The Effect Of Pressure Control Inverse Ventilation On The Dead Space Fraction And Inflammatory Response In Elderly Patients With Laparoscopic Surgery

Objective:The purpose of this study was to observe the effects of dead space fraction and inflammatory response in elderly patients by using pressure-controlled reverse ventilation in laparoscopic surgery,and to adjust the inhalation/exhalation ratio according to the flow-time curve of the patients individually,so as to provide a mechanical ventilation method for clinical reference in laparoscopic surgery.Methods:Sixty elderly patients who planned to undergo laparoscopic radical gastrectomy were randomly divided into volume control ventilation group(VCV),pressure control ventilation group(PCV)and pressure control inverse ratio ventilation group(PC-IRV),with 20 cases in each group.Operation began after the construction of the pneumoperitoneum,change the corresponding mechanical ventilation.Intraoperative respiratory mechanics and hemodynamic parameters were recorded at 10 min after anesthesia induction(T1),30 min(T2)and 90 min(T3)after pneumoperitoneum built,and closed pneumoperitoneum(T4).At these fourmoments,arterial blood gas analysis indexes were taken,and parameters such as dead space fraction were calculated according to relevant measurement values.Taken venous blood at 10 min after anesthesia induction(T1),30 min after extubation(T5)and 24 hour after surgery(T6),the content of TNF-a and IL-6 in serum was measured by ELISA.The preoperative and postoperative blood oxygen saturation(T6)and the occurrence of hypoxemia at T6 were recorded.Results:Compared with the ventilation mode of traditional respiratory ratio,during the pneumoperitoneum period,the dead fraction of PC-IRV group was significantly decreased,and the lung dynamic compliance was significantly increased,with statistically significant difference(P<0.05).Oxygenation index at T2 and T4 was significantly higher than that in the VCV group(P<0.05),and there was no significant difference from that in the PCV group.The contents of TNF-αand IL-6 in serum collected at three time points were all higher than the previous one.At T5,the content of IL-6in PC-IRV group was lower than that in PCV group(P<0.05);the content of TNF-αin PC-IRV group was lower than that in VCV group at T6(P<0.05);and the content of IL-6 in PC-IRV group was lower than that in PCV group(P<0.05).The difference was statistically significant.At T6,the blood oxygen saturation of PC-IRV group was higher than that of VCV group andPCV group(P<0.05),and the difference was statistically significant.Conclusions:When the elderly undergoing the laparoscopic surgery,using the pressure control inverse ventilation mode with individualized adjusting inspiration and expiration ratio according to expiratory flow time curve can reduce dead space fraction,improve oxygenation index,the dynamic lung compliance and reduce inflammatory response,without dynamic pulmonary hyperinflation,can be used as a line of laparoscopic surgery in an alternative way of mechanical ventilation.