents, the triggering factors, first-line choice, dosing, timing, targets, additional treatment strategy, and suggested effect of inotropes. In addition, a group of 42 international ESICM experts was asked to formulate recommendations for the use of inotropes based on 11 questions. Results: A total of 839 physicians from 82 countries responded. Dobutamine was the first-line inotrope in critically ill patients with acute heart failure for 84% of respondents. Two-thirds of respondents (66%) stated to use inotropes when there were persistent clinical signs of hypoperfusion or persistent hyperlactatemia despite a supposed adequate use of fluids and vasopressors, with (44%) or without (22%) the context of low left ventricular ejection fraction. Nearly half (44%) of respondents stated an adequate cardiac output as target for inotropic treatment. The experts agreed on 11 strong recommendations, all of which were based on excellent (> 90%) or good (81–90%) agreement. Recommendations include the indications for inotropes (septic and cardiogenic shock), the choice of drugs (dobutamine, not dopamine), the triggers (low cardiac output and clinical signs of hypoperfusion) and targets (adequate cardiac output) and stopping criteria (adverse effects and clinical improvement). Conclusion: Inotrope use in critically ill patients is quite heterogeneous as self-reported by individual caregivers. Eleven strong recommendations on the indications, choice, triggers and targets for the use of inotropes are given by international experts. Future studies should focus on consistent indications for inotrope use and implementation into a guideline for circulatory shock that encompasses individualized targets and outcomes.La lista completa de autores que integran el documento puede consultarse en el archivo.Facultad de Ciencias Médica

Falta de concordância entre diferentes observadores e métodos na mensuração do tempo de reenchimento capilar em voluntários saudáveis: estudo observacional

Objective: Peripheral perfusion abnormalities are relevant manifestations of shock. Capillary refill time is commonly used for their evaluation. However, the reproducibility of capillary refill time measurements and their correlation with other variables of peripheral perfusion, have not been comprehensively evaluated. Our goal was to determine, in healthy volunteers, the agreement between different methods of capillary refill time quantification and different observers, as well as their correlation with other markers of peripheral perfusion. Methods: We studied 63 healthy volunteers. Two observers measured capillary refill time by means of two methods, direct view (CRTchronometer) and video analysis (CRTvideo). We also measured perfusion index (PI) derived from pulse plethysmography and finger pad temperature (T°peripheral). The agreement between observers and methods was assessed using the Bland and Altman method. Correlations were calculated using Pearson's correlation. A p-value<0.05 was considered significant. Results: The 95% limits of agreement between the two observers were 1.9 sec for CRTchronometer and 1.7 sec for CRTvideo. The 95% limits of agreement between CRTchronometer and CRTvideo were 1.7 sec for observer 1 and 2.3 sec for observer 2. Measurements of CRTchronometer performed by the two observers were correlated with T°peripheral. Measurements of CRTvideo performed by the two observers were correlated with T°peripheral and perfusion index. Conclusion: In healthy volunteers, measurements of capillary refill time performed by either different observers or different methods showed poor agreement. Nevertheless, capillary refill time still reflected peripheral perfusion as shown by its correlation with objective variables of peripheral perfusion.Facultad de Ciencias Médica

Peripheral arterial blood pressure monitoring adequately tracks central arterial blood pressure in critically ill patients: an observational study

INTRODUCTION: Invasive arterial blood pressure monitoring is a common practice in intensive care units (ICUs). Accuracy of invasive blood pressure monitoring is crucial in evaluating the cardiocirculatory system and adjusting drug therapy for hemodynamic support. However, the best site for catheter insertion is controversial. Lack of definitive information in critically ill patients makes it difficult to establish guidelines for daily practice in intensive care. We hypothesize that peripheral and central mean arterial blood pressures are interchangeable in critically ill patients. METHODS: This is a prospective, observational study carried out in a surgical-medical ICU in a teaching hospital. Fifty-five critically ill patients with clinical indication of invasive arterial pressure monitoring were included in the study. No interventions were made. Simultaneous measurements were registered in central (femoral) and peripheral (radial) arteries. Bias and precision between both measurements were calculated with Bland-Altman analysis for the whole group. Bias and precision were compared between patients receiving high doses of vasoactive drugs (norepinephrine or epinephrine >0.1 μg/kg/minute or dopamine >10 μg/kg/minute) and those receiving low doses (norepinephrine or epinephrine <0.1 μg/kg/minute or dopamine <10 μg/kg/minute). RESULTS: Central mean arterial pressure was 3 ± 4 mmHg higher than peripheral mean arterial pressure for the whole population and there were no differences between groups (3 ± 4 mmHg for both groups). CONCLUSION: Measurement of mean arterial blood pressure in radial or femoral arteries is clinically interchangeable. It is not mandatory to cannulate the femoral artery, even in critically ill patients receiving high doses of vasoactive drugs

Improving acid-base evaluation: The proper use of the old tools

This reply refers to the comment "Reply to Dubin".Facultad de Ciencias Médica