Shock : molecular, cellular, and systemic pathobiological aspects and therapeutic approaches : the official journal the Shock Society, the European Shock Society, the Brazilian Shock Society, the International Federation of Shock Societies
-
Glucocorticoid and epinephrine are important stress hormones secreted from the adrenal gland during critical illness. Adrenal glucocorticoid stimulates phenylethanolamine N-methyltransferase (PNMT) to convert norepinephrine to epinephrine in the adrenal medulla. Glucocorticoid is sometimes used in catecholamine-resistant septic shock in critically ill patients. ⋯ We conclude that without stress, when adrenocorticotropic hormone is low, high doses of exogenous dexamethasone stimulate PNMT and catecholamine synthesis, likely independently of adrenal corticosterone concentration. After stress, adrenocorticotropic hormone levels are elevated, and exogenous dexamethasone suppresses endogenous corticosterone and PNMT production. Nonetheless, catecholamines increase, possibly due to direct neural stimulation, which may override the hormonal regulation of epinephrine synthesis during stress.
-
There are only few strategic and therapeutic options to improve the functional outcome of patients after cardiac arrest and resuscitation (CPR). The pathophysiology of reperfusion injury after global ischemia is not completely understood. We present here a murine model of cardiac arrest and resuscitation that allows an analysis of the pathophysiology of reperfusion injury, especially focusing on survival, tissue damage, and functional neurological parameters. ⋯ Histological examinations and blood analyses of CPR animals revealed significant leukocyte tissue infiltration and morphological damage of brain, lung, and kidneys. In summary, mice undergoing CPR after cardiac arrest present distinct neurological deficits, marked organ damage, and a 54% mortality rate. Our highly standardized and reproducible model of mice resuscitation provides a means for a better understanding of the post-CPR pathophysiology and thus opens new perspectives to develop relevant therapeutic approaches to minimize global I/R injury.
-
Identification of occult shock is a major clinical problem compounded by inadequate criteria for assessing the efficacy of fluid resuscitation. We suggest that these problems may be resolved in part by understanding both the physiological mechanisms underlying oxygen debt accumulation and, more importantly, the debt repayment schedule during resuscitation. We present a simplified tutorial that incorporates the concept of the oxygen supply-delivery relationship with that of oxygen debt and show how this is relevant to the understanding of shock and resuscitation. ⋯ Because of difficulties inherent in measuring oxygen debt in the prehospital and emergency settings, various metabolic end points such as lactate and base deficit have been proposed as surrogates. We demonstrate the heuristic value of this model in providing a predictive framework for both the optimum therapeutic time window and optimum fluid loadings before critical transitions to an irreversible shock state can occur. The model also provides an unambiguous and objective standard for quantifying the behavior of various postulated shock "markers".
-
Hemoglobin solutions have demonstrated a pressor effect that could adversely affect hemorrhagic shock patient resuscitation through accelerated hemorrhage, diminished perfusion, or inadequate resuscitation. Data from two parallel, multicenter traumatic hemorrhagic shock clinical trials in 17 US emergency departments and in 27 EU prehospital systems using diaspirin cross-linked hemoglobin (DCLHb), a hemoglobin-based resuscitation fluid. In the 219 patients, patients were 37 years old, 64% sustained blunt injury, 48% received DCLHb, and 36% expired. ⋯ In the United States alone, treatment group was not correlated by regression with BP at any time point. Neither mean BP readings nor elevated BP readings were correlated with DCLHb treatment of traumatic hemorrhagic shock patients. As such, no clinically demonstrable DCLHb pressor effect could be directly related to the adverse mortality outcome observed in the US study.
-
The present study was designed to find out whether SB431542, an inhibitor of transforming growth factor beta1 activin receptor-like kinase, could protect the lung from LPS-induced injury. Inflammatory lung injury model was induced by intratracheal administration of LPS. C57BL/6 mice were randomly divided into the sham control group (S group), the LPS stimulation group (L group), the LPS + early SB431542 treatment group (Ie group), and the LPS + delayed SB431542 treatment group (Id group). ⋯ Those parameters were further aggravated in the Ie group whereas relieved significantly in the Id group. These data suggest that SB431542 therapy for inflammatory lung injury could be harmful if performed during early-phase inflammatory response. However, the therapy would prevent lung from inflammatory injury and fibrosis if it was initiated late.