Epidural anaesthesia

Ephedrine is a vasoconstrictor sympathomimetic agent that causes an increase in blood pressure and an increase in heart rate. It is used in spinal or epidural anaesthesia where it is administered by slow intravenous injection to reverse... 

It is a potent and long acting local anaesthetic used for spinal, infiltration, epidural anaesthesia and nerve block. 

Ng K, Parsons J, Cyna AM, Middleton P. Spinal versus epidural anaesthesia for caesarean section. Cochrane Database Syst Rev. 2004 CD003765. 

Senagore AJ, Delaney CP, Mekhail N, et al. Randomized clinical trial comparing epidural anaesthesia and patient-controlled analgesia after laparoscopic segmental colectomy. BrJ Surg. 2003 90 1195-1199. 

Atanassoff PG, Alon E, Pasch T. Recovery after propofol, midazolam, and methohexitone as an adjunct to epidural anaesthesia for lower abdominal surgery. Eur J Anaesthesiol 1993 10(4) 313-8. 

CALCIUM CHANNEL BLOCKERS ANAESTHETICS - LOCAL Case reports of severe 1 BP when bupivacaine epidural was administered to patients on calcium channel blockers Additive hypotensive effect both bupivacaine and calcium channel blockers are cardiodepressant in addition, epidural anaesthesia causes sympathetic block in the lower limbs, which leads to vasodilatation and 1 BP Monitor BP closely. Preload intravenous fluids prior to the epidural... 

Extradural (epidural) anaesthesia is used in the thoracic, lumbar and sacral (caudal) regions. Lumbar epidurals are used widely in obstetrics and low thoracic epidurals provide excellent analgesia after laparotomy. The drug is injected into the extradural space where it acts on the nerve roots. This technique is less likely to cause hypotension than spinal anaesthesia. Continuous analgesia is achieved if a local anaesthetic, often mixed with an opioid, is infused through an epidural catheter. 

Spinal anaesthesia is now used more commonly then epidural anaesthesia for Caesarean section. The vast majority of Caesarean sections are now undertaken with regional rather than general... 

Bonnet F, Derosier JP, Pluskwa F, Abhay K, Gaillard A. Cervical epidural anaesthesia for carotid artery surgery. Can J Anaesth 1990 37(3) 353-8. 

Mollmann M, Cord S, Holst D, Auf der Landwehr U. Continuous spinal anaesthesia or continuous epidural anaesthesia for post-operative pain control after hip replacement Eur J Anaesthesiol 1999 16(7) 454-61. 

It has a slow onset of action, up to 30 minutes, and a long duration of action, up to eight hours when used for nerve block. Bupivacaine can also be used with adrenaline. Bupivacaine is often used to produce continuous epidural anaesthesia during labour. 

This is smaller to epidural anaesthesia where the injection is made through sacral hiatus into the vertebral canal which contains the cauda equina. It is used for operations on the pelvic viscera. 

Techniques range from inhltraiion of anac-sthctic around a single nerve (e.g. dental anaesthesia) to epidural and spinal anaesthesia. In. spinal anaesthesia (intrathecal block) a drug is injected into the ccrebrospina) fluid in the subarachnoid space. In epidural anaesthesia the anaesthetic is injected outside the dura. Spinal anaesthesia is technically far easier to produce than cpidural anaesthesia, but the latter technique virtually eliminates the postanaesihetic complications such as headache. 

A randomised, double-blind, placebo-controlled study involving 44 patients found that lidocaine epidural anaesthesia (15 mL of 2% plain lidocaine) reduced the MAC of sevoflurane required for general anaesthesia by approximately 50% (from 1.18 to 0.52%). This implies that a lower dose of inhalational anaesthetic provides adequate anaesthesia during combined epidural-general anaesthesia than for general anaesthesia alone. ... 

Mixtures of local anaesthetics are sometimes used to exploit the most useful characteristics of each drug. This normally seems to be safe although it is sometimes claimed that it increases the risk of toxicity. There is a case report of a man who developed toxicity when bupivacaine and mepivacaine were mixed together. Spinal bupivacaine followed by epidural ropivacaine may also interact to produce profound motor blockade. However, the effectiveness of bupivacaine in epidural anaesthesia may be reduced if it is preceded by chloroprocaine. 

A study on the use of chloroprocaine 3%, bupivacaine 0.5% or a mixture of chloroprocaine 1.5% with bupivacaine 0.375% in obstetric epidural anaesthesia found that time to onset of analgesia, time to maximum analgesia, and effectiveness of analgesia were similar irrespective of the treatment regimen. Bupivacaine 0.5% alone had a longer duration of action than chloroprocaine or the mixture of anaesthetics. Another study found that lidocaine did not affect the pharmacokinetics of bupivacaine. ... 

Accidental intravenous administration of local anaesthetics during spinal anaesthesia may cause cardiovascular collapse and, on theoretical grounds, the serious cardiac depressant effects could be enhanced in patients taking antihypertensives, especially elderly patients with impaired cardiovascular function. Particular care would seem to be important with any patient given epidural anaesthesia while taking antihypertensives. 

Pretreatment with eimetidine 300 mg intramuseularly 1 to 4 hours before epidural anaesthesia with 0.5% bupivaeaine (for eaesarean section) had no effect on the pharmacokinetics of bupivacaine in 16 women or their foetuses when compared with 20 control women, although the maternal unbound bupivacaine plasma levels rose by 22%. These findings were confirmed in two similar studies in which women were pretreated with cimetidine before caesarean section, and a further study in 7 healthy subjects (6 women and one man) given two oral doses of cimetidine 400 mg before intramuscular bupivacaine. However, the AUC of bupivacaine in 4 healthy male subjects was increased by 40% (when compared to placebo) by cimetidine 400 mg at 10 pm the previous evening and 8 am on the study day, followed by a 50-mg infusion of bupivacaine at 11 am. ... 

In 7 women given epidural anaesthesia for caesarean section the pharmacokinetics of 400 mg of lidocaine 2%, (given with adrenaline (epinephrine) 1 200 000) were unchanged after a single 150-mg oral dose of ranitidine given about 2 hours preoperatively. A similar study in 8 women also found no statistically significant rises in whole blood lidocaine levels in the presence of ranitidine 150 mg given orally at least 2 hours preoperatively. ... 

Two studies " have found that chloroprocaine decreases the duration of epidural morphine analgesia (16 hours for chloroprocaine compared with 24 hours for lidocaine ). Another study found that morphine requirements after caesarean section were much higher in women who had received chloroprocaine for epidural anaesthesia than in those receiving Udocaine. The authors of one of the studies suggest that chloroprocaine should be avoided if epidural morphine is used. Epidural fentanyl also appears to be antagonised by chloroprocaine. ... 

Use of heparin and ibuprofen were eonsidered to be eontributing faetors in a ease of spinal haematoma oeeurring after epidural anaesthesia. ... 

Martyr JW, Orlikowski CEP. Epidural anaesthesia, ephedrine and phenylephrine in a patient... 

Epidural anaesthesia is a technique whereby a local anaesthetic is injected through a catheter placed into the epidiual space, see Fig. 13.2. 

Waurick R, Van Aken H. Update in thoracic epidural anaesthesia. Best Pract Res Clin... 

McLeod GA, Gumming C. Thoracic epidural anaesthesia and analgesia 2004. 

Sundberg A, Wattwil M, Arvill A. Respiratory effects of high thoracic epidural anaesthesia. Acta Anasthesiol Scand 1986 30 215-217. 

Based on an extensive review (with 679 references cited) Usubiaga (3 ) concludes that although epidural anaesthesia is much safer than intradural, neurological complications after the epidural anaesthesia can occur. His literature study located 69 cases of such adverse reactions. 

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