Revisión clínica: depresión miocárdica en sepsis y shock séptico / Clinical revision: myocardial depression in sepsis and septic shock

La sepsis y el shock séptico son patologías de gran mortalidad, cuyo evento final es la hipotensión refractaria, colapso cardiocirculatorio y falla multiorgánica. En los últimos años se han realizado importantes esfuerzos para entender la disfunción cardiaca asociada a este cuadro, que puede objetivarse hasta en el 50 por ciento de los pacientes con sepsis severa y shock séptico. A pesar de que hoy se acepta que la disfunción miocárdica juega un importante rol en la sepsis, aún no existe consenso respecto a la manera de evaluar la función cardiaca en este contexto, surgiendo nuevas propuestas como el uso de marcadores séricos. Por otra parte, el tratamiento más utilizado hasta hoy han sido los inótropos como la dobutamina, sin embargo con los nuevos estudios sobre la etiología de la disfunción miocárdica, se ha logrado el desarrollo de nuevas líneas experimentales de tratamiento.

The sepsis and the septic shock are pathologies of the great mortality, whose final event is the refractory hypotension, circulatory collapse and multiorganic failure. In the last years important efforts have been made to understand the associate cardiac dysfunction to this picture, which can appear until in 50 percent of the patients with severe sepsis and septic shock. Although today it is accepted that the myocardial dysfunction plays an important role in the sepsis. It does not yet exist consensus with respect to the way to evaluate the function cardiac. New proposals arising as the use from seric markers. On the other hand, the more used treatment until today has been the inotropic agent like the dobutamine. But with the new studies on the etiology of the myocardial dysfunction, has been obtained the development of experimental new line of treatment.

Differentiation of autonomic reflex control begins with cellular mechanisms at the first synapse within the nucleus tractus solitarius

Visceral afferents send information via cranial nerves to the nucleus tractus solitarius (NTS). The NTS is the initial step of information processing that culminates in homeostatic reflex responses. Recent evidence suggests that strong afferent synaptic responses in the NTS are most often modulated by depression and this forms a basic principle of central integration of these autonomic pathways. The visceral afferent synapse is uncommonly powerful at the NTS with large unitary response amplitudes and depression rather than facilitation at moderate to high frequencies of activation. Substantial signal depression occurs through multiple mechanisms at this very first brainstem synapse onto second order NTS neurons. This review highlights new approaches to the study of these basic processes featuring patch clamp recordings in NTS brain slices and optical techniques with fluorescent tracers. The vanilloid receptor agonist, capsaicin, distinguishes two classes of second order neurons (capsaicin sensitive or capsaicin resistant) that appear to reflect unmyelinated and myelinated afferent pathways. The differences in cellular properties of these two classes of NTS neurons indicate clear functional differentiation at both the pre- and postsynaptic portions of these first synapses. By virtue of their position at the earliest stage of these pathways, such mechanistic differences probably impart important differentiation in the performance over the entire reflex pathways.

Síndrome cardiopulmonar por Hantavirus: utilidad de la monitorización con el sistema PiCCO / Hantavirus cardiopulmonary syndrome: utility of the PICCO(Pulse contour cardiac output) system for monitoring

We report a 68 years old man, farmer from the metropolitan region, admitted with a Hantavirus Cardiopulmonary Syndrome. The diagnosis was made using serologic test and was later confirmed by the Public Health Institute. He evolved to an early multiple organ failure, requiring high concentrations of oxygen and invasive ventilatory assistance, vasopressor drugs and renal replacement therapy. Swan Ganz and PiCCO were used simultaneously for hemodynamic monitoring. Treatment consisted in global support therapy, antimicrobial therapy and systemic corticosteroids. Intrathoracic blood volume was a more reliable parameter than pulmonary capillary wedge pressure for the assessment of preload. As expected in situations of increased vascular permeability, there was an increase in extravascular lung water. There was a good correlation between extravascular lung water and oxygenation parameters (PaO2/FiO2 and oxygenation index). PiCCO system may become a helpful tool in the management of patients with Hantavirus Cardiopulmonary Syndrome.

Impacto hemodinámico de la presión positiva de fin de espiración (PEEP) durante la falla respiratoria grave: visión actual / Hemodynamic impact of positive end expiratory pressure (PEEP) during severe respiratory failure: present view

Bedside evaluation of pulmonary mechanics and thoracic computed axial tomography have changed the ventilatory management of patients suffering an acute respiratory failure caused by adult respiratory distress syndrome (ARDS). Mortality has been reduced limiting tidal volumes, which avoids alveolar overdistention and by the use of positive end expiratory pressure (PEEP), that reduces the damage caused by cyclical alveolar collapse-reopening. Nowadays, it is well known that inappropriate mechanical ventilation enhances lung damage caused by the underlying disease. However, the optimal adjustment of PEEP is not yet established. Usually, it is not easy to achieve an equilibrium between an optimal lung recruitment without producing alveolar overdistention and hemodynamic adverse effects such as hypotension and reduction of cardiac output. This paper reviews the interactions between heart and lung.