The Role Of Individualized Tidal Volume Setting In Lung Protection During Anesthesia

Objective Through mechanical ventilation under general anesthesia in patients undergoing laparoscopic cholecystectomy,combined with respiratory mechanics and hemodynamic parameters during operation,the effects of individual tidal volume and conventional tidal volume on lung injury were compared.Methods Forty patients who underwent elective laparoscopic cholecystectomy in our hospital from November 2018 to August 2019 were selected.All patients have signed the informed consent form,and the gender is not limited,aged between 30 and 50 years old.American Society of Anesthesiologists（ASA）Grade I～II,Body Mass Index（BMI）18～24kg/㎡,no basic diseases of respiratory system,circulatory system and blood system,no contraindication to conventional anesthesia,the selected patients were divided into control group by random number table method（Group C）,experimental group（T group）,20 patients in each group.Sufentanil induced by general anesthesia0.4ug/kg,etomidate 0.3mg/kg,rocuronium bromide 0.6mg/kg,and the EEG dual frequency index（BIS）value will reach the specified value（both patients in both groups are 40～60）,perform tracheal intubation,confirm that the catheter enters the trachea and the position of the catheter is good,connect the catheter with anesthesia machine,monitor to monitor the value of partial expiratory carbon dioxide partial pressure（Pet CO₂）,and set the parameter of the anesthesia machine to 50%of inhaled oxygen,Oxygen flow rate is 1L/min,inhalation and exhalation ratio（I:E）is 1:2,peak airway pressure is less than 30cm H₂O;tidal volume setting:group C adopts conventional tidal volume setting of 8ml/kg,initial respiratory frequency of 12 times/minute,The tidal volume of patients in the T group was measured before surgery.The tidal volume of mechanical ventilation during the operation was measured during the resting state,that is,the individualized tidal volume was set,and the initial respiratory rate was 12 times/minute.The two groups of patients were set to the corresponding tidal volume.After the measurement,the respiratory rate was adjusted according to Pet CO₂to achieve equivalent ventilation in both groups（ie,Pet CO₂was maintained between 40±5mm Hg）.General anesthesia maintenance micropump intravenous injection of propofol（3～5mg/kg/h）and remifentanil（0.1～0.2ug/kg/min）to maintain the depth of anesthesia,according to the BIS value and hemodynamic index during the operation Adjust the pumping dose.Two groups of patients were collected at the following points:T1（before anesthesia）and T4（6h after operation）.5ml of venous blood was collected from the patients,and the supernatant was taken after centrifugation（3000r×10min）.Immunosorbent assay（ELISA）detects human type I cytoplasmic membrane protein（HTI56）,lung surfactant-related protein-A（SP-A）,tumor necrosis factor-α（TNF-α）,and interleukin-6（IL-6）concentration;record heart rate（HR）and mean arterial pressure（MAP）at T1（before anesthesia）,T2（20 minutes after intubation）,T3（40minutes after intubation）,and T4（6h after operation）;T2（20 minutes after intubation）and T3（40 minutes after intubation）recorded peak airway pressure（Ppeak）,plateau pressure（Pplat）,and mean pressure（Pmean）.Results（1）There was no significant difference between the two groups in age,gender,BMI,ASA classification,anesthesia time,operation time,and time after admission to the recovery room（PACU）（P>0.05）;and the respiratory mechanics of the two groups of patients There was no statistically significant difference between groups and hemodynamic index fluctuations（P>0.05）.（2）There was no significant difference in the concentrations of T1（before anesthesia）inflammatory factors IL-6,TNF-α,HTI56 and SP-A in the two groups of patients（P>0.05）,and T4（6 hours after operation）of IL-6 and TNF-α,HTI56 and SP-A were all higher than before operation,and the increase of IL-6,TNF-α,HTI56 and SP-A in group C was larger than that in group T,and the differences were statistically significant（P<0.05）.Conclusions（1）Compared with conventional tidal volume mechanical ventilation,the setting of individualized tidal volume in anesthesia can also maintain the stability of respiratory mechanics and hemodynamics without causing increased respiratory resistance and large fluctuations in hemodynamics.（2）Compared with conventional tidal volume mechanical ventilation,the setting of individualized tidal volume during anesthesia can reduce the release of inflammatory indicators such as IL-6,TNF-α,HTI56 and SP-A,and reduce pulmonary blood caused by inflammatory reactions.Barrier damage,thereby exerting lung protection.