Standard, segmental and modified segmental epidural blockade in obstetrics

[摘要] A project was carried out to compare 3 different techniques ofepidural block. The project was motivated because many shortcomingswere noted in the techniques in current use. Theseinclude a high incidence of hypotension after epidural block.This incidence was found to be higher than what is usuallyreported. The incidence and severity of hypotension wasreduced by using lower dosages of Bupivacaine and by at thesame time avoiding aorto-caval compression. The latter wasachieved by placing the patient in the kneeling position.The quality of analgesia achieved by using Segmental blockadewas inferior to that achieved by Standard Epidural blockade.On the other hand, the Modified Segmental block produced resultswhich were statistically comparible with the Standard Block.This was not a true reflection of the clinical experience, andmay indicate an inadequacy in our scoring system. Although wewere unable to improve the analgesic quality by Segmental blockade,this may be merely a factor of inexperience at the presenttime, or due to inaccurate catheter placement.The duration of the second stage, is commonly reported to beprolonged by epidural blockade. Although we were able toshorten the second stage by using Segmental blockade, thedifference was not significant.The Apgar scores of neonates born after epidural block have notbeen reported to be negatively influenced by epidural block.We fond a higher incidence of slightly reduced Apgar scores inthe Standard and Segmental blocks, but acceptable resultsafter Modified Segmental blockade.The Acid-base status of mothers and neonates is not known to benegatively influenced by epidural blockade. Our study confirmedthis. In fact, we found that the umbilical vein p02values to be significantly higher after the Modified Segmentalblock when compared with the other two techniques.Bupivacaine is to-day regarded as the best drug for epidural·block. It is however not completely without danger to motherand foetus. It is important to keep down the dosage of thedrug. We used Bupivacaine with Adrenaline 1:200000. Wefound our blood levels to be lower than those reported in theliterature. By using the Segmental blocks, the maternal bloodlevels were reduced significantly when compared with those ofthe Standard Block.Because it was reported in the literature that epiduralcatheters were difficult to place accurately,we performedEpidurograms to determine the fate of epidural catheters.When catheters were threaded for 10 cm or more, accurate placementwas achieved in unacceptably low percentages of patients.By using the technique of Modified Epidural block, accuratecatheter placement was achieved in 100% of cases. The techniqueof placement was safe, repeatable and reliable. Itallows for a more scientific approach to epidural blockade.Foetal heart rate abnormalities are commonly associated withepidural blockade. This was confirmed by the present series -in the first 2 groups. By employing the Modified SegmentalBlock, we were able to reduce the incidence of foetal heartrate abnormalities to nill. This alone has made the projecta worth while undertaking to us.Flaccidity of the pelvic floor, malposition of the foetal headand a high instrumental delivery rate are commonly reportedafter epidural block. These were confirmed by our Group A.By using the Segmental Blocks, the incidences of all thesewere greatly reduced.The incidence of major complications in this series was notgreatly elevated above the incidence commonly reported in theliterature. None of the 3 blocks tested was prone to anyparticular type of complication.Although the Modified Segmental block was found to have somedisadvantages, these were outweighed greatly by its advantages �?We introduced two modifications into the current practiceof Segmental Epidural blockade.i. We placed the top catheter at T12, after entering theepidural space in the thoracic region.ii. We placed patients in the kneeling position duringepidural block.By these two modifications we hope to have made some contributionto the present status of epidural blockade. We aresatisfied that this Modified Segmental Blockade has manyadvantages over the other techniques in use presently. Wehope to do a further large study using this technique, toconfirm the findings of the present (small) series.

[发布机构] University of the Free State