Combined subarachnoid and epidural block for Caesarean section

Abstract

REFERENCES Combined subarachnoid and epidural block for Caesarean sectionTo the Editor: I would be grateful for the use of your columns to comment on the letter from Dr. Rawal.l The single-space double-needle technique has been described previously 2 .~ and 1 would like to mention our modifiation of the technique.'* This involves clamping the spinal needle with a light-weight artery clip at the point where it enters the Tuohy needle. This avoids the difficulty commonly encountered with a long flexible needle, whereby when attempting to firn'fly attach a syringe with a leak-proof seal and then inject, the needle may be advanced through the ventral surface of the dura, or passed out through the original dorsal puncture. In either case, the local anaesthetic solution is deposited extradurally, resulting in failure of the technique. The dose and drag recommended by Rawal was 1.5 to 2.0 ml of hyperbaric 0.5 per cent bupivacaine. In their 24 cases they noted that the block rose to T4 with the subarachnoid injection in only 25 per cent of the patients.We use 1.5 to 1.6 ml of 0.5 per cent isobaric (slightly hypobaric) bttpivacaine and, in a series of over 400 patients, the subarachnoid injection consistently reached T2 to "1'4. In less than five per cent of patients does the epidural cannula need to be used to bring the sensory block up to a level suitable for surgery. This has the advantage of reliably quick onset, because the patient can be moved into theatre immediately after the block is performed and preparation for operation commenced. We now, except in the most llfe-threatening emergencies, use this technique for emergency Caesarean section, as the patient, with a skilled team, can be in the operating room with a block at T s and undergoing skin preparation, five minutes after starting the procedure.At the beginning of our series, we noted a similar incidence of hypntension to that noted by Rawal, i.e., about 10 to 15 per cent. We now administer 9rag ephedrine IV immediately after the epidural cannula is inserted, plus supplementary injections of 6my if the systolic blood p~ssure falls below 110, following a "pre-toad" of two litres of lactated Ringer's solution. The incidence of hypotension, defined as systolic blood pressure below 100, is now less than five per cent.1 would agree with Dr. Rawal about the incidence of headache. We had two spinal headaches in the first 400 patients. Whether or not this is attributable to extradural opiates is a matter of controversy. We use 0.3mg bupmnorphlne in 10 ml 0.25 per cent bupivacaine extradurally and the patients are allowed to mobilize as soon as they have sufficient motor power.A final point to make is that although our sensory block is usually at a high thoracic level, we have had no respiratory problems from intercostal weakness, suggesting again the beneficial effect of 0.5 per cent isobaric bupivacaine in producing a differential marked sensory block with little motor block.

Effects of epidural injection on spinal block during combined spinal and epidural anesthesia for cesarean delivery

“…This can be explained by the reduced CSF volume caused by epidural venous engorgement and increased block of nerve fibers to local anesthetics. 17 When using the needle-through-needle technique in cesarean delivery, much smaller doses of spinal anesthetic may be possible compared with single-injection. 14,15 One possible explanation for this reduced requirement of spinal anesthetic for cesarean delivery with the needle-through-needle technique is that the epidural pressure becomes atmospheric and this change in pressure somehow interferes with the circulation and volume of the CSF and, hence, better spread.…”

CSE vs. augmentierte Epiduralanästhesie zur Sectio caesarea

“…Demgegenüber finden sich nur spärliche Hinweise zur Dosierungsempfehlung sowohl für die initiale spinale Applikation als auch für die epidurale Nachinjektion, die die Analgesie vertieft oder die segmentale Wirkung ausdehnt, also eine "Augmentation" [3,4,7,16,22,23,26,27]. In mehreren Arbeiten wurden Varianten zur Durchführung vor allem bei der Sectio caesarea beschrieben, deren Schwerpunkte allerdings eher technischen Details zugewandt waren.…”

“…Ihr häufigstes Einsatzgebiet ist die operative Schnittentbindung [3,4,7,16,22,23,26,27]. Ihr häufigstes Einsatzgebiet ist die operative Schnittentbindung [3,4,7,16,22,23,26,27].…”

“…Dennisson [7] erwähnt nur die Anwendung in 5% bei insgesamt 400 untersuchten Fällen. Dennisson [7] erwähnt nur die Anwendung in 5% bei insgesamt 400 untersuchten Fällen.…”

“…Dennisson verwendet 7,5 bis 8 mg Bupivacain isobar und erreicht in 95% eine Höhe von Th4 bis Th2 [7]. Anders als in der aEA-Gruppe erfolgte die Dosisbemessung für die Nachinjektion ausschließlich nach der Körpergröße, da es sich hier um die erste epidurale Injektion während des Anästhesieverlaufs handelte.…”