Dr.K.VENKATESAN MD II YEAR

SYNERGISTIC EFFECT OF MAGNESIUM SULPHATE AND FENTANY ADDED TO INTRATHECAL BUPIVACAINE FOR MILD PREECLAMSIA

GUIDE

PROF&HOD.DR.P.S.SHANMUGAM MD,DA. DEPARTMENT OF ANESTHESIA KILPAUK MEDICAL COLLEGE & HOSPITAL CHENNAI

AIM OF THE STUDY 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)

BACKGROUND 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

METHODS 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 position25G quincke needle

PATIENT SELECTION 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

METHODOLOGY 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

CRITERIA

INCLUSION EXCLUSION

Age between 18-35 years

Elective LSCS under spinal

anesthesia Mild PIH

(BP<160/110mmhg)

ASA I/II

Contraindication to regional anesthesia

Heart disease Fetal distress Seizure disorder Severe eclampsia Pts with

coagulation defect Allergy to LA

GROUPS Group C:

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 M:Mgso4 group (N=20),0.5% 2cc bupivacaine

+0.5cc fentanyl +0.1cc 50%(50mg) Mgso4 .

STATISTICS Variables were analysed by ANOVA Variables analysed and interperted by

post Hoc test Statistical significance is ‘p’ <0.05

INTRA OP MONITORING NIBP PULSEOXIMETER ECG RESPIRATORY RATE URINE OUTPUT

BROMAGE MOTOR SCALE

GRADE RESPONSE DEGREE OF BLOCK

0 NO MOTOR BLOCK NIL(0%)1 UNABLE TO

STRAIGHT LEG RAISE

PARTIAL(33%)

2 UNABLE TO FLEX KNEE AGAINST RESISTANCE

ALMOST COMPLETE(66%)

3 UNABLE TO FLEX ANKLE

COMPLETE

RAMSEY SEDATION SCORESCORE 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

SENS0RY SCORESCORE RESPONSE

0 NORMAL SENSATION

1 ANALGESIA (LOSS OF PIN PRICK SENSATION)

2 ANAESTHESIA (LOSS OF TOUCH SENSATION)

PARAMETERS OBSERVED

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

ATTRIBUTES SENSORY BLOCK ONSET TIME

Time interval between end of anesthetic injection and appearance of cutaneous analgesia in dermatomes T-12,T-10,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

RESULTS 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)

CONTD… 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)

CONTD.. 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 SULPHATE 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

MAGNESIUM SULPHATE Mgso4 has been shown to have anti-

nociceptive 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 effect3.inhibition of catecholamine release

CONT.. 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.

CONT… 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

CONT… 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

FENTANYL 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.

FACTOR INFLUENCING BLOCK HEIGHT

CONCLUSION 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 durationDelayed onset of sensory blockProlongs post op analgesia

Ref.pubmed,intl.journal of obstetric anesthesia ,SOAP.

THANK U