Effects Of Different Pauses Before Thoracoscopic One-lung Ventilation On Lung Collapse In Elderly Patients

Objective:To investigate the effect of apnea duration before one lung ventilation（OLV）on the collapse of the operated lung in elderly patients undergoing video-assisted thoracoscopic surgery（VATS）.Methods:Sixty patients with thoracoscopic pulmonary lesion resection under general anesthesia,aged 65-80 years old,gender not limited,ASA classⅡ-Ⅲ,were selected.Patients were randomly divided into three groups:A（single lung ventilation immediately after skin incision）,B（single lung ventilation for 1min after skin incision）,and C（single lung ventilation for 2mins after skin incision）,with 20 cases in each group.Venipuncture is performed routinely after the patient enters the room,and vital signs of the patient are monitored:Mean arterial pressure（MAP）,heart rate（HR）,pulse oxygen saturation（Sp O₂）,brain oxygen saturation（r SO₂）,BIS index,etc.After anesthesia induction and muscle release had taken full effect,a visual double-lumen bronchial catheter was inserted（the opposite double-lumen bronchial catheter was selected according to the surgical location）,and pure oxygen dual-lung ventilation was given.After positioning,the position of the double-lumen canal is checked and OLV is performed according to the group when the cuticle is started.After the implantation of rigid optical thoracoscopy,the quality ratings of lung collapse of patients were recorded after thoracoscopic opening（T2）,2 mins（T3）,10mins（T4）,20 mins（T5）and 30 mins（T6）.The duration of pure oxygen ventilation before OLV,the duration of pleura incision,the duration of OLV,the duration of operation,and the occurrence of complications were recorded.Total collapse time and surgeon’s overall satisfaction were recorded;MAP,HR,Sp O₂,r SO₂,and arterial blood gas results were recorded at the following 5 time points:air breathing in the room（T0）,Double lung pure oxygen ventilation for 5 mins under anesthesia（T1）,2mins after pleura incision（T3）,30 mins after single lung ventilation（T7）,and 5 mins after lung reexpansion（T8）.Arterial blood gas results mainly include:arterial partial oxygen pressure（Pa O₂）、arterial partial carbon dioxide pressure（Pa CO₂）、oxygenation index（OI）.occurrence of intraoperative hypoxemia,and the incidence of complications related to respiratory system were recorded at one and three days after surgery.Results:1.There were no significant differences in the general and clinical conditions（OLV time,pleural incision time,OLV pure oxygen ventilation time,operation time）among the three groups（P>0.05）.There was no significant hypoxemia during single lung ventilation or double lung ventilation in the three groups.Respiratory complications on the first postoperative day:Postoperative atelectasis occurred in two patients in group A and one patient in group B,but one patient in group C had pulmonary inflammation after operation,the difference was not statistically significant（P>0.05）.The condition of the three patients improved and no other complications were observed at the three days follow-up.2.There were no significant differences in MAP,HR and Sp O₂among the three groups at each time point（P>0.05）.Compared with group A,r SO₂and Pa CO₂in group B and group C were significantly increased at T3 time point（P<0.05）;Compared with group B,r SO₂and Pa CO₂in group C were increased at T3 time point（P<0.05）;At the same time,the postoperative OI of the three groups was≥200mm Hg.3.Compared with group A and group B,the proportion of group C with very poor rating of collapsed lung quality decreased and the proportion of good rating increased at T2 time point（P<0.05）,and the proportion of poor rating of collapsed lung quality decreased and the proportion of good rating of collapsed lung quality decreased at T4 time point（P<0.05）.Compared with group A,the percentage of good lung collapse quality rating in group B increased at T3 time point（P<0.05）,and the lung collapse quality rating at T5 time point were all excellent,with statistical significance（P<0.05）.4.Compared with group A,the time of complete lung collapse in groups B and C was significantly shortened（17.5±0.9min vs 16.2±0.9min vs 24.2±1min）（P<0.05）.The satisfaction of surgeons in groups B and C was significantly higher[8（7,8）vs 9（9,10）vs 5（5,6）]（P<0.05）;Compared with group B,the time of complete lung collapse in group C was significantly shortened（P<0.05）.Meanwhile,the satisfaction of surgeons in group C was increased（P<0.05）.Conclusion:For elderly patients undergoing VATS,Two-minute disconnection technique before OLV not only shortened the time of complete lung collapse and improved the satisfaction of surgeons,but also had the best safety.