Effects Of Inhaling Different Concentrations Of Oxygen Before Endotracheal Extubation On Postoperative Atelectasis In Thoracic Surgery

Objective:To compare the effects of inhaling different concentrations of oxygen before extubationon on the occurrence of postoperative atelectasis and the changes of respiratory indexes,so as to provide some reference for the perioperative management of thoracic surgery.Methods:The design type of this study is experimental.A total of 58 patients who underwent thoracoscopic lobectomy in Shengjing Hospital from December 2021 to August 2022 were randomly divided into 30%oxygen concentration（group A）and100%oxygen concentration（group B）.At the beginning of anesthesia,both groups were preoxygenated with 1.0Fi O₂（5min）and maintained with 0.8Fi O₂after intubation.More 30 minutes before the end of operation:group A:0.3Fi O₂was given;group B:1.0Fi O₂was given,to make it sure that the oxygen level in the lung was balanced.The patient was given the last lung distension before extubation.10 minutes before extubation（T1）,10 minutes after extubation（T2）and 30min（T3）after extubation,atelectasis was examined by ultrasonography in the anesthetic recovery room,the score of atelectasis was scored,and the incidence of atelectasis reexamined by chest CT 2 days after operation was observed.Respiratory index:oxygenation index（Pa O₂/Fi O₂）,alveolar arterial oxygen partial pressure difference（A-a DO₂）,peripheral oxygen saturation（Sp O₂）,arterial oxygen saturation（Sa O₂）of 10min before and after extubation,peripheral blood oxygen saturation（Sp O₂）,blood pressure（BP）and heart rate（HR）of 10min before and after extubation were recorded.Statistical software SPSS26.0 was used for data analysis.Normal distribution with mean±standard deviation（X±S）said,non-normal distribution data with median（M）and quarterback spacing（IQR are much less）said.Comparison between groups was conducted by the t test of two independent samples or the Mann-Whitney U test.Repeated measure analysis of variance was used to compare different time points within the group.Count data cases（%）,said the group comparison between using squared test or Fisher’s exact probability method;P<0.05 indicated statistically significant difference.Results:The pulmonary ultrasound score at T3 in group A was significantly lower than that in group B,and the incidence of CT atelectasis in group A was 17.2%,which was significantly lower than that in group B（41.4%）.The A-a DO₂at T2 in group A was significantly lower than that in group B,and the Pa O₂/Fi O₂in group A was higher than that in group B,but the difference was not statistically significant.The Sa O₂of group A was higher than that of group B,but there was no significant difference,the Sp O₂of group A was higher than that of group B,the BP of group A was higher than that of group B,but the difference was not statistically significant,the HR of group A was lower than that of group B,but there was no significant difference in Sp O₂between group A and group B 2 hours after operation.Conclusion:Inhaling 30%oxygen before endotracheal extubation in thoracic surgery does not lead to hypoxic events during resuscitation after extubation compared with inhaling 100%oxygen,on the contrary,it will reduce the incidence of postoperative atelectasis.