INTODUCTION TO ANAESTHESIA

1. Anasthessia
Dr. Lamture Y.R.
Department of surgery
Datta Meghe medical college Nagpur

2. 2
Learning objectives’
• Types of Local Anesthesia
• Drugs used in Local Anaesthesia
• General Anesthesia & drugs for
GA
• Muscle Relaxants
• Stages of GA
• Spinal Anesthesia
• Comparision of LA & GA

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• Local Anesthesia –
• Reversible depression of nerve impulse
conduction
• So temporary loss of sensation & relief of pain

4. 4
Equipments for Anesthesia
• 1) Laryngoscope 2) Endo Tracheal Tube (ETT)
• 3) Ambubag 4) Boyle’s apparatus
• 5) Pulse oximeter 6) Cardiac monitor
• 7) B. P. Instrument 8) Stethoscope
• 9) Spinal Needle 10) Tray of Emergency drug
• 11) Suction catheter 12) O2 cylinder

5. Anaesthetic machine
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Pre Anesthesia
• Physical fitness must
• Control of DM & BP
• Oral hygiene ( there should not be Pyorrhoea
like septic focus , loose or artificial denture )
• Nutritional & hydration should be normal
• Base line Lab reports should be normal like Hb,
Bl sugar ,KFT,LFT, & ECG
• Systemic Examination findings – Normal

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Grades of Patient by ASA
• ASA = Americal Society of Anesthesiologist
• Grade 1=No abnormality
• Grade 2= Mild systemic disorders
• Grade 3 = Severe systemic disease
• Grade 4 = Life threatening severe systemic
disease
• Grade 5 = Highest risk
• Grade 6 = Dead

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Anesthesia - Premedication
• Tab Calmpose – 1 hs ,previous night of
operation ( As a Tranquiliser)
• Inj Calmpose – at the time of surgery
• Inj Atropine – 0.6 mg IM ( reduces secretions)

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Types Local Anesthesia
• 1) Infiltration Anesthesia
• 2) Field Block
• 3) Nerve Block
• 4) Surface Anesthesia

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1) Infiltration Anaesthesia
• Local anesthetic drug is injected into the area
which is to be incised in a circular manner
• Used in - Excision of lipoma, polyp, dermal
cyst, etc.

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1) Infiltration Anaesthesia
• Anesthetic is infiltrated into the tissues to be
operated upon
•
• Suitable for small skin lesions ,for suturing
small lacerations
• Xylocaine with adrenaline is used .But if
longer duration of action is required
Bupivacaine is used

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1) Infiltration Anaesthesia
• In case of lacerated wound ,the injection may
be given from inside the margin of wound
• In palms ,soles ,nose ,infiltration is difficult (
because skin is tightly bound down)
• For infiltrating dome of an abscess ,a small
quantity is given by insulin syringe ,very
superficially

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2) Field Block
• Zone of analgesia is created around the
operative field by injecting local Anesthetic
• Used in Minor surgery ( when unconsciousness
with GA can be fatal )

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3)Nerve Block
• Local anesthetic drug is injected near the
nerve ,which is supplying operated area
• Used as Brachial block, Finger (ring) block,
Intercostal nerve block etc.

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Regional Anesthesia
• Particular area is anesthetized by a field or
nerve block
• For removal of a sebaceous cyst on the back
,field block can be used ( Local aneasthetic is
infiltrated on the skin of back in the area
,encircling the cyst )

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Regional Anesthesia
• In Nerve block ,the anaestheic drug is
deposited near the nerve
• Flooding technique – As there are anatomical
variations in localization of nerves ,large
volume of Anaesthetic drug is given in wider
area
• Injection should never be given in nerves (
recognized by the occurance of paraesthesia
during infiltration )

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Examples of Nerve blocks
• 1) Supraorbital Nerve block – To anesthetize skin of
forehead
• 2) Digital Nerve block – without adrenaline.By
blocking dorsal digital nerve ,whole finger can be
anaesthetized
• 3) Median Nerve block – This nerve lies behind
palmaris longus tendon at the wrist .This will
anaesthetize thumb,index,middle & half of ring finger
& corresponding of area of palm –dorsal & palmer
aspect

18. Local Anesthesia
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Examples of Nerve blocks
• 4) Ulnar nerve block -- This will block little
finger & medial half of ring finger .A combined
median & ulnar block will anaesthetise the
whole hand
• 5) Posterior Tibial nerve block – Xylocaine is
injected ,just anterior to Achilles tendon at the
level of medial malleolus .Used in cases of
injuries on plantar aspect of foot

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Examples of Nerve blocks
• 6) Calcaneal Nerve block – 5 ml Xylocaine is
injected as a band into the skin below the level
of medial malleolus .Skin of heel is
anaesthetized .
• Useful for removal of corn ,For suturing
laceration in Plantar skin .Useful for giving
steroid injection to a patient of Plantar fasciitis

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Examples of Nerve blocks
• 7) Ankle block – This will anesthetize whole
foot .Rarely used
• 8) Penile block – Never use Xylocaine with
adrenaline .Use plain Xylocaine .Complete ring
block is not required ,because nerve enters
only along dorsal aspect .Useful for
circumcision & for correcting paraphimosis

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4) Surface Anaesthesia
• Local anesthetic agents is used in the form of
spray, ointment, cream & jelly, lotion to
anesthetized surface skin
• Used in Catheterization, Cystoscopy,
Insertion of Ryle’s tube, etc.

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4) Surface Anaesthesia
• Anesthesia is obtained by application of local
anaestheic drug to the surface of skin or
mucous membrane
• EMLA skin cream ( Lignocaine + prilocaine)
• With this cream anaethesia is produced after 1
hour ,after thick application
• Mucous membrane can easily anaesthetised
by eye or ear drops ,throat lozenges,rectal
jelly

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5) Spinal & Epidural Anesthesia
• Both are Types of Local Anesthesia

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Advantages of LA
• 1) Simple & easy to administer
• 2) Body metabolism is not disturbed .So
special attention is not required
• 3) Less bleeding
• 4) Cheap
• Note – In spite of these advantages some
patients prefer GA ,due to fear of remain
conscious during operation

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Examples of Medicines for LA
Sr.No Specialty of Drug Drug
1 Low potency + short acting Procaine
2 Moderate Potency +
moderate duration
Lignocaine
( Xylocaine)
3 High Potency + Long
duration
Bupivacaine,
Marcaine

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Local Anesthetic drugs
• Commonly used drugs – Lignocaine –either
plain or with adrenaline ,Bupivaine ,
Procaine, Amethocaine
• Procaine ( Novocaine ) & Amethocaine (
Tetracaine) – Less potent & give frequently
Hypersensitive reactions

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Lignocaine ( Xylocaine)
• Most commonly used
• Stable & can be stored at room temperature
• Onset of action is rapid & duration of action ranges
from 30 to 60 min ( depending on local vascularity &
site)
• Addition of Adrenaline ( 1 in 2 Lakhs) – prolongs
action up to 2 hours
• Available as 2 % solution with or with out adrenaline

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Adrenaline
• Usually combined with Lignocaine
.Adavantages are –
• Adrenaline is local vasoconstrictor .So less
amount of Lignocaine is absorbed by which it
remains in tissue longer & we get prolonged
local anaesthetic effect
• Combination is useful in highly vascular areas
like face & scalp .It gives dry operative field
within 10 min

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Adrenaline
• Although there are advantages ,there is risk as well –
• Due to effect of local vaso constriction ,if it is used
around end arteries ( around digit or penis) ,it will
cause gangrene
• So Lignocaine with adrenaline should be avoided at
digits,tip of nose,pinna of ear,shaft of penis
• Plain & lignocaine with adrenaline are available in
different colour bottles

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Reaction to Lignocaine
• Anaphylactic is possible but rare
• Reactions occur due to use of large doses or large
amount enters into systemic circulation
• Aspirate ,before injecting locally .Needle should be
kept constantly moving forward & backward ( so
even if needle enters into blood vessel ,small amount
enters in circulation)
• Lignocaine poisoning – Hypotension, Bradycardia,
Heart block

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Bupivacaine ( Marcaine)
• More prolonged action
• 4 times more potent than Xylocaine
• So popular for spinal anaesthesia & painless
labour
• No benefit in minor surgeries of GP level

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For LA
• Enquire about history of allergy to anaesthetic
drug
• Do not exceed Toxic dose
• Be carful in patients with heart & liver disease
• Select proper site for nerve block
• Avoid accidental IV injection
• Keep watch on bradycardia & twitching on
face ( These are early signs of Toxicity)

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Lignocaine
• Used for –
• Nerve block & Infiltration 0.5 to 2 %
• Ointment 2 %
• Eye drops 4%
• Spinal Anesthesia 5%
• Dose – 5 mg / kg

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Lignocaine – Caution
• Lignocaine with adrenaline should never used
,where end arteries are present
• Tip of fingers
• Lips & Ear
• Penis
• Otherwise – Vasoconstriction effect – Necrosis
• Lignocaine with adrenaline is contraindicated in
MI & HT
• Dose of Lignocaine with adrenaline –
• 5 to 7 mg /kg --- Max 300 mg

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Bupivacaine
• Basically this is long acting Anesthesia ,but can
be used for LA
• Max dose = 150 mg
• Duration = 4 to 6 hours

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LA – Disadvantages
• Allergic reaction – From minor to serious like
Anaphylactic shock
• Nerve or vessel injury
• Lignocaine can not act in the acidic condition
of pus

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GA
• Reversible loss of sensations & consciousness
• Clinical features – Loss of sensations ,muscle
relaxation, diminished reflexes,
unconsciousness
• Types – 1) Inhalation of Nitrous oxide ,Ether 2)
Intravenous – Thiopentone sodium ,ketamine

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GA
• Techniques – Open drop method or Nitrous
oxide through Boyle’s apparatus
• Complications – Hypotension, Respiratory
depression, Nausea & vomiting, Hepato or
renal Toxicity

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Drugs for GA – Nitrous oxide
• Laughing gas ,Non irritating ,better smelling
,safest, administered with oxygen ,Post OP
complications less
• Disadvantages are BP may increase ,
Teratogenic effect

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Drugs for GA – Ether
• Colourless volatile liquid
• Muscle relaxation is good so used in all
abdominal surgeries ,safe
• Disadvantages are as vapours are highly
irritative to URT,causes Nausea & vomiting
,increases secretions of all glands

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Drugs for GA – Thiopentone sodium
• Ultra short acting for minor surgeries
• Non irritant to lungs .Less nausea & vomiting
,Muscle relaxation is rapid
• Disadvantages are shock may occur due to fall
in BP ,respiratory depression,recovery period
is long
• Dose – 5mg/kg ,IV

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Drugs for GA – Ketamine
• Called as ‘Dissociative Anesthesia’
• Good for repeated use
• Respiration not depressed
• Used while dressings of burn ,Incision &
Drainage
• Contraindicated in IHD (HR,BP –Elevated)
• 2mg/kg IV & 10mg/kg IM

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Muscle relaxants
• During abdominal surgeries or in fracture
reduction process ,in addition to Anesthetic
drugs muscle relaxants are also used
• Scoline – 50 to 70 mg –action for 5 min
• Flaxedil – 80 to 120 mg – action for 30 min
• Curare – 15 to 18 mg IV –action for 45 min
• Pavulon – 6 mg – action for 60 min
• Neostigmine – Antidote for Curare

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Stages of Anesthesia
• 1) Stage of Analgesia
• 2) Stage of Excitement
• 3) Stage of surgical Anesthesia
• 4) Stage of respiratory paralysis

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Stages of Anesthesia
• I) Stage of Analgesia ---
• Stage is from giving of Anesthetic drugs up to
loss of consciousness
• In this stage pain is diminished
• Respiration & reflexes are normal
• Used for minor operations like labour & for
Incision & Drainage

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Stages of Anesthesia
• II) Stage of Excitement
• This stage is from loss of consciousness to
regular respiration
• Patient gets excited , involuntary movements
occur , pupils are dilated, blood pressure and
heart rate increases

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Stages of Anesthesia
• III) Stage Of Surgical Anesthesia
• In this stage there will be shift of respiration
from regular to irregular
• BP goes down ,Muscle tone decreases

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3 – Stage of Surgical Anesthesia
• This stage is divided into 4 planes
• 1) Roving eye balls
• 2) Loss of Corneal & laryngeal reflexes
• 3) Pupils starts dilating & light reflex loss
• 4) Intercostal paralysis, shallow abdominal
respiration

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Stages of Anesthesia
• IV) Stage Of Respiratory Paralysis
• Irregular respiration
• BP drops down
• Pupils fully dilate
• Finally patient may die if situation is not
treated properly

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Complications of Anesthesia
• Airway obstruction, Bronchospasm,
Respiratory failure
• Hypertension or hypotension, Arrhythmias,
Cardiac arrest
• Drowsiness, Nausea & vomiting, Renal failure,
Hepatic failure

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Epidural Anesthesia
• Type of local anesthesia
• Direct block of spinal nerve roots in epidural
space leading to centrifugal spread ,which
affects the nerve in block
• It can be done with the patient in the lateral
decubitus position.

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Epidural Anesthesia
• Epidural needle does not have sharp tip, so chance of
puncture in dura matter is very rare.
• In epidural anesthesia 16 to 18 number touhy
needle is used
• Needle is passed through the midline or para median
• Needle passes structure as similar to spinal
anesthesia except penetration into sub-arachnoid
space

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Spinal Anesthesia
• Also called as saddle block or saddle
anesthesia
• Local anesthetic drugs is injected around
spinal cord to block transmission of neural
impulses
• When drugs are injected in sub arachnoid
space it is called as Spinal Anesthesia.

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Spinal Anesthesia
• After injecting anesthetic drug in subarachnoid space
patient is given sitting position on table for 10 min.
Then it is known as Saddle Block or Saddle
Anesthesia.
• In sitting position CSF has more than 375 mm of Hg
pressure & in supine position CSF has 180 mm of Hg
pressure.
• So that drug does not go upward but spreads mostly
in lower limb .Hence more effect of drug can be seen
in lower abdomen

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Spinal Anesthesia
• Types –
• 1) Low spinal Anesthesia
• 2) Mid spinal Anesthesia
• 3) High Spinal Anesthesia
• Advantages
• Adequate relaxation with retention of
consciousness + No irritation of lungs
• Operative haemorrhage is less due to fall of Blood
pressure

57. Spinal Anesthesia
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Spinal Anesthesia – Used in --
• Prostectomy, LSCS, Hysterectomy
• Hemorrhoidectomy & Fistulectomy
• Lower limb fractures
• Urological, gynaecological, lower limb, &
below umbilical operations
• If patient is unfit for GA due to respiratory
diseases ,liver & kidney diseases , diabetes

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Spinal Anesthesia can not be used
• Severe Anaemia
• Shock
• Hypoxia
• Nerological diseases
• Patient of migraine or chronic headache

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Drugs for Spinal Anesthesia
• 1) Lignocaine
• Dose - 15 to 100 mg Duration – 1 to one &
half hour
• 2) Bupivacaine
• Dose - 25 to 50 mg Duration – up to 3 hours

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Drugs for Spinal Anesthesia
• 3) Tetracaine
• Dose - 5 to 25 mg , Duration – up to 2 & half
hour
• 4) Cinchocaine (Nupercaine) / Dibucaine
• Dose - 2.5 to 10 mg , Duration – Up to 3 hours

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Spinal Anesthesia Procedure
• In sitting position or in left lateral position.
• In lying position ,back is kept parallel to edge
of table.
• In sitting position Leg should be flexed with
back bent forward & advised to rest his arm
on his shoulder.
• The back is cleaned with savlon, iodine &
spirit, under strict aseptic precautions.

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Spinal Anesthesia Procedure
• L3, L4 intervertebral space or L4 & L5 space is
commonly used.
• Lumbar puncture needle 25 to 27 G is inserted
in midline between intervertebral space
perpendicular to skin.

64. Spinal Anesthesia Procedure
Sitting position Lying down position
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Spinal needle passes through
• 1) Skin
• 2) Subcutaneous tissue
• 3) Supra spinal ligament
• 4) Inter spinal ligament
• 5) Ligamentum Flaveum
• 6) Epidural space
• 7) Dura matter
• 8) Sub arachnoid space

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Spinal needle
• How to confirm of correct insertion of spinal
needle in subarachnoid space ?
• Free resistant to hand & continuous CSF free
flow

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Complications of Spinal
Anesthesia
• 1) Hypotension due to vasodilation
• 2) Septic meningitis
• 3) Backache
• 4) Retention of urine
• 5) Headache

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Difference in LA & GA
• 1) Site of action in LA is peripheral nerve but
in in GA it is CNS
• 2)LA gives anesthesia to restricted area & GA
gives to whole body
• 3) Patient remains conscious in LA but not in
GA
• 4) LA is for minor procedures but GA is for
major operations

69. References.
1. Bailey & Love’s Short Practise of surgery 25th edition.
2. ACS Surgery: Principles & Practice, 2007 Edition
3. Heffner, Hess.Clinics in Chest Medicine 22 , 2001.
4. Cummings: Otolaryngology: Head & Neck Surgery, 4th ed.2005
5. SCHWARTZ'S PRINCIPLES OF SURGERY 2-volume set 11th edi.19
May 2019
21 October 202069

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