Effect And Safety Analysis Of Different Internal Diameter Endotracheal Tubes On Respiratory Mechanics And Pulmonary Gas Exchange In Patients Undergoing Laparoscopic Colorectal Surgery

Objective:This study aims to explore the analysis of the influence of different types of endotracheal catheter on respiratory mechanics and pulmonary ventilation function and safety analysis through patients with laparoscopic colorectal surgery,so as to select better tracheal catheter models,optimize ventilation function,reduce lung injury of mechanical ventilation,and improve perioperative respiratory function,to provide reference for clinical work.Methods:72 patients underwent elective laparoscopic colorectal surgery from October 2021 to June 2022,ASA I～Ⅲ,age 35～75 years,height 160～180cm,BMI 18.5～28 kg/m²,male and female.Use a single-use endotracheal tube（Tampa wire reinforced）ID7.0,ID7.5,and ID8.0.After entering the operating room,the patient opens intravenous access in the supine position,and basic monitoring of oxygenation,breathing,circulation,and body temperature（heart rate,blood pressure,electrocardiogram,pulse oximetry）is performed.Radial arterial blood pressure was monitored by radial artery catheterization,muscle relaxation monitoring and EEG double-frequency index（BIS）monitoring were performed.After anesthesia induction,insert the corresponding tracheal catheter under mouth and connect the Drager Fabius GS anesthesia machine and the paraairflow monitor.Volume ventilation mode is adopted.the parameters are set as follows:VT=8 ml/kg（ideal body mass）[ideal body mass calculation formula:male（kg）=height-100（cm）,female（kg）=height-105（cm）].I:E=1:2;inhaled oxygen concentration（Fi O₂）=0.6,ventilation flow rate 2L/min,respiratory rate initially set at 12 times/min,maintain P_ETCO₂at35-40 mm Hg,adjust respiratory rate according to P_ETCO₂,no PEEP,airway platform pressure 35cm H₂O,manual lung inflation every 30 min;pay attention to keep the ventilator pipeline unobstructed.The pneumoperitoneum pressure was 12 mm Hg（1 mm Hg=0.133 k Pa）,and all three groups received propofol and remifentanil under intravenous anesthesia（TIVA）.BIS was maintained at 40 to 60,intermittent intravenous cis-atracurium 0.1mg/kg,and the T1 of TOF was about 10%.After coughing,swallowing,throat and reflex recovery,and remove the tracheal tube after inhaling oropharyngeal secretions.The general conditions of age,gender,BMI,pneumoperitoneum time and operation time in each group were recorded;Raw,Cdyn,Ppeak,5min after endotracheal intubation（T1）,5minafter establishing pneumoperitoneum（T2）,5minafter Trendelenburg position（T3）,and 5 min after pneumoperitoneum removal（T5）;Record arterial blood oxygen partial pressure（PaO₂）,arterial blood partial carbon dioxide pressure（PaCO₂）,alveolar arterial blood oxygen partial pressure difference（A-a DO₂）at T0（before anesthesia induction）,T4（30min after pneumoperitoneum）;the occurrence of immediate complications（hypertension/tachycardia,arrhythmia）,and extubation complications（laryngeal spasm,sore throat,hoarseness,laryngeal edema）were recorded.Results:1.Comparison of general situations:no significant differences in gender,age,BMI,time of pneumoperitoneum,and operation time among the three groups（P>0.05）.2.Comparison of respiratory mechanics indicators:the results of intragroup comparison showed that Raw and Ppeak were significantly higher than T1 and significantly lower than T1 in T2 and T3,and Cdyn was significantly lower than T1,and the difference was statistically significant（P<0.05）.The results of the comparison between the groups showed that the Raw and Ppeak of the ID8.0 group were significantly lower than those in the ID7.0 group and the ID7.5 group（P<0.05）at T1 and T5,and there was no significant difference between the ID7.0 and ID7.5 groups（P>0.05）.The Cdyn of the ID8.0 group was higher than that of the ID7.5 group,and the ID7.5 group was higher than that of the ID7.0 group（P<0.05）.At T2 and T3,the Raw and Ppeaks of the ID8.0 group were significantly lower than those in the ID7.0 group,and the differences were statistically significant,and the differences between ID7.0 and ID7.5 and ID7.5 and ID8.0 were not statistically significant.The difference between the three groups was not statistically significant（P>0.05）.3.Comparison of blood gas analysis indicators:blood gas analysis compared at time T0 and T4,PaO₂,PaCO₂and A-a DO₂were not significantly different among the three groups（P>0.05）.4.Comparison of complications:complications after intubation and extubation were not different among the three groups（P>0.05）.Conclusions:In laparoscopic colorectal surgery,the use of a larger inner diameter endotracheal tube within the permissible range is beneficial in reducing intraoperative Raw and Ppeak,improving Cdyn,and does not increase intubation and extubation complications,but it does not optimize intraoperative pulmonary ventilation.