Effects Of Different Ventilation Modes During One-lung Ventilation Anesthesia On Respiratory Function And F_A/F_I Changes In Sevoflurane Inhalation

Objective:To investigate the effects of different ventilation modes on arterial blood-gas, airway pressure and intrapulmonary shunt, and FA/FI changes in sevoflurane inhalation in one lung ventilation patients, in order to select the proper ventilation pattern.Method:Thirty ASAⅡ-Ⅲpatients with lung cancer aged 20-65 years old, BMI 18-25 undergoing lung resection with the same group of surgeons, were randomly divided into 3 groups with 10 subjects in each group. When TLV:VT on 10ml·kg-1, Rf on 10 times·min-1, PEEP on 0,I:E on 1:1.5, FIO2 on 100%, Oxygen flow on 1.5L·min-1. During OLV:group A(VCV), VT on 8 ml·kg-1, Rf on 12 times·min-1, PEEP on 0; group B (PCV), ventilation mode the same with group A first to get a stable airway pressure, then switch the ventilation mode into PCV with Ppeak unchanged, Rf on 12 times·min-1, PEEP on 0; group C (low tidal volume+PEEP), VT on 6 ml·min-1, Rf on 16 times·min-1, PEEP on 5 cmH2O. Blood gas analysis was determined 10 mins after TLV (T1),20 mins (T2),45mins (T3) and 70 mins (T4) after OLV respectively. At the same time, HR, MAP, SpO2 and Ppeak were drawn. Blood samples were collected from artery and jungular vein at different time points including T1, T2, T3 and T4.1.5% Sevoflurane inhalation was started at 20 minutes of OLV for 20 minutes. Result:1.There were no significant differences in demographics in all three groups (P>0.05). There were no significant differences in haemodynamics in all three groups (P>0.05);2. Changes in Ppeak, lung compliance, arterial oxygenation (PaO2) and intrapulmonary shunt (Qs/Qt)(1) Ppeak increased in all three groups during OLV, among which group A and B were with significant changes (P<0.05);(2) Lung compliance decreased in all three groups during OLV, among which group A and C were with significant changes (P<0.05), and also, group B was significantly higher than group A and C at all time points (P<0.05);(3) PaO2 decreased in all three groups during OLV (P<0.05), but with no significant changes among groups (P<0.05);(4) Intrapulmonary shunt increased in all three groups during OLV (P< 0.05), among which group C was significantly lower than group A and B at all time points (P<0.05).3. There were no significant differences in FA/FI among three groups during 20 minutes of 1.5% sevoflurane inhalation (P>0.05). According to curves based on FA/FI, group B had the fastest increase in the early 8 minutes, with group A and C followed. As time went on, three curves approached and looked the same. Conclusions:1. During OLV, PCV increased pulmonary compliance;2. During OLV, there were no differences in arterial oxygenation in the three ventilation modes, i.e. VCV, PCV and low tidal volume+PEEP;3. During OLV, in order to reduce intrapulmonary shunt, low tidal volume+PEEP was a better choice;4. In the early time of 1.5% sevoflurane inhalation during OLV, FA/FI increased fatest in PCV, followed by VCV and low tidal volume+PEEP, but with no differences in FA/FI at last.