General anesthesia Presentation by Muhammad Saeed

2. GENERAL ANESTHESIA
Presented by:
Muhammad Saeed AHS 6th BS Anesthesia
Technology
Presented to:
Sir Irshaad and AHS-1

3. Loss of sensation with or without loss
of consciousness
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WHAT IS ANESTHESIA

4. p
General Anesthesia
Regional Anesthesia.
Local Anesthesia.
Types of Anesthesia

5.  General Anesthesia –
 General anesthesia is a combination
of medications that put you in a sleep-
like state before a surgery or other
medical procedure

6. General Anesthesia
Inhalational
Gas
Nitrous oxide
Zenon
Volatile liquids
Ether
Halothane
Enflurane
Isoflurane
Desflurane
Sevoflurane
Methoxyflurane
Intravenous
Slower
acting
Opioid analgesia
Fentanyl
Benzodiazepines
Diazepam
Lorazepam
Midazolam
Inducing agents
Thiopentone sod.
Methohexitone sod.
Propofol
Etomidate
Ketamine

7. Criteria for General Anesthesia
Patient condition
Check vital signs
Premedication
Induction of general anaesthesia
Maintenance of General Anesthesia
Intraoperative Monitoring
Reversal of anaesthesia
Post operative instructions

8. STAGES OF ANAESTHESIA
Stage of
Analgesia
Begins with the administration of the anesthetic agent and
ends when the patient becomes unconscious.
Stage of
Delirium
Muscles become tense but swallowing and vomiting
reflexes are still present. breathing may become irregular
or the breath may be held.
There are four stages and 4 planes of GA

9. Begins with onset of regular breathing again.
Vital functions are depressed, eyes are fixed.
and reflexes are lost or temporally depressed
Depression of vasomotor and respiratory
center, coma and death
Surgical
anaesthesia
Medullary
paralysis
Continue…

10. Stages of
anesthesia
Guedel (1920) described four stages with ether
anesthesia, dividing the III stage into 4 planes.
The order of depression in the CNS is:
1. Cortical centers
2. Basal ganglia
3. Spinal cord
4. Medulla

11. Indication of Genral Anesthesia
For the obstetrical procedures
To perform a surgical operation or procedure
For the radiographic procedures
For the special diagnostic procedure, e-g in case of Endoscopy
For the cast application
Euthanasia by giving over dose of anesthesia
To control the convulsion e-g in case of epilepsy

12. Contraindication of General Anesthesia
1. Lack of adequate training by the doctor.
2. Lack of adequate trained personnel.
3. Lack of adequate equipment.
4. Lack of adequate facilities.
5. ASA IV and certain ASA III medically
compromised patients.

13. Procedures of anesthesia
Induction
Induction of anesthesia should be achieved with an
intravenous anesthetic agent.
●Hypnosis
●Amnesia
●Analgesia

14. Inhalation anesthetics
• Common features of inhaled anesthetics
– Modern inhalation anesthetics are nonflammable, nonexplosive agents.
– Decrease cerebrovascular resistance, resulting in increased perfusion of the brain
– Cause bronchodilation, and decrease both minute ventilation and hypoxic
pulmonary vasoconstriction
• MAC (potency): The alveolar concentration of an anesthetic gas
needed to eliminate movement among 50% of patients challenged
by a standardized painful stimulus (skin incision).
– MACis the ED50 of the anesthetic.
– the inverse of MACis an index of potency of the anesthetic.
Procedures of anesthesia
Maintenance
Maintenance of anesthesia should be on
volatile anesthetic agent

15.  Anesthetic concentration in the inspired air (Alveolar wash-in):
 replacement of the normal lung gases with the inspired anesthetic mixture.
 The time required for this process is
 directly proportional to the functional residual capacity of the lung,
 inversely proportional to the ventilatory rate; it is independent of the physical properties of the gas.
 Anesthetic uptake:
 is the product of gas solubility in the blood, cardiac output, and the alveolar to venous partial pressure gradient of the anesthetic.
 Solubility in the blood: called the blood/gas partition coefficient.
 The solubility in blood is ranked in the following order: halothane > enflurane > isoflurane > sevoflurane > desflurane > n2o.
 An inhalational anesthetic agent with low solubility in blood shows fast induction and also recovery time (e.g., N2O), and an agent
with relatively high solubility in blood shows slower induction and recovery time (e.g., halothane).
 Wash out:
 when the administration of anesthetics discontinued, the body now becomes the “source” that derives the anesthetic into the
alveolar space. The same factors that influence attainment of steady-state with an inspired anesthetic determine the time course of
clearance of the drug from the body. Thus N2O exits the body faster than halothane.
Procedures of anesthesia
Recovery
Reversal agents
Anticholinergics are given as reversal agents if muscle
relaxants are used
Specific reversal agents exists for benzodiazepines and
opioids.

16. Complication of General Anesthesia
Damage teeth 1-4500 case
Sore throat and laryngeal damage
Respiratory depression
Aspiration pneumonitis
Hypothermia
Hypoxic brain damage
Nerve damage 0.4%
Headache
Death