Abstract:Objective To explore the impact of amino acid intake on the occurrence of diaphragmatic dysfunction（VIDD）in patients with mechanical ventilation（MV）exceeding 48 hours. Methods A post-hoc analysis of a prospective，multicenter clinical trial was conducted. Adult patients who underwent MV for more than 48 hours in the Department of Critical Care Medicine of West China Hospital，Sichuan University and Sichuan Provincial People's Hospital from January to December 2019 were included. All patients underwent daily weaning tests，and the ventilator was adjusted to pressure support mode. Thickening fraction of diaphragm（TFdi）was measured and calculated using ultrasound，with TFdi<20% defining the VIDD group and TFdi≥ 20% defining the non-VIDD group. The intake of all amino acids，including enteral and parenteral nutrition（including human serum albumin），was collected to analyze its impact on VIDD and determine the optimal cutoff value for amino acid prediction in VIDD. Results A total of 126 patients were included，with a VIDD incidence rate of 40.48%（51/126）. There were 51 cases in the VIDD group and 75 cases in the non-VIDD group. The amino acids intake［（0.7±0.3）g/ （kg·d）vs（1.0±0.3）g/ （kg·d），t=6.530，P<0.01］and the final TFdi（17.7%±1.8% vs 24.7%±3.1%，t=15.924，P<0.01）in the VIDD group were significantly lower than those in the non-VIDD group. The area under the receiver operating characteristic（ROC）curve was 0.828 for amino acid prediction VIDD. Amino acids intake showed a negative curvilinear correlation with the occurrence of VIDD（P=0.014），with a cutoff value of 1.0 g/ （kg·d）. The incidence of VIDD and mortality were significantly reduced in the group with amino acids intake >1.0 g/ （kg·d）（P<0.05）. Conclusion Amino acids intake can predict the occurrence of VIDD. An intake of 1.0 g/ （kg·d）can be used as the baseline intake for mechanically ventilated patients to reduce the occurrence of VIDD and mortality.