Download Anesthesia in Proctology

JI(
TH
NA
UP
.R
DR
AK
UP
.R
Anesthesia in Proctology
DR
H
NA
T
5
)
INTRODUCTION
Among good operative conditions to perform proctological surgery optimal
anesthesia is mandatory.
n Efficacious anesthesia for proctology should fulfill at least five criteria:
— deep and lasting analgesia of the anal canal;
— blood-free operative field;
— no side effects on the bladder;
— suppression of vagal reflex;
— easy use in outpatients;
n Several different types of techniques can be used:
— local anesthesia;
— local infiltration analgesia associated with sedative or light general
anesthesia;
— locoregional or posterior perineal block;
— caudal anesthesia;
— epi-and peridural anesthesia;
— general anesthesia.
Local anesthesia, posterior perineal block, and caudal block give good
operating conditions to perform nearly all proctological procedures. These
methods do not require a long bed rest as compared to spinal block. They may be
performed by the surgeon and may be used on outpatients.1,5,7,10,11,12 Careful
patient selection is nevertheless necessary. The proctologist should be able to
recognize and treat any cardiovascular and respiratory complication; adequate
resuscitation equipment must be immediately accessible.
UP
AK
NA
TH
)
#
.R
CHOICE OF LOCAL ANESTHETIC AGENTS
DR
.R
UP
NA
TH
JI(
DR
Local anesthetic agents may be classified according to their intrinsic potency
compared to that of procaine, to the time needed until the onset of action, and to
the duration of anesthesia 5,14,16,17 (Table 5-1).
All local anesthetic agents have a relaxant effect on the musculature of blood
vessels resulting in vasodilatation. This effect is directly related to the potency of
the drug: more potent and long-acting agents produce a greater and longer
duration of vasodilatation.
The most frequently used drug is lidocaine, which has a great security margin.
Without any vasoconstrictor, the maximal dosage is 200 mg; if vasoconstrictors
163
6
1
10
2
1,5
2
2
*In comparison to procaine.
Procaine
Tetracaine
Lidocaine
Prilocaine
Hostacaine
Mepivacain
Tolycaine
Bupivacaine
Toxicity*
DRTable 5-1. Dosage and toxicity of local anesthesic agents
.R
Maximal dosage
UP
Analgesic power*N Without adrenaline With adrenaline Onset of action
(mg)
(min)
A(mg)T
H
1
500
1000
5-10
JI(
10
100
20
10
DR 500
2
200
<2
.R600
2
400
<2
4
?
?U
<2
PA
2
300
500
K <2-25
250
600
NA5-10
8
150
150
TH
)
45 - 60 min
60 - 90 min
60 - 120 min
60 - 120 min
60 - 120min
60 - 120 min
60 - 90 min
5 - 15 hours
Duration of action
164
5 ❑ Anesthesia in Proctology
165
5 ❑ Anesthesia in Proctology
are added, the maximum dosage increases to 500 mg that means a total amount
of 100 ml 0,5% lidocaine.
Bupivacaine and Naropin result in a long lasting anesthesia of several hours.
Naropin is less cardiotoxic than Bupivacine.13
USE OF A VASOCONSTRICTOR
UP
AK
NA
T
H
)
A vasoconstrictor may be added in order to diminish the risk and severity of
induced vasodilatation and to reduce tissular resorbtion. Epinephrine or adrenaline
has been widely used at following concentrations:
n Adrenaline or epinephrine: 1:200 000.
n Ornithine-vasopressine (POR 8): 1 int. unit in 4 to 10 ml.
The use of these drugs result in low local capillary bleeding, reduces
resorbtion, less toxic side effects and prolonged duration of analgesia. They have
nevertheless their own toxicity.
Caution is mandatory in cases of hypertension as well as coronary and
cerebrovascular disease and on old patients. The dosage should be reduced
accordingly.8
.R
USE OF NA - BICARBONATE
NA
TH
JI(
DR
Lidocaine has a low pH value of about 6. Injection of the drug results in a
painful burning sensation. If 1 ml of an 8.4% solution of Na-bicarbonate is added
to 9-10 ml of lidocaine the burning effect disappears and patient’s comfort is
improved. The pH increases to 7.4. The nervous blockade is speeder and lasts
longer. If a lidocaine-adrenaline solution is used, 2 to 2.5 ml of 8.4%
Na-bicarbonate should be added.10
USE OF HYALURONIDASE
DR
.R
UP
Hyaluronidase is a mucolytic enzyme, which allows anesthetic solutions to
spread into the tissue by inactivating the hyaluronic acid present in the interstitial
space. It reduces swelling and increases absorption.18 Hyaluronidase is not toxic
and rarely produces allergic reactions. Thanks to the increased diffusion of the
anesthetic solution, a smaller volume may be used, but toxic reactions to the local
anesthetic agent and to the vasoconstricting drug may be increased.2 Usually 150
units hyaluronidase are added to 50 ml solution. Hyaluronidase is rarely used
nowadays.
SYSTEMIC TOXICITY
Surgeons should be well aware of toxic reactions due to local anesthetics and
to vasoconstrictors; they must be able to manage and to treat them.3,4,5,11,12
SYSTEMIC TOXICITY OF LOCAL ANESTHETICS
Allergic reactions to local anesthetics are rare and are usually limited to
ester-linked agents, such as procaine and tetracaine, and not to amino-linked
drugs like lidocaine and prilocaine. The majority of systemic reactions are due to
166
5 ❑ Anesthesia in Proctology
Table 5-2. Signs and symptoms of local anesthetic toxicity
PR interval I
QRS duration I
Cardiac output I
H
)
Blood pressure l
PR interval II
NA
T
Speach difficulties
Confusion
Vomiting
Unconsciousness
Muscle twitching
Tremor of face and
Extremities
AK
QRS duration II
UP
Sinus bradycardia
Hypotension
Coma
Generalized convulsions
Respiratory problems
Respiratory arrest
Atrioventricular block
Asystole
TH
JI(
Severe
Dizziness
Lightheadedness
Daze
Tinnitus
Tremor
Agitation
Disorientation
.R
Medium
Cardiovascular effects
DR
Light
Central nervous system effects
DR
.R
UP
NA
inadvertent intravascular injection or to administration of an excessive dose. Toxic
reactions can be classified, according to their severity, as light, medium, or severe
(Table. 5-2). Central nervous system excitation represents the earliest
manifestation of toxicity. Respiratory and cardiovascular complications result from
direct cardiac and vascular action due to overdosage or from indirect action by
blockade of the autonomic nerve fibers. Bupivacaine causes the greatest cardiac
toxicity.9
TOXICITY OF VASOACTIVE DRUGS
If vasoactive drugs have been injected with local anesthetics, side effects due
to them should also be considered and recognized (Table 5-3).5,8
Treatment is different according to whether toxic reactions are due to local
anesthetics or to vasoconstrictors, especially in the most severe forms. Oxygen
should be administered and sedatives injected in cases of arrhythmia or
tachycardia; i. v. lidocaine or B-blockers should be considered in cases of toxic
reactions due to vasoconstrictors. Electric defibrillation may be necessary. To
prevent severe complications some rules must be observed (Table 5-4).
167
5 ❑ Anesthesia in Proctology
Table 5-3. Side effects due to vasoconstrictors
NA
T
H
)
- Apprehension
- Excitation
- Sweating
- Tremor
- Palor
- Dizzines
- Hypertension
- Arrythmia
- Tachycardia
TECHNIQUE OF LOCAL ANESTHESIA
DR
.R
UP
NA
TH
JI(
DR
.R
UP
AK
Local anesthesia is useful for many minor anorectal procedures not requiring
muscular relaxation.
Indications to local anesthesia are very restrictive.1,6,12 Local injection is used
to perform sphincterotomies in the treatment of fissures, to excise hypertrophic
anal papillae and skin tags, to treat short fistulous tracts, and to treat perianal
hematoma. Contraindications include local septic conditions, the patient’s anxiety,
the patient’s insufficient compliance, and the prolonged time required for the
procedure.
If necessary, the patient can be given premedication 30 min to 1 h before the
procedure: 5-10 mg diazepam administered orally is very effective.
The skin is cleaned and disinfected with an antiseptic solution. The anesthetic
solution is injected at first subdermally and then submucosally around the lesion to
be treated with a continuous motion of the needle or frequent aspiration to
prevent intravascular injection.
Injection within the muscle may be avoided depending on the depth of the
lesion.
One should never inject near a septic lesion to avoid bacteremia. The only
septic condition where local anesthesia is possible is an abscess requiring
emergency drainage without any surgical exploration. We should only infiltrate
the place where the knife will be pushed to evacuate the pus.
Table 5-4
— Complete resuscitation equipment (suction, mask and intubation set, O2,
resuscitative drugs) must always be available
— Maximal dosage of the local anesthetic drugs must not be exceeded
— Premedication is not reliable in preventing systemic toxic reactions
— Patients have to be observed carefully after completion of the injection
— Any complication should be correctly evaluated
— Any type of complication must be expected and, if necessary, treated
— Any type of complication or reaction should not be over- or undertreated
168
5 ❑ Anesthesia in Proctology
POSTERIOR PERINEAL BLOCK
Posterior perineal block is a technique based on precise knowledge of the
anatomy of perineal nerves (Fig. 5-1).
We use routinely following mixture:
60 ml 0,5% lidocaine,
10-15 units POR 8 (Ornithine - 8 vasopressine)
6 ml bicarbonate 8,4%.
i
e
d
TH
b
JI(
h
a
a
UP
.R
Ischion
c
e
h
b
NA
g
f
i
.R
c
NA
T
j
AK
j
DR
Ischion
k
UP
f
k
H
)
Symphyse pubienne
d
g
Muscle grand
fessier
Coccyx
sacrum
DR
Fig. 5-1. Innervation of the perineum: a, ano-coccygeal nerve; b, cutaneous bundle of the
pudendal plexus giving a gluteal nerve and an perineal nerve; c, three branches of posterior
femoro-cutaneous nerve; d, gluteal branch; e, posterior perineal branch; f, anterior perineal
branch); g, four branches of the pudendal nerve; h, hemorroïdal nerve or anal nerve or inferior
rectal nerve; i, anterior sphincteric nerve; j, dorsal penis or clitoris nerve; k, perineal nerve.
After subdermal infiltration at two sites (Fig. 5-2A), anterior and posterior but
outsite the rima ani, the anococcygeal ligament is deeply infiltrated (Fig. 5-2B)
with 2 - 5 ml anesthetic solution; through the previously dermal papula 8-10 ml
solution are injected into both ischiorectal spaces when withdrawing the needle
which is oriented at 45° cranially and 45° laterally (Fig. 5-2C). This allows
anesthesia of the deep nerve endings. Through the anterior puncture in front of
the anus, 5-10 ml solution are then infiltrated subdermally on each side (Fig. 5-2D)
169
5 ❑ Anesthesia in Proctology
B
NA
T
H
)
A
D
NA
TH
JI(
DR
.R
UP
AK
C
DR
.R
UP
Fig. 5-2. Technique of local infiltration. A. Anterior and posterior subdermal infiltration.
B. Infiltration of the anococcygeal ligament. C. Infiltration of both ischiorectal spaces.
D. Subdermal infiltration at the level of the rima ani.
at the level of the rima ani to secure analgesia of the more superficial nerve
endings. The total amount injected is less than 60 ml.
This type of anesthesia is our usual one to perform hemorrhoidectomies. It
allows a short hospital stay, a dry operative field, prolonged anesthesia with a low
rate of bladder retention. If used on an outpatient, he or she should not leave the
hospital until he or she has completely recovered from the premedication and has
passed urine.
CAUDAL BLOCK
Caudal block is a type of epidural block.12,14 With the patient in a prone
jackknife position, 15-20 ml 2% lidocaine with epinephrine or 0.25% bupivacaine
with epinephrine are injected into the sacral canal through the sacrococoygeal
space after ensuring by suction that no blood or cerebrospinal fluid can be
170
5 ❑ Anesthesia in Proctology
AK
NA
T
H
)
withdrawn. Immediately after injection, the patient is turned on the back side and
put in anti-Trendelenburg position to ensure sacral distribution of the drug. This
technique should not be used in patients with inadequate coagulation as in case
of hepatic insufficiency.
Contraindications to such an anesthesia are constituted by extensive septic
lesions, sacral dermoid cysts and sequellae of traumatic lesions of the sacrum and
coccyx.
Success rate of this technique is about 90-95%.
Two major complications are feared:
1. Puncture of the dura mater with injection of the drug in the cerebro-spinal
fluid which results in a total spinal anesthesia, respiratory insufficiency and
death.
2. Too rapid injection or injection within the venous plexus resulting in high
systemic toxicity.
SIDE EFFECTS AND COMPLICATIONS
CONCLUSIONS
.R
UP
NA
TH
JI(
DR
.R
UP
Further to the complications related to the toxicity of drugs used, anesthesia
in proctological surgery may induce urinary retention. Zaheer15,19 in an extensive
study noticed bladder retention rates ranging from 0 to 43% in relation to the
type of procedure and type of anesthesia (Table 5-5). The lowest rate was
observed with local anesthesia and the highest with caudal anesthesia.
In our experience,5,12 the posterior perineal block results in a urinary retention
rate of 0,5%. Such a low rate could be achieved because several operative
conditions were strictly observed:
1. Empty bladder before surgery.
2. No intravenous infusion.
3. No oral fluid intake before first miction.
Such a law rate allows ambulatory surgery even for hemorrhoidectomies.
DR
Most surgical procedure involving the anal canal can be performed in local
anesthesia, posterior perineal block and caudal block. Successful anesthesia can be
achieved by the surgeon himself if he knows the exact anatomy of perineal
Table 5-5. Urinary retention and type of anesthesia19
General anesthesia
Spinal anesthesia
Local anesthesia
Caudal anesthesia
Hemorrhoidectomies
Sphincterotomies
fistulotomies
incision-drainage
37 %
36 %
17 %
43 %
6%
8%
0%
3%
171
5 ❑ Anesthesia in Proctology
innervating, if he applies a precise infiltration technique and uses well selected
drugs at a correct dosage.
REFERENCES
DR
.R
UP
NA
TH
JI(
DR
.R
UP
AK
NA
T
H
)
1. Auberger HG. Praktische Lokalanästhesie: ein Kompendium Thieme, Stuttgart, 1969.
2. Barry BA. Die Lokalanästhesie bei ambulanten Eingriffen. In Kinoch HG, Hager TH,
Frank WL (Eds.): Aktuelle Koloproktologie, Vol. 1. Nymphenburg, Munich, 1985.
3. Bonica JJ, Akamatsu TJ, Berges PU et al. Circulatory effects of peridural block, Vol. II:
effects of epinephrine. Anesthesiology 1971;34:514–522.
4. Clery AP. Local anesthesia containing hyaluronidase and adrenaline for anorectal
surgery experiences with 576 operations. Proc R Soc Med 1973;66:680–681.
5. Cuccia G, Forster A and Marti M-C. Positioning and anesthesia for anorectal surgery. In
Marti M-C, Givel J-C: Surgical management of anorectal and colonic diseases.
Berlin-Heidelberg: Springer-Verlag, 1998, pp 113–120.
6. De Jong RH. Toxic effects of local anesthetics. JAMA 1978;239:1166–1168.
7. Guinard JP, Carpenter RL, Owens BD et al. Comparison between ropivacaine and
bupivacaine after subcutaneous injection in pigs cutaneous blood flow and surgical
bleeding. Reg Anesth 1991;16:268–271.
8. Kam PCA and Tay TM. The pharmacology of ornipressin (POR-8): a local
vasoconstrictor used in surgery. European Journal of Anesthesiology 1998;15:133–139.
9. Kratzer GL. Local anesthesia in anorectal surgery. Dis Colon Rectum 1965;8:441–446.
10. McKay W, Morris R, Mushlin P. Sodium bicarbonate attenuates pain on skin infiltration
with lidocaine, with or without epinephrine. Anesth Analg 1987;66:572–574.
11. Marti MC Froidevaux A, Rifat K Préparatin préopératoire et choix de l’anesthésie en
proctologie. Med Hyg 1977;35:2334–2338.
12. Marti MC. Anesthésie loco-régionale en chirurgie proctologique Ann Chir
1993;47:250–255.
13. Moore DC, Bridenbaugh LD, Thompson GE et al. Bupivacaine: a review of 11080 cases
Anesth Analg 1978;57:42–53.
14. Moore DC Regional block, 4th ed. Thomas, Springfield. 1981
15. Pertek JP, Haberer JP Effets de l’anesthésie sur la miction et rétention aiguë d’urine
postopératoire. Ann Fr Anesth Réanim 1995;14:340–351.
16. Pittet JF Pharmacologie et toxicité des anesthésiques locaux. Schweiz Rundsch Med
Prax 1987;76:865–871.
17. Scott DB Maximum recommended doses of local anaesthetic drugs Br J Anaesth
1989;62:373–374.
18. Watson D Hyaluronidase Br J Anaesth 1993;71:422–425.
19. Zaheer S et al. Urinary retention after operations for benign anorectal disease Dis Colon
Rectum 1998;41:696–704.