Critical care medicine
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Critical care medicine · Feb 1996
ReviewEvidence based critical care medicine; what is it and what can it do for us? Evidence Based Medicine in Critical Care Group.
To describe the philosophy and approach to patient care called evidence based medicine, and to highlight how it can enhance the practice of intensive care. ⋯ Evidence based medicine can complement other foundation disciplines in intensive care. This is the first article in a series entitled "Evidence Based Critical Care Medicine" which will demonstrate how this approach can be used at the bedside.
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Suspended animation is defined as the therapeutic induction of a state of tolerance to temporary complete systemic ischemia, i.w., protection-preservation of the whole organism during prolonged circulatory arrest ( > or = 1 hr), followed by resuscitation to survival without brain damage. The objectives of suspended animation include: a) helping to save victims of temporarily uncontrollable (internal) traumatic (e.g., combat casualties) or nontraumatic (e.g., ruptured aortic aneurysm) exsanguination, without severe brain trauma, by enabling evacuation and resuscitative surgery during circulatory arrest, followed by delayed resuscitation; b) helping to save some nontraumatic cases of sudden death, seemingly unresuscitable before definite repair; and c) enabling selected (elective) surgical procedures to be performed which are only feasible during a state of no blood flow. ⋯ The following topics are addressed: the epidemiologic facts of sudden death in combat casualties, which require a totally new resuscitative approach; the limits and potentials of reanimation research; complete reversibility of circulatory arrest of 1 hr in dogs under profound hypothermia ( < 10 degrees C), induced and reversed by portable cardiopulmonary bypass; the need for a still elusive pharmacologic or chemical induction of suspended animation in the field; asanguinous profound hypothermic low-flow with cardiopulmonary bypass; electric anesthesia; opiate therapy; lessons learned by hypoxia tolerant vertebrate animals, hibernators, and freeze-tolerant animals (cryobiology); myocardial preservation during open-heart surgery; organ preservation for transplantation; and reperfusion-reoxygenation injury in vital organs, including the roles of nitric oxide and free radicals; and how cells (particularly cerebral neurons) die after transient prolonged ischemia and reperfusion. The majority of authors believe that seeking a breakthrough in suspended animation is not utopian, that ongoing communication between relevant research groups is indicated, and that a coordinated multicenter research effort, basic and applied, on suspended animation is justified.
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Critical care medicine · Feb 1996
ReviewCerebral resuscitation from cardiac arrest: treatment potentials.
In 1961, in Pittsburgh, PA, "cerebral" was added to the cardiopulmonary resuscitation system (CPR --> CPCR). Cerebral recovery is dependent on arrest and cardiopulmonary resuscitation times, and numerous factors related to basic, advanced, and prolonged life support. Postischemic-anoxic encephalopathy (the cerebral postresuscitation disease or syndrome) is complex and multifactorial. ⋯ Treatments without permanent beneficial effects may at least extend the therapeutic window. All of these investigations will require coordinated efforts by multiple research groups, pursuing systematic, multilevel research--from cell cultures to rats, to large animals, and to clinical trials. There are still many gaps in our knowledge about optimizing extracerebral life support for cerebral outcome.
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Resuscitative (postinsult) hypothermia is less well studied than protective-preservative (pre- and intra-arrest) hypothermia. The latter is in wide clinical use, particularly for protecting the brain during cardiac surgery. Resuscitative hypothermia was explored in the 1950s and then lay dormant until the 1980s when it was revived. ⋯ Among many clinically feasible rapid cooling methods, carotid cold flush and peritoneal cooling look promising. After traumatic brain injury or focal brain ischemia, which seem to still benefit from even later cooling, surface cooling methods may be adequate. Resuscitative hypothermia after cardiac arrest, traumatic brain injury, or focal brain ischemia should be considered for clinical trials.
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To study sequential changes in heart rate, respiratory rate, blood pressure, heart rate power spectra, and plasma catecholamine concentrations in patients with acute brain injury and correlate these variables with the severity of neurologic dysfunction and patient outcome. ⋯ Our results imply that autonomic nervous system control of heart rate is disrupted in proportion to the degree of neurologic insult in children after acute brain injury. Thus, heart rate power spectral analysis and plasma catecholamine concentrations may prove to be useful adjuncts in determining severity of neurologic injury and prognosis for recovery in children suffering from brain injury. In addition, these techniques may aid in the determination of brain death.