Spinal anaesthesia

Me2NCH2) C2H5)(Me)C-OOC Ph-HCI. Colourless crystalline powder with a bitter taste, m.p. 177-179"C. Prepared by the action of ethyl magnesium bromide on dimethyl-aminoaceione. It is a local anaesthetic, mainly used to produce spinal anaesthesia. 

Adrenaline along with local anaesthetics may be used for infiltration, nerve block and spinal anaesthesia for prolonging the action and to reduce the systemic toxicity of local anaesthetics. 

When used for spinal anaesthesia, 0.75% ropivacaine produces less intense sensory and motor block than 0.5% bupivacaine. It is suitable for regional, spinal and epidural block but not for regional intravenous anaesthesia. The addition of adrenaline (epinephrine) does not prolong the duration of anaesthesia in brachial plexus or epidural block. Ropivacaine is indistinguishable from bupivacaine when used in obstetric anaesthesia. Its direct myocardial toxicity is somewhat less than that of bupivacaine. 

Ephedrine has positive inotropic and chronotropic effects and increases peripheral vascular resistance. It is preferable to methoxamine for maintaining blood pressure in elderly patients during spinal anaesthesia, possibly because it has less effect on coronary blood flow (less pronounced a activity). It is also less likely to impair placental blood flow than some other vasopressors, for the same reason. It is used as a bronchodilator because of its 32-agonist effects. 

Pinder AJ, Dresner M, Calow C, Shorten GD, O Riordan J, Johnson R. Haemodynamic changes caused by oxytocin during caesarean section under spinal anaesthesia. Int J Obstet Anesth 2002 ll(3) 156-9. 

Gogarten W. Spinal anaesthesia for obstetrics. Best Pract Res Clin Anaesthesiol. 2003 17 377-392. 

Inoue S, Kawaraguchi Y, Kitaguchi K, Furaya H. Inclusion of epinephrine to hyperbaric tetracaine and the supine position enhance the cephalad spread of spinal anaesthesia compared with hyperbaric tetracaine alone in the lithotomy position. Acta Anaesthesiol Stand. 2004 48 342-346. 

Pitkanen M, Rosenberg PH. Local anaesthetics and additives for spinal anaesthesia—characteristics and factors influencing the spread and duration of the block. Best Pract Res Clin Anaesthesiol. 2003 17 ... 

Cunningham, A. J., McKenna, J. A., and Skene, D. S. (1983). Single injection spinal anaesthesia with amethocaine and morphine for transurethral prostatectomy. Br. J. Anaesth. 55, 423-426. 

Chanimov M, Cohen ML, Grinspun Y et al. (1997) Neurotoxicity after spinal anaesthesia induced by serial intrathecal injections of magnesium sulphate. Anaesthesia 52 223-228 Cole DJ, Lin DM, Drummond JC, Shapiro HM (1990) Spinal tetracaine decreases central nervous system metabolisms during somatosensory stimulation in the rat. Can J Anesth 37 231-237... 

Cowan CM, Kendall JB, Barclay PM, Wilkes RG. Comparison of intrathecal fentanyl and diamorphine in addition to bupivacaine for caesarean section under spinal anaesthesia. Br J Anaesth 2002 89(3) 452-8. 

PROCARBAZINE SPINAL ANAESTHETICS Risk of hypotensive episodes Uncertain Recommendation is to discontinue procarbazine for at least 10 days before elective spinal anaesthesia... 

Dose. 5 to 20 mg of amethocaine hydrochloride (0.5% solution) is injected for spinal anaesthesia 0.5 to 2% solutions have been used for surface anaesthesia. 

COMPLEMENTARY DRUG ephedrine (in spinal anaesthesia during delivery to prevent h5Lpotension)... 

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. 

Subarachnoid (intrathecal) block (spinal anaesthesia). By using a solution of appropriate specific gravity and tilting the patient the drug can be kept at an appropriate level. Sympathetic nerve blockade causes hypotension. Headache due to CSF leakage is virtually eliminated by using very narrow atraumatic penal point needles. 

Bupivacaine is long-acting 3 h) (see Table 18.1) and is used for peripheral nerve blocks, and epidural and spinal anaesthesia. Whilst onset of effect is comparable to lidocaine, peak effect occurs later (30 min). 

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... 

Kaukinen S, Eerola R, Eerola M, Kaukinen L. A comparison of carticaine and lidocaine in spinal anaesthesia. Ann Clin Res 1978 10(4) 191-4. 

Keld DB, Hein L, Dalgaard M, Krogh L, Rodt SA. The incidence of transient neurologic symptoms (TNS) after spinal anaesthesia in patients undergoing surgery in the supine position. Hyperbaric lidocaine 5% versus hyperbaric bupivacaine 0.5%. Acta Anaesthesiol Scand 2000 44(3) 285-90. 

Williams NE. Profound bradycardia and hypotension following spinal anaesthesia in a patient receiving an ACE inhibitor an important drug interaction Eur J Anaesthesiol 1999 16(ll) 796-8. 

Fujii Y, Tanaka H, Toyooka H. Prevention of nausea and vomiting with granisetron, droperidol and metoclopramide during and after spinal anaesthesia for caesarean section a randomized, double-blind, placebo-controlled trial. Acta Anaesthesiol Scand 1998 42(8) 921-5. 

Kathirvel S, Sadhasivam S, Saxena A, KannanTR, Ganjoo P. Effects of intrathecal ketamine added to bupivacaine for spinal anaesthesia. Anaesthesia 2000 55(9) 899-904. 

Esteban JL, Gomez A, Gonzalez-Miranda F. Unintended total spinal anaesthesia with ropivacaine. Br J Anaesth 2000 84(5) 697-8. 

Ahmed SM, Khan RM, Bano S, Ajmani P, Kumar A. Is spinal anaesthesia safe in pre-eclamptic toxaemia patients J Indian Med Assoc 1999 97(5) 165-8. 

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. 

Hemmingsen C, Poulsen JA, Risbo A. Prophylactic ephe-drine during spinal anaesthesia double-bhnd study in patients in ASA groups I-III. Br J Anaesth 1989 63(3) 340-2. 

Kiran S, Singal NK. A comparative study of three different doses of 0.5 % hyperbaric bupivacaine for spinal anaesthesia in elective caesarean section. Int J Obstet Anesth 2002 ll(3) 185-9. 

Casati A, Fanelli G, Beccaria P, Aldegheri G, Berti M, Senatore R, Torri G. Block distribution and cardiovascular effects of unilateral spinal anaesthesia by 0.5% hyperbaric bupivacaine. A clinical comparison with bilateral spinal block. Minerva Anestesiol 1998 64(7-8) 307-12. 

Tobias JD, Burd RS, Helikson MA. Apnea following spinal anaesthesia in two former pre-term infants. Can J Anaesth 1998 45(10) 985-9. 

Chan YK, Gopinathan R, Rajendram R. Loss of consciousness following spinal anaesthesia for caesarean section. Br J Anaesth 2000 85(3) 474-6. 

Standi T, Eckert S, Schulte am Esch J. Microcatheter continuous spinal anaesthesia in the post-operative period a prospective study of its effectiveness and comphcations. Eur J Anaesthesiol 1995 12(3) 273-9. 

Loo CC, Irestedt L. Cauda equina syndrome after spinal anaesthesia with hyperbaric 5% lignocaine a review of six cases of cauda equina syndrome reported to the Swedish Pharmaceutical Insurance 1993-1997. Acta Anaesthesiol Scand 1999 43(4) 371-9. 

Tetzlaff JE, Dilger J, Yap E, Smith MP, Schoenwald PK. Cauda equina syndrome after spinal anaesthesia in a patient with severe vascular disease. Can J Anaesth 1998 45(7) 667-9. 

Salazar F, Bogdanovich A, Adalia R, Chabas E, Gomar C. Transient neurologic symptoms after spinal anaesthesia using isobaric 2% mepivacaine and isobaric 2% lidocaine. Acta Anaesthesiol Scand 2001 45(2) 240-5. 

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