Spinal block

Specific Local Anesthetic Agents. Clinically used local anesthetics and the methods of appHcation are summarized in Table 5. Procaine hydrochloride [51-05-8] (Novocain), introduced in 1905, is a relatively weak anesthetic having along onset and short duration of action. Its primary use is in infiltration anesthesia and differential spinal blocks. The low potency and low systemic toxicity result from rapid hydrolysis. The 4-arninobenzoic acid... 

Paresthesias, weakness and paralysis of lower extremity, hypotension, high or total spinal block, urinary retention or incontinence, fecal incontinence, headache, back pain, septic meningitis, meningismus, arachnoiditis, shivering cranial nerve palsies due to traction on nerves from loss of CSF, and loss of perineal sensation and sexual function Rare... 

In theory, epidural and spinal blocks can be done at any level of the cord, but they are usually administered at the L3-4 or L4-5 vertebral interspace (i.e., caudal to the L-2 vertebral body, which is the point where the spinal cord ends). Epidural anesthesia is somewhat easier to perform than spinal blockade because the epidural space is larger and more accessible than the subarachnoid space. However, spinal anesthesia is... 

Lidocaine is effective in producing analgesia when administered by infiltration, or by nerve, epidural, caudal, and spinal block. In addition, it is effective when applied topically, with an onset of action of 5 min and a duration of action of 15 to 30 min. Lidocaine (1.5 pg/ml) is the agent of choice for the acute suppression of most ventricular arrhythmias. 

A 26-year-old woman with a history of multiple substance abuse required emergency caesarean section at 30 weeks of gestation as a result of crack cocaine-induced placental abruption and fetal distress (251). Her admission blood pressure was 145/95 mmHg, heart rate 95/minute and respiratory rate 20/minute. The fetal heart rate was 130/minute and non-reactive, with late and variable decelerations and no response to maternal oxygen administration. Spinal block with bupivacaine, fentanyl, and morphine was performed with the patient in a sitting position. No maternal or neonatal postoperative complications were reported. 

Different combinations of fentanyl, bupivacaine, and clonidine were investigated in a multicenter (6 sites) trial of 78 women undergoing elective cesarean section under spinal block (30). In some cases, this appeared to imply intrathecal administration, and in others combined intrathecal and epidural administration. Patients received hyperbaric bupivacaine alone, or with 75 pg of clonidine, or with 75 pg of clonidine and 12.5 pg of fentanyl. There were no reported hemodjmamic differences between the groups, but sedation and pruritus were significantly more common in those who received fentanyl, occurring in 65% and 25% of... 

High spinal block has previonsly been reported as a rare complication of epidnral anesthesia. 

The possibility of increased maternal mortality is a topic of debate. In 1979 there were 150 maternal deaths (0.27 per 1000 births) in Germany, of which 15-25% were apparently related to regional anesthesia, with such complications as hypotension, systemic toxicity, total spinal block, hematoma, catheter rupture, and uterine injury (SED-12, 253) (154). However, obstetric regional... 

A receding spinal block to level Ll-2 gave rise to acute bradycardia (34-40/minute) and transient loss of consciousness in a 31-year-old man 5 hours after spinal anesthesia on waking he complained of severe low back pain, and although he had no symptoms of urinary retention, urinary catheterization yielded 900 ml of urine with immediate relief of symptoms. 

Slow injection of hyperbaric bupivacaine 8 mg has been compared with hyperbaric bupivacaine 15 mg used to achieve bilateral block in 30 patients of ASA grades I-II (194). There was significantly greater cardiovascular stability in the patients who had a unilateral spinal block. 

The authors concluded that the local anesthetic may have passed down a fistulous track into the subarachnoid space, producing spinal block. 

Beck GN, Griffiths AG. Failed extradural auaesthesia for caesareau sectiou. Complicatiou of subsequent spinal block. Anaesthesia 1992 47(8) 690-2. 

Bandi E, Weeks S, Carli F. Spinal block levels and cardiovascular changes during post-Cesarean transport. Can J Anaesth 1999 46(8) 736 0. 

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. 

A study involving 40 elderly patients undergoing spinal anaesthesia found that bupivacaine 9 mg, with fentanyl 20 micrograms reduced the incidence of hypotension compared with bupivacaine 11 mg alone. Respiratory rates were not depressed in either group. The rate of failed spinal block and discomfort was similar in both groups. The addition of the fentanyl allowed a reduction in the minimum dose of bupivacaine to produce an adequate block, and consequently less hypotension. ... 

In 60 patients undergoing spinal block with bupivacaine and sufentanil for cesarean section who were randomized to prophylactic phenylephrine 80 micrograms or ephedrine 10 mg, hypotension (a blood pressure at least 80% below baseline) was treated with a bolus dose of the vasoconstrictor at 50% of the initial dose [33 ]. Ephedrine was more effective than phenylephrine, but... 

Magalhaes E, Govdia CS, de Aradjo Ladeira LC, Nascimento BG, Kluthcouski SM. Ephedrine versus phenylephrine prevention of hypotension during spinal block for cesarean section and effects on the fetus. Rev Bras Anestesiol 2009 59 (1) 11-20. 

Spinal anaesthesia (spinal block or sub-arachnoid block) is used to administer the injection into the subarachnoid space. Several local anaesthetics are used for spinal anaesthesia such as procaine, lidocaine, tetracaine, and bupivacaine. Vasoconstrictors such as adrenaline (0.1-0.2 mg) and phenylephrine (0.5-2 mg) can be added to subarachnoid blocks to decrease vascular uptake and prolong diuation of action. 

Spinal and epidural techniques are shown to provide effective anaesthesia for caesarean section. Spinal block differs from an epidiual block in a number of ways ... 

A smaller needle is used to perform a spinal block compared to an epidural block. 

A spinal block is a single injection of local anaesthetic medications and so there is only one opportunity to deliver the medications in an epidural, an indwelling catheter may be placed that avails for additional injections. 

A prospective randomised double-blind controlled trial comparing lidocaine and chloroprocaine for outpatient transurethral prostatectomy yielded similar clinical end points (primary end point duration of spinal block) [36 ]. Four patients in the lidocaine group developed TNS and one patient in the chloroprocaine group developed an acute cauda equina syndrome, which fully recovered after several weeks. Based on this, the authors conclude that they cannot recommend lidocaine in view of the high incidence of TNS and recommend close follow-up for chloroprocaine to ensure its safety profile. 

An epidurally placed catheter can enter the subarachnoid space in the course of a continuous epidural anaesthesia. In 2 recently reported obstetric cases, repetition of the injection caused a spinal block (19, 20 -). It is therefore advisable to aspirate each time before injecting the local anaesthetic drug. 

The recent case of a parturient who developed a massive spinal block with hemi-cranial palsy after a test dose of 2.5 ml of 2% chloroprocaine, administered with the patient in the sitting position, demonstrates the dangers of giving a test dose of a hypo-baric solution with the patient in this position (21 ). One always has to bear in mind the possibility of infection after epidural and spinal anaesthesia. The recommendation has been made to place a bacterial filter between the syringe and the catheter. Five out of 101 syringes were contaminated by skin commensals, but all the catheter tips remained sterile when a bacterial filter was used. 

Kim, Y. I., Mazza, N. M. and Marx, G. F. (1975) Massive spinal block with hemicranial palsy after a test dose for extradural analgesia. Anesthesiology, 43, 370. 

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