Static Pressure - Volume Curve To Guide Individual Protective Lung Ventilation In The Role Of Open Heart Surgery Patients

Objective: To evaluate the effect of positive end-expiratory pressure based onquarsi-static press-volume curve and continuous positive airway pressure in agedpatientsundergoing thoracic surgery.Methods:96undergoing lobectomy aged patients were divided into group N（normal）and group D（decreased） according to the pulmonary function before operation. Thesetwo groups were randomly divided into two subgroups: control group （NC, n=30; DC,n=18） and protective lung ventilation group （NP, n=30; DP, n=18）. During OLV, Vt wasset at9ml/kg in group NC and DC, meanwhile Vt was set at6ml/kg, PEEP at Pinfs+2cmH2O and CPAP at5cmH2O in group NP and DP. Plateau airway pressure （Pplat）,peak airway pressure （Ppeak） and lung compliance（Cdyn） were measured and recordedat5minutes before OLV（T1）,30minutes （T2）,60minutes after OLV （T3）. Arterial bloodsamples were taken at T1, T2, T3and5minutes after TLV （T4） for blood gas analysis.Venous blood samples were collected at T1, T4and18h after thoracotomy surgery （T5）for the determination of plasma concentration of TNF-α and IL-6（by ELISA）. Chestfeature, chest radiographic feature, blood routine were monitored on1,3,5days afterthoracic surgery.Results: Compared with group DC and NC, Pplat, Ppeak in group DP and NP decreasedsignificantly during T2and T3. Compared with group DC, Qs/Qt decreased, and PaO2 increased in group DP at T2,T3. Compared with group DC and NC, concentration ofTNF-α、IL-6in group NP and DP then decreased respectively at T4and T5.Conclusion: Mechanical ventilation with Vt at6ml/kg, PEEP at Pinfs+2cmH2O,CPAP at5cmH2O and PH provides best ventilation efficacy for OLV. It is more effectivein aged patients with abnormal pulmonary function. Objective: To evaluate the effect of strategy positive end-expiratory pressure based onquarsi-static press-volume curve and alveolar recruitment in obesity patientsundergoing thoracic surgeryMethods:24undergoing lobectomy obesity patients were randomly divided into groupC, group P（n=12）. During OLV, Vt was set at8-9ml/kg in group C, Vt was set at6ml/kg,a lung-recruiting strategy consisting in a RM followed PEEP at Pinfs+2cmH2O in groupP. Plateau airway pressure（Pplat）, peak airway pressure（Ppeak） and lungcompliance（Cdyn） were measured and recorded at5minutes before OLV（T1）,30minutes（T2）,60minutes after OLV （T3）. Arterial blood samples were taken at T1, T2, T3and5minutes after TLV （T4） for blood gas analysis. Venous blood samples were collected at T1,T4and18h after thoracotomy surgery （T5） for the determination of plasma concentrationof TNF-α and IL-6（by ELISA）.Results: Compared with TLV, Pplat, Ppeak decreased significantly during OLV.Compared with group C, Qs/Qt decreased, and PaO₂increased in group P at T2, T3and T4.Compared with group C, concentration of TNF-α、IL-6in group then decreased at T4.Conclusion: Mechanical ventilation with Vt at6ml/kg, a lung-recruiting strategyconsisting in a RM followed PEEP at Pinfs+2cmH2O, provides best ventilation efficacy for OLV in obesity patients.