detail description of anaesthesia......

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SYLLABUS POINT : SANGYAHARAN / ANAESTHESIA: DEFINITION & TYPES.
ANAESTHESIA
DEFINITION
 Anaesthesia or anaesthesia is a state of temporary induced loss of sensation or awareness.
 A patient under the effects of anesthetic drugs is referred to as being Anesthetized.
 Anaesthesia enables the painless performance of medical procedures that would cause
severe or intolerable pain to an unanesthetized patient.
TYPES
1. General Anaesthesia
2. Local Anaesthesia
3. Regional Anaesthesia
PROPERTIES OF AN IDEAL ANAESTHETIC
1. For the patient
 It should be pleasant, nonirritating, should not cause nausea or vomiting. Induction
and recovery should be fast with no after effects.
2. For the surgeon
 It should provide adequate analgesia, immobility and muscle relaxation. It should be
noninflammable and nonexplosive so that cautery may be used.
3. For the anaesthetist
 Its administration should be easy, controllable and versatile.
4. Margin of safety should be wide—no fall in BP.
5. Heart, liver and other organs should not be affected.
6. It should be potent so that low concentrations are needed and oxygenation of the patient
does not suffer.
7. Rapid adjustments in depth of anaesthesia should be possible.
8. It should be cheap, stable and easily stored.
9. It should not react with rubber tubing or soda lime.
PREOPERATIVE ASSESSMENT
A patient posted for surgery is examined at least one day before of surgery.
If patient has any associated disease. which need to be control first as Diabetes melitis &
Hypertension
 HISTORY
1. Chronic Cough, Smoking, Alcohol, Drug Intake, Drug Allergy.
2. Any previous diseases like Hypertension, Diabetes Mellitus, Epilepsy, Bronchial Asthma,
Tuberculosis, Hepatitis, Cardiac Diseases.
3. Drug therapy: Steroids, Antihypertensives, Sedatives, Antibiotics, Antiepileptics.
 EXAMINATION
1. GENERAL
i. Posture
ii. Teeth
iii. Mouth Openiing
iv. Dilated Veins
v. Neck Movements
vi. Tremor
vii. Airway
viii. Anaemia
ix. Oedema
x. Jaundice
xi. Cyanosis.
2. SYSTEMIC EXAMINATION

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SYSTEM EXAMINATION
1. Respiratory System Asthma, Tuberculosis, Emphysema, COPD
2. Airway Mouth opening, Temporomandibular Joint Assessment
3. CVS HTN, IHD, Arrhythmias, Cardiac Failure, Valvular Diseases
4. Spine Curvature, Intervertebral Space, Skin over the area for any infn
.
5. Other Systems Abdomen, Skeletal System
PREOPERATIVE INVESTIGATIONS
1. Haematocrit
2. Blood Sugar
3. Blood Urea
4. Serum Creatinine
5. Electrolytes
6. Chest X-Ray
7. Blood-Gas Analysis
8. Cardiac Assessment
9. Renal Function Tests
10.Liver Function Tests
11.ECG
PRE OPERATIVE PREPARATION
1. Establish a good conversation with patient.
2. Collect History of patient with examination.
3. Informed written consent should be taken.
4. If significant disease is present, then first it is brought under controlled.
5. Strictly NBM before 4 hrs of surgery.
6. Control of respiratory and cardiac diseases.
7. Improvement of Hb% status, if anaemia is present.
8. Preoperative antibiotics are given.
9. Blood should be kept ready for major cases.
10.Starvation for 4 hours for liquids and 6 hours for solids.
11.Bladder and bowel should be emptied to prevent soiling on the operation table.
12.Urinary catheter may be passed and enema may
13.Dentures, contact lenses, jewellery must be removed.
14.Surgical area should be cleaned and properly prepared.
PREOPERATIVE MEDICATIONS
CAUSE DRUGS USED DOSE
To reduce Sedation and Anxiety Pethidine
Morphine & Diazepam
50 mg
10 mg
To reduce Vomiting Promethazine 12.5 mg
To reduce Secretion Inj. Atropine 0.6 mg
Blood Loss Blood Transfusion If Needed
PHYSICAL EXAMINATION
1. Oral Hygiene
2. Examination of loose & artificial
teeth
3. Nutritional & Hydration Status
4. Body Built
5. Pallor
6. Clubbing & Cyanosis
7. BP
8. Heart Sounds
9. Peripheral Pulsation
EQUIPMENTS FOR ANAESTHESIA
1. Laryngeal scope
2. Endo Tracheal Tube (ETT)
3. Oropharyngeal airway
4. Nasopharyngeal airway
5. Ambubag
6. Boyle’s apparatus
7. Pulse oximeter
8. Cardiac monitor

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9. B. P. Instrument
10.Stethoscope
11.Spinal Needle
12.Emergency drug Tray
13.Suction catheter
14.Source of 02
CLASSIFICATION
(ACC. TO AMERICAN SOCIETY OF ANESTHESIOLOGISTS (ASA) )
GRADE FEATURE
ASA I  No abnormality
ASA II  Mild systemic disorders
ASA III  Moderate systemic disease with normal activity
ASA IV  Severe systemic disease that is threatening to the life of the patient
ASA V  Moribunt- not expected to survive 24 hrs with or without operation.
 Patient is dead posted for organ donation.
I. LOCAL ANAESTHESIA – DRUGS, TECHNIQUES, INDICATIONS,
CONTRAINDICATIONS, COMPLICATIONS AND THEIR MANAGEMENT.
DEFINITION
 LA is defined as reversible depression of nerve impulse conduction leading to temporary
loss of sensation and relief of pain because of disturbed nerve conductivity.
 Local anaesthesia is any technique to induce the absence of sensation in a specific part of
the body, generally for the aim of inducing local analgesia, that is, local insensitivity
to pain, although other local senses may be affected as well.
 Local anaesthesia is anaesthesia of a small part of the body such as a tooth or an area of
skin.
 A local anaesthetic is a medication that causes reversible absence of pain sensation,
although other senses are often affected, as well.
 It blocks both conduction and generation of impulse.
CLASSIFICATION :
1. Injectable Anaesthetics
A. Low Potency, Short Duration
Procaine Chloroprocaine
B. Intermediate Potency And Duration
Lidocaine (Lignocaine) Prilocaine
C. High Potency, Long Duration
Tetracaine (Amethocaine)
Bupivacaine
Ropivacaine
Dibucaine (Cinchocaine )
2. Surface Anaesthetics
A. Soluble
Cocaine
Lidocaine
Tetracaine
Benoxinate
B. Insoluble
Benzocaine
Oxethazaine
Butylaminobenzoate
TECHNIQUES & USES

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1. SURFACE ANAESTHESIA / TOPICAL ANAESTHESIA
 Skin is anaesthetized by local anaesthetic agents used as spray, ointment, cream, jelly
and lotion.
2. INFILTRATION ANAESTHESIA
 Injection of local anesthetic drug into area which is to be incised in a circular manner.
 Infiltration is used for minor operations, e.g. incisions, excisions, hydrocele,
herniorrhaphy, etc. when the area to be anaesthetised is small.
3. FIELD BLOCK
It is produced by injecting the LA subcutaneously which blocks entire field of
excisionwhere disease is located.
4. NERVE BLOCK
It is produced by injecting the LA around the appropriate nerve trunks or plexuses.
Frequently performed nerve blocks are—lingual, intercostal, ulnar, sciatic,
femoral, brachial plexus, trigeminal, facial, phrenic, etc.—used for tooth
extraction, operations on eye, limbs, abdominal wall, fracture setting, trauma to
ribs, neuralgias, persistent hiccup, etc.
The primary purpose of nerve block anaesthesia is to abolish pain and other
sensations.
TECHNIQUE
Supraclavicular approach is commonly used
Needle is passed downwards, backwards and medially towards first rib, 1cm
above midpoint of clavicle
Once needle hits the first rib, 15-20 ml of 1.5% xylocaine is injected .

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5. INTRAVENOUS LOCAL ANAESTHESIA ( BIER’S BLOCK )
TECHNIQUE
 Limb is exsanguinated & occluded with tourniquet with pressure 30mmhg more than
systolic pressure of the patient.
 Needle is placed in the selected vein.
 Xylocaine – 40 ml of 0.5% for upper limb
80ml of 0.25% for lower limb
 Side effects: Hypotension, Convulsions, Death
6. SPINAL ANAESTHESIA
 Spinal anaesthesia is also known as saddle block/saddle anaesthesia .
 It is the injection of LA into the subarachnoid space between L2–3 or L3–4 i.e. below
the lower end of spinal cord, causing loss of sympathetic tone, sensation and motor
function.
 Spinal anaesthesia is used for operations on the lower limbs, pelvis, lower abdomen, e.g.
prostatectomy, fracture setting, obstetric procedures, caesarean section, etc
 When they are injected in sub arachnoid space it is called as Spinal Anaesthesia.
 Saddle Anaesthesia means after injecting anesthetic drug in subarachnoid space patient
gives sitting position on table for 10 min. Then it is known as Saddle Block or Saddle
Anaesthesia.
TYPES
TYPE INJ. LEVEL
1. Caudal Anaesthesia  Upto L5
2. Low Spinal Anaesthesia  Upto L1
3. Mid Spinal Anaesthesia  Upto T10
4. High Spinal Anaesthesia  Upto T6
5. Unilateral Spinal Anaesthesia
USEFUL DRUGS IN SPINAL ANAESTHESIA
ADVANTAGES
1. Profound relaxation.
2. Retention of consciousness.
3. No irritation of lungs
4. Operative hemorrhage less due to fall of Blood Pressure
5. Economical
DISADVANTAGES

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1. Technical difficulties by unexpert.
2. CSF leak
INDICATIONS
1. Provide excellent muscle relaxation
2. Prostectomy
3. LSCS
4. Hysterectomy and Hemorrhoidectomy
5. Fistulectomy
6. Lower limb fractures,
7. Urological, gynaecological, lower limb, & below umbilical operations.
8. Respiratory diseases.
9. Suffering from liver & kidney diseases as well as diabetes.
CONTRAINDICATIONS
1. Without patient’s will
2. Shock
3. Hypoxia
4. Severe anemia
5. Dehydration
6. Active neurological disease
7. Infection
8. Hypotension and hypovolemia.
9. Uncooperative or mentally ill patients.
10.Infants and children—control of level is difficult.
11.Bleeding diathesis.
12.Raised intracranial pressure.
13.Vertebral abnormalities e.g. kyphosis, lordosis, etc.
14.Sepsis at injection site.
PROCEDURE OF SPINAL ANAESTHESIA
1. Spinal Anaesthesia may be administrated to patient in sitting position or in right & left
lateral position.
2. The patient lies either in left or right lateral position & back is kept parallel to edge of
table.
3. Leg should be flexed while in sitting position patient sits on table with back bent forward
& advised to rest his arm on his shoulde.
4. The back is cleaned with savlon, iodine & spirit, under strict aseptic precautions.
5. Vertebral spines are identified from highest point of iliac crest L3, L4. intervertebral
space L 4 & L5 space commonly used.
6. In uncooperative patients, wheel of local anesthetic drug is injected at the site of spinal
anaesthesia.
7. Lumbar puncture needle 25 to 27 G is inserted in midline. between intervertebral space
perpendiculars to skin.
8. Spinal needle passes following structures. .
i. Skin
ii. Subcutaneous tissue
iii. Supra spinal ligament
iv. Inter spinal ligament
v. Ligamentum Flaveum
vi. Epidural space
vii. Dura. matter
viii. Sub arachnoid space

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9. Correct position of tip of needle is identified by:-
a. Free resistant to hand
b. Continuous CSF free flow
10.After making confirmation tip of needle is in subarachnoid space. Drug is then injected
slowly as per requirement.
COMPLICATIONS OF SPINAL ANAESTHESIA
1. Hypotension due to vasodilation
2. Septic meningitis
3. Paraplegia
4. Backachce
5. Cauda equina syndrome
6. Infection.
7. Retention of urine
8. Intravertebral disc injury
9. Headache
10.Respiratory depression
CAUDAL ANAESTHESIA
 It is the sacral component of spidural space and access is through the sacral hiatus.
PROCEDURE
1. It is given in lateral position.
2. Needle is inserted through the sacral hiatus to enter the caudal epidural space.
3. Drug is then injected into the space.
INDICATIONS
1. Haemorrhoidal surgery
2. Circumcision
3. Small procedures in perineum like cystoscopy.
COMPLICATIONS
1. Trauma to the anal canal
2. Intravascular injection
7. EPIDURAL ANAESTHESIA
 Epidural anaesthesia is a type of local anaesthesia.
 It isa direct block of spinal nerve roots in epidural space leading to centrifugal spread
which affects the nerve in block known as epidural anaesthesia.
TECHNIQUE
1. It can be done with the patient in the lateral decubitus position.
2. Epidural needle does not have sharp tip, so chance of puncture in dura matter is very
rare.
3. In epidural anaesthesia 16 to 17 touhy needle is used. Needle is passed through the
midline or para medium. Needle passes structure as similar to spinal anaesthesia except
penetration into sub-arachnoid space.
ADVANTAGES OF EPIDURAL ANAESTHESIA
1. It can be used for continuous repeated prolonged anaesthesia.

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2. It can be used for postoperative analgesia.
3. It can be kept for several days.
ADVANTAGES OF LOCAL ANAESTHESIA
1. Technically simpler.
2. GA is avoided.
3. Consciousness is retained.
4. Pt. can have food earlier after surgery.
COMPLICATIONS OF LOCAL ANAESTHESIA
1. CNS effects are -
i. Light-Headedness
ii. Dizziness
iii. Auditory And Visual
Disturbances
iv. Mental Confusion
v. Disorientation
vi. Shivering
vii. Twitching
viii. Involuntary Movements
ix. Finally Convulsions
x. Respiratory Arrest.
These can be prevented and treated by diazepam.
2. Cardiovascular toxicity of LAs –
i. Bradycardia
ii. Hypotension
iii. Cardiac Arrhythmias
iv. Vascular Collapse
3. Injection of LAs may be painful.
4. Delayed wound healing .
5. Hypersensitivity reactions-
i. Rashes
ii. Angioedema
iii. Dermatitis
iv. Contact Sensitization
v. Asthma
vi. Rarely Anaphylaxis Occur.
CONTRAINDICATION TO LOCAL ANAESTHESIA
Absolute Contraindications
1. History of Allergy to Local Anesthetic Agents
2. Local anesthetic agents belonging to the same chemical group should not be used.
3. Documented Allergy to Other Constituents of the solution.
4. History of allergy to any of the constituents of the local anesthetic solution.
Relative Contraindications
1. Fear and apprehension
2. Presence of acute inflammation or Suppurative infection at the site of insertion of the
needle.
3. Infants or small children
4. Mentally retarded patients
5. Restricted mouth opening
6. Patients with Medical disease-
i. Cardiovascular Disease
ii. Hepatic Dysfunction
iii. Renal Dysfunction
iv. Clinical Hyperthyroidism
DIFFERENCE BETWEEN SPINAL AND EPIDURAL ANAESTHESIA

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SPINAL ANAESTHESIA EPIDURAL ANAESTHESIA
1. Onset of blockage is fast ( 1 min.).
2. Only lumbar puncture.
3. Duration limited.
4. Needle used : 23-25 no.
5. Less chance of CSF contamination.
6. Small dose inj.
7. Headache absent.
8. Backache more persistant.
9. Less severe hypotension.
10.Faulty anaesthesia.
1. Onset of blockage is slow ( 2 min.).
2. Lumbar, sacral, thoracic, cervical puncture.
3. Duration prolonged.
4. Needle used : 16-17 no.
5. More chance of CSF contamination.
6. Large dose inj.
7. Headache present.
8. Backache present.
9. More severe hypotension.
10.Excellent anaesthesia.
I. REGIONAL AND GENERAL ANAESTHESIA – DRUGS, TECHNIQUES,
INDICATIONS, CONTRAINDICATIONS, COMPLICATIONS AND THEIR
MANAGEMENT.
REGIONAL ANAESTHESIA
DEFINITION
 Regional anaesthesia is the use of local anesthetics to block sensations of pain from a large
area of the body, such as an arm or leg or the abdomen by using local anaesthetic agent.
 Regional anaesthesia allows a procedure to be done on a region of the body without your
being unconscious.
 For regional anaesthesia, the anesthetic is injected close to a nerve, a bundle of nerves, or the
spinal cord.
DRUGS
USES
Regional anaesthesia is most often used when the procedure:
Is confined to a specific region of the body.

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Involves a large area of the body where injection of large amounts of an anesthetic might
cause side effects that affect the entire body.
Does not require general anaesthesia.
RISKS AND COMPLICATIONS FROM REGIONAL ANAESTHESIA
1. For regional anaesthesia, an anesthetic is injected close to a nerve, a bundle of nerves, or the
spinal cord. In rare cases, nerve damage can cause persistent numbness, weakness, or pain.
2. Regional anaesthesia also carries the risk of systemic toxicity if the anesthetic is absorbed
through the bloodstream into the body.
3. Other complications include heart or lung problems, and infection, swelling, or bruising
(hematoma) at the injection site.
CONTRAINDICATIONS
DIFFERENCE BETWEEN LOCAL ANAESTHESIA & REGIONAL ANAESTHESIA
LOCAL ANAESTHESIA REGIONAL ANAESTHESIA
1. A local anaesthesia only blocks the
injected direct area.
2. Agents such as lidocaine or
marcaine are local anesthetics that
can be injected directly into the
area to be operated upon with a 1-4
hour blockade.
3. Local anaesthesia numbs just a
small area of tissue where a minor
procedure is to be done.
4. Local anaesthesia is where a drug
is injected near nerves in
or through the skin providing loss
of sensation to the area of the
surgical operation.
5. Risks include infection,
1. Regional anaesthesia blocks pain to a
large portion of the body at one time.
2. This includes epidural, spinal, and
peripheral nerve blocks. The nerve
block is delivered approximate to the
nerve bundle or group for peripheral
nerve blockade.
3. Regional anaesthesia numbs a larger
(but still limited) part of the body and
does not make the person unconscious.
4. Regional anaesthesia is where a drug
is injected into the veins of an arm or
leg while using a tourniquet to create
temporary loss of feeling and/or
movement of a limb.
5. Risks include infection, convulsions,

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convulsions, weakness, persistent
numbness, residual pain and injury
to the blood vessels.
6. For local anaesthesia the patient is
conscious.
persistent numbness, residual pain and
injury to the blood vessels.
6. For regionals, the patient can either be
under conscious sedation or awake.
GENERAL ANAESTHESIA
DEFINITION
 General anaesthetics (GAs) are drugs which bring about loss of modalities of sensation
particularly pain along with all reversible loss of all sensation.
 The cardinal features of general anaesthesia are:
1. Loss of all sensation, especially pain
2. Sleep (unconsciousness) and amnesia
3. Immobility and muscle relaxation
4. Abolition of somatic and autonomic reflexes.
CLASSIFICATION
MECHANISM OF ACTION

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 Depresses all functional unit of CNS.
 Particularly inhibit ascending reticular artibating system ( ARAS) which maintain state
of wakefulness.
STAGES OF ANAESTHESIA
1. STAGE OF ANALGESIA
 Starts from beginning of anaesthetic inhalation and lasts upto the loss of consciousness.
 Pain is progressively abolished.
 Patient remains conscious, can hear and see, and feels a dream like state; amnesia
develops by the end of this stage.
 Reflexes and respiration remain normal.
 Though some minor operations can be carried out during this stage, it is rather difficult to
maintain—use is limited to short procedures.
2. STAGE OF DELIRIUM
 From loss of consciousness to beginning of regular respiration.
 Apparent excitement is seen—patient may shout, struggle and hold his breath; muscle
tone increases, jaws are tightly closed, breathing is jerky; vomiting, involuntary
micturition or defecation may occur.
 Heart rate and BP may rise and pupils dilate due to sympathetic stimulation.
 No stimulus should be applied or operative procedure carried out during this stage. This
stage is inconspicuous in modern anaesthesia.
3. SURGICAL ANAESTHESIA
 Extends from onset of regular respiration to cessation of spontaneous breathing. This
has been divided into 4 planes which may be distinguished as:
i. PLANE 1 - Roving eyeballs. This plane ends when eyes become fixed.
ii. PLANE 2 - Loss of corneal and laryngeal reflexes.
iii. PLANE 3 - Pupil starts dilating and light reflex is lost.
iv. PLANE 4 - Intercostal paralysis, shallow abdominal respiration, dilated pupil.
 As anaesthesia passes to deeper planes, progressively— muscle tone decreases, BP
falls, HR increases with weak pulse, respiration decreases in depth and later in
frequency also.
4. MEDULLARY PARALYSIS

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 Cessation of breathing to failure of circulation and death.
 Pupil is widely dilated, muscles are totally flabby, pulse is thready or imperceptible and
BP is very low.
INHALATIONAL ANAESTHETICS
TECHNIQUES OF INHALATION OF ANAESTHETICS
1. Open Drop Method
 Liquid anaesthetic is poured over a mask with gauze and its vapour is inhaled with
air.
 Eg. Ether.
2. Through Anaesthetic Machines
 The gases are delivered to the patient through a tightly fitting face mask or
Endotracheal Tube or Boyle’s Apparatus.
 Eg. Nitrous oxide, Ethylene.
INHALATIONAL ANAESTHETICS
DRUGS DEFINITION ADVANTAGES DISADVANTAGES
1. Nitrous oxide
 Non-Irritating
 Better Smelling
 Colorless
 Inorganic Gas
 Safest Anesthetic Drug
 Non- Inflammable
 Non-irritant to patient
 Pleasant to inhale
 Post - operative
complication is less
 Muscle relaxation is
unsatisfactory
 Teratogenic effect
 Blood pressure is
increased
2. Ether
 Colorless,
Volatile Liquid
 Used for all types of
surgery
 Safe
 Simple to administrate
 Little toxic axn. on
heart
 Highly irritative to
upper respiratory
tract
 Vapor inhalation is
unpleasant for
patient
 Increases secretions
of all the glands
3. Halothane
(Fluothane)
 Colorless Liquid
 Volatile
Anesthetic
 Volatile anesthetic drug
& most expensive.
 Non - inflammable
 Non-irritant to
respiratory tract.
 Rapid,smooth & with
fast recovery
 Respiratory
Depression
 No Analgesic
Properties
 Hepatotoxic Effect
INTRAVENOUS ANAESTHETICS

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DRUGS DEFINITION ADVANTAGES DISADVANTAGES
1. Thiopentone
Sodium
 Ultra short acting
barbiturate.
 Used mainly for
minor surgeries.
 Non-irritant to lungs
& non-explosrve.
 Less nausea &
vomiting.
 Muscle relaxation is
rapid.
 Fall in blood pressure.
 Poor analgesic &
relatively large quantity
is needed to produce
true anaesthesia.
 Recovery period is
long & drowsiness
persists after one hour.
2. Ketamine
 Also known, as
“Dissociative
(sudden temporary
alteration)
anaesthesia.
 Respiration is not
depressed.
 Muscle tone
increases.
 Useful for burn
dressing & I & D.
 Good for repeated
use.
 Dangerous for IHD
patients.
 Delirium,
Hallucinations &
Involuntary
movements.
 Heart rate, cardiac
output & blood
pressure are elevated.
COMPLICATIONS OF GENERAL ANAESTHESIA
1. Hypotension
2. Respiratory
Depression
3. Laryngeal Spasm
4. Delirium
5. Nausea
6. Vomiting
7. Organ Toxicity
8. Airway Obstruction
9. Bronchospasm
10.Respiratory Failure
11.Arrythmias
12.Cardiac Arrest
13.Renal Failure
14.Hepatic Failure

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