Effects Of Ultrasound Guided Thoracic Paravertebral Block At Different Segments On Pulmonary Shunt,PaO₂ And Circulation In The Patients Underwent Thoracic Surgery During One Lung Ventilation

Methods: To discuss the effects of different segments' thoracic paravertebral block(TPVB) guided by ultrasound on pulmonary shunt, PaO2 and circulation in the patients underwent thoracic surgery during one lung ventilation.Methods: 63 patients(ASA?~?) of both sexes scheduled for esophageal carcinoma resection or cardiac carcinoma resection through left chest were randomized into 3 groups: groupT4(n1=21), groupT8(n2=21) and group C(n3=21). All of these patients were aged from 18 to 80 years old and were voluntarily to join the study and sign the Informed Consent Form for the study. Their BMIs were between 19~28 kg/m2 and they were all with a normal cardiopulmonary function. These patients did not have anemia or other diseases in blood system. They did not have a chemotherapy or radiotherapy history.After they entered the operation room, an upper limb venous access was founded. Then the patients were given with penehyclidine hydrochloride 1mg and midazolam 0.05mg/kg 30 minutes before the operation. The electrocardiogram(ECG) and saturation of pulse oximetry(SpO2) were monitored with the Philips IntelliVue MP50 multifunctional monitor. The radial artery and internal jugular venous puncture were proceeded under local anesthesia, so the continuous arterial pressure and CVP could be monitored. Then the patients in group T4 and group T8 would receive a TPVB guided by ultrasound at the corresponding segment, while the patients from group C would not have this procedure.15 minutes later, we would measure and record the block plane. Then the patients would be anesthetized by a vein rapid induction proceeded by sufentanil(0.2~1?g/kg), etomidate(0.2~0.3mg/kg) and cisatracurium(0.2~0.3mg/kg), and all the patients would be intubated with a single-lumen endotracheal tube(8.0# for male patients and 7.5# for female patients) in about 3 minutes. Then an endobronchial blocker was inserted into the target bronchus. Fiberoptic bronchoscopy was essential for examining if the endobronchial blocker was correctly positioned. During the maintenance of anesthesia, remifentanil, cisatracurium and sevoflurane would be continuously given to keep the BIS ranging from 40 to 60, and 4ug norepinephrine would be injected through the vein when the systolic pressure was below 95 mm Hg.Results:1 There were no significant differences among the three groups in age, gender, height, weight, PaO2, EF, FEV1/FVC, operation type, fluid volume and urine volume(P>0.05)(Table1).2 The pulmonary shunt(Qs/Qt) of all the patients in the three groups showed a similar trend and there were no significant differences(P>0.05), but there were significant differences within each group(P<0.05)(Fig.6,Table4).3 The arterial partial pressure of oxygen(PaO2) of the three groups also showed a similar trend and there were no significant differences(P>0.05), but there were significant differences within each group(P<0.05)(Fig.6,Table4).4 Within each group, the differences of mean arterial pressure(MAP) and heart rate(HR) at different time point were significant, but there were no significant differences among the three groups(P>0.05)(Fig.8,Fig.9,Table4).5 There were no significant differences among the three groups in the consumption of vasopressor(norepinephrine)(P>0.05)(Table3).6 There were no significant differences among the three groups in the consumption of sufentanil in anesthesia induction(P>0.05)(Fig.6).7 There were significant differences among the three groups in the consumption of remifentanil during the maintenance of anesthesia. Compared with group C, the consumption of remifentanil was significantly reduced in group T4 and group T8(P<0.05). But there were no significant differences between group T4 and group T8(P>0.05)(Fig.10).Conclusion: For patients undergoing thoracotomy, both of a low segment TPVB(T4) or a high segment TPVB(T8) will not increase the Qs/Qt, nor reduce the PaO2 during one-lung ventilation. TPVB can significantly reduce the usage of narcotic analgesics in the operation, and it does not inhibit respiratory system or circulatory system, does not increase the consumption of vasopressor and does not have influences on hemodynamics while an epidural block will seriously does. Ultrasound guided TPVB is a simpler, safer and more effective anesthesia method than epidural block which should be widespread applied in clinical practice.