Critical care clinics
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Normal water balance with strict maintenance of plasma osmolality depends on appropriate water conservation (controlled by ADH release and action) and additional water intake if required (triggered by the awareness of thirst). Central nervous system pathology (including trauma) commonly involves the hypothalamus and pituitary stalk, leading to impaired osmoreceptor function or diminished ADH production or release, resulting in diabetes insipidus (with potentially life-threatening abnormalities in fluid and electrolyte status). Assessment of the relationships between plasma and urine osmolality and plasma ADH levels will usually lead to an accurate diagnosis. Central diabetes insipidus is effectively treated with replacement of free water deficits and exogenous ADH analogues.
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Along with the development of more specific and potent immunosuppressive agents, improvements in perioperative care of the allograft recipient have made transplantation of nonrenal organs a reality and contributed greatly to overall improvements in graft and patient survival. Thorough pretransplant evaluation, intensive care therapy and monitoring (when indicated), and meticulous postoperative care are essential to a successful outcome and to minimize the occurrence of complications.
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The non-conventional techniques for ventilatory support represent a new approach to the management of patients with respiratory failure. A large number of studies indicate that these techniques can maintain adequate gas exchange under conditions in which the traditional concepts of gas transport no longer hold. We have reviewed the group of techniques, collectively called high frequency ventilation (HFV), in which the tidal volumes are much less (1 to 5 ml per kg) than those observed during conventional mechanical ventilation. ⋯ However, results in neonates have been quite encouraging. ECCO2R allows less exposure of blood to the extracorporeal circuit and avoids the reduction in pulmonary blood flow associated with ECMO. Although the reported survival of adults with severe acute respiratory failure treated with ECCO2R is extremely promising, it is important to point out that none of the published reports are controlled, randomized studies.(ABSTRACT TRUNCATED AT 400 WORDS)
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Although the majority of patients can be easily weaned from mechanical ventilation, a substantial minority pose considerable difficulty. These patients account for a disproportionate amount of health care costs, and they pose enormous clinical, economic, and ethical problems. ⋯ Several techniques of weaning can be used, and there are no data to suggest the superiority of one technique over another. Management of the problem patient should be directed at the underlying cause of ventilator dependency, and an organized plan should be followed.
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Critical care clinics · Jul 1990
ReviewStrategies to minimize breathing effort during mechanical ventilation.
A primary objective of mechanical ventilation is to alleviate the intolerable effort of breathing while allowing the patient to perform enough work to prevent atrophy. By assuming the workload associated with breathing, mechanical support averts ventilatory failure, prevents respiratory arrest, assures CO2 removal and pH homeostasis, while permitting the overtaxed respiratory muscles to replenish energy reserves as the primary process is addressed. Skillful manipulation of the breathing workload can often facilitate the ventilator withdrawal process. The objectives of this article are to characterize the magnitude of ventilatory work performed by the machine and patient during mechanical ventilation and to formulate a strategy for minimizing the breathing workload.