Pulmonary Ultrasound Was Used To Evaluate The Effects Of Inhaled Oxygen Concentrations And Individual PEEP On Atelectasis In Patients Undergoing Laparoscopic Surgery

Object Lung Ultrasound?LU?was used to evaluate the effects of different intraoperative inhaled oxygen concentrations and individual PEEP on postoperative atelectasis in patients undergoing elective laparoscopic gastrointestinal surgery,and to explore the optimal intraoperative inhaled oxygen concentrations and PEEP values,so as to provide a reference for the selection of respiratory parameters during mechanical ventilation.Methods From December 2018 to October 2019,a total of line 120 patients were selected for laparoscopic gastrointestinal surgery,with no gender limitation and age ranging from 40 to 75 years old,ASA physical status?-?,BMI<30kg/m².Exclusion criteria:Patients with obvious respiratory diseases,such as Chronic obstructive pulmonary disease,severe respiratory tract infection,pulmonary infection and cardiopulmonary insufficiency,SpO₂ <90%in preoperative air breathing condition or SpO₂ <95%in oxygen breathing condition;The patient was unable to cooperate with the pulmonary ultrasound examination;Pulmonary ultrasound imaging was not clear;After surgery,was transferred to ICU Previous history of chest surgery.Four groups?n=30?were divided by random number table method:80%inhaled oxygen?group A?,40%inhaled oxygen?group B?,80%inhaled oxygen+individualized PEEP?group C?,and 40%inhaled oxygen+individualized PEEP?group D?.Four groups were given 100%oxygen for preoxygenation,and mask positive pressure ventilation was performed after administration.After endotracheal intubation,all the four groups adopted pressure control volume guarantee ventilation mode?PCV-VG?,VT 6-8 ml/kg,?I:E?1:2,respiratory frequency 10 to 16 times/min,and maintained end expiratory partial carbon dioxide pressure(P_ETCO₂)35-45 mm Hg,intraopreative oxygen inhalation concentration of group A and group C was 80%,oxygen inhalation concentration of group B and group D was 40%,After pneumoperitoneum,the four groups underwent recruitment maneuver?airway pressure was set to 30 cm H₂O,time was 30 s?,PEEP of group A and group B was 0 cm H₂O,in groups C and D the individual PEEP value was set by PEEP titration,and the intraoperative blood pressure was maintained within 20%of the fluctuation of the patient's basal blood pressure.Preoperative records were made of age,sex,weight,height and body mass index of the four groups.In 10 min after endotracheal intubation?T₁?,after pneumoperitoneum?T₂ ?,deflated?T₃?after recording the Airway Peak Pressure?Airway Peak Pressure,Ppeak?,the dynamic lung compliance?Pulmonary dynamic around,Cdyn?,End of Carbon Dioxide Partial Pressure?End of Carbon Dioxide Partial Pressure,Pet CO₂ ?,Heart Rate,Heart Rate,HR),Mean Blood Pressure?MBP?and intraoperative use of vasoactive drugs.Arterial Oxygen Pressure?PaO₂?and Arterial carbon dioxide?Pa CO₂ ?were monitored by collecting 1ml of blood samples from the radial artery at each time point of T₁,T₂ ,T₃and T₄,respectively,and the oxygenation index?PaO₂ /FiO₂ ?was calculated.Pulmonary ultrasound examination and examination of pulse oxygen saturation?SpO₂ ?were performed before induction of anesthesia?T₁?,30min after extubation?T₄?,and 24h after surgery?T₅?.Clinical Pulmonary Infection Score?CPIS?was recorded one and seven days after surgery.Results A total of 106 patients were included in this study,all of whom completed the operation smoothly.There were 25 cases in group A,27 cases in group B,28 cases in group C and 26 cases in group D.Compared with T₀,the pulmonary ultrasound score of patients in the four groups increased at T₄and T₅?P<0.05?.Compared with group A,PaO₂ /FiO₂ increased in group B at T_1-4,PaO₂ and PaO₂ /FiO₂ increased in group C at T_2-4,MAP decreased at T₂ ,Ppeak and Cdyn increased at T_2-3,and PaO₂ /FiO₂ increased at T_1-4and Ppeak and Cdyn increased at T_2-3in group D.Compared with group B,group C showed decreased PaO₂ /FiO₂ at T₁,decreased MAP at T₂ ,increased PaO₂ /FiO₂ ,Ppeak and Cdyn at T_2-4,increased PaO₂ /FiO₂ and PaO₂ at T_2-4,and increased Ppeak and Cdyn at T_2-3at group D.Compared with group C,group D showed an increase in PaO₂ /FiO₂ at T₁,an increase in MAP at T₂ ,and a decrease in Ppeak at T_2-3.PEPP was individualized in group C?12.89±1.47cm H2O?,and PEEP was individualized in group D?7.04±1.43cm H2O?.The difference in PEEP between the two groups was statistically significant?P<0.05?.Compared with group A,B and D,the utilization rate of vasoactive drugs increased significantly in group C,and the difference was statistically significant?P<0.05?.Compared with group A,B,and C,the postoperative 1d?7d CPIS of group D were all reduced?P<0.05?.Conclusion Pulmonary ultrasonography can diagnose atelectasis by virtue of its simplicity and safety.Reducing inhaled oxygen concentration alone cannot effectively improve postoperative atelectasis and postoperative oxygenation In the process of mechanical ventilation,the optimal PEEP value determined by the method of PEEP titration can increase the dynamic compliance of the lung,improve atelectasis of the lung and postoperative oxygenation to some extent,and have a certain protective effect on the lung.80%inhaled oxygen concentration+individualized PEEP can also play a role in lung protection to some extent,However,high PEEP values often lead to intraoperative application of vasoactive drugs to maintain hemodynamic stability,which should be used with caution.The 40%inhaled oxygen concentration+individualized PEEP not only had a protective effect on the lung and reduced the incidence of postoperative pulmonary complications,but also had little effect on the hemodynamics of the patients.