The Effect Of Preemptive Alveolar Recruitment Strategy And Lower Fraction Of Inspired Oxygen On Lung Cancer Patients With Video-assisted Thoracoscopic Surgery

ObjectiveTo evaluate the effect of a preemptive alveolar recruitment strategy(ARS)before one lung ventilation and lower fraction of inspired oxygen(FiO2=0.6)on perioperative gas exchange, systemic inflammatory makers, oxidative stress and postoperative recovery of lung cancer patients with video-assisted thoracoscopic surgery(VATS)Methodssixty patients for elective thoracoscopic lung cancer surgery were randomly allocated into three groups(n=20). Control group received conventional ventilation(FiO2=1,no ARS), while Group A received preemptive ARS before one lung ventilation(FiO2=1,with ARS), and Group B received preemptive ARS combined with fraction of inspired oxygen 0.6(FiO2=0.6,with ARS), anesthesia induction,anesthesia maintanance, fluid management and monitoring were administration in a unified way. For all patients, two lung ventilation strategy concluded a tidal volume of 8~10 ml /kg, respiratory frequency of 10~12 times/min, inspiration/expiration of1:2, while the dependent lung was ventilated with a tidal volume of 5 ~ 6ml/kg,respiratory frequency of 14 ~ 16 times/min, and 5cmH2 O PEEP during OLV. The method of preemptive ARS was 10 slow manual breaths during two lung ventilation with a peak inspiratory pressure of 40cmH2 O, followed by positive end-expiratory pressure(PEEP) increasing to 5,10,15cmH2 O minutely interval with volume control ventilation,and then decreasing every three breath to 5cmH2 O to start OLV. In all groups, if arterial blood pressure decreased 20% more than baseline value, fluid challenge or other symptomatic treatment was needed. When hypoxemia happened during OLV(SpO2<95%), improve FiO2 immediately and check the location of DLT,if SpO2<90%, CPAP of the operative lung or intermittent TLV was applied and cases were excluded for analysis. If severe arrhythmia or other circulation systerm disorders occured, improve FiO2 to 1.0, give treatment and recored the case. Testing indexes:blood samples of radial artery for concentration of IL-6,IL-8,MDA,SP-D were colleted at baseline before anesthesia induction(T0), 10 minutes after lateral position but before applying ARS(T1), after 30min(T2), 60 min(T3),120min(T4) of OLV, 10 minutes after re-establishing TLV(T5), and 2 hours after surgery(T6). In addition,radial artery gas analysis was racorded at T0 ~ T5, MAP,CVP,HR, Ppeak,Pplat,Cd were recorded at T1 ~ T5 and the period of ARS. After surgery, we followed up patients’ recovery including hospital stay, postoperative chest x-rays, pulmonary or other complications.Results :1. The basical information such as gender, age, weight, operation time and preoperative lung function among groups had no significant difference(P>0.05).2. Compared to T1, the PaO2 in all groups decreased significantly at T2(P<0.05), and gradually increased when OLV continued,with PaO2 at T4 significantly higher than that at T2(P<0.05). Compared to control group,PaO2 was significantly higher in group A during the whole time of OLV at T2 ~ T4(P<0.05), while PaO2 in group B was similar(P>0.05). The Oxygenation index(OI) at T4 was significantly higher in group A and group B than that in control group(P<0.05).3. At different time points, the MAP, HR, CVP and Ppeak, Pplat, Cdyn had nosignificant difference among three groups(P> 0.05). while CVP had a transient increase during inplementing lung recruitment(P <0.05).4. Compared to control group, The serum concentration of IL-6, IL-8, MDA,SP-D had no significant difference in group A at each time(P> 0.05). Compared to control group and Group A, The serum concentration of IL-6 at T4~T6, IL-8 at T5~T6 and MDA at T4~T5 decreased significantly in group B(P <0.05).5. The extubation time and postoperative hospital stay had no significant difference in three groups(P> 0.05).Conclusion1. Once preemptive alveolar recruitment strategy(ARS)for two lung is effective in improving arterial oxygenation during OLV and keep it in the entire period of OLV in thoracoscopic surgery.2. Once preemptive ARS has no significant effect on systematic inflammatory biomarkers IL-6, IL-8,MDA and surfactant protein D(SP-D) in serum during surgery and 2 h after surgery.3. Once preemptive ARS combined with FiO2 = 0.6 can maintain proper oxygenation level,while serum MDA level including IL-6 、 IL-8 was significantly decreased during surgury especially after the end of OLV, which may be helpful to alleviate oxidative injury and inflammatory response after OLV.