The metabolic syndrome in critically ill patients

Metabolic support in intensive care is a rapidly evolving field with new information being gathered almost on a daily basis. In endocrine practice, over the last 20 years, researchers have focussed on a new entity, termed the "metabolic syndrome". This describes the constellation of abnormalities which include central adiposity, insulin resistance and inflammation. All of these predispose the individual to a greater risk of cardiovascular events. Of interest is the observation that some of the metabolic abnormalities in sepsis and multiple organ dysfunction syndrome of critical illness share several common features with that of the metabolic syndrome. In this chapter we describe the features of the metabolic syndrome as is understood in endocrine parlance, the metabolic abnormalities of critical illness and explore the common threads underlying the pathophysiology and the treatment of the two syndromes. The role of adiponectin in the metabolic abnormalities in both the metabolic syndrome and in sepsis are reviewed. The potential role of the pleiotropic effects of statins in the therapy of sepsis is also discussed.     

肺复张对重症患者血流动力学的影响

各种原因引起的肺不张常常导致肺内分流增加、静脉血氧合不充分最终出现低氧血症甚至呼吸衰竭。肺复张的目的就是通过迅速短暂的增加气道压力来打开塌陷的肺泡。虽然肺复张可以改善氧合,但由于心肺以及心脏的左、右心室间的相互作用,可能造成胸内压力升高从而对心血管系统产生严重的影响。这篇综述的目的就是总结肺复张过程中心肺间的病理生理特征并探讨在肺复张过程中如何更好地监测这些特征的变化,从而在临床工作中更好地使用肺复张。     

Fibrinolysis in critically ill patients

Impaired fibrinolysis may contribute to development of adult respiratory distress syndrome (ARDS). Pathologic increases in endogenous plasminogen activator inhibitor (PAI-1) may blunt normal fibrinolysis and unmask alternate fibrinolytic mechanisms, such as elastase-induced fibrin degradation. We measured PAI-1 and elastase-induced fibrin(ogen) degradation products in 69 critically ill patients in our medical intensive care unit (MICU) and in nine healthy volunteers. Factor VIII-related antigen protein (VIII:Ag), a reported marker of acute lung injury, and alpha-1-protease inhibitor (alpha-1-PI), an acute phase reactant, were also measured. MICU patients included 24 control patients with no known risk of ARDS, 35 patients with risk factors for ARDS including sepsis, pneumonia, aspiration, and shock, and 12 patients with ARDS including two patients from at-risk groups who developed ARDS. Plasma PAI-1 was determined by chromogenic assay, elastase-induced peptides by a new radioimmunoassay, VIII:Ag by immunoelectrophoresis, and alpha-1-PI by immunodiffusion. When compared to normal volunteers, MICU control patients had elevated PAI-1, VIII:Ag, elastase-induced peptides, and alpha-1-PI. Patients with ARDS had significantly higher PAI-1 and VIII:Ag than did MICU control patients; elastase-induced peptides and alpha-1-PI were not higher. However, at-risk patients who did not develop ARDS also had high PAI-1 or VIII:Ag. Although these data cannot refute the possible role of these compounds in the pathogenesis of ARDS, they demonstrate that PAI-1 and VIII:Ag may be elevated in many critically ill patients but may not be useful markers for the subsequent development of ARDS.     

Thrombocytopenia in critically ill patients

Critically ill patients often have a low platelet count. A proper identification of the underlying cause of this abnormality is required, because various underlying disorders may necessitate different diagnostic and therapeutic management strategies. Platelets are part of the first line of defense of the body against bleeding, hence, thrombocytopenia may increase the risk of hemorrhage. In case of systemic inflammatory syndromes, such as the response to sepsis, disseminated intravascular platelet activation may occur, which will contribute to microvascular failure and thereby play a role in the development of organ dysfunction. A low platelet count is a strong and independent predictor of an adverse outcome in critically ill patients, thereby facilitating a simple and practical risk assessment in these patients and potentially guiding the use of complex or expensive treatment strategies.     

Anemia in critically ill patients

Anemia is common in acute critically ill patients. Although blood loss, either by trauma, surgery, phlebotomies or gastrointestinal bleeding, may play a role, the anemia in these patients bears many similarities to the anemia characteristic of chronic disease. Serum iron is low with a high concentration of ferritin and low-to-normal transferrin and serum transferrin receptor levels. Several mechanisms may be involved, with inflammation playing a crucial role. Although the exact nature of the inflammatory response and the role of various cytokines need further elucidation, it is known that inflammation blunts the responsiveness of the hormone erythropoietin and induces functional iron deficiency. Iron is trapped in cells of the mononuclear phagocytic system and its release is temporarily blocked. The bone marrow is still capable of incorporating iron and of responding to treatment with recombinant human erythropoietin (rh-EPO). The duration of the anemia is related to the persistence of the inflammation. Although the effects of anemia on morbidity and mortality in the critically ill are poorly defined, a restrictive transfusion policy, in which hemoglobin concentration is maintained between 7.0 and 9.0 g/dl, proves to be at least as effective as, if not superior to, a more liberal regimen. In individual situations, such as in cardiovascular and cancer patients, higher thresholds may be appropriate. The administration of rh-EPO is an alternative to reduce the need for red blood cell transfusions and to avoid transfusion-related complications. Although its efficacy has been shown, questions regarding cost-benefit, dose regimen and clinical outcomes need to be answered before its large-scale use can be recommended.     

Acute hemodynamic effects of levothyroxine loading in critically ill hypothyroid patients

To evaluate the acute cardiovascular effects of high-dose levothyroxine sodium therapy, the hemodynamic findings in eight critically ill hypothyroid patients treated with high-dose levothyroxine were compared with those in two critically ill hypothyroid and nine critically ill euthyroid patients not receiving this therapy. The initial cardiac index was significantly lower in the hypothyroid group; all other hemodynamic values were similar to those of the euthyroid patients. Following levothyroxine loading, the free thyroxine index increased to normal while the free triiodothyronine index was unchanged; all patients had a significant rise in cardiac index but no consistent changes in the other hemodynamic values. Cardiac index correlated positively with heart rate (three patients) and/or stroke volume index (six patients). Increases in stroke volume index correlated with decreases in systemic vascular resistance (five patients), but not with increases in pulmonary artery wedge pressure. No consistent patterns of hemodynamic changes were observed in the untreated hypothyroid or the euthyroid patients.     

The effects of real-time continuous glucose monitoring on oxidative stress and mortality in critically ill patients

Objective To evaluate the effects of real-time continuous glucose monitoring(RT-CGM) system on oxidative stress and mortality in critically ill patients and to explore the correlation between glucose index,oxidative stress and mortality. Methods 123 selected cases of     

Condition on arrival of transferred critically ill patients

We performed a retrospective inventory of the condition of transferred patients to our 11-bed medical ICU, aimed firstly to measure the quality of these transports and secondly to identify variables that may predict a high risk of deterioration during transferral. By a search in our hospital database, we identified 112 consecutive patients (47 women/65 men) transferred from other hospitals (distance 20-350 km) to our ICU over a period of 14 months. The following data were collected on departure (if available) and on arrival: blood pressure, heart rate, temperature, oxygen saturation, routine laboratory parameters, arterial blood gas analysis, lactic acid, settings of mechanical ventilation, use of vasopressor/inotropic medication, presence of venous and arterial catheters and Apache II score on arrival. No major worsening during transportation was found, looking at the whole group. However, individual data showed severe deterioration of some patients during transport. We were not able to point out parameters that could predict hemodynamic or respiratory instability during transport or condition on arrival. In conclusion, quality of transport seems fairly good; in individual cases, improvements are possible. Therefore, we plan to investigate whether or not a strict protocol, based on recommendations in the literature and on local feasibility can further improve condition on arrival and survival of transferred ICU patients in our adherence region.     

Transesophageal echocardiography in critically ill patients

The feasibility, safety and clinical impact of transesophageal echocardiography were evaluated in 51 critically ill intensive care unit patients (28 men and 23 women; mean age 63 years) in whom transthoracic echocardiography was inadequate. At the time of transesophageal echocardiography, 30 patients (59%) were being mechanically ventilated. Transesophageal echocardiography was performed without significant complications in 49 patients (96%), and 2 patients with heart failure had worsening of hemodynamic and respiratory difficulties after insertion of the transesophageal probe. The most frequent indication, in 25 patients (49%), was unexplained hemodynamic instability. Other indications included evaluation of mitral regurgitation severity, prosthetic valvular dysfunction, endocarditis, aortic dissection and potential donor heart. In 30 patients (59%), transesophageal echocardiography identified cardiovascular problems that could not be clearly diagnosed by transthoracic echocardiography. In the remaining patients, transesophageal echocardiography permitted confident exclusion of suspected abnormalities because of its superior imaging qualities. Cardiac surgery was prompted by transesophageal echocardiographic findings in 12 patients (24%) and these findings were confirmed at operation in all. Therefore, transesophageal echocardiography can be safely performed and has a definite role in the diagnosis and expeditious management of critically ill cardiovascular patients.     

Pleural effusions in critically ill patients

Pleural effusions (PEs) are common in critically ill patients mainly as a consequence of severe cardiopulmonary disorders frequently encountered in these patients. Their impact on the pathophysiology of acute respiratory failure remains unknown. They are usually small and uncomplicated transudates that are easily overlooked on a supine portable chest X-ray and do not require drainage or infectious exudates that always require thoracocentesis. The diagnosis of PEs in critically ill patients has been revolutionized with the advent of chest ultrasound allowing easy bedside quantification of pleural fluid and making thoracocentesis a safe procedure especially in high-risk patients on mechanical ventilation. CT provides a much more accurate evaluation of the size and location of PEs and is extremely helpful in the guidance of catheters into loculated fluid collections. Hemothorax in critically ill patients is usually related to trauma or surgical interventions and requires early drainage and possibly surgical exploration.     

Hematologic disorders in critically ill patients

Hematologic disorders are frequently encountered in the intensive care unit. Thrombocytopenia, often defined as a platelet count below 100,000/microL, is common in critically ill patients and may be associated with adverse outcomes. A systematic evaluation of clinical and laboratory findings is necessary to ascertain the cause of the thrombocytopenia and to determine the correct therapy. Recognition of heparin-induced thrombocytopenia (HIT) is particularly important, given the risk of thrombosis associated with this condition. Prompt cessation of all heparin products is required, and anticoagulation with a direct thrombin inhibitor is recommended if HIT is strongly suspected. Coagulopathies are also common in the critically ill, and are often due to vitamin K deficiency or disseminated intravascular coagulation (DIC). A careful history and interpretation of clotting studies are useful in defining the coagulation defect. Advances in understanding the pathogenesis of DIC have generated new treatment approaches, such as the use of recombinant activated protein C. Recombinant factor VIIa (rFVIIa) is a novel drug approved for use in patients with congenital hemophilia and inhibitors. Although its use as a hemostatic agent is currently being evaluated in several off-label scenarios, including trauma, intracerebral hemorrhage, and liver disease, there are limited data to guide therapy in these conditions.     

Autonomic dysfunction in critically ill patients

Zum Thema Unser Wissen über die charakteristischen Ver?nderungen der autonomen Funktion kritisch kranker Patienten ist in den letzten Jahren sprunghaft angestiegen. Letztmalig wurde dieses Thema in dieser Zeitschrift im Jahr 1998 diskutiert [42]. Die Intention des vorliegenden Artikels ist es, dem Leser die neuen Erkenntnisse hinsichtlich der Ver?nderung der autonomen Funktion kritisch Kranker in einer praxisrelevanten Form darzustellen, neue Trends in diesem Gebiet aufzuzeigen und ein Modell zur Bestimmung der autonomen Dysfunktion beim Multiorgandysfunktionssyndrom (MODS) vorzustellen. Auf die Techniken zur Bestimmung der autonomen Funktion wird nur insoweit eingegangen, wie sie zum Verst?ndnis des Wechselspiels von Sympathikus und Parasympathikus kritisch Kranker notwendig sind.     

Fusarium infections in critically ill patients

Invasive mold infections (IMIs) are significant causes of infectious mortality in immunocompromised patients, such as those with hematologic malignancies and allogeneic bone marrow transplant recipients. Of the IMIs, invasive aspergillosis is by far the most common. Nevertheless, over the past decade, other filamentous molds, such as Fusarium species, have been increasingly reported as the cause of severe IMIs in these patient populations. Herein we critically review the epidemiology, pathogenesis, clinical presentation, diagnostic methods, and therapeutic approaches for invasive fusariosis in immunocompromised hosts. We also present the key characteristics and differentiating features of invasive fusariosis and invasive aspergillosis. Current therapeutic approaches for fusariosis are suboptimal, resulting in exceedingly high mortality rates. At present, prompt diagnosis along with rapid initiation of appropriate treatment and, more importantly, reconstitution of the host immune responses are critical for a favorable outcome of this devastating opportunistic mycosis.     

危重症患者高血糖处理

近年来的流行病学调查表明,我国成年人糖尿病患病率在大中城市已达10%或更高,在农村也超过了5%,糖耐量减低也很常见.由于背景人群血糖异常比例非常高,住院患者,特别是危重症患者经常伴有高血糖.