Seminars in dialysis
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Seminars in dialysis · Nov 2006
ReviewMechanical ventilation in the management of acute respiratory distress syndrome.
The occurrence of acute respiratory distress syndrome (ARDS), is now common in intensive care units throughout the world. The diagnosis of ARDS is based on a definition that includes bilateral pulmonary infiltrates on chest radiographs, impaired oxygenation, and the absence of clinical evidence of elevated left atrial pressure. ARDS is the clinical result of a group of diverse processes, which range from physical or chemical injury, to extensive activation of innate inflammatory response. ⋯ Other strategies such as high positive end expiratory pressure and prone positioning have not been shown to reduce mortality. Clinicians who are involved in the care of patients with ARDS should have a basic understanding of mechanical ventilation and the evidence guiding the mechanical ventilation strategies of these patients. Until further evidence is published, providers should adopt the use of a volume and pressure limited approach to mechanical ventilation.
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The development of many electrolyte disturbances in the ICU can be prevented by attention to the use of intravenous fluids and nutrition. Hyponatremia is a relative contraindication to the use of hypotonic intravenous fluids and hypernatremia calls for the administration of water. Formulae have been devised to guide the therapy of severe hyponatremia and hypernatremia. ⋯ Thus, therapy of severe hyponatremia and hypernatremia must be closely monitored with serial electrolyte measurements. The significance of hypocalcemia in the critically ill is controversial. Hypokalemia, hypophosphatemia, and hypomagnesemia should be corrected.
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Seminars in dialysis · Nov 2006
ReviewPerioperative fluid management: current consensus and controversies.
The scientific knowledge base that supports clinical decisions about perioperative fluid management continues to evolve. However, despite these advancements in the understanding of the physiology of fluid replacement, the definition of ''optimal'' perioperative fluid management remains a matter of clinical judgment. With an appreciation of the many factors, both sensible and insensible, that contribute to changes in blood and extracellular fluid volume during surgery, clinicians have tried to create reproducible and generally applicable formulas for replacement of fluid during surgery. ⋯ The relative ease of pre-identified fluid replacement protocols is being slowly replaced by data-guided interventions that take into account a variety of factors. Clinicians are therefore required to tailor their fluid replacement strategies based on preoperative patient characteristics, the type of surgery and even the type of anesthetic that is utilized. Some of the benefits of this new approach range from relatively ''minor'' outcomes such as diminished nausea after surgery to preventing postoperative complications such as wound breakdown and cardiopulmonary failure.
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Pulmonary artery catheterization has been a routine part of care for critically ill patients over the past 25 years. Primary hemodynamic data regarding cardiac output and pulmonary pressures can be utilized to make diagnoses and guide therapy. Tissue oxygen delivery and utilization allow inferences about the efficiency of the cardiopulmonary system and the impact of disease and medical therapies on tissue metabolism. ⋯ Optimizing renal perfusion and minimizing pulmonary congestion with precise volume titration are common reasons for performing pulmonary artery catheterization in the intensive care unit. Despite being reassuring to clinicians that hemodynamic therapy is optimal, multiple data from well conducted clinical studies have not demonstrated outcome benefits to patients related to pulmonary artery catheterization. Less invasive techniques to obtain data regarding hemodynamic function are now entering the clinical arena and are being actively investigated.
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The appropriate and timely evaluation and treatment of patients with severely elevated blood pressure is essential to avoid serious adverse outcomes. Most importantly, the distinction between a hypertensive emergency (crisis) and urgency needs to be made. A sudden elevation in systolic (SBP) and/or diastolic blood pressure (DBP) that is associated with acute end organ damage (cardiovascular, cerebrovascular, or renal) is defined as a hypertensive crisis or emergency. ⋯ In patients with a hypertensive emergency, blood pressure control should be attained as expeditiously as possible with parenteral medications to prevent ongoing and potentially permanent end organ damage. In contrast, with hypertensive urgency, blood pressure control can be achieved with the use of oral medications within 24-48 hours. This paper reviews the management of hypertensive emergencies.