摘要:

ObjectivesTo review the hormonal changes that have been reported after trauma, to define their etiologies, and to describe their consequences.Data SourcesLiterature review using MEDLINE and original data.Data SynthesisHormonal responses to trauma are bidirectional. Functional derangements include increases in adrenocorticotropin hormone and cortisol, growth hormone, and prolactin levels. In contrast, gonadotropin and gonadal steroid, and thyroid hormone concentrations decrease. The response is immediate but not necessarily sustained for those hormones that respond with increased secretion, whereas the effect may not become apparent for several hours, may be maximal after 1 to 4 days, and may persist for the duration of illness for those hormones that decrease. The reduction in hormone concentrations generally reflect diminished secretion, with the exception of the thyroid hormones where altered metabolic pathways and enhanced metabolic clearance play a major role.ConclusionsThe changes in circulating levels do not appear to be injury specific, but tend to reflect the severity of the traumatic insult, and there are some data for cortisol and thyroxine that show their concentrations may be of predictive value. In head-injured patients, structural as well as functional pituitary changes may be present. Patients may show varying degrees of pituitary insufficiency. However, the presence of hyperprolactinemia strongly suggests involvement of the hypothalamus. With the exception of bonafide hypopituitarism, the relevance of the hormonal changes after trauma awaits clarification.

ISSN:0090-3493    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ObjectiveTo review the physiology of the chloride ion and its relationship to various disease states encountered in the ICU. Special emphasis was paid to the renal handling of chloride and its role in the evaluation of the urine and serum anion gaps. Metabolic acidosis and alkalosis are discussed.Data SourcesEnglish-language articles were identified through a search of the MEDLINE and Index Medicus databases. Bibliographies of retrieved articles were examined for relevant articles.Study SelectionApproximately 125 articles and 25 textbook chapters were reviewed. Those articles most applicable to the ICU were used. Information contained in text chapters was included primarily in the tables.Data ExtractionAll available information was reviewed and analyzed by the authors before inclusion.Data SynthesisGuidelines for the evaluation of urine and serum electrolyte concentrations are presented. The use of the urine anion gap is discussed, particularly as it relates to the diagnosis of hyperchloremic metabolic acidosis. Stool chloride provides information relevant to congenital and acquired diarrheas. The evaluation of metabolic acidosis requires the calculation of the serum anion gap. Both normal and increased gap acidoses are discussed, although increased gap acidoses are more commonly encountered in the ICU. Urine chloride is invaluable in defining whether the metabolic alkalosis is sodium-chloride responsive (urine chlorideConclusionsMeasurement of chloride is a valuable tool in the evaluation and treatment of a variety of disorders. Serum chloride is most helpful in assessing both normal and increased anion gap metabolic acidoses, while urine chloride finds utility in the diagnosis of metabolic alkalosis and hyperchloremia metabolic acidosis. The evaluation of any disturbance in chloride homeostasis that defies easy explanation necessitates the measurement of stool electrolytes.

ISSN:0090-3493    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ObjectiveTo provide a brief overview of the causes, diagnosis, and therapies of electrolyte abnormalities frequently seen in critically ill children.Data SourcePublished articles and bibliographies identified from pertinent review articles and books published in the past 20 yrs on fluid and electrolyte therapy in children.ConstraintThe review includes only human studies and articles published in the English language.Study SelectionHuman studies pertaining to abnormalities of water homeostasis, sodium, potassium, calcium, and magnesium homeostasis in children were selected. Prospective randomized studies were selected as much as possible.Data ExtractionPertinent data abstracted from multiple, independent clinical studies were used to develop an approach to electrolyte abnormalities in critically ill children.Data SynthesisAn approach to diagnosis and therapies of common electrolyte abnormalities in critically ill children.ConclusionsElectrolyte abnormalities are common in critically ill children and can be easily treated once recognized. Further studies are needed to better understand the role of ionized calcium and magnesium in neonatal and pediatric critical illness.

ISSN:0090-3493    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

PurposeTo review calcium regulation, causes of hypocalcemia during critical illness, clinical features and treatment of hypocalcemia, hemodynamic effects of calcium administration, calcium-catecholamine interactions, and the role of calcium in ischemic injury.DesignRepresentative articles from the medical literature are used to support the discussion of selected aspects of calcium metabolism which are important to the practice of critical care medicine.SubjectsResults from both animal and human investigations and both in vitro and in vivo studies are discussed.ResultsCirculating calcium levels are best measured using ionized calcium electrodes. Ionized hypocalcemia is common in critically ill patients and usually results from impaired parathyroid hormone secretion or action, impaired vitamin D synthesis or action, or calcium chelation/precipitation. Ionized hypocalcemia most commonly presents as cardiovascular or neuromuscular insufficiency. Mild ionized hypocalcemia (>0.8 mmol/L) is usually asymptomatic and frequently does not require treatment. Moderate-to-severe ionized hypocalcemia is best treated with iv calcium in the critically ill patient. The majority of studies report no increase in cardiac output but a significant increase in BP after iv calcium administration. When administered with β-adrenergic agonists, calcium frequently impairs their cardiovascular actions. Intracellular calcium dysregulation is common during ischemic and shock states. Agents which increase intracellular calcium may be harmful during cellular ischemia.ConclusionsAlterations in calcium regulation and calcium concentrations are common during critical illness. Optimal management of altered calcium concentrations requires an understanding of the pathophysiology behind these alterations.

ISSN:0090-3493    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

PurposeTo review the rationale for adenosine triphosphate-magnesium chloride (ATP-MgCl2) administration in shock, ischemia, and sepsis; the beneficial effects on cellular and organ functions and survival; and possible mechanisms of these effects.Data SourcesCurrent literature review.Study SelectionArticles deemed most pertinent, current, and representative were utilized.Data SynthesisDespite apparent, adequate resuscitation of hypovolemic shock and sepsis in experimental animals and patients, persistent cellular and organ dysfunction is apparent. Disturbances in organ microcirculation and tissue hypoxia appear to play an important role. These disturbances occur when the energy needs are increased. Because of the theoretical benefits of ATP-MgCl2as an energy source, as well as a vasodilator, the administration of ATP-MgCl2has been investigated extensively, and considerable evidence suggests that ATP-MgCl2restores the depressed cell and organ functions following ischemia, hypovolemic shock, and sepsis.ConclusionsATP-MgCl2improves cellular and organ function and survival following experimental shock, ischemia, and sepsis. Studies also indicate that ATP-MgCl2can be administered safely in experimental animals and in normal human volunteers, as well as in patients following various adverse circulatory conditions. Further trials should be undertaken to determine the effects on cell and organ function in patients following traumatic shock and sepsis.

ISSN:0090-3493    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

PurposeTo review the diagnosis and management of thyroid diseases, both metabolic (thyroid storm and myxedema coma) and anatomic (substernal goiter, lymphoma, anaplastic carcinoma) that may require intensive care therapy.Data SourcesEnglish-language articles were identified through a search of the MEDLINE and Index Medicus databases. Bibliographies of retrieved articles were examined for relevant articles.Study SelectionApproximately 250 articles were reviewed. Those articles deemed most representative were utilized. Case reports were included to highlight rare, but potentially lethal complications.Data ExtractionAll data were analyzed by one observer. Limitations of the data are discussed.Data SynthesisGuidelines for determining the etiology of thyrotoxic crisis are outlined. Criteria for distinguishing critically ill hypothyroid patients from those patients with the euthyroid sick syndrome are given. Therapy for both disorders must be aggressive and multifaceted, and detailed management is indicated. Substernal goiter is almost always benign, but may cause various acute complications, including dyspnea, respiratory failure, superior vena caval syndrome, esophageal varices (downhill), and others. Surgery almost always corrects the problem. Lymphomas present with rapid thyroid enlargement. Recent studies suggest that surgery may assume more of a supportive role, used principally to obtain adequate tissue for histologic classification.ConclusionsThyroid disorders can produce emergencies requiring the attention of multiple medical and surgical specialists. While management is often successful, future studies should address the following three areas: a) optimization of thyroid hormone dose for treatment of myxedema coma; b) clarification of the role of radiotherapy and/or chemotherapy for thyroidlymphoma; and c) more effective therapy for anaplastic carcinoma.

ISSN:0090-3493    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ObjectiveTo evaluate the physical and functional characteristics of pediatric self-inflating resuscitators.DesignTested under simulated clinical conditions. Results were analyzed by descriptive analysis.SettingA pulmonary laboratory in a university hospital.MethodsEight new pediatric self-inflating resuscitators were obtained from the manufacturers and evaluated for functional characteristics including: a) fraction of delivered oxygen at 10 L/min and a tidal volume of 300 mL; b) maximum stroke volume against no resistance; and c) maximum cycling frequency at −5°C, 20°C, and 48°C. The resuscitators were also evaluated for physical characteristics, including potential for misassembly, pressure relief valves, expiratory valve leak, and inspiratory resistance.ResultsAll resuscitators met the minimum standards of the Canadian Standards Association and American Standards for Testing of Materials. However, one bag cycled at only 32 breaths/min at-5°C, marginally within accepted standards. Only five self-inflating resuscitators had pop-off valves. These valves malfunctioned, with valve activation occurring well above the accepted standards. Three of the self-inflating resuscitators could be misassembled for use. Four of the resuscitators were unable to deliver tidal volumes required for preoxygenation in a 20-kg child.ConclusionsWhile these self-inflating resuscitators met the minimum standards, they are all unable to deliver 100% oxygen. One unit is probably not appropriate in the out-of-hospital setting when ambient temperatures are

ISSN:0090-3493    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ObjectiveTo evaluate the effect of intra-aortic balloon membrane response under increasing intracatheter pressure by indexing these data to associated barometric pressures that occur with changes in altitude.DesignA static compliance test was performed to assess the effect of internal pressure on intra-aortic balloon compliance (simulating helium gas within the intra-aortic balloon affected by barometric pressure). Testing consisted of incrementally increasing pressure within eight percutaneous intra-aortic balloons from four leading manufacturers.SettingThe University of Utah Department of Mechanical Engineering Laboratory.PatientsNo patients were involved. This study was a bench test lab study.InterventionsNo patient interventions were utilized.ResultsResults for all trials showed a curvilinear relationship between intracatheter pressure and balloon volume. Clinically significant balloon expansion data were obtained, with manufacturer variation observed at moderate-to-high pressures.ConclusionsBased on the results of this study, recommendations for operation of intra-aortic balloon pumps during altitude ascent and descent are proposed, from which individual institutional protocols may be developed.

ISSN:0090-3493    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Vecuronium, a nondepolarizing neuromuscular blocking agent, has been used in patients with severe respiratory failure to reduce oxygen consumption and improve total thoracic compliance (1, 2). For short-term administration, vecuronium is regarded as a medication producing therapeutic benefits with few side-effects (3–5). However, the long-term use of vecuronium (>3 days) has been the topic of only two published reports (6, 7).In our ICU, patients initially receive a loading dose of 0.1 mg/kg vecuronium followed by a maintenance infusion of 0.07 to 0.14 mg/kg-hr (8). Some patients exhibit a “resistance” to the agent and require considerably greater hourly doses to permit controlled mechanical ventilation. Nerve stimulators may not be of value to assess degree of paralysis, since the ulnar nerve response to Train-of-Four method does not accurately represent the degree of diaphragmatic paralysis (9). Despite higher than recommended doses and lack of monitoring, most patients regain neuromuscular function within 24 to 48 hrs. Occasionally, however, a patient remains paralyzed for weeks.We describe a patient with severe adult respiratory distress syndrome without renal or hepatic dysfunction, who manifested prolonged paralysis after longterm use of a continuous vecuronium infusion.

ISSN:0090-3493    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1992

数据来源: OVID