It is very common aspect to administer premed drugs before each surgical procedures, invasive and non invasive procedures.

1. Basic
Principles of
Anaesthesia
Courtesy
Abiyad Ahmed
2nd Professional Critical Care Technology
Vivekanada Institute of Medical Sciences &
Sishumongal Hospital, Kolkata

2. Contents
 Pre anaesthetic Check up
 Consent
 Fasting guidelines
 Drugs
 Route of drug administration
 Premedication

3. Published by – Medical Biology Editor – Abiyad Ahmed
Pre anaesthetic Check up
The assessment of the patient before the elective
surgery is mandatory and it plays a vital role.
An anesthetics ask a few questions by means of
psychological counseling related to the present
complaint, medical history, surgical history, addiction
of the patient, habitus and the medication.
This is required for determination of anaesthetic
medicines, gases and post operative medication.

4. Published by – Medical Biology Editor – Abiyad Ahmed
Medical History:
• History of known complaint
• History of family disease
• History of past surgeries and the treatment
• Addiction of alcohol or smoking or anything else

5. Published by – Medical Biology Editor – Abiyad Ahmed
Pre anaesthetic examinations:
o Vitals (Blood Pressure, Pulse, Saturation)
o Systemic examination
o Blood test for Complete blood count, Blood group determination,
Hb%, TC, DC, ESR, Serum Urea, Serum Creatinin, Na+, K+, Fasting
blood sugar, Post Meal Blood Sugar, Lipid Profile, Serology test
(HIV, Hepatitis), Thyroid
o Urine routine examination
o Electrocardiography, Echocardiography
o Chest X-Ray (PA or AP view)
o Any specified test as directed

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Consent (Paper based Written Permission)
Consent is nothing but a written permission from the patient and patient
party. In case of minor or unconscious patient the consent is taken from
the legal guardian.
An anesthetics describes the Pros and Cons of the anaesthesia, he
detailed on this paper about the risk and post operative complication in
the patient party’s known/local language.
After detailing the medical aspects of risk and complications the
anesthetics sign the document with his/her Professional Registration
number and the same thing is done by the patient and or relative
mentioning their relationship.
It is legal bond and mandatory before any invasive or non-invasive
procedure.

7. Fasting Guidelines
Perioperative aspiration (foreign particle into lungs) can occur during or after
intubation, to prevent this condition the fasting guidelines are referred to a
patient undergoing elective surgery requiring anaesthesia.
Published by – Medical Biology Editor – Abiyad Ahmed
Food Material Timings for fasting
Clear fluid 2 hours
Breast milk 4 hours
Infant formula 4-6 hours
Non human milk 6 hours
Light meal 6 hours
Processed meal
(fried, fatty food, meats)
8 hours
Source: Preoperative Fasting, College of Anaesthesiologist, Singapore

8. Drugs in
Premedication
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9. What is drug?
Drugs are the chemical substances that is taken
orally or intravenously into the body to alter the
body’s normal physiology by producing chemical
effects.
Published by – Medical Biology Editor – Abiyad Ahmed
Anaesthetic drugs are widely used to produce the
therapeutic anaesthesia, analgesia, amnesia and
muscle relaxation. These are used for manipulation of
major systemic effects pharmacologically to
maintain hemostasis and prevent injury to reduce
the rate of adverse effect.

10. Factors of Premedication
• Patient’s desire
• Age, Sex, Height, Weight
• Type & Duration of Surgery
• Medical & Past surgical history
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11. Route of drug administration
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Routes
Systemic
Enteral
1. Oral
2. Sublingual
3. Rectal
Parenteral
1. Inhalational
2. Intravenous
3. Intramuscular
4. Intra-theacal
5. Sublingual
6. Intra-arterial
Local
1. Oral activity
2. Rectum & Anal canal
3. Eye, Ear, Nose
4. Bronchi
5. Vaginal, urethral

12. Goals of
Premedication
 To reduce secretion
 To produce amnesia &
 To produce analgesia
 To reduce nausea & vomiting
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13. Anticholinergic
 Atropine
 Glycopyrrolate
The anticholinergic drugs acts by the blocking of neurotransmitter
acetylcholine. These drugs inhibit the transmission of parasympathetic nerve
impulses , thereby reducing the spasm of smooth muscle. It is used to reduce
secretion during anaesthesia.
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14. Injection Atropine
This injection/ drug is given either by intravenous route or
intramuscular route to treat slow heart rate and to reduce
salivary production and gastric secretion during surgery.
Published by – Medical Biology Editor – Abiyad Ahmed
Pharmacological Properties:
Onset of action 1 min (IV)
Duration of action 30-60 min
Dose 0.6 mg
Metabolism Hepatic
Excretion Renal
Indication Preanaesthetic medication, antidote for OP
compounds, Cardiac vagolytic
Contraindication
Adverse effect Dysphagia, Dry mouth, dilated pupil

15. Analgesic Drugs
 Opioids
 NSAID
Analgesics are the pain killer. It acts on Peripheral and Central nervous
system without blocking the conduction of nerve impulses, altering sensory
perception, or affecting consciousness.
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16. Non Steroidal Anti
Inflammatory Drugs
Opioids
Most of the NSAID are
derived from salicylic acid,
pyrazolone and
acetophenetidine.
Opioids are chemical
compounds closely related to
morphine.
Drugs – Aspirin, Ibuprofen,
Diclofenac, Paracetamol
Drugs – Morphine, Tramadol,
Pentazocine
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17. NSAIDs
Pharmacological
Properties
Aspirin Ibuprofen
Mechanism Blocks prostaglandin synthesis by
inhibiting cyclooxygenase enzyme
Blocks prostaglandin synthesis by
inhibiting cyclooxygenase enzyme
Dose 1200-1500mg TDS 600mg QDS
Elimination half life
(t1/2)
0.25 hours 2 hours
Metabolism Deacyetylation in liver, gut wall,
plasma to salicylic acid
Hydroxylated and conjugated in
liver
Excretion Urine Urine
Indication Musculoskeletal pain, Joint pain,
Rheumatic fever, Rheumatoid
arthritis, Post myocardial and
stroke
Osteo and rheumatoid arthritis,
Musculoskeletal pain,
Dysmenorrhoea, Fever
Adverse Effect Nausea, Vomiting,
Hypersensitivity
Heart burn, Anorxia, Pruritus,
Rashes, Dizziness
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18. Opioids
Pharmacologica
l Properties
Fentanyl Morphine
Mechanism Modulate G protein coupled receptor. Modulate G protein coupled receptor.
Dose Adult: 1-5μg/kg (IV)
Paediatric: 1-5μg/kg
Adult: 10-30mg/kg/4hourly (IV)
Paediatric: 0.3-0.5mg/kg/4hourly
Elimination half
life (t1/2)
1-2 hours 3-4 hours
Onset Rapid Slow
Duration of action 1-1.5 hours 3-4 hours
Excretion Urine Urine
Action CVS↓
HR ↓
BP ↓
ICP↓
CVS↓
HR ↓
BP ↓
ICP↓
Adverse Effect Sedation, Respiratory depression,
Constipation, Nausea vomiting
Sedation, Respiratory depression,
Constipation, Nausea vomiting
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19. Produce Sedation &
Amnesia
 Diazepam
 Lorazepam
 Midazolam
Benzodiazepines are the intravenous anaesthetic agent. It is a psycho active
drug, it act on gamma-aminobutric acid A receptors (GABA-A).
Benzodiazepines reduce the activity of nerves in the brain and spinal cord by
enhancing the effect of GABA.
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20. Pharmacological
Property
Diazepam Midazolam Lorazepam
Dose Induction: 0.3-0.5 mg/kg
Seduction: 2 mg repeated
Maintenance: 0.1 mg/kg
Induction: 0.05-15 mg/kg
Seduction: 0.7 mg/kg (IM)
Maintenance: 1μg/kg
Induction: 0.1 mg/kg
Seduction: 0.25 mg
repeated
Maintenance: 0.02 mg/kg
Onset 3-5 min < 3 min 10-20 min
Systemic Action BP ↓
HR ↑
Cerebral O2 requirement ↓
BP ↓
HR ↑
Cerebral O2 requirement ↓
BP ↓
HR ↑
Cerebral O2 requirement ↓
Indication Premedication, Sedation
Induction and maintenance
of anaesthesia, Induce
seizure
Sedation, Premedication,
Sedation Induction and
maintenance of
anaesthesia, Induce seizure
Anticonvulsant, Sedation,
Premedication, Sedation
Induction and maintenance
of anaesthesia, Induce
seizure
Adverse effect Respiratory depression,
Drowsiness,
Thrombophlebitis
Respiratory depression Respiratory depression,
Amnesia, Drowsiness
Published by – Medical Biology Editor – Abiyad Ahmed
Benzodiazepines

21. Reduce postoperative nausea
vomiting
 5HT3 antagoinst – Ondansetron
 H2 antagonist – Ranitidine
 Proton pump inhibitor – Pantoprazole
Antiemetic drugs are broadly used to treat nausea and vomiting, motion
sickness. These acts by blocking some Neuro transmiter.
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22. Antiemetic
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Pharmacological
Property
Ondansetron Ranitidine Pantoprazole
Mechanism Inhibit the ion channel of
5HT3 receptor
Competitive agonist at H2
receptors
Inactivates the enzyme H+
K+ ATPase to decrease
secretion
Dose 0.06 mg/kg 50 mg/6-8hourly 40mg OD
Metabolism Liver Liver Liver
Indication Postoperative vomiting,
Chemotherapy induced
vomiting
Peptic ulcers, GERD ZE Syndrome, GERD, Peptic
ulcers
Adverse effect Headache, Mild constipation Diarrhoea, Hepatic injury,
Dizziness
Leucopenia, Hepatic
dysfunction, Atrophic
gastritis, Diarrhoea

23. Thank You!
With regards
Abiyad Ahmed
Dept. of Anaesthesiology & Critical Care
Vivekananda Institute of Medical Sciences &
Sishumongal Hospital, Kolkata