IntroductionBased on the hypothesis that failure of weaning from mechanical ventilation is caused by respiratory demand exceeding the capacity of the respiratory muscles, we evaluated whether extubation failure could be characterized by increased respiratory drive and impaired efficiency to generate inspiratory pressure and ventilation.MethodsAirway pressure, flow, volume, breathing frequency, and diaphragm electrical activity were measured in a heterogeneous group of patients deemed ready for a spontaneous breathing trial. Efficiency to convert neuromuscular activity into inspiratory pressure was calculated as the ratio of negative airway pressure and diaphragm electrical activity during an inspiratory occlusion. Efficiency to convert neuromuscular activity into volume was calculated as the ratio of the tidal volume to diaphragm electrical activity. All variables were obtained during a 30-minute spontaneous breathing trial on continuous positive airway pressure (CPAP) of 5 cm H2O and compared between patients for whom extubation succeeded with those for whom either the spontaneous breathing trial failed or for those who passed, but then the extubation failed.ResultsOf 52 patients enrolled in the study, 35 (67.3%) were successfully extubated, and 17 (32.7%) were not. Patients for whom it failed had higher diaphragm electrical activity (48%; P < 0.001) and a lower efficiency to convert neuromuscular activity into inspiratory pressure and tidal volume (40% (P < 0.001) and 53% (P < 0.001)), respectively. Neuroventilatory efficiency demonstrated the greatest predictability for weaning success.ConclusionsThis study shows that a mixed group of critically ill patients for whom weaning fails have increased neural respiratory drive and impaired ability to convert neuromuscular activity into tidal ventilation, in part because of diaphragm weakness.Trial RegistrationClinicaltrials.gov identifier NCT01065428. ©2012 Liu et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Background Cardiovascular diseases (CVDs) are the main cause of death in patients with chronic kidney disease (CKD). Interleukin-4 (IL-4) is considered an inflammatory cytokine. However, few studies have investigated the association between serum IL-4 and cardiovascular events in CKD. This study investigated whether serum IL-4 levels were associated with an increased risk of cardiovascular (CV) events in patients with CKD. Patients and Methods A total of 302 patients with stage 1–5 CKD were followed up for a mean of 32 (range=4–36) months for end points (CV events). Serum IL-4 levels were measured at baseline. The independent relationship between serum IL-4 and the risk of CV events was assessed with multivariate Cox regression analysis. Results The average age of this cohort (N=302) was 65.4 years. A total of 69.9% of them were male. CV events numbered 41 (13.6%) during the follow-up period. The Kaplan–Meier analysis showed that the rate of CV events was higher in patients with CKD with IL-4 levels above the mean (126.2 pg/mL) than in those with IL-4 levels below the mean. The multivariate Cox proportional hazard analysis revealed that serum IL-4 (HR=1.650, 95% CI 1.266–2.210, P <0.001) was associated with CV events in these patients with CKD. Sensitivity analysis showed that the association between serum IL-4 and CV events was not affected by the use of anti-inflammatory medication. The significant association between higher IL-4 levels and increased risk of CV events existed in patients with CKD3-5 but not in patients with CKD1-2 by using the stratified analysis. Conclusion Higher serum IL-4 levels were associated with an increased risk of CV events during follow-up. Elevated serum IL-4 levels may help clinicians predict early CV events in patients with CKD.

Lung injury is aggravated after bilateral vagotomy, demonstrating that pulmonary stretch reflex may have protective effect on the lung.

Background Studies involving the association of blood albumin with prognosis in patients with chronic kidney disease (CKD) during intensive care unit (ICU) were scarce. Aim We investigated whether reduced blood albumin level independently associated with an increased risk of cardiovascular (CV) complications and 1-year mortality risk in ICU patients with CKD. Methods The Medical Information Mart for Intensive Care III (MIMIC-III) database was used. Disease diagnosis and death information among a number of 925 ICU patients with CKD, who have been measured for blood biochemistry, were recorded. Here, multivariable logistic regression Models were structured to evaluate the associations between blood albumin levels (first value on admission, maximum and minimum value during ICU) and risks for CV complications and 1-year mortality among these CKD patients. Results In 925 CKD patients, the number of CV complication with heart failure (HF), myocardial infarction (MI) or stroke was 470 (50.8%). 406 (43.9%) patients were dead during the follow-up of 1 year after patients were discharged. Our smooth curve results suggested a curvilinear relation on association between blood albumin level and risk of CV complications. The “inflection point” of blood albumin level that patients were at highest risk of CV complications was 3.4 g/dL. The almost linear relationship with a downward trend was observed on the association between blood albumin level and 1-year mortality risk. We found that reduced blood albumin level contributed to lower risk for CV complications and higher risk for 1-year mortality respectively when blood albumin levels in CKD patients were below 3.4 g/dL. Additionally, albumin therapy had an obvious modifying effect on the independent association, suggesting a possible improved effect of albumin therapy on risk of CV complications and 1-year mortality risk in these CKD patients. Conclusions Our study reported that reduced blood albumin levels in CKD patients during ICU were related to lower risk for CV complications and increased risk of 1-year mortality.