Anesthetic Management Of Robotic Assisted Cardiac Surgery In Terms Of One Lung Ventilation And Carbon Dioxide-Pneumothorax

Part Ⅰ The effects of one lung ventilation, carbon dioxide-pneumothorax,and cardiopulmonary bypass during robotic assisted cardiac surgery onpulmonary functionObjective To observe the effect of OLV, CO₂-pneumothorax and CPB on pulmonaryfunction during robotic assisted cardiac surgery. Methods Ninety-eight patientsunderwent robotic assisted cardiac surgery using the da Vinci system, including58on-pump （on-pump group, n=58） and40off-pump （off-pump group, n=40）. Mechanicalventilation parameters and arterial blood gas were assessed at the following time points:20min after induction of anesthesia with two-lung ventilation （TLV）（T1）,20min afterOLV （T2）,20min after termination of CPB with OLV in on-pump group （T3） or20minafter main surgery intervention in off-pumpgroup （T3′）, and20min before surgeryfinished （T4）. Dynamic lung compliance （Cdyn）, alveolar-arterial PO₂different（PA-aDO₂）, artery-alveolar O₂pressure ratio （a/A） and oxygenation index （OI） were thencalculated. Results No significant differences were observed in pulmonary functionparameters between T3′and T2points after operation in off-pump group. But inon-pump group, compared with those in T2point, PETCO₂, Ppeak, PaCO₂, PA-aDO₂in T3point were higher whereas SpO₂, Cdyn, PaO₂, OI, a/A were lower （P<0.05）. Comparingbetween the two groups, SpO₂, Cdyn, PaO₂, OI, a/A were higher while Ppeak, PaCO₂,PA-aDO₂were lower at T3′point in off-pump group compared with those at T3point inon-pump group （P<0.01）. Conclusions In robotic assisted cardiac surgery with OLV and carbon dioxide pneumothorax, the CPB could aggravate the pulmonary functionand the tolerance to OLV.Part Ⅱ The application of monitoring end-tidal pressure of carbon dioxidein robotic assisted cardiac surgeryObjective This study was performed to estimate the relationship between end-tidalpressure of carbon dioxide （PETCO₂） and arterial partial pressure of carbon dioxide（PaCO₂）, and evaluate the application of PETCO₂during robotic assisted cardiac surgery.Methods Eighty patients were divided into three groups: congenital heart disease group（group A, n=35）, mitral valve disease group （group B, n=27）, and coronary heart diseasegroup （group C, n=18）. Measurements of PETCO₂from capnography values and PaCO₂from arterial blood gases were registered. Data were obtained at baseline with TLV,30min after institution of OLV,30,60and90min during carbon dioxide pneumothorax,30min after CPB during OLV, and30min after return to TLV. The arterial-to-end-tidalcarbon dioxide tension difference （Pa-ETCO₂） was calculated. Results Agood agreementwith a moderate variation was observed between PETCO₂and PaCO₂in three groups（P<0.05） except at30min after institution of OLV during robotic assisted cardiacsurgery. Compared with those before CPB, PETCO₂, PaCO₂and Pa-ETCO₂increased ingroup Aand B （P<0.05）, and they also increased gradually in group C from30to90minduring carbon dioxide pneumothorax （P<0.05）. Conclusion There was good correlationof PETCO₂and PaCO₂in robotic assisted cardiac surgery. Pa-ETCO₂increased inprolonged OLV, especially after CPB. The PaCO₂cannot be substituted by the PETCO₂thoroughly during anesthesia of robotic assisted cardiac surgery.Part Ⅲ Hypoxemia associated with one lung ventilation and carbon dioxidepneumothorax during robotic cardiac assisted surgeryObjective To analyse the causes and therapeutic measures of hypoxemia during roboticassisted cardiac surgery with OLV and carbon dioxide-pneumothorox. Methods130 consecutive patients undergoing robotic assisted cardiac surgery using the da Vincisystem were studied. SpO₂and arterial blood gases were monitored. When hypoxemiawas identified as SpO₂less than90%, appropriate measures were taken to correct it.Results Hypoxemia has occurred during OLV after CPB with the incidence of21.5%.Of which the minimum value of PaO₂was53mmHg. Partial open （not loosen） the pliersclamping on the non-ventilated side of bronchial catheter restored partial ventilation forthe non-dependent lung was effective for correcting hypoxemia. The PaO₂raised from（65.4±8.8） mmHg to （104.4±10.5） mmHg within （3.7±1.4） min. Conclusions Theincidence of hypoxemia was higher, and mechanism of hypoxemia was more complexduring robotic cardiac surgery than non-cardiac surgery which needed OLV. Takingcareful preoperative assessment and immedicate treatment are important to avoidassociated complications.