New horizons (Baltimore, Md.)
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Septic shock is a complex pathophysiologic state which often leads to multiple organ dysfunction, multiple organ failure, and death. This review summarizes current views on the molecular biology of three aspects of septic shock: recognition of bacterial invasion and induction of the cytokine response; genetic variability among humans and their predispositions toward pathologic inflammatory responses; and the signal transduction mechanisms which account for the transfer of molecular signals from cytokine receptors on the plasma membrane to cytokine-responsive genes in the nucleus. In particular, the review summarizes the pathway involved in tumor necrosis factor signaling through nuclear factor-kappaB, and elucidates the molecular signals involved in inflammatory responses and apoptosis.
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Hypovolemic shock is a common disease treated in pediatric ICUs and emergency departments worldwide. A wide variety of etiologic factors may cause this disease, with the common net result of decreased intravascular volume leading to decreased venous return to the heart and decreased stroke volume. Inadequate perfusion results in impairment of delivery of nutrients and oxygen to vital end organs. ⋯ This is best accomplished by large peripheral or central intravenous access, with intraosseous access an alternative option in the pediatric patient. The amount as well as the type of volume administered must be tailored for each individual patient, taking into account the amount of intravascular depletion and the disease state in which the shock has occurred. It is not uncommon for children to require large amounts of fluid for resuscitation, and close attention must be paid to children with fluid-refractory shock, who may require catecholamine and/or exogenous steroid support in combination with aggressive fluid resuscitation.
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Shock in the pediatric population has many preventable causes. Treatment of children in shock will depend on access to health services, training of health personnel, availability of diagnostic procedures, monitoring, and therapeutic measures. Countries will differ among themselves and within themselves in the care provided to children developing shock. ⋯ Many children in shock do not even reach healthcare services. Investment in training healthcare personnel in a simplified and systematic approach to shock and access to equipped health services are basic to improved outcomes in the treatment of pediatric shock. The Brazilian experience in the treatment of children in shock outside hospital facilities, in the emergency department, and in the ICU is described.
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Shock in childhood is most commonly related to injury and blood loss, but hemodynamic compromise is occasionally caused by severe head or spinal injury, tension pneumothorax, myocardial injury, arrhythmias, and sepsis. Regardless of the cause, the initial management of the hypertensive child is establishment of a secure airway, maintenance of ventilation, and initiation of volume replacement via an adequate intravenous catheter. ⋯ With appropriate management, the typical clinical signs of shock will be reversed and the child will demonstrate improved vital signs, peripheral circulation and sensorium, normalization of body temperature, reversal of metabolic acidosis, and resumption of normal urine output. The more aggressive the approach to resuscitation, the more prompt the patient's response and the more likely morbidity and mortality will be minimized.
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The end point of uncorrected shock is cardiac arrest. Once cardiac arrest occurs, the outcome in children is typically poor, reflecting the fact that cardiac arrest does not occur until the child's physiologic reserves are exhausted. Despite more than 35 years of research in cardiac arrest, the optimal management and treatment remain uncertain. ⋯ The role of bicarbonate in the management of acidosis and the role of calcium in restarting the heart remain controversial. If and when the heart is restarted following cardiac arrest, the work is just beginning for the intensivist to manage the postarrest shock state. Dobutamine is useful in the normotensive child while epinephrine infusions are used to stabilize hypotensive, postarrest shock in the child.