General Anesthesia

Question 1

General anesthesia

Answer 1

They are agents tht bring about loss of sensation and consciousness

Question 2

Uses if GA

Answer 2

Surgery
Epilepsy
Ect (electroconvulsive therapy)

Question 3

Features of gA

Answer 3

Reversible loss of all sensation
Unconsciousness and amnessia
Immobility, muscle relaxation
Abolition of somatic and autonomic reflexes

Question 4

Pre anesthetic medication

Answer 4

Prior to anesthesia certain drugs has to be administered in order to make anesthesia safer
1.decrease anxiety
2.provide amnesia
3.Relieve pre operative pain
4.make anesthesia safer
5.reduce side affects
6.reduce gastric acidity

Anti anxiety
★Anti anxiety agents like benzodiazepam are used extensively as per anesthetic medication
★reduce anxiety and produce* sedation*
★Amnesia
★barbuturates are not prefered due to its effect on respiratory
★tab-alprazolam

Antihistamine
★have sedative,antiemiticand anticholinegic properties eg- promithazine

Antiemetics
★to prevent nausea and vomiting
★domperidone /ondansteron

Anticholinergic drugs
Some anesthetics may increase secretory functions which may lead to laryngospasm and aspirational Pneumonia this indicates the need for the drugs tht reduce secretions
★eg-atropine
-glycopurulate -long acting than atropine les
likely to cause tachycardia
-scopalamine causes more sedation
★reduce secretions
Prevent bradycardia due to vagal stimulation
Prevent laryngospasm

Reduce acidity
GA may induce vomiting
Acid contents -lungs-aspiration - damage
★h2 blockers rantidine reduce acidity

Gastrokinetic agents
Metoclopramide -promites gastric mobility and increases speed of gastric emptying

Analgesics
★opiods morphine and fentanyl reduce anxiety and provide analgesia
★reduce dosage of anaesthetic required
★respiratory depression, hypotension

Antibiotics
★cefoxiline

Question 5

Anesthetic procedure

Answer 5

Pre anesthetic medication
Induction maintainance and recivery
Induce throught iv
Anesthetic analgesic skeletal muscle relaxant
Reversal
Anesthetic recovery by stopping after surgery and consciousness.is regained
Muscle relaxation reversed by neostigmine pyridostigminen
Opiod reversal by naraxome

Question 6

Complications

Answer 6

Respiratory Failure
-atelectasis
-aspiration pneumonia
-hypotension
Injury to peripheral nerves
Cornea

Question 7

Second gas effect

Answer 7

When certain anesthetics like nitric oxide are administered in high concentration ,the other anesthetic gases are also pulled in and their alveolar tension rises more rapidly

Question 8

Concentration effect

Answer 8

When an anesthetic is administered in high concentration it’s alveolar tension rises rapidly than when the same gas is inhaled in lower concentration For example if 75% nitrous oxide is administered,it’s alveolar tension rises faster than 50% nitrous oxide administration

Question 9

Nitrous oxide

Answer 9

It is a gas with slightly sweetish odour ,it produces light anaesthesia without significant depression of respiratory and vasomotar centre

Advantages
1.strong analgesic
2. Induction is rapid and smooth
3.non irritating and non inflammable
4.recovery is rapid
5.post operative nausea is not significant
6. Has little effect on respiration and cardio vascular functions ,hence ideal for combination
7.its a non toxic to liver ,kidney and brain and is quickly removed from lungs
8. It’s innexpensive

Disadvantages
1.it is less potent and should be used with other
agents
2.poor muscle relaxant
3. N2O diplaces nitrogen in the air filled cavities and while doing so it enters the cavities faster ie.
Even before the nitrogen escapes . This result in expansion of such cavities leading to pneumothorax and air embolism .hence n2O should be avoided in such patients
4. Repeated use can depreess the bone marrow
5. Long term exposure to low dose can impair dna synthesis which may result in foetal abnormalities on conception .may also cause vit b12 deficiency