Objective:To establish a risk prediction model dominated by diaphragm thickening fraction (DTF) and intra-abdominal pressure (IAP) monitoring, and to explore the predictive value of the model for weaning failure in patients with severe acute pancreatitis (SAP).Methods:A prospective research was conducted. Sixty-three patients undergoing invasive mechanical ventilation treatment who diagnosed with SAP admitted to intensive care unit of the First Affiliated Hospital of Jinzhou Medical University from August 2020 to October 2021 were enrolled. The spontaneous breathing trial (SBT) was carried out when the clinical weaning criteria was met. The stable cardiovascular status, good pulmonary function, no chest and abdominal contradictory movement, and adequate oxygenation were defined as successful weaning. Otherwise, it was defined as failure weaning. The clinical indicators such as SBT 30-minure DTF, IAP, tidal volume (VT), respiratory rate (RR), body mass index (BMI), and blood lactic acid (Lac) were compared between the weaning success group and the weaning failure group. The indicators with statistically significant differences in the single-factor analysis were included in the secondary multivariable Logistic regression analysis to establish a risk prediction model. The correlation between the DTF and IAP at 30 minutes of SBT was analyzed. Receiver operator characteristic curve (ROC curve) was drawn to analyze the predictive value of the risk prediction model for SAP patient withdrawal failure at 30 minutes of SBT.Results:Finally, 63 patients with SAP were enrolled. Among the 63 patients, 42 were successfully weaned and 21 failed. There were no significant differences in age, gender, and oxygenation index (PaO 2/FiO 2), sequential organ failure assessment (SOFA) score, acute physiology and chronic health evaluation Ⅱ (APACHEⅡ) score at admission between the two groups, indicating that the data in the two groups were comparable. Compared with the weaning success group, IAP, RR, BMI and Lac at 30 minutes of SBT in the weaning failure group were significantly increased [IAP (mmHg, 1 mmHg≈0.133 kPa): 14.05±3.79 vs. 12.12±3.36, RR (times/min): 25.43±8.10 vs. 22.02±5.05, BMI (kg/m 2): 23.71±2.80 vs. 21.74±3.79, Lac (mmol/L): 5.27±1.69 vs. 4.55±1.09, all P < 0.05], while DTF and VT were significantly decreased [DTF: (29.76±3.45)% vs. (31.86±3.67)%, VT (mL): 379.00±98.74 vs. 413.60±33.68, both P < 0.05]. Secondary multivariable Logistic regression analysis showed that DTF [odds ratio ( OR) = 0.758, 95% confidence interval (95% CI) was 0.584-0.983, P = 0.037], IAP ( OR = 1.276, 95% CI was 1.025-1.582, P = 0.029), and RR ( OR = 1.145, 95% CI was 1.014-1.294, P = 0.029) were independent risk factors for SBT withdrawal failure in 30 minutes in SAP patients. The above risk factors were used to establish the risk prediction model of aircraft withdrawal failure at 30 minutes of SBT: Logit P = -0.237-0.277×DTF+0.242×IAP+0.136×RR. Pearson correlation analysis showed that SBT 30-minute DTF was significantly correlated with IAP in SAP patients, and showed a significant positive correlation ( r = 0.313, P = 0.012). The ROC curve analysis results showed that area under the ROC curve (AUC) of the risk prediction model for SAP patient withdrawal failure at 30 minutes of SBT was 0.716, 95% CI was 0.559-0.873, P = 0.003, with the sensitivity of 85.7% and the specificity of 78.6%. Conclusions:DTF, IAP and RR were independent risk factors for SBT withdrawal failure in 30 minutes in SAP patients. The DTF and IAP monitoring-oriented risk prediction model based on the above three variables has a good predictive value for weaning failure in patients with SAP.