Anesthesia affects multiple organ systems and induces a reversible state of unconsciousness. It progresses through stages from induction to maintenance. Common types include intravenous agents like propofol and barbiturates, inhalational gases, and regional techniques. Special populations like diabetics and elderly patients require careful consideration due to altered drug metabolism and responses. The brain remains highly active under anesthesia through synchronized neural firing rather than ceasing activity.

1. Anesthesia
Under supervision of Dr Eman Mantawy

2. Presentation overview
• Anesthesia definition
• Organs Affected
• Stages of anesthesia
• Types of anesthesia
• Special population

3. Story begins
here
• The situation : My father is
having an open heart
surgery
• And my sister was worried
that he will feel pain
during the surgery
• So she asked the surgeon
• And he answered ( he will
be asleep don’t worry  )
• This got my sister more
worried saying
“I wake up when I
hear any sound ,
won’t the cut in
the surgery let my
father wake up
and feel pain :’(

4. Definition of anesthesia
• General Anesthesia is described as a
reversible state of unconsciousness with
inability to respond to standard surgical
stimulus
• Because no single agent provides all
desirable properties, several categories
• of drugs are combined to produce optimal
anesthesia

7. Organs affected
• Drugs are chosen to provide safe and efficient
anesthesia based on the patient
characteristics such as organ function, and
concurrent medications. So must consider the
organs affected by anesthesia :
• Cardiovascular system
• Respiratory system
• Liver and kidney
• Nervous system

8. • DEPRESS
ION of
FUNCTIO
N

9.  The awake cortex showed
complex activity patterns, with
individual cells firing at different
times.
 Under anesthesia, all neurons
displayed identical activity
patterns and fired at the same
time.
 Neurons remain highly active
but change their
communication mode.
 During unconsciousness they
become highly synchonized
“While one might expect the brain to
cease its activity under anesthesia, in
reality, the situation is quite different.”

10. Stages of Anesthesia

11. Cont.

14. Intravenous anesthesia
• IV anesthetics cause rapid induction
• Anesthesia may then be maintained with
an inhalation agent.
• IV anesthetics may be used as sole
agents for short procedures or
administered as infusions to help
• maintain anesthesia during longer cases.

16. Propofol

17. Disadvantages of propofol
• Although propofol depresses the CNS, it is
occasionally
• accompanied by excitatory phenomena,
such as muscle twitching,
• spontaneous movement, yawning, and
hiccups. Transient
• pain at the injection site is common.

18. Barbiturates and Benzodiazepines
• binding to the GABA
channel they lead to
prolonged
opening(increase
duration of
opening) of the
channel letting in
Chloride ions into
the cells in the brain.
• binding to the
GABA-A receptor
increases the affinity
of gamma amino
butyric acid (GABA)
and its receptor,
thereby increasing
the opening
frequency of
GABA-A receptor

19. Barbiturates Benzodiazepines
Thiopental
ultra–short-acting barbiturate. It is a potent
anesthetic but a weak analgesic.
Midazolam
Diazepam and lorazepam
are alternatives.
in conjunction with anesthetics
for sedation
quickly enter the CNS and depress
function,
often in less than 1 minute
All three facilitate amnesia while causing
sedation
Thiopental has minor effects
on the normal CVS, but may contribute to
hypotension in patients with hypovolemia
or shock
all are potential respiratory depressants
(especially when
administered IV)
All barbiturates
can cause apnea, coughing, chest wall
spasm, laryngospasm, and
bronchospasm
Benzodiazepines can induce a temporary
form of anterograde
amnesia in which the patient retains
memory of past events
Thiopental is no longer available in
many countries,

20. Opioids
• Because of their
analgesic
property(agonists on mu
receptors) opioids are
commonly combined with
other anesthetics.
• The choice of opioid is
based primarily on the
duration of action
needed
• The most commonly used
opioids are fentanyl
sufentanil and remifentanil
• they can all cause
hypotension, respiratory
depression, and muscle
rigidity, as well as
postanesthetic nausea and
vomiting.
• Opioid effects can be
antagonized by naloxone.

23. in which the patient is
unconscious (but
may appear to be awake) and
does not feel pain. This
dissociative
anesthesia provides sedation,
amnesia, and immobility

24. Cont.
• stimulates central
sympathetic outflow,
• causing stimulation of
the heart with
increased blood
pressure and CO.
• It is also a potent
bronchodilator.
• Therefore, it is
beneficial in patients
with hypovolemic or
• cardiogenic shock
and
• in asthmatics
• Conversely, it is
contraindicated in
hypertensive or
stroke patients.
Ketamine is used mainly in children
and elderly adults for
short procedures. It is not widely
used, because it increases
cerebral
blood flow and may induce
hallucinations,

25. Inhalation anethesia

28. Diabetic patients
undergoing surgeries

29. The metabolic challenge of surgery
for the diabetic patient
The secretion of catecholamines,
cortisol, growth hormone and, in
some cases, glucagon. These
hormones oppose glucose
homeostasis, as they have ‘anti‐
insulin’ and hyperglycaemic effects.

31. Geriatrics anesthesia

32. Agents affecting Geriatrics

33. but prolonged
neuromuscular blockade
with suxamethonium is
uncommon due to
increased blood volume
causing an increased
volume of distribution.

34. • interacts predominately with the opioid mu-
receptor
• class: B in small doses and D in high doses