Objetivos de la reanimación hemodinámica

Abstract

Cardiovascular failure or shock, of any etiology, is characterized by ineffective perfusion of body tissues, inducing derangements in the balance between oxygen delivery and consumption. Impairment in oxygen availability on the cellular level causes a shift to anaerobic metabolism, with an increase in lactate and hydrogen ion production that leads to lactic acidosis. The degree of hyperlactatemia and metabolic acidosis will be directly correlated to the development of organ failure and poor outcome of the individuals. The amount of oxygen available at the tissues will depend fundamentally on an adequate level of perfusion pressure and oxygen delivery. The optimization of these two physiologic parameters can re-establish the balance between oxygen delivery and consumption on the cellular level, thus, restoring the metabolism to its aerobic paths. Monitoring variables such as lactate and oxygen venous saturations (either central or mixed) during the initial resuscitation of shock will be helpful to determine whether tissue hypoxia is still present or not. Recently, some new technologies have been developed in order to evaluate local perfusion and microcirculation, such as gastric tonometry, near-infrared spectroscopy and videomicroscopy. Although monitoring these regional parameters has demonstrated its prognostic value, there is a lack of evidence regarding to its usefulness during the resuscitation process. In conclusion, hemodynamic resuscitation is still based on the rapid achievement of adequate levels of perfusion pressure, and then on the modification of oxygen delivery variables, in order to restore physiologic values of ScvO(2)/SvO(2) and resolve lactic acidosis and/or hyperlactatemia.

Skeletal Muscle Oxygen Saturation (StO2) Measured by Near-Infrared Spectroscopy in the Critically Ill Patients

“…This compensatory mechanism can mask significant hypovolemia associated with hypoperfusion in certain territories, with significant negative impact on outcome [1]. Accordingly, in situations of hypovolemia, a decrease in blood flow to skeletal muscle is expected, with increases in oxygen extraction and decreases in the content of hemoglobin at the regional level.…”

“…Cumulative evidence on the association between microcirculatory alterations persistence, despite normalization of macrohemodynamic variables, and poor prognosis [1] has led to the idea that evaluating regional oxygenation parameters should be performed at the end of conventional “global” resuscitation. In addition to several in vivo videomicroscopy studies, Lima et al recently found, in a population of septic patients, that alterations in StO 2 values at the end of the Early Goal-Directed Therapy (EGDT) were associated with higher degrees of organ failure and mortality [16].…”

“…In our daily clinical practice, hemodynamic resuscitation of shock states aims to restore global tissue oxygenation markers, such as venous saturations (either central or mixed) or lactate. Including these endpoint variables in the management of shock has led to remarkable improvements in the survival of critically ill patients [1]. However, there is overwhelming evidence demonstrating that, despite normalization of these global tissue hypoxia markers, perfusion disorders might persist at the microcirculatory level [2, 3].…”

Central venous-to-arterial carbon dioxide difference combined with arterial-to-venous oxygen content difference is associated with lactate evolution in the hemodynamic resuscitation process in early septic shock

“…Current guidelines for hemodynamic management of severe sepsis and septic shock recommend the use of global markers of tissue hypoxia as resuscitation endpoints [ 1 , 2 ]. In the initial resuscitation period, targeting either central venous oxygen saturation (S cv O 2 ) normalization or lactate clearance, or the combination of both, is accepted [ 1 , 3 , 4 ].…”

La saturación venosa central de oxígeno es un factor predictor de mortalidad en el paciente con choque séptico

“…Tomando en cuenta los datos anteriores, es evidente, que la principal complicación de la sepsis es el choque séptico, que se caracteriza por la inadecuada perfusión tisular, secundaria a una situación de desequilibrio entre el aporte de oxígeno (DO 2 ) y el consumo de oxígeno (VO 2 ), producto de este desequilibrio, se incrementa la extracción de oxigeno (ExO 2 ) contenido en la sangre arterial. 5 . En la actualidad, las variables más valiosas en cuanto a detección de hipoxia tisular son el lactato en sangre y las saturaciones venosas de oxígeno (SvO 2 y SvcO 2 ).…”