Objective To investigate the relationship between the changes in preoperative serum creatinine (Cr), myoglobin (Mb), alanine aminotransferase (ALT) and postoperative fibrinogen (Fib), hemoglobin (Hb) expression levels with postoperative hypoxemia in patients with aortic dissection aneurysm (ADA). Based on this, a predictive model is constructed. Additionally, the study explores the role of transpulmonary pressure-guided positive end expiratory pressure (PEEP) in improving postoperative hypoxemia. Methods A retrospective analysis was conducted on the clinical data of ADA patients admitted to Tianjin University’s Thoracic Hospital from April 2021 to August 2023. Patients were divided into a hypoxemia group [partial pressure of oxygen/fraction of inspiration oxygen (PaO₂/FiO₂) ≤200 mm Hg] and a non-hypoxemia group (PaO₂/FiO₂ >200 mm Hg) based on whether they developed postoperative hypoxemia. Univariate and multivariate regression analyses were used to identify risk factors for postoperative hypoxemia in ADA patients and to construct a predictive model for postoperative hypoxemia. The receiver operating characteristic (ROC) curve was plotted, and the Hosmer-Lemeshow goodness-of-fit test was used to evaluate the predictive value of the model. Furthermore, the impact of different ventilation modes on the improvement of postoperative hypoxemia was analyzed. From April 2021 to August 2023, 16 ADA patients with postoperative hypoxemia who received conventional mechanical ventilation were included in the control group. From September 2023 to December 2024, 28 ADA patients with postoperative hypoxemia who received transpulmonary pressure-guided PEEP were included in the experimental group. ICU stay duration, mechanical ventilation duration, hospital mortality rate, and respiratory and circulatory parameters were analyzed to evaluate the effect of transpulmonary pressure-guided PEEP on patients with postoperative hypoxemia after acute aortic dissection. Results A total of 98 ADA patients were included, of which 79 (80.61%) were males and 19 (19.39%) were females. Their ages ranged from 32 to 79 years, with an average age of (49.4±11.2) years. Sixteen (16.3%) patients developed postoperative hypoxemia. Body mass index (BMI), smoking history, cardiopulmonary bypass (CPB) duration, preoperative serum Cr, Mb, ALT, postoperative Fib, and postoperative C-reactive protein showed a certain correlation with postoperative hypoxemia in ADA patients (P<0.05). There was no statistically significant difference in other baseline data between the two groups (P>0.05). Logistic regression analysis results indicated that BMI [OR=1.613, 95%CI (1.260, 2.065)] and preoperative Mb [OR=2.The results showed that preoperative BMI [OR=1.324, 95%CI (1.080, 2.065)], preoperative ALT [OR=1.012, 95%CI (1.000, 1.024)], preoperative Cr [OR=1.752, 95%CI (1.045, 2.940)], postoperative Fib [OR=1.165, 95%CI (1.080, 1.258)] and intraoperative CPB time [OR=1.433, 95%CI (1.017, 2.020)] were influencing factors of postoperative hypoxemia in ADA patients (P<0.05). Based on this, a prediction model for postoperative hypoxemia in ADA patients was established, with the prediction equation being P=1−1/(1+e^{constant + 0.67×BMI+1.14×CPB+0.52×Cr+0.73×Mb+ 0.44×ALT+1.12×Fib}. The area under the curve corresponding to the optimal critical point was 0.837 [95%CI (0.799, 0.875)], with a sensitivity of 87.5% and a specificity of 79.3%. The Hosmer-Lemeshow goodness of fit test showed P=0.536. Before treatment, there were no statistically significant differences in respiratory and circulatory parameters between the conventional group and the experimental group (P>0.05). After treatment, the levels of PEEP, PaO₂/FiO₂, end-expiratory esophageal pressure, and end-inspiratory transpulmonary pressure in the experimental group were higher than those in the control group, with statistically significant differences (P<0.05). The duration of mechanical ventilation and ICU stay in the experimental group were shorter than those in the control group, with statistical differences (P<0.05), while there was no statistical difference in mortality between the two groups (P=0.626). Conclusion The hypoxia prediction model based on preoperative Cr, Mb, ALT and postoperative Fib levels, combined with transpulmonary pressure-guided PEEP optimization, provides a scientific basis for the precise management of postoperative hypoxemia in ADA. This approach not only improves the predictive ability of hypoxemia risk but also significantly improves the postoperative oxygenation status of patients through personalized mechanical ventilation strategies, providing new insights into the management of postoperative complications.

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