The document discusses the autonomic nervous system and its implications in anaesthesia. It provides details on the anatomy and physiology of the sympathetic, parasympathetic, and enteric nervous systems. It describes the effects of these systems on various target organs and the neurotransmitters involved. Tests for evaluating autonomic integrity are discussed. Drugs acting on the autonomic nervous system and their sites of action are also summarized. The implications of autonomic nervous system dysfunction for anaesthesia are outlined.

1. The AutonomicThe Autonomic
Nervous System AndNervous System And
Its Implications InIts Implications In
AnaesthesiaAnaesthesia
Guided byGuided by ::
Dr. BakshiDr. Bakshi
MadamMadam
Presented by :Presented by :
Dr. Neha SoaresDr. Neha Soares
Dated : 26Dated : 26thth
July 2007July 2007

2.  IntroductionIntroduction
 AnatomyAnatomy
 PhysiologyPhysiology
 Drugs acting on ANSDrugs acting on ANS
 Tests for autonomic integrityTests for autonomic integrity
 Anaesthesia and ANSAnaesthesia and ANS a) Generala) General
b) Regionalb) Regional
 Autonomic reflexes during anaesthesia andAutonomic reflexes during anaesthesia and
surgerysurgery
 ANSANS 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

3. INTRODUCTIONINTRODUCTION
Anesthesiologists manipulate the physiology andAnesthesiologists manipulate the physiology and
pharmacology of the autonomic nervous system.pharmacology of the autonomic nervous system.

4. ANATOMYANATOMY
 ComprisesComprises all afferent fibresall afferent fibres from the CNSfrom the CNS
except those supplying skeletal muscles.except those supplying skeletal muscles.
 Includes :Includes :
1)1) sympatheticsympathetic nervous systemnervous system
2)2) parasympatheticparasympathetic nervous systemnervous system
3)3) entericenteric nervous systemnervous system

6. Sympathetic Nervous SystemSympathetic Nervous System
 Originates from theOriginates from the Thoraco-lumbarThoraco-lumbar spinalspinal
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

8.  PairedPaired sympathetic chains havingsympathetic chains having 22 paired ganglia22 paired ganglia

9.  UnpairedUnpaired prevertebral ganglia in the abdomen andprevertebral ganglia in the abdomen and
pelvispelvis
 CeliacCeliac
 Superior mesentericSuperior mesenteric
 Inferior mesentericInferior mesenteric
 Aortico renalAortico renal
• terminal/collateral gangliaterminal/collateral ganglia

10.  Terminal or collateral gangliaTerminal or collateral ganglia
 Small and few in numberSmall and few in number
 PresentPresent near targetnear target organorgan
 Eg. Nerves supplying adrenal medullaEg. Nerves supplying adrenal medulla
and other chromaffin tissueand other chromaffin tissue
 CompriseComprise preganglionicpreganglionic fibres itself thatfibres itself that
pass to target tissue without synapsingpass to target tissue without synapsing

11. PARASYMPATHETIC NERVOUSPARASYMPATHETIC NERVOUS
SYSTEMSYSTEM
 75% from75% from vagusvagus
 Arises fromArises from III, VII, IX, X cranialIII, VII, IX, X cranial nerves,nerves,
S2-3S2-3 and occasionally S1and4and occasionally S1and4
 Occur proximal to or within the innervatedOccur proximal to or within the innervated
organorgan
 Hence,Hence, pre-ganglionic fibres very longpre-ganglionic fibres very long
 PNS more targetedPNS more targeted

13. Preganglionic fibresPreganglionic 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

14. ENTERIC NERVOUS SYSTEMENTERIC NERVOUS SYSTEM
 FoundFound within the wallswithin the walls
of the GIT, pancreasof the GIT, pancreas
and gall-bladderand gall-bladder
 High degree ofHigh degree of
autonomyautonomy
 Peristalsis andPeristalsis and
digestion persists evendigestion persists even
if sphincter functionif sphincter function
impaired followingimpaired following
SAB/transections.SAB/transections.
 Submucous(Submucous(Meissner’sMeissner’s
plexus)plexus)
 Myenteric(Myenteric(Auerbach’sAuerbach’s
plexus)plexus)

15. PHYSIOLOGYPHYSIOLOGY
 EitherEither sympathetic or parasympathetic systemsympathetic or parasympathetic system
dominatesdominates a particular organ function, hencea 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 parasympatheticSome organs have only parasympathetic
innervation – stomach, pancreasinnervation – stomach, pancreas
 Sympathetic deals with FIGHT OR FLIGHTSympathetic deals with FIGHT OR FLIGHT
 Parasympathetic deals with discrete adjustmentsParasympathetic deals with discrete adjustments
in relaxed homeostasisin relaxed homeostasis

17. Target organTarget organ SNSSNS ReceptorReceptor PNSPNS
1.1. Hair follicleHair 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 – nasalGlands – nasal
parotid,lacrimalparotid,lacrimal
submandibularsubmandibular
gastric,pancraeticgastric,pancraetic
ContractionContraction
PiloerectionPiloerection
MydriasisMydriasis
NoneNone
SlightSlight
MydriasisMydriasis
SlightSlight
increaseincrease
Alpha1Alpha1
Alpha 1Alpha 1
BetaBeta
Alpha 1Alpha 1
NoneNone
NoneNone
MiosisMiosis
Accomoda-Accomoda-
tiontion
CopiousCopious
IncreaseIncrease
Action of SNS and PNS on various organsAction of SNS and PNS on various organs

18. Target organTarget organ SNSSNS ReceptorReceptor PNSPNS
6. Sweat gland6. Sweat gland
7. Apocrine gland7. Apocrine gland
8. Heart8. Heart
-Rate-Rate
-Force of contractn-Force of contractn
-Coronaries-Coronaries
CopiousCopious
IncreaseIncrease
ThickThick
odoriferousodoriferous
IncreaseIncrease
IncreaseIncrease
DilatedDilated
ConstrictedConstricted
Alpha 1Alpha 1
Beta 1Beta 1
Beta 1Beta 1
Beta 2Beta 2
AlphaAlpha
Sweating ofSweating of
PalmsPalms
NoneNone
DecreaseDecrease
DecreaseDecrease
xcept atriaxcept atria

19. Target organTarget organ SNSSNS ReceptorReceptor PNSPNS
9. Lungs9. Lungs
-Bronchi-Bronchi
-Blood vessels-Blood vessels
10. Gut lumen10. Gut lumen
SphincterSphincter
11.Pancreas11.Pancreas
12.Liver12.Liver
13.Gall bladder13.Gall bladder
14.Kidney14.Kidney
DilationDilation
ConstrictedConstricted
DecreasedDecreased
IncreasedIncreased
DecreasedDecreased
GlucoseGlucose
releasedreleased
RelaxedRelaxed
Output andOutput and
renin lessrenin less
Beta 2Beta 2
Alpha2Alpha2
Alpha2Alpha2
Alpha2Alpha2
Alpha1Alpha1
Beta1Beta1
ConstrictnConstrictn
DilationDilation
IncreasedIncreased
peristalsisperistalsis
RelaxedRelaxed

20. Target organTarget organ SNSSNS ReceptorReceptor PNSPNS
15.Bladder15.Bladder
- Detrusor- Detrusor
- TrigoneTrigone
16. Ureter16. Ureter
17. uterus, vas17. uterus, vas
deferens,deferens,
prostrateprostrate
18.Arterioles18.Arterioles
-viscera,skin-viscera,skin
-muscle-muscle
RelaxedRelaxed
ContractedContracted
ContractedContracted
ContractedContracted
ConstrictedConstricted
ConstrictedConstricted
DilatedDilated
BetaBeta
Alpha1Alpha1
Alpha1Alpha1
Alpha1Alpha1
AlphaAlpha
beta2beta2

21. Target organTarget organ SNSSNS ReceptorReceptor PNSPNS
19.Veins19.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

22. 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 :
 ArteriolesArterioles
 VeinsVeins
 Sweat glandsSweat glands
 SpleenSpleen

23. ANS of HeartANS of Heart

24. NeurotransmittersNeurotransmitters
 AcetylcholineAcetylcholine – Secreted by– Secreted by
**all preganglionic fibresall preganglionic fibres
*Postganglionic parasympathetic*Postganglionic parasympathetic
fibrespostganglionic sympathetic fibresfibrespostganglionic sympathetic fibres
of sweat gland,piloerctor muscle andof sweat gland,piloerctor muscle and
blood vesselsblood vessels
 NorepinephrineNorepinephrine – Secreted by all– Secreted by all
postganglionic sympatheticpostganglionic sympathetic fibresfibres

25.  Acetylcholine receptors are of 2 types:Acetylcholine receptors are of 2 types:
-- MuscarinicMuscarinic: action similar to that: action similar to that
produced byproduced by parasympatheticparasympathetic systemsystem
-- NicotinicNicotinic: action on: action on skeletal andskeletal and
ganglionicganglionic synapses onlysynapses 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 inbeta2 (smooth muscle relaxation in
somesome organs)organs)

26. Action of Important Drugs on ANSAction of Important Drugs on ANS
Site of actionSite of action
1.Sympathetic1.Sympathetic
andand
parasympatheticparasympathetic
gangliaganglia
2.Endings of post2.Endings of post
ganglionic nonganglionic non
adrenergicadrenergic
NeuronsNeurons
AgonistAgonist
1.Stimulate post-1.Stimulate post-
ganglionganglion- nicotin- nicotin
2.2.InhibitACh’trsInhibitACh’trse-e-
PhysostigminePhysostigmine
NeostigmineNeostigmine
ParathionParathion
Release NARelease NA
-TyramineTyramine
-EphedrineEphedrine
-AmphetamineAmphetamine
AntagonistAntagonist
HexamethoniumHexamethonium
MecamylamineMecamylamine
TrimethaphanTrimethaphan
High conc.Ach,High conc.Ach,
AnticholinestrsesAnticholinestrses
CurareCurare
Block NA synthBlock NA synth
-metyrosine-metyrosine
Stop NA storageStop NA storage
-reserpine,guane-reserpine,guane
thidinethidine

27. Site of actionSite of action
3.Alpha receptors3.Alpha receptors
AgonistAgonist
Stimulate alpha1Stimulate alpha1
-methoxamine-methoxamine
-phenylephrine-phenylephrine
Stimulate alpha2Stimulate alpha2
-clonidine-clonidine
AntagonistAntagonist
Stop NAStop NA
breakdownbreakdown
-MA inhibitors-MA inhibitors
FalseFalse
transmitterstransmitters
-methydopa-methydopa
-phenoxybenza-phenoxybenza
minemine
-phentolamine-phentolamine
-prazocin-alpha1-prazocin-alpha1
-yohimbin-alpha2-yohimbin-alpha2

28. Site of actionSite of action
4.Beta receptors4.Beta receptors
5.Domaninergic5.Domaninergic
receptorsreceptors
AgonistAgonist
-isoproterenol-isoproterenol
-dobutamine-dobutamine
-salbutamol-salbutamol
(beta2)(beta2)
DA1 – dopamineDA1 – dopamine
DA2DA2
-bromocriptine-bromocriptine
AntagonistAntagonist
-propanolol-propanolol
-metoprolol-metoprolol
-esmolol-esmolol
-Butoxamine-Butoxamine
(beta2)(beta2)
DA1 –DA1 –
metoclopramidemetoclopramide
DA2-haloperidolDA2-haloperidol

29. TESTS FOR AUTONOMICTESTS FOR AUTONOMIC
INTEGRITYINTEGRITY
Autonomic functions can be evaluated by:Autonomic functions can be evaluated by:
 HistoryHistory
 Non-invasive testsNon-invasive tests
 Invasive testsInvasive tests

30. HistoryHistory
CVSCVS (postural/orthostatic hypotension)(postural/orthostatic hypotension)
 Fainting episodesFainting episodes
 DizzinessDizziness
 HeadacheHeadache
 Diminution of visionDiminution of vision
GenitourinaryGenitourinary
 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

31. CNSCNS (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

32. 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 duringBradycardia during
phenylephrine challengephenylephrine challenge
 Absence of tachycardia withAbsence of tachycardia with
atropineatropine
Tests for sympathetic functionTests for sympathetic function
I) CARDIACI) CARDIAC
 Tachycardia during standing orTachycardia during standing or
head-up tilthead-up tilt
 Tachycardia during vasalvaTachycardia during vasalva
strain(PhaseII)strain(PhaseII)
II) PERIPHERALII) PERIPHERAL
 Blood pressure overshootBlood pressure overshoot
after vasalva releaseafter vasalva release
 BP increase with coldBP increase with cold
pressure testpressure test
 Diastolic BP rise withDiastolic BP rise with
isometric handgripisometric handgrip
 Systolic and diastolic BPSystolic and diastolic BP
response to uprightresponse to upright
positionposition

33. Respiratory sinus arrhythmiaRespiratory sinus arrhythmia
 TestsTests parasympatheticparasympathetic functionfunction
 Determines the max. to min. heart rate variation inDetermines 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 RRE : 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

34. Postural stress: Supine to standingPostural stress: Supine to standing
 Tests theTests the sympatheticsympathetic functionfunction
 Commonly performed bed-side testCommonly performed bed-side test
 Note HR and BP in supine position afterNote HR and BP in supine position after
10mins rest10mins rest
 Note changes in HR and BP after assumingNote 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/orDrop 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 isAbsence of tachycardia when standing is
abnormal (Marrey’s Law of baro receptorabnormal (Marrey’s Law of baro receptor
stimulation)stimulation)

37. Cold Pressure testCold Pressure test
 Tests theTests the peripheral sympatheticperipheral sympathetic
vasoconstrictorsvasoconstrictors
 Record BP 1min after immersing hand inRecord BP 1min after immersing hand in
ice cold waterice cold water
 Both systolic and diastolic BP shouldBoth systolic and diastolic BP should
increase by 10mm of Hgincrease by 10mm of Hg

39. Isometric Hand grip ExerciseIsometric Hand grip Exercise
 Tests theTests the efferent sympatheticefferent sympathetic functionfunction
 Sustained isometric contraction at 30% ofSustained isometric contraction at 30% of
patients max. strength should increase BP bypatients max. strength should increase BP by
10-15mm of Hg10-15mm of Hg

40. Vasalva ManouverVasalva Manouver
 Tests bothTests both sympathetic and parasympatheticsympathetic and parasympathetic functionfunction
 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 ofpiece 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

41.  HR increasesHR increases 10to15secs after initiating blowing(PhaseII) and10to15secs after initiating blowing(PhaseII) and
before release of pressurebefore release of pressure
 This implies that theThis implies that the sympathetic response is intactsympathetic response is intact
 On release of strain(PhaseIV), preload and cardiac outputOn 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, reflexBaroreceptors stimulated, reflex bradycardiabradycardia…this implies that the…this implies that the
parasympathetic system is intactparasympathetic system is intact

42.  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

43. 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 = dilation
COCAINE 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 size
HISTAMINE 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

44. 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 HR
ATROPINE TESTATROPINE TEST ––
 Give 0.8mg imGive 0.8mg im
 Normal subjects = HR increases by 20Normal subjects = HR increases by 20
beats/minbeats/min
 Sympathetic denervation = no changeSympathetic denervation = no change
NEOSTIGMINE TESTNEOSTIGMINE TEST ––
 Give 1mg imGive 1mg im
 Normal subjects = HR decreasesNormal subjects = HR decreases
 Parasympathetically denervated = no changeParasympathetically denervated = no change

45. Power Spectral Analysis of HRPower Spectral Analysis of HR
variabilityvariability
 Slower periodic oscillations in heart, can be decomposedSlower periodic oscillations in heart, can be decomposed
into a series of sine waves with diff. amplitudes andinto a series of sine waves with diff. amplitudes and
frequenciesfrequencies

46.  This frequency domain reveals aThis frequency domain reveals a consistant peakconsistant peak/ power at the breathing/ power at the breathing
frequencyfrequency 0.2 to 0.3Hz0.2 to 0.3Hz… this implies… this implies intact parasympatheticintact parasympathetic innervaton ofinnervaton of
SA nodeSA node
 There is another peak at low frequenciesThere is another peak at low frequencies 0.05 to 0.150.05 to 0.15 Hz…due to changingHz…due to changing
cardiaccardiac sympatheticsympathetic activityactivity
 This low frequency component is augmented by increased sympatheticThis low frequency component is augmented by increased sympathetic
drive eg.head up tilt, mental arithmatics and is reduced in quadriplegics duedrive eg.head up tilt, mental arithmatics and is reduced in quadriplegics due
to interrupted sympathetic pathways.to interrupted sympathetic pathways.

47. INVASIVE TESTSINVASIVE TESTS
 Done to locateDone to locate precise siteprecise site of pathologyof pathology
 Done forDone for researchresearch purposepurpose
 Intraneural recordingIntraneural recording of post-ganglionicof post-ganglionic
sympathetic activitysympathetic activity
 ElicitingEliciting axon reflexaxon reflex by intradermal injection ofby intradermal injection of
acetyl-cholineacetyl-choline
 Response of ANS to infusion ofResponse 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

48. OTHER TESTSOTHER TESTS
 Measurement of skinMeasurement of skin temperaturetemperature
 Tests forTests for sudomotorsudomotor functionfunction
 Weight of sweatWeight of sweat
 Galvanic skin resistance testGalvanic skin resistance test
 Tests forTests for lacrimallacrimal functionfunction
 Tests forTests for bladder and GITbladder and GIT dysfunctiondysfunction
 LaboratoryLaboratory teststests
 Measure plasma levels of catecholamines and other vasoactiveMeasure 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 areTo assess ANS involvement, 5 simple non-invasive tests are
sufficientsufficient
To assess definitive abnormality, 2 or more specific tests areTo assess definitive abnormality, 2 or more specific tests are
recommendedrecommended

49. ANAESTHESIA AND AUTONOMICANAESTHESIA AND AUTONOMIC
NERVOUS SYSTEMNERVOUS SYSTEM
GENERAL ANAESTHESIAGENERAL ANAESTHESIA
Pre medicationPre medication ::
 Agents used to decrease secretions likeAgents used to decrease secretions like
atropine,glycopyrolate areatropine,glycopyrolate are anti cholinergicsanti cholinergics
 Antiemetic metoclopramide is aAntiemetic metoclopramide is a dopaminergicdopaminergic
anti emeticanti emetic
 Opiods cause respiratory depression byOpiods 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

50.  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 intubationreduce stress response during intubation
 Alpha2 agonist,Alpha2 agonist, clonidine,clonidine, reduces dose of induction agent andreduces dose of induction agent and
stress response duringstress response during
Induction agents –
All induction agents except ketamine reduce sympathetic
activity
Arterial pressure drops
Baroreceptor mediated tachycardia may/may not occur
Ketamine stimulates the sympathetic system
Etomidate is a potent inhibitor of adrenergic
steroidogenesis

51. Inhalational AgentsInhalational Agents ––
 Halothane, enflurane, isoflurane reduce pre-ganglionicHalothane, enflurane, isoflurane reduce pre-ganglionic
sympathetic activity and hence decrease plasmasympathetic activity and hence decrease plasma
catecholaminescatecholamines
 Cyclopropane and diethyl ether increase sympatheticCyclopropane and diethyl ether increase sympathetic
activity by central action and by action on vasomotoractivity 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 decreasingAutonomic changes like decreasing
arterial BP,HR and plasmaarterial BP,HR and plasma
catecholamines and cortisol indicatecatecholamines and cortisol indicate
increasing depth of anaesthesiaincreasing depth of anaesthesia

52. SPINAL ANAESTHESIASPINAL ANAESTHESIA
 Causes sympathetic blockade, hypotension andCauses sympathetic blockade, hypotension and
bradycardia depending on the level of blockadebradycardia depending on the level of blockade

53. • In low SAB sacral parasympathetic and lumbar plusIn low SAB sacral parasympathetic and lumbar plus
lower thoracic sympathetics are blocked,lower thoracic sympathetics are blocked, uninhibited vagaluninhibited 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 visceraparasympathetics to thoracic and abdominal viscera
become over active and cause severe bradycardia andbecome over active and cause severe bradycardia and
even asystoleeven asystole
 InIn saddle blocksaddle block sacral parasympathetic is blocked,sacral parasympathetic is blocked,
thoracolumbar sympathetic is intact…causing minimalthoracolumbar sympathetic is intact…causing minimal
physiologic disturbancephysiologic disturbance

54. Features of Autonomic Imbalance afterFeatures of Autonomic Imbalance after
Spinal AnaesthesiaSpinal Anaesthesia
CVSCVS
 HypotensionHypotension
 BradycardiaBradycardia
GITGIT
 Increased peristalsisIncreased peristalsis
 Intestines usually activeIntestines usually active
RSRS
 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 possibletype 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

55. Autonomic reflexes duringAutonomic reflexes during
Anaesthesia and SurgeryAnaesthesia and Surgery
Oculocardiac reflexOculocardiac reflex ::
 Pressure over eyeballs or traction of externalPressure over eyeballs or traction of external
ocular musclesocular muscles
 Causes bradycardia, asystole, cardiacCauses 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 aProphylaxis with anticholinergics..still a
controversycontroversy

56. Abdominal reflexAbdominal reflex ::
 Due to stimulation of ANS by traction orDue to stimulation of ANS by traction or
pressure during surgeries within the abdominalpressure 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 reflexreflex
• Coeliac plexusCoeliac plexus reflex – traction of stomach,gallreflex – traction of stomach,gall
bladder, hilum of liver or retraction of duodenumbladder, hilum of liver or retraction of duodenum
• Brewer LuckhardtBrewer Luckhardt reflex/ Diaphragmatic tractionreflex/ Diaphragmatic traction
reflexreflex
• Reflexes associated with pelvic nerveReflexes associated with pelvic nerve

57. 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 toAfferent is via pelvic and sacral nerve to vagalvagal motormotor
nucleusnucleus
 Efferent is viaEfferent is via recurrent laryngealrecurrent laryngeal nervenerve
 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 adequateThese 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 andAsk surgeon to avoid manipulations, proceed gently and
slowlyslowly

58. ANS DYSFUNCTIONANS DYSFUNCTION
PRIMARY –PRIMARY –
 Idiopathic orthostatic hypotensionIdiopathic orthostatic hypotension
 Shy Dragger syndromeShy Dragger syndrome
FAMILIAL –
Riley Day syndrome
Leesch Neehan syndrome
•Genetic disorder of purine metabolism in
males
•Sympathetic response to stress is
enhanced
Gill Familia dysautonomia

59. SECONDARY TO SYSTEMICSECONDARY 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
 HypertensionHypertension
 TetanusTetanus
 PheochromocytomaPheochromocytoma
 Spinal cord injurySpinal cord injury
 Guillian BarreGuillian Barre
syndromesyndrome
 CarcinomatosisCarcinomatosis

60. AGINGAGING
 20% of people over 65yrs have20% of people over 65yrs have postural hypotensionpostural hypotension
 Symptoms – dizziness, faintness, loss of consciousnessSymptoms – dizziness, faintness, loss of consciousness
 Selective/Selective/ early parasympatheticearly parasympathetic involvementinvolvement
 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

61. ALCOHOLISMALCOHOLISM
 Acute, chronic or alcohol withdrawal causes orthostaticAcute, 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 ivVasalva ratio and cardiac acceleration following iv
atropine is diminished in presence of neurologicalatropine is diminished in presence of neurological
impairmentimpairment

62. TETANUSTETANUS
 Sympatho adrenalSympatho adrenal
hyperactivity is thehyperactivity is the
chief cause of deathchief cause of death
 Direct effect ofDirect effect of
tetanus toxin on SNStetanus toxin on SNS
causes rise in plasmacauses rise in plasma
catecholaminescatecholamines

63. 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

64. GUILLIAN BARREGUILLIAN BARRE
SYNDROMESYNDROME
• ANS involvementANS involvement
secondary tosecondary to axonalaxonal
degenerationdegeneration
• Variable BP, facialVariable BP, facial
flushing, urinaryflushing, urinary
retention, tachy –retention, tachy –
brady arrhythmiasbrady arrhythmias
• Neuropathic lesions inNeuropathic lesions in
afferent limb ofafferent limb of
baroreceptor may leadbaroreceptor may lead
toto SIADH,SIADH,
hyponatremiahyponatremia

65.  Neuronal degenerationNeuronal degeneration
 Metabolically related neuronalMetabolically related neuronal
dysfunctiondysfunction
 Afferent, central and efferentAfferent, central and efferent
pathways involvedpathways involved
 Vagal neuropathyVagal neuropathy occurs beforeoccurs before
systemic neuropathysystemic neuropathy
 Symptomatic posturalSymptomatic postural
hypotension implies poorhypotension implies poor
prognosisprognosis
 Esophageal gastric hypomotility,Esophageal gastric hypomotility,
bradycardia, silent myocardialbradycardia, silent myocardial
infarcts, impaired ventilatoryinfarcts, impaired ventilatory
control, unexplained cardiocontrol, unexplained cardio
respiratory arrests may occurrespiratory arrests may occur

66. AUTONOMIC CHANGES IN SPINALAUTONOMIC 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

67.  Management of Anaesthesia :Management of Anaesthesia :
• AirwayAirway managementmanagement
• Avoidance ofAvoidance of hypovolemiahypovolemia
 Anaesthesia is given so that pt. toleratesAnaesthesia is given so that pt. tolerates
tubetube
 Muscle relaxant is used as neededMuscle relaxant is used as needed

68. ANAESTHESIA IN PATIENTS WITH ANSANAESTHESIA IN PATIENTS WITH ANS
DYSFUNCTIONDYSFUNCTION
 UnderstandUnderstand the impactthe impact
Reduced ANS activity on CVSReduced ANS activity on CVS
responses to change inresponses to change in
o body positionbody position
o positive airway pressurepositive airway pressure
o acute blood lossacute blood loss
o effects due to negativeeffects due to negative
inotropic anaesthetic agentsinotropic anaesthetic agents
 PosturePosture – shift patient to OT– shift patient to OT
and induce in supine positionand induce in supine position
 PreloadingPreloading should be doneshould be done
properlyproperly
 Pre medicationPre medication ––
 Atropine may fail to produceAtropine may fail to produce
tachycardiatachycardia
 Ranitidine and metoclopramideRanitidine and metoclopramide
to avoid regurg and aspirationto avoid regurg and aspiration
 Narcotics and other respiratoryNarcotics and other respiratory
depressants are avoideddepressants are avoided
 MonitoringMonitoring ––
 Pulse oxPulse ox
 Continuous arterial BPContinuous arterial BP
 ECGECG
 CVPCVP
 TemperatureTemperature
 Urine outputUrine output

69. GENERAL ANAESTHESIAGENERAL ANAESTHESIA
 InductionInduction ––
 Thiopentone given slowly with proper iv fluidThiopentone 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 haveas patients have
gastro-paresisgastro-paresis
 Maintenance on spontaneous breathing withMaintenance on spontaneous breathing with
N2O and O2, withN2O and O2, with minimal halothaneminimal halothane
 If needed, cardio stable muscle relaxants likeIf needed, cardio stable muscle relaxants like
Vec should be usedVec should be used

70.  IPPV produces exaggerated reduction inIPPV produces exaggerated reduction in
BPBP
 Blood loss should be replaced promptly asBlood loss should be replaced promptly as
compensatory tachycardia is absentcompensatory tachycardia is absent
 Volatile anaesthetics produce excessiveVolatile anaesthetics produce excessive
myocardial depression and hypotensionmyocardial depression and hypotension
 Maintain fluid balanceMaintain fluid balance
 Avoid hypothermiaAvoid hypothermia (pts may become(pts may become
poikilothermic due to sympatheticpoikilothermic due to sympathetic
dysfunction)dysfunction)
 Vasopressors should be used with cautionVasopressors should be used with caution

71. REGIONAL ANAESTHESIAREGIONAL ANAESTHESIA
 Risk of hypotension with SAB andRisk of hypotension with SAB and
epiduralsepidurals
 Post spinal urinary retention may occurPost spinal urinary retention may occur
 Pre opPre op presence ofpresence of impotenceimpotence must bemust be
brought to notice to avoidbrought to notice to avoid medico legalmedico legal
implicationsimplications

72. ANS IN INTENSIVE CAREANS IN INTENSIVE CARE
 Mechanical IPPVMechanical IPPV causes increased intra thoraciccauses 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 fallsAll reflex mechanisms fail hence cardiac output falls
drasticallydrastically
 Suction careSuction care

73. ANS IN CHRONIC PAINANS IN CHRONIC PAIN

74. LUMBAR SYMPATHETIC BLOCKLUMBAR SYMPATHETIC BLOCK
 Used to alleviate theUsed to alleviate the rest pain of chronic PVDrest pain of chronic PVD
 Preganglionic sympathetics are from lowerPreganglionic sympathetics are from lower
thoracic chain and pre ganglionic somatic fibresthoracic chain and pre ganglionic somatic fibres
are from 1are from 1stst
and 2and 2ndnd
lumbar nerveslumbar nerves
 Post ganglionic fibres are vasoconstrictor toPost ganglionic fibres are vasoconstrictor to
arterioles, pilomotor and sudomotor to skinarterioles, pilomotor and sudomotor to skin
 Hence, its block causes absence of sweatingHence, its block causes absence of sweating
and warm dry skinand warm dry skin

75. COELIAC PLEXUS BLOCKCOELIAC PLEXUS BLOCK
 Used for intractable pain caused byUsed for intractable pain caused by
cancer of pancreas, stomach, gall bladdercancer of pancreas, stomach, gall bladder
and liverand liver
SUPERIOR HYPOGASTRIC PLEXUSSUPERIOR HYPOGASTRIC PLEXUS
BLOCKBLOCK
 Relates pain from pelvic organsRelates pain from pelvic organs
 Used in cancer pain due toUsed in cancer pain due to
cervical,prostate,testicular cancers and incervical,prostate,testicular cancers and in
radiation injuryradiation injury

76. COMPLEX REGIONAL PAIN SYNDROMECOMPLEX REGIONAL PAIN SYNDROME
 Consequence of limb trauma with orConsequence of limb trauma with or
without obvious nerve lesionswithout obvious nerve lesions
 Characterised by motor, sensory and ANSCharacterised by motor, sensory and ANS
symptomssymptoms
 ANS features include abnormal skin bloodANS features include abnormal skin blood
flow, temperature and sweatingflow, temperature and sweating
PHANTOM LIMBPHANTOM LIMB
Ectopic discharge ofEctopic discharge of epinephrine from a stump neuromaepinephrine from a stump neuroma isis
an important peripheral mechanisman important peripheral mechanism
Sympathetic block, sympathectomies or beta blockersSympathetic block, sympathectomies or beta blockers
increase blood flow and reduce intensity of burning painincrease blood flow and reduce intensity of burning pain
Decreased blood flow causes phantom limb painDecreased blood flow causes phantom limb pain

77. CONCLUSIONCONCLUSION
 ANS plays a very dominant role in maintainingANS plays a very dominant role in maintaining
haemodynamic stabilityhaemodynamic stability
 Influences the outcome after anaesthesia and surgeryInfluences the outcome after anaesthesia and surgery

78. THANKTHANK
YOU…YOU…
THANKTHANK
YOU…YOU…