Weaning critically ill patients from mechanical ventilation: a protocol from a multicenter retrospective cohort study.

BACKGROUND: Mechanical ventilation (MV) is an important lifesaving method in intensive care unit (ICU). Prolonged MV is associated with ventilator associated pneumonia (VAP) and other complications. However, premature weaning from MV may lead to higher risk of reintubation or mortality. Therefore, timely and safe weaning from MV is important. In addition, identification of the right patient and performing a suitable weaning process is necessary. Although several guidelines about weaning have been reported, compliance with these guidelines is unknown. Therefore, the aim of this study is to explore the variation of weaning in China, associations between initial MV reason and clinical outcomes, and factors associated with weaning strategies using a multicenter cohort. METHODS: This multicenter retrospective cohort study will be conducted at 17 adult ICUs in China, that included patients who were admitted in this 17 ICUs between October 2020 and February 2021. Patients under 18 years of age and patients without the possibility for weaning will be excluded. The questionnaire information will be registered by a specific clinician in each center who has been evaluated and qualified to carry out the study. DISCUSSION: In a previous observational study of weaning in 17 ICUs in China, weaning practices varies nationally. Therefore, a multicenter retrospective cohort study is necessary to be conducted to explore the present weaning methods used in China. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR) (No. ChiCTR2100044634).

Design and performance analysis of a new optimization algorithm based on Finite Element Analysis.

Aiming at the problem that many algorithms could not effectively balance the global search ability and local search ability, a new optimization algorithm is proposed. Inspired by Finite Element Analysis (FEA) approach, a relationship of mapping between Finite Element Analysis approach and a population-based optimization algorithm is constructed through comparing the similarities and differences of FEA node and ideal particle. In algorithm framework, the stiffness coefficient corresponds to a user-defined function of the value of an objective function to be optimized, and the node forces among individuals are defined and an attraction-repulsion rule is established among them. The FEA approach that can simulate multi- states of matter is adopted to balance the global search ability and local search ability in the novel optimization algorithm. A theoretical analysis is made for algorithm parallelism. The conditions for convergence are deduced through analyzing the algorithm based on discrete-time linear system theory. In addition, the performance of the algorithm is compared with PSO for five states which include free state, diffusion state, solid state, entirely solid state, synthesis state. The simulation results of six benchmark functions show that the algorithm is effective. The algorithm supplies a new method to solve optimization problem.

[A pilot study of a novel method for bedside placement of post-pyloric feeding tubes in critically ill patients].

OBJECTIVE: To investigate a novel method of bedside placement of post-pyloric feeding tubes in critically ill patients, and to evaluate its success rate, time used, and safety of this bedside method. METHODS: Data of consecutive patients requiring post-pyloric feeding from February 2009 to July 2009 were collected. In this new method, a non weighted 130-cm-long nasoenteric feeding tube with a guide wire was used under 10 mg of intravenous metoclopramide. The tube was gradually advanced, and the position of the tube was confirmed by auscultation to detect bubbling sound and respiration of inflated air (the vacuum test), as well as pH measurement of aspirated fluid. An abdominal radiograph was made finally for confirmation of the position of the tube before the feeding was initiated. The time taken to insert the tube, the success rate, the time between the decision to feed and commencement of feeding, and the complications of the procedure were recorded. RESULTS: In 28 patients the post-pyloric feeding tube was placed. The main indication was 18 cases with high risk of aspiration, 3 with gastroparesis, and 7 with acute pancreatitis. Of the 28 tube placements performed, 26 (92.9%) were successful, and in 21 (75.0% of 28) the tube was in the jejunum. The average time for successful placement was (20.36+/-6.41) minutes. The time between the decision for feeding and commencement of feeding was (4.15+/-1.68) hours. No complications occurred. CONCLUSION: Using a conventional nasoenteric feeding tube with a guide wire, and only one medical staff needed for the placement of the tube, this method is an efficient and cost-effective method of bedside post-pyloric feeding tube placement.