Effects Of General Anesthesia And Epidural Analgesia On Endothelin,Atrial Natriuretic Peptide,PGI₂ And TXA₂ In Patients Undergoing Upper Abdominal Surgery

Objective To observe the effects of anesthesia on plasma levels of endothelin (ET) , atrial natriuretic peptide(ANP), PGI2 and TXA2 in the patients undergoing upper abdominal surgery. Methods Thirty patients, ASA physical status I or II undergoing elective upper abdominal surgery,were randomly allocated to one of the three groups with 10 cases each. Group I was given T8..9 epidural blockade with 1% lidocaine and 0.25% tetracaine. Gerenal anesthesia was used in group II and group 111. Anesthesia was induced with midazepam 0.1mg/kg, propofol 1mg/kg, vecuronium 0.1 5mg/kg and fentanyl 4g/kg. After intubation, 1 .OMAC isoflurane was inhaled and maitained in group II, while propofol 60-70 iA g kg1 mm1 was continuely pumped in group III. ECG, HR,SBP,DBP,MAP,SpO2,PETCO2,concentration of inhalat- ed isoflurance,compliance,VT,Ppeak,Pplat and FEVi were monitored. Venous samples were taken at five time points of before anesthesia, after induction, at 10mm and 50mm after incision and at the end of surgery to measure contents of ET,ANP,6-keto-PGF1a and TXB2 by radioinimumoassay. Results (1) The levels of plasma ET had no statistical difference between group I and group Ill. But plasma ET was significantly decreased at 1 0mm after incision( p?O.OS) and even more at 50mm after incision and at the completion of operation in group II (P<0.0 1). (2) The levels of plasma ANP were not obviously changed in group I. In comparison to the pre-anesthetic value, plasma AKP was decreased markedly at 50 mm after incision in group II (P<0.05) and increased at the completion of operation in group III (P<0.05). (3) The levels of plasma TXB2 were significantly decreased (P< 0.01) after epidural block in group I . TXB2 was significantly decreased after induction in groups II and III (both,P<0.0 1). At the completion of operation, it retuned to the baseline in group II, but it was obviously higher than the pre-anesthesia value in group III (P<0.05). (4) The levels of plasma 6-keto-PGF1a were gradually increased after epidual anesthsia and obviously higher than pre- anesthesia value at the completion of operation in group I (P<0.05). 6-keto-PGF1a was significantly decreased (P<0.05) after induction in comparison with that before anethesia in groups II and IH. The highest level of 6-keto-PGF1a was seen at 50mm after incision in group II (P<0.01) and at the completion of operation In group III (P<0.05). (5) The ratio of 6-keto-PGF1a to TXB2 was significant- ly increased in after anesthesia in group I (all, P<0.0 1). It was significantly increased after inducc in groups II and III (both, P<0.05). The ratio was increased significantly at 50 mm after incision and kept at the high level till the completion of operation in group II (P<0.0 1). In group III, it was gradually decreased and restored to the baseline at the completion of operation. (6) HR was not significantly changed in each group. HR was higher in group II than that in the other groups at 10mm after incision and the completion of opera- tion...