Effects Of Different Ventilation Models For The Nondependent Lung On The Inflammatory Response Of Lungs In Patients Undergoing Thoracotomy

Objective: To compare the effects of continuous oxygen supply orHigh-Frequency Jet Ventilation for the nondependent lung on theinflammatory response, oxidative stress and respiratory function.Methods: Forty-five ASAⅠor Ⅱpatients of both sexes, aged45-68yr, weighing65-80kg, were randomly divided into three groups(n=15each): control group(group A), non-ventilated lung with continuousoxygen supply group(group B) and non-ventilated lung withHigh-Frequency Jet Ventilation group(group C). Perioperative monitoringincluded peripheral oxygen saturation, electrocardiogram, heart rate,invasive mean arterial blood pressure, heart rate variability, bispectralindex and PETCO₂. ECG-guided internal jugular vein was cannulated.Anesthesia was induced with fentanyl2-4μg·kg^-1, propofol1-2mg·kg^-1,rocuronium0.6mg·kg^-1. After tracheal intubation, the patients weremechanically ventilated. The ventilation modes were performed(VT₁0ml·kg^-1, I:E with1:1.5, oxygen flow rate1.5L·min^-1). BIS wasmaintained at40-45with TIVA during the operation. The OLV ventilationmodes were performed(VT6ml·kg^-1, I:E with1:1.5, oxygen flow rate1.5L·min^-1). PETCO₂was maintained at35-45mmHg, the peak voltage of airtube was undered35cmH2O. During OLV, there was no treatment ingroup A; continuous oxygen was supplied to non-ventilated lung in groupB; while, non-ventilated lung was ventilated by High-Frequency JetVentilation in group C. Blood samples were taken from radial and internaljugular, blood gas analysis and plasma IL-6, IL-8, SOD, MDA, SP-Aconcentration were determinated at after intubation(T₀),1.5h(T₁) and2h(T₂) of OLV,24h after operation (T3)again. The differences of the variables were measured between radial and internal jugular. Respiratoryindex(RI) was calculated.A sample (1.0ml3) was extracted from the visually estimatedadjacent lung cancer, fixed in10%buffered formalin, sectioned, stained,and scored by a pathologist blinded to experimental conditions. Sampleswere assigned an injury score.Results: There were no significant differences in the age, gender,BMI, the types of surgery, the duration of OLV, the duration of surgery,fluid volume, urine volume in all the groups(P>0.05).No significant differences were found in IL-6n,IL-8n,SODn,MDAn,SP-A and RI at T₀in all the groups(P>0.05). IL-6n,IL-8n,SODn,MDAn and SP-A were significantly increased at T₁-2comparedwith the baselines at T₀and the indice were higher in group A than ingroup B,C(P <0.05). RI was significantly increased at T₁-2comparedwith the baselines at T₀and the indice were higher in group A than ingroup B,C(P <0.05). SP-A was significantly increased at T₁, IL-6n,MDAn was increased at T₂in group C than in group B, SODn wassignificantly lower in group C at T₁-2, while SP-A was only significantlylower at T₂in group C compared with group B(P <0.05). At T3, SOD,MDA was decreased in all the groups. There was significantly changes ingroup B and C(P <0.05). Compared with the baseline at T₀, RI wassignificantly increased at T₁-2and the index were higher in group A(P<0.05).It is significantly lower in group C than in group B(P <0.05).Lung indury score: histologic damage were seen significantlyseverer in group A than in group B and C(P <0.05).Conclusion: Non-ventilated lung with continuous oxygen supplyand non-ventilated lung with High-Frequency Jet Ventilation can relievethe inflammatory response and oxidative stress and reprove therespiratory function in patients with OLV.