Magnesium sulphate as an adjuvant to intrathecal

Report
 Dr.K.VENKATESAN
MD II YEAR
PROF&HOD.DR.P.S.SHANMUGAM MD,DA.
DEPARTMENT OF ANESTHESIA
KILPAUK MEDICAL COLLEGE & HOSPITAL
CHENNAI
 To
study and compare the effect of added
fentanyl 25(mic gm) & Mgso4 0.1cc
50%(50mg) to 0.5% 2cc(10mg)bupivacaine in
spinal anesthesia
 Patients undergoing elective LSCS
 With mild gestational hypertension(PIH)
 Adequate
analgesia following caesarian
section decreases morbidity , improves
patient ambulation &outcomes ,facilitate
care of the new born.
 Intrathecal MgSO4 , NMDA antagonist has
been shown to prolong analgesia without
significant side effects in healthy parturients
 Correlation was found between serum & CSF
Mg concentration in patients with
preeclampsia
 Ethical
committee approval
 Informed patient consent
 Randomised double blind controlled study
 Statistical significance is ‘p’ value less than
0.05
 SAB performed


With pt in right lateral position
25G quincke needle
 60
patient ASA risk I &II undergoing elective
caesarian section with mild PIH .
 IV line secured with 18G venflon, and
preloaded with RL 10-12ml /kg
 All pts received 5L of O2 / min through face
mask throughout procedure
 Pts treated with titrated doses of


Inj.ephedrine 6mgI.V if BP<90mmhg
Inj.Atropine 0.6mg if HR<60/min
 After
delivery of baby Inj. Syntocin 10 IU in
drip and 10 IU IM given
 Mild
PIH is defined as SBP 140 – 160 and DBP
90 – 110mm Hg with or without proteinuria
after 20 wk. gestation
 60 pts with average age of 18 – 35 undergoing
elective LSCS under SA were randomized into
three groups of 20 each
 Minimal fasting period is 8hrs
 All pts received premedication with Inj.
Ranitidine 50mg IV and Inj. Metoclopramide
10 mg IV, 15 min before surgery
Age between 18-35
years
 Elective LSCS
 under spinal
anesthesia
 Mild PIH
(BP<160/110mmhg)
 ASA I/II

INCLUSION
Contraindication to
regional anesthesia
 Heart disease
 Fetal distress
 Seizure disorder
 Severe eclampsia
 Pts with coagulation
defect
 Allergy to LA

EXCLUSION
 Group

control group,(N=20) patients 0.5%
2cc(10mg)bupivacaine + 0.6cc normal saline .
 Group

F:
Fentanyl(N= 20) patients received 0.5% 2cc
bupivacaine +0.5cc( 25mic gm )fentanyl +0.1cc
NS.
 Group

C:
M:
Mgso4 group (N=20),0.5% 2cc bupivacaine +0.5cc
fentanyl +0.1cc 50%(50mg) Mgso4 .
 Variables
were analysed by ANOVA
 Variables analysed and interperted by post
Hoc test
 Statistical significance is ‘p’ <0.05
 NIBP
 PULSEOXIMETER
 ECG
 RESPIRATORY
RATE
 URINE OUTPUT
GRADE
RESPONSE
DEGREE OF BLOCK
0
NO MOTOR BLOCK
NIL(0%)
1
UNABLE TO STRAIGHT PARTIAL(33%)
LEG RAISE
2
UNABLE TO FLEX
KNEE AGAINST
RESISTANCE
ALMOST
COMPLETE(66%)
3
UNABLE TO FLEX
ANKLE
COMPLETE
SCORE
RESPONSE
1
ANXIOUS OR RESTLESS OR BOTH
2
COPERATIVE, ORIENTED & TRANQUIL
3
RESPONDS TO COMMANDS
4
BRISK RESPONSE TO STIMULUS
5
SLUGGISH RESPONSE TO STIMULUS
6
NO RESPONSE TO STIMULUS
SCORE
RESPONSE
0
NORMAL SENSATION
1
ANALGESIA (LOSS OF PIN PRICK SENSATION)
2
ANAESTHESIA (LOSS OF TOUCH SENSATION)
 Block
onset time
 Duration of sensory blockade
 Higher level of sensory block
 Time to reach highest block
 Two segment regression time
 Duration of postop analgesia
 Hemodynamic parameters

SENSORY BLOCK ONSET TIME
Time interval between end of anesthetic injection and
appearance of cutaneous analgesia in dermatomes T-12,T10,T-8,T-6
DURATION OF MOTOR BLOCK
 Administration of anesthetic and attainment of grade 0 in
Bromage motor scale
DURATION OF ANALGESIA
 Administration of anesthetic and disappearance of cutaneous
level of sensation at each dermatomal level
POST-OP ANALGESIA DURATION
 Administration of anesthetic and time of analgesic
requirement in PACU










The onset of both sensory and motor block was
delayed in the group M ,when compared to both C&F
group(p<0.001)
Motor block and analgesic duration was prolonged in
the Group M , level of significance (p<0.05)
Two segment regression time increased in M group
(P<0.001)
Group M is hemodynamicaly stable when compared to
other groups (p<0.019)
Attainment highest level sensory block varies from
T1-T6 , delayed in group M with significance level
(p<0.08)
Intensity of motor block is more with group M, but
with less significance (p<0.291)
Occurrence of other complications like
Bradycardia , nausea ,shivering were comparable
in all groups
 Two Patient in group F complained of itching
 Usage of vasopressors is more in group C when
compared to other groups
 Fetal outcome assessed by first min and fifth min
APGAR was similar between groups (p>0.3)
 Height and weight are similar between
groups(p<0.586)
 Investigations were similar between groups
(p<0.32)

 Duration
of post-op analgesia is prolonged in
M group when compared to other groups
(p<0.001)
 Use of vasopressors is reduced in group
M(p<0.03)
SENSORY BLOCK ONSET TIME
F
M
C
F
M
C
F
M
C
ANALGESIC & MOTOR BLOCK DURATION
F
M
C
MOTOR BLOCK ONSET TIME
F
M
C
POST-OP ANALGESIA DURATION
F
M
C
 Magnesium
is the second most abundant
intracellular cation
 Involved in the regulation of many ion
channels and enzymatic reaction
 Has application in anesthesia because of its
action as a non competitive NMDA receptor
antagonist with anti-nociceptive effect
 Mgso4
has been shown to have antinociceptive effects , because of its
antagonistic action on the NMDA receptor
 Passage of magnesium across BBB is limited
 It can potentiate opioid analgesia by both
central and peripheral mechanism
 MgSO4 causes
1.vasodilation by ca2+ block
2.analgesic effect
3.inhibition of catecholamine release
 Mg
inhibit calcium entry into the cell via a
non-competitive NMDA receptor blockade
 Mg is also a physiological calcium antagonist
at different voltage gated calcium channel,
it may be important for anti-nociception
 Mg decreases incidence of post operative
shivering
 Response to NMDA receptor is greatly
enhanced when ECF Mg concentration below
physiological level.
 Decrease
in pain intensity is not due to direct
analgesic effect of Mg
 But due to prevention of subsequent
NMDA activation
 Baseline CSF Mg level in pt with preeclamsia
differ from normal patients which suggest
base line alteration in BBB
 Normal CSF Mg level was 2.2meq+/- 0.9,
plasma 1.6Meq, CSF:plasma ratio 1.39
 Mg is neuroprotective in ischemic as well as
excitotoxic brain injury
 Mg
may dilate cerebral blood vessel and thus
responsible for relieving vasospasm in pt with
preeclampsia
 Clinical relevant dose of Mg has no significant
effect on V MCA, autoregulation and cerebral
reactivity CO2
 Mg produce central desensitisation
 Mg can potentiate NM junction
 Spinal NMDA receptor antagonist is the
reason for potentiation of LA and
prolongation of post operative analgesia
 It
is a synthetic opioids
 Phenylpiperidine derivatives
 Directly inhibit the NMDA receptor
 Action of opioids in the bulbospinal pathways
are critical for analgesic efficacy
 Distribution of opioids receptors in
descending pain control circuits indicates
substantial overlap between µ & Κ receptors
 µ receptors produce analgesia within
descending pain control circuits.
 In
parturients with mild PIH undergoing LSCS
the addition of Mgso4 50mg to the
intrathecal combination of bupivacaine &
fentanyl




prolongs the duration of analgesia
Prolongs motor block duration
Delayed onset of sensory block
Prolongs post op analgesia
 Ref.pubmed,intl.journal
anesthesia ,SOAP.
of obstetric
THANK U

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