general anesthesia for medical & dentist students

1. General anesthesia
By: mohammad k younus

2.  Drugs that produse a generalized reversible
depreesion of the CNS such that perception of ;
• Loss of all sensation, especially pain
• Sleep (unconsciousness) and amnesia
• Immobility and muscle relaxation
• Abolition of reflexes.

3. 1.INHALATIONAL
Gases : nitrous oxide
Liquids: Ether, Halothane, Enflurane, Desflurane,
Isoflurane, Sevoflurane, Methoxyflurane

4. 2.INTRAVENOUS
Inducing Agents: Thiopentone
sodium,Methohexitone sodium,Propofol, Etomidate
slower acting drugs: benzodizeoines – midazolam,
lorazempam
dissociative anaesthesia-Ketamine,
Neuroleptanalgesia: Fentanyl+Droperidol
(Analgesic)(Neuroleptic)

5.  General anesthesia has many purposes,
including:
 Analgesia (loss of response to pain)
 Amnesia (loss of memory)
 Immobility (loss of motor reflexes)
 Hypnosis (unconsciousness)
 Paralysis (skeletal muscle relaxation)

6.  In 1937 they describes four stages of anesthesia
Stage 1: also known as induction, is the period
between the administration of induction agents
and loss of consciousness. During this stage,
the patient progresses from analgesia without
amnesia to analgesia with amnesia. Patients can
carry on a conversation at this time

7.  Stage 2: also known as the excitement stage, is
the period following loss of consciousness and
marked by excited and delirious activity.
During this stage, the patient'srespiration
and heart rate may become irregular
 Stage 3: also known as surgical anaesthesia,
the skeletal muscles relax, vomiting stops,
respiratory depression occurs, and eye
movements slow and then stop

8. And this stage is divided into four planes:
 The eyes roll, then become fixed;
 Corneal and laryngeal reflexes are lost;
 The pupils dilate and light reflex is lost;
 Intercostal paralysis and shallow abdominal
respiration occur

9.  Stage 4: also known as overdose, occurs
when too much anesthetic medication is
given relative to the amount of surgical
stimulation and the patient has
severe brainstem or medullary depression,
resulting in a cessation of respiration and
potential cardiovascular collapse. This stage
is lethal without cardiovascular and
respiratory support.

10.  Confusion and memory loss - more common in
the elderly, it is not necessarily permanent
 Dizziness
 Difficulty passing urine
 Nausea and vomiting
 Shivering and feeling cold

11.  Overall, general anesthesia is very safe. Even
particularly ill patients can be safely
anesthetized; it is the surgical procedure itself
which offers the most risk
However, older adults and those undergoing
lengthy procedures are most at risk of negative
outcomes. These outcomes can include
postoperative confusion, heart
attack, pneumonia and stroke.

12.  Obstructive sleep apnea
 High blood pressure
 Alcoholism
 Smoking
 History of reactions to anesthesia
 Medications that can increase bleeding-
aspirin for example
 Drug allergies
 Diabetes
 Obesity or overweight.

13. Thanks for your attention