Hyponatremia in critically ill patients

Context:

Hyponatremia is a common electrolyte disturbance in critically ill hence understanding its implications is important.

Aims:

This study was carried out to ascertain frequency, predisposing conditions and outcome in critically ill patients with hyponatremia on intensive care unit (ICU) admission.

Settings and Design:

This was an observational, prospective study of a series of ICU patients during a 12-month period.

Materials and Methods:

The patients were divided into two groups: Hyponatremic (serum sodium < 135 mmol/L) and Eunatremic groups (135-145 mmol/L). Clinical examination included volume status and drug history, biochemistries, clinical diagnosis and cause of hyponatremia.

Statistical Analysis Used:

Fisher''s exact test, unpaired t-tests Wilcoxon ranksum tests, profile-likelihood method, log-rank test and Kaplan—Meier curves were used. P < 0.05 were considered to be statistically significant.

Results:

In the hyponatremic group, the frequency of hyponatremia on ICU admission was 34.3%, most were euvolumic, 58.96%. Females comprised of 36.5%. The mean age was 60.4 ± 17.2. The Syndrome of inappropriate Antidiuretic Hormone (SIADH) criteria was met in ninety-one patients (36.25%), peumonia being the leading cause of SIADH. Patients with severe sepsis, elective surgery patients, renal failure and heart failure, cirrhosis of liver and subarachnoid hemorrhage were other more likely etiologic causes (P < 0.05). The hyponatremic group spent a longer time in the ICU (P = 0.02), had longer mechanical ventilator days (P < 0.05) and had an increased mortality rate (P = 0.01).

Conclusions:

Hyponatremia present on admission to the ICU is independent risk factors for poor prognosis.     

Immune balance in critically ill patients

The systemic inflammatory response reflects the non-specific clinical expression of a profound activation of the body's immune responsive elements. Immune activation and immune suppression coexist in the blood of patients with severe sepsis. It is their interaction and the resultant host parenchymal responses that ultimately define the course of sepsis. Importantly, neither profound immune activation (pro-inflammatory) or immune suppression (anti-inflammatory) characterize the dominant process. Rather, there is a combined low grade pro-inflammatory state associated with an immune hyporesponsiveness that defines the usual immunologic state of the patient with severe sepsis.     

Laboratory assessment of nutritional status

Malnutrition is one of the major causes of increased morbidity and mortality among hospitalized patients. The availability of nutritional therapy for these patients has made clinicians aware of the need for reliable methods of nutritional assessment. A variety of anthropometric, biochemical, and immunologic parameters has been used as indicators of protein-calorie malnutrition. Recently, the concentration of several rapid-turnover visceral proteins (transferrin, thyroxine-binding prealbumin and retinol-binding protein) has been shown to be a very sensitive parameter for indicating both the efficiency of nutritional therapy and conditions of borderline protein intake in apparently healthy children. Likewise, several immunologic parameters (including T cells, delayed hypersensitivity response, and complement components) have been shown to correlate with morbidity, mortality risk, sepsis, and death.     

Candida endophthalmitis in non-neutropenic critically ill patients

Six non-neutropenic critically ill patients who developed hematogenous endophthalmitis due toCandida spp. were studied prospectively. In all cases the yeast was isolated in blood cultures. The incidence of endophthalmitis in patients with candidemia was 13%, the predominant species beingCandida albicans. Four patients were treated with fluconazole, but its efficacy could not be evaluated because three of the patients died. In patients at risk of candidemia, regular ophthalmoscopic examinations are recommended in order to enable early initiation of systemic antifungal therapy in those who develop endophthalmitis.     

Circadian rhythm disruption in critically ill patients

Patients admitted to the intensive care unit (ICU) are in need of continuous organ replacement strategies and specialized care, for example because of neurological dysfunction, cardio-pulmonary instability, liver or kidney failure, trauma, hemorrhagic or septic shock or even preterm birth. The 24-h nursing and care interventions provided to critically ill patients significantly limit resting and/or recovery phases. Consecutively, the patient's endogenous circadian rhythms are misaligned and disrupted, which in turn may interfere with their critical condition. A more thorough understanding of the complex interactions of circadian effectors and tissue-specific molecular clocks could therefore serve as potential means for enhancing personalized treatment in critically ill patients, conceivably restoring their circadian network and thus accelerating their physical and neurocognitive recovery. This review addresses the overarching issue of how circadian rhythms are affected and disturbed in critically ill newborns and adults in the ICU, and whether the conflicting external or environmental cues in the ICU environment further promote disruption and thus severity of illness. We direct special attention to the influence of cell-type specific molecular clocks on with severity of organ dysfunctions such as severity of brain dysfunction, pneumonia- or ventilator-associated lung inflammation, cardiovascular instability, liver and kidney failure, trauma, and septic shock. Finally, we address the potential of circadian rhythm stabilization to enhance and accelerate clinical recovery.     

Evolving concepts of hemodynamic monitoring for critically ill patients

The last decades have been characterized by a continuous evolution of hemodynamic monitoring techniques from intermittent toward continuous and real-time measurements and from an invasive towards a less invasive approach. The latter approach uses ultrasounds and pulse contour analysis techniques that have been developed over the last 15 years. During the same period, the concept of prediction of fluid responsiveness has also been developed and dynamic indices such as pulse pressure variation, stroke volume variation, and the real-time response of cardiac output to passive leg raising or to end-expiration occlusion, can be easily obtained and displayed with the minimally invasive techniques. In this article, we review the main hemodynamic monitoring devices currently available with their respective advantages and drawbacks. We also present the current viewpoint on how to choose a hemodynamic monitoring device in the most severely ill patients and especially in patients with circulatory shock.     

Current concepts in combination antibiotic therapy for critically ill patients

Widespread emergence of multidrug resistant (MDR) bacterial pathogens is a problem of global dimension. MDR infections are difficult to treat and frequently associated with high mortality. More than one antibiotic is commonly used to treat such infections, but scientific evidence does not favor use of combination therapy in most cases. However, there are certain subgroups where combination therapy may be beneficial, e.g. sepsis due to carbapenem-resistant Enterobacteriaceae (CRE), bacteremic pneumococcal pneumonia, and patients with multiple organ failure. Well-designed prospective studies are needed to clearly define the role of combination therapy in these subgroups.     

Pulmonary disposition of vancomycin in critically ill patients

Vancomycin penetration in epithelium lining fluid was studied in ten mechanically ventilated patients with methicillin-resistantStaphylococcus aureus pneumonia 24 hours after the onset of treatment. Vancomycin was given intravenously at a daily dose of 30 mg/kg. Vancomycin levels were detectable in four patients (range, 1–2.77 g/ml). Concordance between high plasma concentrations (> 20 g/ml) and detectable vancomycin levels in epithelium lining fluid was noted. These results suggest that the pulmonary disposition of vancomycin remains low for most patients 24 h after the onset of treatment compared with the minimum inhibitory concentrations for most gram-positive organisms. One therapeutic goal of vancomycin treatment could be to obtain through plasma levels of 20 g/ml. Further studies are required to determine the clinical relevance of these observations.     

超声诊断方案对重症机械通气患者撤机效果及纵膈移位的影响

目的:分析超声诊断方案对重症机械通气患者撤机效果及纵膈移位情况的影响。方法:选取机械通气时间>48 h并行自主呼吸试验的重症患者96例,超声检测记录SBT不同时间节点的浅快呼吸指数（RSBI）、纵膈肌增厚率（DTF）、膈肌收缩速度和最大右侧膈肌移位（DE）,根据撤机结果将患者分为撤机成功组和撤机失败组,比较两组患者上述指标差异,并利用受试者工作曲线（ROC）评价SBT 30 min时各指标单独及联合对撤机成功的预测价值。结果:撤机成功者62例,撤机失败者34例,撤机失败率为35.42%;SBT 30 min时,撤机成功组患者RSBI值、膈肌收缩速度低于撤机失败组,DTF、DE值高于撤机失败组,差异均具有统计学意义（P<0.05）;Logistic回归分析发现,RSBI、膈肌收缩速度的升高和DTF、DE的降低是撤机失败的独立危险因素（P<0.05）;ROC结果显示,RSBI、DTF、膈肌收缩速度、DE预测撤机失败的Cutoff值分别为74.19次/min·L-1、35.37%、1.74 cm/s、1.61 mm;各指标单独预测撤机失败的AUC分别为0.798、0.809、0.774、0.870,而RSBI+DTF+膈肌收缩速度+DE联合预测的AUC为0.951,显著高于各项指标单独预测（P<0.05）。结论:超声诊断能够通过RSBI、DTF、膈肌收缩速度、DE监测膈肌移位情况,还能很好地预测重症机械通气患者撤机结果,联合诊断效果更佳。     

BNP联合APACHE Ⅱ评分在危重病患者预后评价中的意义

目的: 探讨B型钠尿肽(BNP)水平联合急性生理和慢性健康状况评分Ⅱ(APACHE Ⅱ)在评价危重病患者预后中的意义。方法: 对2009年10月至2010年2月期间进入暨南大学附属第一医院中心ICU病房的62例危重症患者在24 h内进行APACHE Ⅱ评分及测定血清BNP水平,分析两者与危重症患者的病死率、住院时间、机械通气的发生率及通气时间等主要预后指标的关系。结果: 62例患者存活44例,死亡18例,病死率为29.0%。其中死亡组APACHE Ⅱ评分值和血清BNP浓度均明显高于存活组(P<0.01)。APACHE Ⅱ评分、呼吸机使用率及病死率随BNP水平升高而升高。结论: BNP和APACHE Ⅱ评分的升高对危重症患者的存活、机械通气的发生率及通气时间、住院时间等主要预后指标的预测有重要意义。