8/24/2023 0 Comments Normal tidal volume for clin sims![]() We hypothesized that FRC was determined by body length (surrogate for predicted BW) and age in healthy beagle dogs but not in lung injured ones. Therefore, clarifying the relationship between FRC and predicted BW was of significance, especially in injured lungs, which might be helpful to optimize the setting of tidal volume. Meanwhile, previous studies have demonstrated that ventilator-induced lung injury was attributed to the ratio between tidal volume and FRC but not the ratio between tidal volume and predicted BW ( 8- 10). It was obvious the rationale of setting tidal volume for normal lungs might be improperly used in injured lungs. In fact, FRCs might be significantly different from each other in ARDS patients with the same height (in other words, same predicted BW) ( 8). However, FRCs of patients with ARDS might not abide by the same rule. Beyond meeting the requirement of blood gas exchange, the method of selecting tidal volume, according to BW or predicted BW, mainly depended on the fact that normal lung volumes, especially functional residual capacity (FRC), were determined by height (indirectly by predicted BW), sex and age of healthy persons ( 7). This setting has dramatically improved the prognosis ( 2, 4- 6). For patients with acute respiratory distress syndrome (ARDS), low tidal volume (6-8 mL/kg of predicted BW) has become a routine strategy ( 2, 3). Usually, predicted BW was used to correct actual BW inter-individual variations in obesity and muscle weight ( 1). Traditionally, the choice of tidal volume, the most important parameter of ventilator settings, was based on the body weight (BW), which was a certain milliliter for per kilogram of BW. Mechanical ventilation was an important supportive strategy for patients receiving surgery or suffering from respiratory failure. Keywords: Functional residual capacity (FRC) predicted body weight (BW) tidal volume lung protective ventilation The traditional view of setting tidal volume based on predicted BW should be challenged cautiously. For healthy lungs, FRC could be estimated by the following formula: FRC =21.86 × age (months) + 20.55 × body length (cm) – 1,337.98 (P<0.05), while for injured lungs, the formula of multiple linear regression was invalid (P=0.305).Ĭonclusions: FRC was linearly related to body length in healthy dogs but not in lung injured ones. Results: After lung injury, FRC decreased sharply from baseline (414☘4) to (214☗0) mL. ![]() Age, body length and actual BW were also recorded before experiments. Blood gas analysis, extra vascular lung water and respiratory system mechanics were tested at baseline and post-lung injury. FRC was measured by chest computer tomography. Methods: A total of 24 dogs were recruited and ARDS model was induced by intravenous injection of oleic acid. We hypothesized that FRC was determined by body length (surrogate for predicted BW) and age in healthy male beagle dogs but not in lung injured ones. ![]() However, FRCs in patients with acute respiratory distress syndrome (ARDS) might not abide by the same rule and be significantly different from each other in patients with the same height and sex. The method of selecting tidal volume depended on the fact that normal lung volumes, especially functional residual capacity (FRC), were mainly determined by height (indirectly by predicted BW), sex and age in healthy persons. Qi Liu 1, Yong-Hua Gao 1, Dong-Ming Hua 2, Wen Li 3, Zhe Cheng 1, Hui Zheng 4, Rong-Chang Chen 2ġDepartment of Respiratory and Critical Medicine, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China 2Respiratory Mechanics Lab, State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China 3Department of Radiology, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China 4Department of Radiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, ChinaĬontributions: (I) Conception and design: Q Liu, R Chen (II) Performed the experiments: Q Liu, Y Gao, D Hua, W Li, H Zheng (III) Data analysis: Q Liu, W Li, H Zheng (IV) Manuscript writing: Q Liu (V) Supervised this study, discussed and edited the paper: C Zheng, R Chen (VI) Final approval of manuscript: All authors.īackground: Traditionally, the choice of tidal volume for mechanical ventilation was based on body weight (BW) and usually, predicted BW was used to correct actual BW inter-individual variations in obesity and muscle weight. Interviews with Outstanding Guest Editors.Policy of Dealing with Allegations of Research Misconduct.Policy of Screening for Plagiarism Process.
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