Objective To investigate the effect of Dexmedetomidine combined with lung protective ventilation on respiratory mechanics and lung function in patients with intraperitoneal heat perfusion chemotherapy.Methods A total of 75 patients who underwent elective intraperitoneal hyperthermic infusion chemotherapy in Qingyuan People's Hospital from January 2021 to January 2022 were selected as the research objects.According to the random number table method,they were divided into conventional group (37 cases) and combined group (38 cases).Patients in the conventional group received conventional anesthesia and conventional two-lung ventilation,while patients in the combined group received Dexmedetomidine anesthesia combined with lung protective ventilation strategy on the basis of the conventional group.The levels of serum tumor necrosis factor-α (TNF-α),interleukin-6 (IL-6),respiratory mechanics,pulmonary function indexes and the incidence of pulmonary complications were compared between the two groups immediately(T1),30 min(T2),60 min(T3)and before extubation(T4).Results The levels of TNF-α and IL-6 at T2,T3 and T4 in the two groups were higher than those at T1 in the same group,and the differences were statistically significant (P＜0.05).The levels of TNF-α and IL-6 at T2,T3 and T4 in the combined group were lower than those in the conventional group,and the differences were statistically significant (P ＜0.05).The peak airway pressure (Ppeak),plateau airway pressure (Pplat)and airway resistance (Raw)at T2 and T3 in the two groups were higher than those at T1 in the same group,and the differences were statistically significant (P＜0.05).Ppeak,Pplat and Raw at T4 in the conventional group were higher than those at T1 in the control group,and the differences were statistically significant (P＜0.05).Ppeak,Pplat and Raw at T2,T3 and T4 in the combined group were lower than those in the conventional group,and the differences were statistically significant (P ＜0.05).The alveolar arterial oxygen partial pressure difference (A-aDO2),respiratory index (RI)and death cavity rate (VD/VTmean)at T2 and T3 were higher than those at T1,and oxygenation index(OI)was lower than those at T1 in the two groups,and the differences were statistically significant (P＜0.05).A-aDO2,RI,VD/VTmean at T2 and T3 in the combined group were lower than those in the conventional group,and OI was higher than that in the conventional group,and the differences were statistically significant(P＜0.05).There was no significant difference in the partial pressure of carbon dioxide(PaCO2)between the two groups at each time(P＞0.05).The total incidence of pulmonary complications in the combined group was lower than that in the conventional group,and the difference was statistically significant (P ＜0.05).Conclusion Dexmedetomidine combined with lung protective ventilation in patients with intraperitoneal heat perfusion chemotherapy can effectively improve patients' respiratory function,reduce the release of inflammatory factors,and reduce the risk of pulmonary complications.