The Autonomic The Autonomic Nervous System And Nervous System And

Its Implications In Its Implications In AnaesthesiaAnaesthesia

Guided byGuided by : :

Dr. Bakshi Dr. Bakshi MadamMadam

Presented by :Presented by : Dr. Neha SoaresDr. Neha Soares

Dated : 26Dated : 26thth July 2007 July 2007

IntroductionIntroduction Anatomy Anatomy Physiology Physiology Drugs acting on ANSDrugs acting on ANS Tests for autonomic integrityTests for autonomic integrity Anaesthesia and ANS Anaesthesia and ANS a) Generala) General b) Regionalb) Regional Autonomic reflexes during anaesthesia and Autonomic reflexes during anaesthesia and

surgerysurgery ANS ANS dysfunctiondysfunction Anaesthesia in patients with ANS dysfunctionAnaesthesia in patients with ANS dysfunction ANS in intensive careANS in intensive care ANS and chronic painANS and chronic pain

INTRODUCTIONINTRODUCTIONAnesthesiologists manipulate the physiology and Anesthesiologists manipulate the physiology and

pharmacology of the autonomic nervous system.pharmacology of the autonomic nervous system.

ANATOMYANATOMY

Comprises Comprises all afferent fibresall afferent fibres from the CNS from the CNS except those supplying skeletal muscles.except those supplying skeletal muscles.

Includes :Includes :

1) 1) sympatheticsympathetic nervous system nervous system

2) 2) parasympatheticparasympathetic nervous system nervous system

3) 3) entericenteric nervous system nervous system

Sympathetic Nervous SystemSympathetic Nervous System

Originates from the Originates from the Thoraco-lumbarThoraco-lumbar spinal spinal cord (T1 to L2/L3)cord (T1 to L2/L3)

Composed of 2 neurons:Composed of 2 neurons:

a) a) prepre-ganglionic-ganglionic

b) b) postpost-ganglionic-ganglionic

PairedPaired sympathetic chains having sympathetic chains having 22 paired ganglia22 paired ganglia

Unpaired Unpaired prevertebral ganglia in the abdomen and prevertebral ganglia in the abdomen and pelvispelvis

Celiac Celiac

Superior mesenteric Superior mesenteric

Inferior mesentericInferior mesenteric

Aortico renalAortico renal

• terminal/collateral gangliaterminal/collateral ganglia

Terminal or collateral gangliaTerminal or collateral ganglia Small and few in numberSmall and few in number Present Present near targetnear target organ organ Eg. Nerves supplying adrenal medulla Eg. Nerves supplying adrenal medulla

and other chromaffin tissueand other chromaffin tissue Comprise Comprise preganglionicpreganglionic fibres itself that fibres itself that

pass to target tissue without synapsingpass to target tissue without synapsing

PARASYMPATHETIC NERVOUS PARASYMPATHETIC NERVOUS SYSTEMSYSTEM

75% from 75% from vagusvagusArises from Arises from III, VII, IX, X cranialIII, VII, IX, X cranial nerves, nerves,

S2-3S2-3 and occasionally S1and4 and occasionally S1and4Occur proximal to or within the innervated Occur proximal to or within the innervated

organorganHence, Hence, pre-ganglionic fibres very longpre-ganglionic fibres very longPNS more targetedPNS more targeted

Preganglionic fibres Preganglionic fibres arise fromarise from

CENTRALCENTRAL Edinger WestpalEdinger Westpal nucleus – nucleus – # oculomotor nerve# oculomotor nerve #synapses in ciliary ganglia#synapses in ciliary ganglia #Innervates smooth muscles #Innervates smooth muscles of iris and ciliary musclesof iris and ciliary muscles Medulla OblongataMedulla Oblongata – – #Facial nerve #Facial nerve #Glossopharyngeal nerve #Glossopharyngeal nerve #Vagus nerve #Vagus nerve

PERIPHERALPERIPHERAL Sacral segments/ Pelvic nervesSacral segments/ Pelvic nerves

ENTERIC NERVOUS SYSTEMENTERIC NERVOUS SYSTEM Found Found within the wallswithin the walls

of the GIT, pancreas of the GIT, pancreas and gall-bladderand gall-bladder

High degree of High degree of autonomyautonomy

Peristalsis and Peristalsis and digestion persists even digestion persists even if sphincter function if sphincter function impaired following impaired following SAB/transections.SAB/transections.

Submucous(Submucous(Meissner’s Meissner’s plexus)plexus)

Myenteric(Myenteric(Auerbach’s Auerbach’s plexus) plexus)

PHYSIOLOGYPHYSIOLOGY Either Either sympathetic or parasympathetic systemsympathetic or parasympathetic system

dominatesdominates a particular organ function, hence a particular organ function, hence providing the resting toneproviding the resting tone

Few organs have only sympathetic innervation – Few organs have only sympathetic innervation – blood vessels, spleen, piloerector muscles, blood vessels, spleen, piloerector muscles, adrenal medulla, uterusadrenal medulla, uterus

Some organs have only parasympathetic Some organs have only parasympathetic innervation – stomach, pancreasinnervation – stomach, pancreas

Sympathetic deals with FIGHT OR FLIGHTSympathetic deals with FIGHT OR FLIGHT Parasympathetic deals with discrete adjustments Parasympathetic deals with discrete adjustments

in relaxed homeostasisin relaxed homeostasis

Target organTarget organ SNSSNS ReceptorReceptor PNSPNS

1.1. Hair follicle Hair follicle smooth musclesmooth muscle

2.2. Iris –radial msIris –radial ms

3.3. Iris- circular msIris- circular ms

4.4. Ciliary msCiliary ms

5.5. Glands – nasal Glands – nasal parotid,lacrimalparotid,lacrimal

submandibularsubmandibular

gastric,pancraeticgastric,pancraetic

ContractionContraction

PiloerectionPiloerection

MydriasisMydriasis

None None

Slight Slight

MydriasisMydriasis

Slight Slight increaseincrease

Alpha1Alpha1

Alpha 1Alpha 1

Beta Beta

Alpha 1Alpha 1

NoneNone

None None

Miosis Miosis

Accomoda-Accomoda-tiontion

CopiousCopious

IncreaseIncrease

Action of SNS and PNS on various organsAction of SNS and PNS on various organs

Target organTarget organ SNSSNS ReceptorReceptor PNSPNS

6. Sweat gland6. Sweat gland

7. Apocrine gland7. Apocrine gland

8. Heart 8. Heart

-Rate-Rate

-Force of contractn-Force of contractn

-Coronaries -Coronaries

CopiousCopious

IncreaseIncrease

Thick Thick odoriferousodoriferous

Increase Increase

Increase Increase

DilatedDilated

Constricted Constricted

Alpha 1Alpha 1

Beta 1 Beta 1

Beta 1Beta 1

Beta 2Beta 2

Alpha Alpha

Sweating of Sweating of

PalmsPalms

NoneNone

DecreaseDecrease

Decrease Decrease

xcept atriaxcept atria

Target organTarget organ SNSSNS ReceptorReceptor PNSPNS

9. Lungs 9. Lungs

-Bronchi -Bronchi

-Blood vessels-Blood vessels

10. Gut lumen10. Gut lumen

Sphincter Sphincter

11.Pancreas 11.Pancreas

12.Liver 12.Liver

13.Gall bladder13.Gall bladder

14.Kidney 14.Kidney

Dilation Dilation

Constricted Constricted

Decreased Decreased

Increased Increased

Decreased Decreased

Glucose Glucose releasedreleased

Relaxed Relaxed

Output and Output and renin lessrenin less

Beta 2 Beta 2

Alpha2Alpha2

Alpha2Alpha2

Alpha2 Alpha2

Alpha1Alpha1

Beta1 Beta1

ConstrictnConstrictn

DilationDilation

IncreasedIncreased

peristalsisperistalsis

RelaxedRelaxed

Target organTarget organ SNSSNS ReceptorReceptor PNSPNS

15.Bladder 15.Bladder

- Detrusor- Detrusor- TrigoneTrigone

16. Ureter16. Ureter

17. uterus, vas 17. uterus, vas deferens,deferens,

prostrateprostrate

18.Arterioles 18.Arterioles

-viscera,skin-viscera,skin

-muscle-muscle

RelaxedRelaxed

ContractedContracted

ContractedContracted

ContractedContracted

ConstrictedConstricted

ConstrictedConstricted

DilatedDilated

BetaBeta

Alpha1Alpha1

Alpha1Alpha1

Alpha1Alpha1

AlphaAlpha

beta2beta2

Target organTarget organ SNSSNS ReceptorReceptor PNSPNS

19.Veins 19.Veins

20.Blood20.Blood

21.Basal metab21.Basal metab

22.Adrenal medulla22.Adrenal medulla

secretionsecretion

23. Mental activity23. Mental activity

24.Fat cell24.Fat cell

ConstrictedConstricted

Coag,lipid, Coag,lipid, glucose ^glucose ^

100% rise100% rise

IncreasedIncreased

IncreasedIncreased

LipolysisLipolysis

Alpha2Alpha2

Dominance at specific siteDominance at specific site

Parasympathetic :Parasympathetic : Ciliary muscleCiliary muscle IrisIris Salivary glandsSalivary glands SA nodeSA node GITGIT UterusUterus Urinary bladderUrinary bladder

Sympathetic :Sympathetic : Arterioles Arterioles Veins Veins Sweat glandsSweat glands Spleen Spleen

ANS of HeartANS of Heart

NeurotransmittersNeurotransmitters

Acetylcholine Acetylcholine – Secreted by – Secreted by

**all preganglionic fibresall preganglionic fibres

*Postganglionic parasympathetic *Postganglionic parasympathetic fibres\postganglionic sympathetic fibres fibres\postganglionic sympathetic fibres of of sweat gland,piloerctor muscle and sweat gland,piloerctor muscle and blood blood vesselsvessels

Norepinephrine Norepinephrine – Secreted by all – Secreted by all postganglionic sympatheticpostganglionic sympathetic fibres fibres

Acetylcholine receptors are of 2 types:Acetylcholine receptors are of 2 types:

- - MuscarinicMuscarinic: action similar to that : action similar to that produced by produced by parasympatheticparasympathetic system system

- - NicotinicNicotinic: action on : action on skeletal andskeletal and ganglionicganglionic synapses only synapses only

Adrenergic receptors are of 2 tyes:Adrenergic receptors are of 2 tyes:

- - AlphaAlpha: alpha1(smooth muscle : alpha1(smooth muscle vasoconstriction)vasoconstriction)

alpha2 (presynapses)alpha2 (presynapses)

- - BetaBeta: beta1 (cardiac tissue): beta1 (cardiac tissue)

beta2 (smooth muscle relaxation in beta2 (smooth muscle relaxation in some some organs)organs)

Action of Important Drugs on ANSAction of Important Drugs on ANSSite of actionSite of action

1.Sympathetic 1.Sympathetic and and parasympatheticparasympathetic

gangliaganglia

2.Endings of post2.Endings of post

ganglionic nonganglionic non

adrenergicadrenergic

NeuronsNeurons

Agonist Agonist

1.Stimulate post-1.Stimulate post-

ganglionganglion- nicotin- nicotin

2.2.InhibitACh’trsInhibitACh’trse-e-

PhysostigminePhysostigmine

NeostigmineNeostigmine

Parathion Parathion

Release NARelease NA-TyramineTyramine-EphedrineEphedrine-Amphetamine Amphetamine

Antagonist Antagonist

HexamethoniumHexamethonium

MecamylamineMecamylamine

TrimethaphanTrimethaphan

High conc.Ach,High conc.Ach,

AnticholinestrsesAnticholinestrses

Curare Curare

Block NA synthBlock NA synth

-metyrosine-metyrosine

Stop NA storageStop NA storage

-reserpine,guane-reserpine,guane

thidinethidine

Site of actionSite of action

3.Alpha receptors3.Alpha receptors

Agonist Agonist

Stimulate alpha1Stimulate alpha1

-methoxamine-methoxamine

-phenylephrine-phenylephrine

Stimulate alpha2Stimulate alpha2

-clonidine-clonidine

Antagonist Antagonist

Stop NA Stop NA breakdownbreakdown

-MA inhibitors-MA inhibitors

False False transmitterstransmitters

-methydopa-methydopa

-phenoxybenza-phenoxybenza

minemine

-phentolamine-phentolamine

-prazocin-alpha1-prazocin-alpha1

-yohimbin-alpha2-yohimbin-alpha2

Site of actionSite of action

4.Beta receptors4.Beta receptors

5.Domaninergic5.Domaninergic

receptorsreceptors

Agonist Agonist

-isoproterenol-isoproterenol

-dobutamine-dobutamine

-salbutamol-salbutamol

(beta2)(beta2)

DA1 – dopamineDA1 – dopamine

DA2 -DA2 -bromocriptinebromocriptine

Antagonist Antagonist

-propanolol-propanolol

-metoprolol-metoprolol

-esmolol-esmolol

-Butoxamine-Butoxamine

(beta2)(beta2)

DA1 – DA1 – metoclopramidemetoclopramide

DA2-haloperidolDA2-haloperidol

TESTS FOR AUTONOMIC TESTS FOR AUTONOMIC INTEGRITYINTEGRITY

Autonomic functions can be evaluated by:Autonomic functions can be evaluated by:HistoryHistoryNon-invasive testsNon-invasive tests Invasive testsInvasive tests

History History CVSCVS (postural/orthostatic hypotension) (postural/orthostatic hypotension) Fainting episodesFainting episodes DizzinessDizziness HeadacheHeadache Diminution of visionDiminution of vision

Genitourinary Genitourinary ImpotencyImpotency Incontinence of urineIncontinence of urine Retention of urineRetention of urine Frequency in urinationFrequency in urination

GlandsGlands Decreased salivation with difficulty in eatingDecreased salivation with difficulty in eating Decreased lacrimation causing eye irritationDecreased lacrimation causing eye irritation Impaired sweating causing temperature elevationImpaired sweating causing temperature elevation

CNS CNS (affection of fibres supplying iris)(affection of fibres supplying iris) Night-blindnessNight-blindness

Chronic diseasesChronic diseases Diabetes mellitusDiabetes mellitus Chronic renal failureChronic renal failure HypertensionHypertension

Family historyFamily history

Personal historyPersonal history Chronic alcoholismChronic alcoholism Drugs like Antihypertensive antidepressants, Drugs like Antihypertensive antidepressants,

tranquilizers , diureticstranquilizers , diuretics

Non – invasive testsNon – invasive tests

Tests for cardiac vagal functionTests for cardiac vagal function Respiratory sinus arrhythmiaRespiratory sinus arrhythmia Vasalva ratio(Phase IV/II)Vasalva ratio(Phase IV/II) Bradycardia during Bradycardia during

phenylephrine challengephenylephrine challenge Absence of tachycardia with Absence of tachycardia with

atropineatropine

Tests for sympathetic functionTests for sympathetic functionI) CARDIACI) CARDIAC Tachycardia during standing or Tachycardia during standing or

head-up tilthead-up tilt Tachycardia during vasalva Tachycardia during vasalva

strain(PhaseII)strain(PhaseII)

II) PERIPHERALII) PERIPHERAL Blood pressure overshoot Blood pressure overshoot

after vasalva releaseafter vasalva release BP increase with cold BP increase with cold

pressure testpressure test Diastolic BP rise with Diastolic BP rise with

isometric handgripisometric handgrip Systolic and diastolic BP Systolic and diastolic BP

response to upright response to upright positionposition

Respiratory sinus arrhythmiaRespiratory sinus arrhythmia Tests Tests parasympathetic parasympathetic functionfunction Determines the max. to min. heart rate variation in Determines the max. to min. heart rate variation in

forceful breathingforceful breathing Patient in sitting or lying down positionPatient in sitting or lying down position 6 breaths/min.(5secs inspiration,5secs expiration)6 breaths/min.(5secs inspiration,5secs expiration) Record mx. and min. HR and RR intervalRecord mx. and min. HR and RR interval Av. variation should be >10 beats/minAv. variation should be >10 beats/min E : I ratio = longest RR interval in expiration/shortest RR E : I ratio = longest RR interval in expiration/shortest RR

interval in inspirationinterval in inspiration In <40yrs age, In <40yrs age, E:I<1.2 is abnormalE:I<1.2 is abnormal

Postural stress: Supine to standingPostural stress: Supine to standing Tests the Tests the sympatheticsympathetic function function Commonly performed bed-side testCommonly performed bed-side test Note HR and BP in supine position after Note HR and BP in supine position after

10mins rest10mins rest Note changes in HR and BP after assuming Note changes in HR and BP after assuming

standing posture unaided after 50 secsstanding posture unaided after 50 secs Drop of systolic BP >20mm of Hg and/or Drop of systolic BP >20mm of Hg and/or

diastolic BP >10 mm of Hg is abnormaldiastolic BP >10 mm of Hg is abnormal Absence of tachycardia when standing is Absence of tachycardia when standing is

abnormal (Marrey’s Law of baro receptor abnormal (Marrey’s Law of baro receptor stimulation)stimulation)

Cold Pressure testCold Pressure test

Tests the Tests the peripheral sympatheticperipheral sympathetic vasoconstrictorsvasoconstrictors

Record BP 1min after immersing hand in Record BP 1min after immersing hand in ice cold waterice cold water

Both systolic and diastolic BP should Both systolic and diastolic BP should increase by 10mm of Hgincrease by 10mm of Hg

Isometric Hand grip ExerciseIsometric Hand grip Exercise

Tests the Tests the efferent sympatheticefferent sympathetic function function Sustained isometric contraction at 30% of Sustained isometric contraction at 30% of

patients max. strength should increase BP by patients max. strength should increase BP by 10-15mm of Hg10-15mm of Hg

Vasalva ManouverVasalva Manouver Tests both Tests both sympathetic and parasympatheticsympathetic and parasympathetic function function Subject sits quietly or lies supine, blows into a mouth-Subject sits quietly or lies supine, blows into a mouth-

piece with an open glottis, holds airway pressure of piece with an open glottis, holds airway pressure of 40mm of Hg for 15secs(PhaseII40mm of Hg for 15secs(PhaseII) and then releases the ) and then releases the pressurepressure

HR increasesHR increases 10to15secs after initiating blowing(PhaseII) and 10to15secs after initiating blowing(PhaseII) and before release of pressurebefore release of pressure

This implies that the This implies that the sympathetic response is intactsympathetic response is intact On release of strain(PhaseIV), preload and cardiac output On release of strain(PhaseIV), preload and cardiac output

restored, restored, BP overshootBP overshoot….this implies that the peripheral ….this implies that the peripheral sympathetic vasoconstriction is intactsympathetic vasoconstriction is intact

Baroreceptors stimulated, reflex Baroreceptors stimulated, reflex bradycardiabradycardia…this implies that the …this implies that the parasympathetic system is intactparasympathetic system is intact

To test cardiac vagal function a ratio has been devisedTo test cardiac vagal function a ratio has been devised Vasalva ratio = longest RR interval[max HR] in Phase IV(x)/Vasalva ratio = longest RR interval[max HR] in Phase IV(x)/

shortest RR interval[min HR] in Phase II(y)shortest RR interval[min HR] in Phase II(y) Vasalva ratio <1.2 is abnormalVasalva ratio <1.2 is abnormal

EPINEPHRINE TESTEPINEPHRINE TEST – – 3 drops in eye at I min. interval 3 times3 drops in eye at I min. interval 3 times Check pupil sixe at 15, 30 and 45 minsCheck pupil sixe at 15, 30 and 45 mins Normal pupil = no effectNormal pupil = no effect Sympathetically denervated pupil = dilationSympathetically denervated pupil = dilationCOCAINE TESTCOCAINE TEST – – Method same as aboveMethod same as above Normal pupil = dilationNormal pupil = dilation Sympathetic denervated pupil = no change in sizeSympathetic denervated pupil = no change in sizeHISTAMINE TESTHISTAMINE TEST – – 0.05ml of 1:1000 histamine injected intracutaneously0.05ml of 1:1000 histamine injected intracutaneously Normal response – triple response with 1cm whealNormal response – triple response with 1cm wheal Familial dysautonomia and peripheral neuropathy – Familial dysautonomia and peripheral neuropathy –

absent whealabsent wheal

EPHEDRINE TESTEPHEDRINE TEST – – Give 25mg imGive 25mg im Normal subjects = HR increasesNormal subjects = HR increases Sympathetic denervation = no change in HRSympathetic denervation = no change in HRATROPINE TESTATROPINE TEST – – Give 0.8mg imGive 0.8mg im Normal subjects = HR increases by 20 Normal subjects = HR increases by 20

beats/minbeats/min Sympathetic denervation = no changeSympathetic denervation = no changeNEOSTIGMINE TESTNEOSTIGMINE TEST – – Give 1mg imGive 1mg im Normal subjects = HR decreasesNormal subjects = HR decreases Parasympathetically denervated = no changeParasympathetically denervated = no change

Power Spectral Analysis of HR Power Spectral Analysis of HR variabilityvariability

Slower periodic oscillations in heart, can be decomposed Slower periodic oscillations in heart, can be decomposed into a series of sine waves with diff. amplitudes and into a series of sine waves with diff. amplitudes and frequenciesfrequencies

This frequency domain reveals a This frequency domain reveals a consistant peakconsistant peak/ power at the breathing / power at the breathing frequency frequency 0.2 to 0.3Hz0.2 to 0.3Hz… this implies … this implies intact parasympatheticintact parasympathetic innervaton of innervaton of SA nodeSA node

There is another peak at low frequencies There is another peak at low frequencies 0.05 to 0.150.05 to 0.15 Hz…due to changing Hz…due to changing cardiac cardiac sympatheticsympathetic activity activity

This low frequency component is augmented by increased sympathetic This low frequency component is augmented by increased sympathetic drive eg.head up tilt, mental arithmatics and is reduced in quadriplegics due drive eg.head up tilt, mental arithmatics and is reduced in quadriplegics due to interrupted sympathetic pathways.to interrupted sympathetic pathways.

INVASIVE TESTSINVASIVE TESTS Done to locate Done to locate precise siteprecise site of pathology of pathology Done for Done for researchresearch purpose purpose

Intraneural recordingIntraneural recording of post-ganglionic of post-ganglionic sympathetic activitysympathetic activity

Eliciting Eliciting axon reflexaxon reflex by intradermal injection of by intradermal injection of acetyl-cholineacetyl-choline

Response of ANS to infusion of Response of ANS to infusion of pressor drugspressor drugs : : injection or epinephrine(1 : 1000) in conjunctival sacinjection or epinephrine(1 : 1000) in conjunctival sac Cocaine (4 to 10%) topical applicationCocaine (4 to 10%) topical application Ephedrine testEphedrine test Atropine testAtropine test Neostigmine testNeostigmine test

OTHER TESTSOTHER TESTS Measurement of skin Measurement of skin temperaturetemperature Tests for Tests for sudomotorsudomotor function function

Weight of sweatWeight of sweat Galvanic skin resistance testGalvanic skin resistance test

Tests for Tests for lacrimal lacrimal functionfunction Tests for Tests for bladder and GITbladder and GIT dysfunction dysfunction LaboratoryLaboratory tests tests

Measure plasma levels of catecholamines and other vasoactive Measure plasma levels of catecholamines and other vasoactive hormones like renin, angiotensin and vasopressinhormones like renin, angiotensin and vasopressin

Measurement of forearm blood flow with plethysmographyMeasurement of forearm blood flow with plethysmography Cerebral EEG blood flow studiesCerebral EEG blood flow studies

SELECTION OF TESTSSELECTION OF TESTS : :To assess ANS involvement, 5 simple non-invasive tests are To assess ANS involvement, 5 simple non-invasive tests are

sufficientsufficientTo assess definitive abnormality, 2 or more specific tests are To assess definitive abnormality, 2 or more specific tests are

recommendedrecommended

ANAESTHESIA AND AUTONOMIC ANAESTHESIA AND AUTONOMIC NERVOUS SYSTEMNERVOUS SYSTEM

GENERAL ANAESTHESIAGENERAL ANAESTHESIA

Pre medicationPre medication : :

Agents used to decrease secretions like Agents used to decrease secretions like atropine,glycopyrolate are atropine,glycopyrolate are anti cholinergicsanti cholinergics

Antiemetic metoclopramide is a Antiemetic metoclopramide is a dopaminergicdopaminergic anti emeticanti emetic

Opiods cause respiratory depression by Opiods cause respiratory depression by inhibiting Ach release from CNSinhibiting Ach release from CNS

Morphine releases histamine, venous pooling, Morphine releases histamine, venous pooling, reduced peripheral vascular resistancereduced peripheral vascular resistance

Pentazocine increases plasma catecholaminesPentazocine increases plasma catecholamines Fentanyl causes vagal bradycardia during intubationFentanyl causes vagal bradycardia during intubation Beta antagonistsBeta antagonists reduce stress response during intubation reduce stress response during intubation Alpha2 agonist, Alpha2 agonist, clonidine,clonidine, reduces dose of induction agent and reduces dose of induction agent and

stress response duringstress response during

Induction agents –

All induction agents except ketamine reduce sympathetic activityArterial pressure dropsBaroreceptor mediated tachycardia may/may not occurKetamine stimulates the sympathetic systemEtomidate is a potent inhibitor of adrenergic steroidogenesis

Inhalational AgentsInhalational Agents – – Halothane, enflurane, isoflurane reduce pre-ganglionic Halothane, enflurane, isoflurane reduce pre-ganglionic

sympathetic activity and hence decrease plasma sympathetic activity and hence decrease plasma catecholaminescatecholamines

Cyclopropane and diethyl ether increase sympathetic Cyclopropane and diethyl ether increase sympathetic activity by central action and by action on vasomotor activity by central action and by action on vasomotor neurons in spinal cordneurons in spinal cord

Muscle RelaxantsMuscle Relaxants – – Pancuronium releases adrenaline and raises HR and BPPancuronium releases adrenaline and raises HR and BP

Autonomic changes like decreasing Autonomic changes like decreasing arterial BP,HR and plasma arterial BP,HR and plasma catecholamines and cortisol indicate catecholamines and cortisol indicate increasing depth of anaesthesiaincreasing depth of anaesthesia

SPINAL ANAESTHESIASPINAL ANAESTHESIA Causes sympathetic blockade, hypotension and Causes sympathetic blockade, hypotension and

bradycardia depending on the level of blockadebradycardia depending on the level of blockade

• In low SAB sacral parasympathetic and lumbar plus lower In low SAB sacral parasympathetic and lumbar plus lower thoracic sympathetics are blocked, thoracic sympathetics are blocked, uninhibited vagal uninhibited vagal parasympathetics acting on splanchnic bed and visceraparasympathetics acting on splanchnic bed and viscera

In high SAB, In high SAB, all sympathetics are blockedall sympathetics are blocked, vagal , vagal parasympathetics to thoracic and abdominal viscera parasympathetics to thoracic and abdominal viscera become over active and cause severe bradycardia and become over active and cause severe bradycardia and even asystoleeven asystole

In In saddle blocksaddle block sacral parasympathetic is blocked, sacral parasympathetic is blocked, thoracolumbar sympathetic is intact…causing minimal thoracolumbar sympathetic is intact…causing minimal physiologic disturbancephysiologic disturbance

Features of Autonomic Imbalance after Features of Autonomic Imbalance after Spinal AnaesthesiaSpinal Anaesthesia

CVSCVS HypotensionHypotension BradycardiaBradycardiaGITGIT Increased peristalsisIncreased peristalsis Intestines usually activeIntestines usually activeRSRS In high SAB(upper 5 or 6 thoracic sympathetic)In high SAB(upper 5 or 6 thoracic sympathetic) Some bronchial spasm due to increased vagal activitySome bronchial spasm due to increased vagal activity

EPIDURAL ANAESTHESIAEPIDURAL ANAESTHESIA Less hypotensionLess hypotension SegmentalSegmental type of anaesthesia is possible type of anaesthesia is possible Onset of action is slowerOnset of action is slower Hence compensatory mechanisms initiated well in advanceHence compensatory mechanisms initiated well in advance

Autonomic reflexes during Autonomic reflexes during Anaesthesia and SurgeryAnaesthesia and Surgery

Oculocardiac reflexOculocardiac reflex : :

Pressure over eyeballs or traction of external Pressure over eyeballs or traction of external ocular musclesocular muscles

Causes bradycardia, asystole, cardiac Causes bradycardia, asystole, cardiac dysrhytthmia, ventricular fibrillationdysrhytthmia, ventricular fibrillation

Light plane on anaesthesia, hypoxia, Light plane on anaesthesia, hypoxia, hypercarbia aggravate this reflexhypercarbia aggravate this reflex

Prophylaxis with anticholinergics..still a Prophylaxis with anticholinergics..still a controversycontroversy

Abdominal reflexAbdominal reflex : : Due to stimulation of ANS by traction or Due to stimulation of ANS by traction or

pressure during surgeries within the abdominal pressure during surgeries within the abdominal cavitycavity

Circulatory effect – bradycardia, hypotentionCirculatory effect – bradycardia, hypotention Respiratory effect – apnea, tachypnea, Respiratory effect – apnea, tachypnea,

laryngospasmlaryngospasm

These are :These are :• Peritoneal and mesentericPeritoneal and mesenteric reflex reflex• Coeliac plexusCoeliac plexus reflex – traction of stomach,gall reflex – traction of stomach,gall

bladder, hilum of liver or retraction of duodenumbladder, hilum of liver or retraction of duodenum• Brewer LuckhardtBrewer Luckhardt reflex/ Diaphragmatic traction reflex/ Diaphragmatic traction

reflex reflex • Reflexes associated with pelvic nerveReflexes associated with pelvic nerve

Recto – laryngeal reflexRecto – laryngeal reflex : : Caused by dilation of anal sphincter under GACaused by dilation of anal sphincter under GA Afferent is via pelvic and sacral nerve to Afferent is via pelvic and sacral nerve to vagalvagal motor motor

nucleusnucleus Efferent is via Efferent is via recurrent laryngealrecurrent laryngeal nerve nerve Causes laryngeal spasm and apneaCauses laryngeal spasm and apnea

Recto – cardiac reflexRecto – cardiac reflex : : Anal sphincter dilation causes bradycardia, hypotensionAnal sphincter dilation causes bradycardia, hypotension

Preventions :Preventions : These autonomic reflexes can be prevented by adequate These autonomic reflexes can be prevented by adequate

depth of anaesthesiadepth of anaesthesia Atropine prophylaxis maybe givenAtropine prophylaxis maybe given Ask surgeon to avoid manipulations, proceed gently and Ask surgeon to avoid manipulations, proceed gently and

slowlyslowly

ANS DYSFUNCTIONANS DYSFUNCTIONPRIMARY –PRIMARY – Idiopathic orthostatic hypotensionIdiopathic orthostatic hypotension Shy Dragger syndromeShy Dragger syndrome

FAMILIAL – Riley Day syndromeLeesch Neehan syndrome•Genetic disorder of purine metabolism in males•Sympathetic response to stress is enhancedGill Familia dysautonomia

SECONDARY TO SYSTEMIC SECONDARY TO SYSTEMIC DISORDERSDISORDERS

AgeingAgeing Diabetes MellitusDiabetes Mellitus Chronic alcoholismChronic alcoholism Chronic renal failureChronic renal failure Neurological diseasesNeurological diseases Tabes dorsalisTabes dorsalis SyringomyeliaSyringomyelia amyloidosisamyloidosis

Chagas diseaseChagas disease Hypertension Hypertension TetanusTetanus PheochromocytomaPheochromocytoma Spinal cord injurySpinal cord injury Guillian Barre Guillian Barre

syndromesyndrome Carcinomatosis Carcinomatosis

AGINGAGING 20% of people over 65yrs have 20% of people over 65yrs have postural hypotensionpostural hypotension Symptoms – dizziness, faintness, loss of consciousnessSymptoms – dizziness, faintness, loss of consciousness Selective/ Selective/ early parasympatheticearly parasympathetic involvement involvement Delayed/ slow sympathetic involvementDelayed/ slow sympathetic involvement Blunting of – Vasalva maneuverBlunting of – Vasalva maneuver

Respiratory cycleRespiratory cycle

HR changes to changes in BPHR changes to changes in BP

Resting and exercise induced NE responseResting and exercise induced NE response

ALCOHOLISMALCOHOLISM Acute, chronic or alcohol withdrawal causes orthostatic Acute, chronic or alcohol withdrawal causes orthostatic

intoleranceintolerance Poor nutrition impairs SNSPoor nutrition impairs SNS Baroreceptors less sensitiveBaroreceptors less sensitive Vasalva ratio and cardiac acceleration following iv Vasalva ratio and cardiac acceleration following iv

atropine is diminished in presence of neurological atropine is diminished in presence of neurological impairmentimpairment

TETANUSTETANUS

Sympatho adrenal Sympatho adrenal hyperactivity is the hyperactivity is the chief cause of deathchief cause of death

Direct effect of Direct effect of tetanus toxin on SNS tetanus toxin on SNS causes rise in plasma causes rise in plasma catecholaminescatecholamines

PHEOCHROMOCYTOMAPHEOCHROMOCYTOMA Catecholamine secreting tumourCatecholamine secreting tumour Hypertension, hypermetabolism, hyperglycemiaHypertension, hypermetabolism, hyperglycemia Preop alpha blockers are given toPreop alpha blockers are given to Restore blood volumeRestore blood volume Assess end organ damageAssess end organ damage Treat cardiac arrhythmiasTreat cardiac arrhythmias

GUILLIAN BARRE GUILLIAN BARRE SYNDROMESYNDROME

• ANS involvement ANS involvement secondary to secondary to axonal axonal degenerationdegeneration

• Variable BP, facial Variable BP, facial flushing, urinary flushing, urinary retention, tachy – retention, tachy – brady arrhythmiasbrady arrhythmias

• Neuropathic lesions in Neuropathic lesions in afferent limb of afferent limb of baroreceptor may lead baroreceptor may lead to to SIADH, SIADH, hyponatremiahyponatremia

Neuronal degenerationNeuronal degeneration Metabolically related neuronal Metabolically related neuronal

dysfunctiondysfunction Afferent, central and efferent Afferent, central and efferent

pathways involvedpathways involved Vagal neuropathyVagal neuropathy occurs before occurs before

systemic neuropathysystemic neuropathy Symptomatic postural Symptomatic postural

hypotension implies poor hypotension implies poor prognosisprognosis

Esophageal gastric hypomotility, Esophageal gastric hypomotility, bradycardia, silent myocardial bradycardia, silent myocardial infarcts, impaired ventilatory infarcts, impaired ventilatory control, unexplained cardio control, unexplained cardio respiratory arrests may occurrespiratory arrests may occur

AUTONOMIC CHANGES IN SPINAL AUTONOMIC CHANGES IN SPINAL CORD TRANSECTIONCORD TRANSECTION

Affects motor, sensory and ANS depending on level of transectionAffects motor, sensory and ANS depending on level of transection Acute effects/ Acute effects/ Spinal ShockSpinal Shock : : Flaccid paralysisFlaccid paralysis Total absence of sensationTotal absence of sensation Loss of temperature regulationLoss of temperature regulation Loss of spinal reflexes below level of injuryLoss of spinal reflexes below level of injury Decreased systolic BPDecreased systolic BP BradycardiaBradycardia Abnormal ECG, ST-T changes, VPCsAbnormal ECG, ST-T changes, VPCs

Management of Anaesthesia :Management of Anaesthesia :• AirwayAirway management management• Avoidance of Avoidance of hypovolemiahypovolemia Anaesthesia is given so that pt. tolerates Anaesthesia is given so that pt. tolerates

tubetube Muscle relaxant is used as neededMuscle relaxant is used as needed

ANAESTHESIA IN PATIENTS WITH ANS ANAESTHESIA IN PATIENTS WITH ANS DYSFUNCTIONDYSFUNCTION

UnderstandUnderstand the impact the impactReduced ANS activity on CVS Reduced ANS activity on CVS

responses to change inresponses to change ino body positionbody positiono positive airway pressure positive airway pressure o acute blood loss acute blood loss o effects due to negative effects due to negative

inotropic anaesthetic agentsinotropic anaesthetic agents

Posture Posture – shift patient to OT – shift patient to OT and induce in supine positionand induce in supine position

Preloading Preloading should be done should be done properlyproperly

Pre medicationPre medication – – Atropine may fail to produce Atropine may fail to produce

tachycardiatachycardia Ranitidine and metoclopramideRanitidine and metoclopramide

to avoid regurg and aspirationto avoid regurg and aspiration Narcotics and other respiratory Narcotics and other respiratory

depressants are avoideddepressants are avoided

MonitoringMonitoring – – Pulse oxPulse ox Continuous arterial BPContinuous arterial BP ECGECG CVPCVP TemperatureTemperature Urine outputUrine output

GENERAL ANAESTHESIAGENERAL ANAESTHESIA

InductionInduction – – Thiopentone given slowly with proper iv fluid Thiopentone given slowly with proper iv fluid

replacementreplacement Diazepam and fentanyl may also be usedDiazepam and fentanyl may also be used Ketamine produces accentuated BP responseKetamine produces accentuated BP response

Rapid sequence intubationRapid sequence intubation as patients have as patients have gastro-paresisgastro-paresis

Maintenance on spontaneous breathing with Maintenance on spontaneous breathing with N2O and O2, with N2O and O2, with minimal halothaneminimal halothane

If needed, cardio stable muscle relaxants like If needed, cardio stable muscle relaxants like Vec should be usedVec should be used

IPPV produces exaggerated reduction in IPPV produces exaggerated reduction in BPBP

Blood loss should be replaced promptly as Blood loss should be replaced promptly as compensatory tachycardia is absentcompensatory tachycardia is absent

Volatile anaesthetics produce excessive Volatile anaesthetics produce excessive myocardial depression and hypotension myocardial depression and hypotension

Maintain fluid balanceMaintain fluid balanceAvoid hypothermiaAvoid hypothermia (pts may become (pts may become

poikilothermic due to sympathetic poikilothermic due to sympathetic dysfunction)dysfunction)

Vasopressors should be used with cautionVasopressors should be used with caution

REGIONAL ANAESTHESIAREGIONAL ANAESTHESIA

Risk of hypotension with SAB and Risk of hypotension with SAB and epiduralsepidurals

Post spinal urinary retention may occurPost spinal urinary retention may occurPre opPre op presence of presence of impotenceimpotence must be must be

brought to notice to avoid brought to notice to avoid medico legalmedico legal implicationsimplications

ANS IN INTENSIVE CAREANS IN INTENSIVE CARE Mechanical IPPVMechanical IPPV causes increased intra thoracic causes increased intra thoracic

pressure, decreased cardiac filling and hence, pressure, decreased cardiac filling and hence, decreased cardiac outputdecreased cardiac output

All reflex mechanisms fail hence cardiac output falls All reflex mechanisms fail hence cardiac output falls drasticallydrastically

Suction careSuction care

ANS IN CHRONIC PAINANS IN CHRONIC PAIN

LUMBAR SYMPATHETIC BLOCKLUMBAR SYMPATHETIC BLOCK Used to alleviate the Used to alleviate the rest pain of chronic PVDrest pain of chronic PVD Preganglionic sympathetics are from lower Preganglionic sympathetics are from lower

thoracic chain and pre ganglionic somatic fibres thoracic chain and pre ganglionic somatic fibres are from 1are from 1stst and 2 and 2ndnd lumbar nerves lumbar nerves

Post ganglionic fibres are vasoconstrictor to Post ganglionic fibres are vasoconstrictor to arterioles, pilomotor and sudomotor to skinarterioles, pilomotor and sudomotor to skin

Hence, its block causes absence of sweating Hence, its block causes absence of sweating and warm dry skinand warm dry skin

COELIAC PLEXUS BLOCKCOELIAC PLEXUS BLOCKUsed for intractable pain caused by cancer Used for intractable pain caused by cancer

of pancreas, stomach, gall bladder and of pancreas, stomach, gall bladder and liverliver

SUPERIOR HYPOGASTRIC PLEXUS SUPERIOR HYPOGASTRIC PLEXUS BLOCKBLOCK

Relates pain from pelvic organsRelates pain from pelvic organsUsed in cancer pain due to Used in cancer pain due to

cervical,prostate,testicular cancers and in cervical,prostate,testicular cancers and in radiation injuryradiation injury

COMPLEX REGIONAL PAIN SYNDROMECOMPLEX REGIONAL PAIN SYNDROMEConsequence of limb trauma with or Consequence of limb trauma with or

without obvious nerve lesionswithout obvious nerve lesionsCharacterised by motor, sensory and ANS Characterised by motor, sensory and ANS

symptomssymptomsANS features include abnormal skin blood ANS features include abnormal skin blood

flow, temperature and sweatingflow, temperature and sweating

PHANTOM LIMBPHANTOM LIMBEctopic discharge of Ectopic discharge of epinephrine from a stump neuromaepinephrine from a stump neuroma is is an important peripheral mechanisman important peripheral mechanismSympathetic block, sympathectomies or beta blockers Sympathetic block, sympathectomies or beta blockers increase blood flow and reduce intensity of burning painincrease blood flow and reduce intensity of burning painDecreased blood flow causes phantom limb painDecreased blood flow causes phantom limb pain

CONCLUSIONCONCLUSION ANS plays a very dominant role in maintaining ANS plays a very dominant role in maintaining

haemodynamic stabilityhaemodynamic stability Influences the outcome after anaesthesia and surgeryInfluences the outcome after anaesthesia and surgery

THANK THANK YOU…YOU…THANK THANK YOU…YOU…

THANK THANK YOU…YOU…