U-Shape Relationship between Plasma Leucine Level and Mortality in the Intensive Care Unit.

Patients in the intensive care unit (ICU) are at high risk of mortality which is not well predicted. Previous studies noted that leucine has prognostic value in a variety of diseases. This study investigated whether leucine concentration was a useful biomarker of metabolic and nutritional status and 6-month mortality in ICU. We recruited 454 subjects admitted to ICU (348 and 106 in the initiation and validation cohorts, respectively) with an acute physiology and chronic health evaluation (APACHE II) score ≥ 15. We measured plasma leucine concentrations, traditional biomarkers, and calculated APACHE II and sequential organ failure assessment (SOFA) scores. Leucine levels were weakly correlated with albumin, prealbumin, and transferrin levels (r = 0.30, 0.12, and 0.15, p = 0.001, 0.029, and 0.007, respectively). During follow-up, 116 (33.3%) patients died. Compared to patients with leucine levels between 109 and 174 µM, patients with leucine > 174 µM or <109 µM had a lower cumulative survival rate. Death was also associated with age, higher APACHE II and SOFA scores, C-reactive protein, and longer stays in the ICU, but with lower albumin, prealbumin, and transferrin. Patients with leucine levels > 174 µM had higher alanine aminotransferase levels, but no significant differences in other variables; patients with leucine levels < 109 µM had higher APACHE II and SOFA scores, higher incidence of using inotropic agents, longer ICU and hospital stays, but lower albumin and transferrin levels. Multivariable analysis demonstrated that leucine > 174 µM was an independent predictor of mortality, especially early mortality. However, among patients who stayed in ICU longer than two weeks, leucine < 109 µM was an independent predictor of mortality. In addition, leucine < 109 µM was associated with worse ventilator weaning profiles. These findings were similar in the validation cohort. Our study demonstrated a U-shape relationship between leucine levels and mortality rate in ICU.

[Factors Related to Successful Ventilator Weaning in Respiratory Care Center Patients: A Retrospective Chart Review Study].

BACKGROUND: The subacute respiratory care unit is an important relay station where respirator-dependent patients may access subsequent chronic respiratory care. Although there is relatively little information in the literature regarding respirator disconnections in subacute respiratory care units, assisting patients to disconnect successfully from respirators is a primary challenge for care teams. PURPOSE: The purpose of this study was to understand respirator disconnections and the factors affecting these events in subacute respiratory care units to improve the effectiveness of ventilator weaning and reduce the burden on families and medical care providers. METHODS: This was a retrospective chart review study. Patients admitted to the subacute respiratory care unit for respiratory training during the study period from January 2016 to December 2019 were recruited as subjects and the data were collected from the Chang Gung Medical Research Database`s health insurance secondary data using a self-made transcription form. RESULTS: The ventilator weaning success rate of the subjects in this study was 78.5%. A bivariate analysis revealed that consciousness status; disease severity; rapid shallow breathing index; days of hospitalization in a respiratory care center; days of ventilator use; blood urea nitrogen, white blood cell, hemoglobin, and blood albumin levels; and mean caloric intake were each significantly associated with successful ventilator withdrawal. The predictors of ventilator weaning in respiratory care center patients were identified as disease severity, rapid shallow breathing index, days of ventilator use, white blood cell level, and hemoglobin level. CONCLUSIONS / IMPLICATIONS FOR PRACTICE: Respirator-dependent patients should be evaluated and monitored as early as possible. Moreover, a ventilator weaning plan should be included as a regular testing and monitoring item. Also, a respirator removal program should be provided on a case-by-case basis. Individualized ventilator weaning programs may reduce the burden on families and medical care providers.

Elevated plasma phenylalanine predicts mortality in critical patients with heart failure.

AIMS: Previous studies found a relationship between elevated phenylalanine levels and poor cardiovascular outcomes. Potential strategies are available to manipulate phenylalanine metabolism. This study investigated whether increased phenylalanine predicted mortality in critical patients with either acute heart failure (HF) or acute on chronic HF, and its correlation with inflammation and immune cytokines. METHODS AND RESULTS: This study recruited 152 subjects, including 115 patients with HF admitted for critical conditions and 37 normal controls. We measured left ventricular ejection fraction (LVEF), plasma concentrations of phenylalanine, C-reactive protein, albumin, pre-albumin, transferrin, and pro-inflammatory and immune cytokines. Acute Physiology and Chronic Health Evaluation (APACHE II), Sequential Organ Failure Assessment (SOFA), and maximal vasoactive-inotropic scores (VISmax ) were calculated. Patients were followed up until death or a maximum of 1 year. The primary endpoint was all-cause death. Of the 115 patients, 37 (32.2%) were admitted owing to acute HF, and 78 (67.8%) were admitted owing to acute on chronic HF; 64 (55.7%) had ST elevation/non-ST elevation myocardial infarction. An LVEF measured during the hospitalization of <40%, 40-50%, and ≥50% was noted in 51 (44.3%), 15 (13.1%), and 49 (42.6%) patients, respectively. During 1 year follow-up, 51 (44.3%) patients died. Death was associated with higher APACHE II, SOFA, and VISmax scores; higher levels of C-reactive protein and phenylalanine; higher incidence of atrial fibrillation and use of inotropic agents; lower cholesterol, albumin, pre-albumin, and transferrin levels; and significant changes in pro-inflammatory and immune cytokines. Phenylalanine levels demonstrated an area under the receiver operating characteristic curve of 0.80 for mortality, with an optimal cut-off value set at 112 µM. Phenylalanine ≥ 112 µM was associated with a higher mortality rate than was phenylalanine < 112 µM (80.5% vs. 24.3%, P < 0.001) [hazard ratio = 5.07 (2.83-9.05), P < 0.001]. The Kaplan-Meier curves revealed that phenylalanine ≥ 112 µM was associated with a lower accumulative survival rate (log rank = 36.9, P < 0.001). Higher phenylalanine levels were correlated with higher APACHE II and SOFA scores, higher C-reactive protein levels and incidence of using inotropic agents, and changes in cytokines suggestive of immunosuppression, but lower levels of pre-albumin and transferrin. Further multivariable analysis showed that phenylalanine ≥ 112 µM predicted death over 1 year independently of age, APACHE II and SOFA scores, atrial fibrillation, C-reactive protein, cholesterol, pre-albumin, transferrin, and interleukin-8 and interleukin-10. CONCLUSIONS: Elevated phenylalanine levels predicted mortality in critical patients, phenotypically predominantly presenting with HF, independently of traditional prognostic factors and cytokines associated with inflammation and immunity.