The Effect Of PCV-VG Mode On Correlation Between PaCO₂ And PetCO₂ During One-lung Ventilation

Objective:In this study,the randomized controlled trial was adopted to study the effect of PCV-VG mode on correlation between PaCO2 and PetCO2 in one-lung ventilation.The effect of PCV-VG mode on lung protective ventilation in patients with one-lung ventilation is evaluated.This work provides a reference to clinical application.Methods:A total of 60 patients from Chengde Central Hospital(11/2016-06/2018)with radical resection of esophageal carcinoma,aged 40-70yr,BMI 20-25 kg/m2 and ASA ?-? level were selected.Exclusion criteria:1)Patients with severe cardiovascular and cerebrovascular diseases;2)Patients with severe respiratory diseases or preoperative oxygen partial pressure<75mmHg;3)Patients with liver and kidney dysfunction;4)Patients who had received open-heart surgery;5)Patients who received mechanical ventilation within 2 weeks before surgery;6)Patients who rejected as experimenters.Those patients were divided into 2 groups(n=30 each)using a random number table:volume-controlled ventilation group(group ?)and PCV-VG group(group P).The ventilator settings were adjusted,with a tidal volume 8 ml/kg and respiratory rate 12 breaths/min during two-lung ventilation(TLV),and with a tidal volume 6 ml/kg and respiratory rate 15 breaths/min during OLV The inspiratory/expiratory ratio was 1:2 and 75%fraction of inspired oxygen(FiO2)at 1.5L/min.Arterial blood gas analysis and respiration parameter were determined 15 minutes after TLV(T0),15 min(Ti),30 min(T2),60 min(T3),90 min(T4)after OLV.All patients had no preoperative medication.The peripheral venous access was established after entering the surgery,and the BP,ECG,SpO2 and BIS were monitored.The radial artery and central venous catheterization were performed under local anesthesia.Anesthesia induction:intravenous midazolam 0.05 mg/kg,sufentanil 0.5 ug/kg,etomidate 0.3 mg/kg,benzene sulfonic shun atracurium 0.2 mg/kg.After induction,the imported single-lumen trachea catheter with open vision was inserted into the tube,Insertion of bronchial blocker under the guidance of fiberoptic bronchoscope(FOB).The fiberoptic bronchoscope was positioned again after the right lateral decubitus position.After successful intubation and bilateral lung isolation,the mechanical ventilation was performed with anesthesia machine WATO EX-65(Shenzhen Mairui Company).The ventilation parameters of the two groups were set as follows:inhaled oxygen concentration(FiO2)75%,inspiratory-to-expiratory ratio 1:2,oxygen flow rate 1.5L/min;the tidal volume(TV)during double lung ventilation 8 ml/kg;the respiratory rate(RR)12 times/min,the VT during one lung ventilation 6 ml/kg and RR 16 times/min.Anesthesia maintenance:Micro pump propofol,remifentanil and cisatracurium besylate continuously.The dosage of propofol and remifentanil was adjusted during operation to maintain BIS between 45 and 55,and maintain hemodynamic stability.After the operation and the patients waking up,the tracheal tube was pulled out.The patients were sent back to the ICU ward when the vital signs were stable.The Actual tidal volume(TV),the end-expiratory carbon dioxide partial pressure(PetCO2),the airway peak pressure(Ppeak),the plateau pressure(Pplat),the arterial partial pressure of oxygen(PaO2)and the arterial partial pressure of carbon dioxide(PaCO2)of the two groups were record after the mechanical ventilation at 15 minutes after TLV(T0),15 min(Ti),30 min(T2),60 min(T3),90 min(T4)after OLV.The collected data were analyzed statistically.Results:(1)General situationThe sex ratio,age,BMI value,one-lung ventilation time and operation time between the two groups are no statistical difference(P>0.05)(Table 1).(2)Actual tidal volume(TV)For TV,the interaction between time point and grouping is not significant(P=0.516),and the main effect of grouping was not significant,that is,there was no significant difference in TV between the two groups at each time point(P=0.462)The TV in group V at T1-T4 time point is lower than To(P<0.001)(Table 2).(2)Ppeak and PplatFor Ppeak and Pplat,The interaction between time point and grouping is significant(P<0.001).The Ppeak and Pplat in group V are higher than those in group P at each time point.The Ppeak in group V at T1-T4 time point is higher than T0(P<0.05)(Table 3).(3)PaO2For PaO2,The interaction between time point and grouping is not significant(p=0.676).The main effect of grouping is not significant,that is,there is no significant difference between the two groups at each time point(P=0.612).The PaO2 in group V at T1-T4 time point is lower than T0(P<0.001)(Table 4).(4)PaCO2 and PetCO2For PaCO2,The interaction between time point and grouping is not significant(P=0.235).The main effect of grouping is not significant,that is,the PaCO2 in the two groups was no difference of statistics(P=0.880).The PaCO2 at T1-T4 is higher than T0 in the two groups(p<0.05)(Table 5).For PetCO2,The interaction between time point and grouping is not significant(P=0.432).The main effect of grouping is significant(P=0.002),that is,The PetCO2 in group P is higher than group V(P<0.05).The PetCO2 in group P and group V at T0 and T1 time point was higher than T2-T4(P<0.01)(Table 5).The correlation between PaCO2 and PetCO2:The correlation coefficient of PaCO2 and PetCO2 in group P is higher than that in group V.Comparing with To,the correlation in T1-T4 time points is reduced(Table 6).Conclusion:(1)Compared with VCV ventilation,one-lung ventilation with PCV-VG mode can better maintain the correlation between PaCO2 and PetCO2.(2)Compared with two-lung ventilation,the correlation between PaCO2 and PetCO2 in one-lung ventilation is lower in both ventilation modes.(3)The PCV-VG mode can effectively reduce the peak airway pressure and the airway platform pressure while guaranteed tidal volume and PaO2,and it can reduce the risk of pulmonary barotrauma.This model can be safely used in one-lung ventilation in esophageal cancer radical surgery.