Effects Of Nitroglycerin On Endothelin And Nitrigen Oxide And Its Synthetase In Plasma During Caesarean Section With SPIHS

Background:pregnancy-induced hypertension syndrome(PIHS) is a state that exists the main clinical manifestations of continuously progressive hypertension, the great amount of proteinuria and severe edema. Severe PIHS (sPIHS) is the serious phases of PIHS, including preeclampsia and eclampsia. It is not clear how the mechanisms of PIHS brings about, but dysfunctions of trophocyte may be the key point of which the PIHS occurring at present[2]. Cold stimulation and uncleared abnormal immunologic factors that maternal individual suffers from may be the important incentives. Pathological changes of PIHS includes sustained spasm of whole body arteriolae and vascular endothelium leading to insufficient perfusion of important organs and function damaged. Patient's conditions are much complicated and still lacking of effective therapy clinicly. Inadequacy of treatment to preeclampsia may lead to eclampsia easily and influencing prognosis of both maternal and newborn. It is reported that Endothlin-1 and nitric oxide and endothelia nitric oxide synthetase take crucial effect in this pathology condition.The ratio disorder of endothlin-1/nitric oxide is not only the important pathogeny but also the evaluation scale of the sPIHS progress and curative effect[3]. The mechanism of nitroglycerin is to combine with sulfhydryl(SH) of molecularbiology in small vascular smooth muscle cells(SMC), creates endothelium-dependent relaxing factors—NO, NO is dispersed to SMC and activate the guanylate cyclase in SMC. The cGMP in cells are made increasing, then the concentration of Ca2- in the cells declines, the action in excitation-contraction process is restrained, the SMC are relaxed, and the va.sa are relaxed[4].Trace amount of nitroglycerine intravenous infusion continuously by micro-infusion pump is equal to supply NO of extrinsic source. Necessarily can it bring effect to ET-1-. NO,eNOS of sPIHS pregnant, at the same time,it can develop the blood supply of womb and placenta[5].Objective:to investigate the effects of trace amount of nitroglycerine intravenous infusion continuously by micro-infusion pump on the level of endothelin-1 and nitric oxide and its synthetase in plasma during caesarean section under epidural block with sPIHS.Method:30 sPIHS pregnants will be choiced. They will be monitored NBP,ECG,SPO2 when they come into the operation room. A vein access of one side upper limb will be opened. After the left flection lying pose has be made, epidural block at L2～3 clearance will be done routinely from the middle pathway. Resistance disappearance will be used to affirm epidural block success. Epidural tubule will be set 3cm towards the head and will be fixup. The test dose will infuse 2% lidocaine 3ml after taking flat lying pose. If the subarachnoid anesthesia sign doesn't appear after 3min, the first dose will infuse 0.75% ropivacaine 10-12ml. It is satisfied that epidural anesthesia level fix on T6-T8 with the needle sting measuring pain.It is time to start nitroglycerol infusion continuously at the speed of 6～8μg/kg/h by micro-infusion pump(WZ-50C6Ttype fabricated by ZheJiang Smith medicine instrument Ltd.)(NTG 5mg is diluted by normal saline50ml). NTG continues infusion untiltheoperation end. Cease NTG infusion and note the total dosage of NTG. We will separately take three blood samples at a moment's notice.The first time is at the vein access opened;the second time is after the epidural anesthesia be satisfied;the third time is at the operation end. At each time,vein blood 5 ml will be taken out and posting into test tube without anticoagulant. The three blood samples will be placed steadily for an hour firstly,then the agglutinate will be discard. Next, the three blood samples will be centrifugated at speed of 3000 revolution for 10 minutes. The centrifugationr was KDC-40 type and was fabricated by KeDa Innovate Stock Ltd.ZhongJia Filiale. The serum will be distilled and will be freezed at-18℃and will be measured ET-1,NO,eNOS. After the newborn is out, resuscitation of newborn and Apgar graded will be done. Then the pregnants will drop asleep after they receive vein infusion pethidine 50～75mg+droperidol 2.5mg and Midazolam 2～3mg. The concentration of ET-1 in sample will be mensurated by Elisa reagent kit 96T type,which was offered by R&D Ltd.of USA,and the lot number was LOT201001—DZE10711; The concentration of eNOS in sample will be mensurated by Elisa reagent kit 96T type,which was offered by R&D Ltd.of USA, and the lot number was LOT201001- DZE10375; the concentration of NO in sample will be mensurated by nitrate reductase method reagent kit,which was offered by Nanking Jiancheng Biological engineering research insititute. The results are measured according SPSS 13.0. The measurement data is expressed byΧ±s, and will be measured by two-way ANOVA;the enumeration data will be measured byΧ2 test. The'p<0.05'shows that the difference has statistics meaning.Result: It is regulated that before anaesthesia is at the vein access opened; among anaesthesia is after the epidural anesthesia be satisfied; after anaeesthesia is at the operation end. Before anaesthesia, the blood pressure of the sPIHS pregnants in this group keep rather high level.There are 12 case whose systolic pressure beyond 170mmHg in this group (40%), there are 24 case whose diastolic pressure beyond 1 OOmmHg in this group (80%), the highest is 200/130mmHg. Before anaesthesia, there are 22 case whose heart rate beyond 100 time per minute in this group (73%) Before anaesthesia,the SpO2 of the sPIHS pregnants in this group keep 95～98% level. After the epidural anesthesia was satisfied, the blood pressure of the sPIHS pregnants in this group declined. The systolic pressure droped 10～25%, the diastolic pressure droped 10-20%. After the epidural anesthesia was satisfied, the heart rate in this group droped to under 100 time per minute basically. After the epidural anesthesia was satisfied, the SpO2 in this group achieved to 100% basically(P<0.05). Comparing the BP,HR,SpO2 of before anaesthesia and among anesthesia, shows that the difference has statistics meaning. Starting NTC infusion continuously by micro-infusion pump the after among anaesthesia time,speed 6～8μg/kg/h, infusion time average 37±5min.The blood pressure of the sPIHS pregnants in this group continue to decline. Starting NTC infusion, the systolic pressure continually droped 3～8%, the diastolic pressure continually droped 3-6%. Starting NTC infusion,the heart rate in this group droped to under 100 time per minute entirely. The SpO2, in this group achieved to 100% entirely (P<0.05), Comparing the BP,HR,SpO2 of among anaesthesia and after anesthesia,shows that the difference has statistics meaning. The ET—1 level of these three times has declined stepwise (P＜0.05). The NO level of these three times has ascended stepwise (P<0.05). The eNOS level of these three times has ascended stepwise (P＜0.05). Surely, the ET - 1 level of the sPIHS pregnants keep rather high level. On the opposition, the NO and eNOS level of the sPIHS pregnants keep rather low level. NTC infusion continuously by micro-infusion pump recombined with continuum epidural block can make advance to NO and eNOS in plasma,at the same time,can promote ET-1 in plasma declining(p<0.05),shows that the difference has statistics meaning. With statistics, the ratio of ET-1/NO changed from 1.29±0.19 (defore anaesthesia)to 1.00±0.13 (after anaesthesia),average declined 23.316%(P<0.05).Obviously, NTC infusion continuously by micro-infusion pump recombined with continuum epidural block can adjust the ratio of ET-1/NO,improve the blood supply of of womb and placenta.reduce combined disease in sPIHS and offer security to pregnants and newborns.So we can say this method have great practical worthiness.Conclusion:NTG infusion continuously by micro-infusion pump recombined with continuum epidural block can make advance to NO and eNOS level in plasma, at the same time.it can reduce ET-1 level in plasma, and amend the ratio of ET-1/NO. Noteworthily.this method can increase eNOS level in plasma,for it can amend the ratio of ET-1/NO.This method can not only reduce the resistance of systemic circulation and pulmonary circulation and improve blood stream dynamical states of low ejection and high block through the operation and develop the blood supply of womb and placenta, but also can reduce combined disease in sPIHS and offer security to mother and infant.So we can say this method have great practical worthiness.