الفهرس 
Material and methodsOnly 14 pages are availabe for public view
 |  | from | 179 |  |  |
| | | from | 179 | | |
Abstract
Epidural clonidine is effective in relieving postoperative pain. It also
can offer effective analgesia in patients with severe intractable cancer pain
tolerant to opioids. Due to the incidence of side effects, epidural clonidine
in the bolus for will be restricted. More extensive use will be as epidural
infusions or epidural patient-controlled analgesia, and in combination with
other agents e.g., local anaesthetics and morphine.
Addition of clonidine intensifies and prolongs anaesthesia from
epidunlly and spinally administered local anaesthetics. Several methods
are used to modify the anaesthetic activity of epidural local anaesthetic
solutions, These include : dosage, addition of a vasoconstrictor, e.g.
epinej hrine, carbonation, use of local anaesthetic mixtures, continuous
infusion through catheters and addition of narcotics, or clonidine.
In the current study, an open label, dose ranging design was used to
examme the analgesic, haemodynamic, and other systemic effects of
clonidine when administered as an adjuvant to bupivacaine during
continuous lumbar epidural and intrathecal techniques. We also studied the
effect of clonidine when added to fentanyl in epidural anaesthesia with
marcame,
120 adult patients ASA physical status 1or II were included in this
study They were randomly allocated into 6 equal groups (n = 20 each) .
SUMMARY AND CONCLUSION Epidural groups:
Group I :
Fatients received plain bupivacaine 0.5%
Group II :
Fatients received plain bupivacaine 0.5% + 150 meg clonidine.
Group III :
«(;-300) received bupivacaine 0.5% + 300 ug clonidine
Group IV:
Fatients received bupivacaine 0.5% with 50 ug fentanyl and 150 ug
clonidir.e.
Spinal groups:
Group I:
Fatients received 3 ml heavy marcaine 0.5%.
Group II:
I’atients received 3 ml heavy marcaine 0.5% with 150 ug clonidine.
To assess the epidural blockade, the following criteria were
recorded dose of bupivacaine 0.5% needed, total volume of local
anaesthetic drug mixtures, onset of epidural analgesia, sensory level,
degree of motor block and the time for two segment regression as a
measur ~for the duration of epidural block.
The cardiovascular parameters MEP (pulse rate, systolic and
diastolic blood pressure) were recorded preoperatively and at 5, 10,20,
30, 60, 90, 120, 150, 180, 240 and 360 mill. intervals following
administration of epidural anaesthetic solution.
There was no significant difference in onset among the four studied
groups. The inclusion of clonidine with epidural bupivacaine produced
significantly higher sensory level. Clonidine was more effective in a dose
dependent manner. Clonidine significantly enhanced motor block. This
favours the addition of clonidine to epidural local anaesthetics in
operatiens requiring adequate muscle relaxation. Thus, clonidine intensify
and pre long bupivacaine induced epidural block. However, its effect is a
dose de oendent.
Epidural clonidine blocks transmission of pain information by
activating presynaptic and postsynaptic (X2- adrenoceptors in the dorsal
hom of the spinal cord, which inhibits substance- P release and dorsal hom
neuron firing.
Eupivacaine induced epidural block produced no significant change
111 pulse rate. Clonidine significantly decreased pulse rate earlier and in a
dose dependent manner. Thus, clonidine has to be avoided in patients with
atrioventricular conduction disturbances or taking drugs slowing
atrioventricular conduction. Epidural bupivacaine significantly decreased
both systolic and diastolic blood pressure. Addition of clonidine had
hypotensive effect a results in agreement with previous reports. The
hypotensive effects of clonidine suggests caution in its use in some
patients, for example the elderly and hypovolaemics and shocked patients.
~,ignificant, dose - dependent sedation was an important observation
111 clonidine groups. Although sedation is considered to be one of the main
side effects of oral and epidural clonidine. Yet, the sedative effects of
clonid ne added to epidural local anaesthetics could be an advantage
during surgery eliminating the need for premedication.
Epidural clonidine was highly effective in the prevention of
shivenng which may accompany epidural and intrathecal blocks. This is
valuable as shivering is stressful to the patients and increases oxygen
consumption.
Postoperative analgesia was monitored for 24 hrs. after injection of
epidural clonidine with bupivacain the addition of clonidine prolonged
anaestlJ.esia as well as analgesia of bupivacaine in a dose dependents
manner so in the group of high dose smaller number of patients needed
postoperative analgesics. Thus inclusion of clonidine with local anaesthetic
in epi jural or spinal spaces decreased the need of postoperative narcotic
analgesia and helps avoidance of opioid systemic effects as respiratory
depres sion and histamine release which is of a great value in asthmatic
patien: undergoing surgery.
Addition of clonidine to epidural fentanyl prolonged the duration
of its analgesic effect and decreased the need for postoperative analgesia.
Clonidine also prolonged the anaesthetic and analgesic effect of intrathecal
marcame when mixture of the two drugs was used.
Pharmacological study on rats proved that clonidine has analgesic
effect by two test :
1- Hot plate test group:
Which contain :
a- Control group.
b- Clorndine injected group
2- Analgesimeter test:
Which contain
a- Control group.
b- Cion dine injected group.
11also has antiarrythmic effect by two group :
- Control group.
- Clonicine injected group.
This effect will be useful of clonidine it used 111 preoperative
medication anaesthesia.