Transcript Magnesium sulphate as an adjuvant to intrathecal
Dr.K.VENKATESAN MD II YEAR
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
Contraindication to regional anesthesia Heart disease Fetal distress Seizure disorder Severe eclampsia Pts with coagulation defect Allergy to LA
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 .
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
0 1 2 3
NO MOTOR BLOCK UNABLE TO STRAIGHT LEG RAISE UNABLE TO FLEX KNEE AGAINST RESISTANCE UNABLE TO FLEX ANKLE
DEGREE OF BLOCK
NIL(0%) PARTIAL(33%) ALMOST COMPLETE(66%) COMPLETE
4 5 6
1 2 3
ANXIOUS OR RESTLESS OR BOTH COPERATIVE, ORIENTED & TRANQUIL RESPONDS TO COMMANDS BRISK RESPONSE TO STIMULUS SLUGGISH RESPONSE TO STIMULUS NO RESPONSE TO STIMULUS
0 1 2 NORMAL SENSATION ANALGESIA (LOSS OF PIN PRICK SENSATION) 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,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
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 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 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 CO 2 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 of obstetric anesthesia ,SOAP.