1. Anesthesia concepts and considerations

2. Anesthesiology
Is the branch of medicine that is concerned with the administration of medication or anesthetic agent to relieve pain and support physiological function during a surgical procedure.
Anesthesia
Loss of feeling or sensation of pain with loss of protective reflexes.

3. Analgesia
Losing of pain sensation without producing loss of consciousness.
Amnesia
loss of memory.
Induction of anesthesia
Period from beginning of administration of anesthesia agent until pt. loses consciousness.
Biotransformation
Metabolism of anesthetic drugs by broken down in hepatic cells.

4. Pain threshold Individual tolerance for pain. Endotracheal intubation
Insertion of endotracheal tube.
Laryngospasm
Involuntary spasmodic reflexes action that partially or completely closes the vocal cord.

5. Pre anesthetic medication
It is given to :
Decrease preoperative anxiety.
To produce some analgesia an amnesia 9 dormice ).
Decrease secretions in the respiratory tract. ( atropine ).
Choice of drugs:
Selection of drugs is made by anesthesiologist and based on:
Assessment of physical and emotional status.
Age, medical history , weight.
Lab test , X rays , ECG, smoking.

6. Classification of Pre anesthetic medication used:
Sedative and Tranquilizer :
To reduce anxiety, and produce amnesia to provide comfort.
Examples :
Valium ( Diazepam )
Nembutal : Has prolong action , it may be given for sleep the night before to reduce anxiety .

7. Antiemetic :
To relieve nausea and vomiting which caused by some sedative drugs
Examples :
Pramine , promethazine (Phenergan).
Narcotics:
To produce analgesia but depress respiration, and may lead to nausea, vomiting and urinary retention.
Pethedine and Fentanyl

8. Anticholinergic :
To decrease mucus secretion and to relieve Bradycardia.
Examples
Atropine and Scopolamine.
Choice of anesthesia :
Anesthesia is defined as" The absence of sensation"
Selection of anesthesia is made by anesthesiologist in consultation with surgeon.

9. The anesthesiologist will consider the following factors:
Age , Wt. , Size of pt.
Physical mental and emotional status of pt.
Presence of disease ( e, g heart, liver k ,kidney, asthma.)
Previous anesthesia experience.
Position required for procedure.
Presence of infection at the site of surgery.
Types an expected length of procedure.

10. An ideal anesthetic agent or technique suitable for all patients does not exist, but the one selected should include the following characteristics:
Provides maximum safety for the patient
Provides optimal operating conditions for the surgeon
Provides patient comfort
Has a low index of toxicity

11. Provides potent, predictable analgesia extending into the postoperative period
Produces adequate muscle relaxation
Provides amnesia
Has a rapid onset and easy reversibility
Produces minimum side effects

12. Types Of Anesthesia General anesthesia :
Pain is controlled by general insensibility, specific drugs are used to achieve the desired result ( amnesia, analgesia and muscle relaxation).
The depth and duration of anesthesia are regulated according to the type of anesthetic employed and the amount of the agent(s) administered

13. Local or Regional block:
Pain is controlled without loss of consciousness , the sensory nerves in one area or region of the body anesthetized.
Spinal or Epidural anesthesia :
Sensation of pain is blocked at the level below the diaphragm without loss of consciousness, the agent is injected in the spinal cord.

14. General Anesthesia
Anesthesia is produced as CNS is affected, un-conciseness is produced when blood circulating to brain contains an adequate amount of anesthetic agent.
Methods of administration general anesthesia:
IV injection .
Inhalation .

15. Induction of general anesthesia
IV injection:
Pre oxygenation : Ventilating the pt. by mask of 100 % oxygen for few minutes , this ensure safety in case of airway obstruction , or apnea occurs during induction.
Loss of consciousness : Is induced by IV administration of drug agent.

16. DRUGES USED :
Pentothal Sodium ( concentration 2.5% ) 5mg / kg short acting drug given for rapid induction within 30 second.
Fentanyl :short acting drug to produce good analgesia.
Muscle Relaxant : drugs which given before intubation to relax jaw , larynx and body muscles.

17. DRUGES USED : pavlon --- long acting ( 30 -45 minutes ).
Scoline --- short acting ( 5 minutes. )
Tracrium ( 15 – 20 minutes ).
Narcorn (20 -30minutes ).

18. Inhalation of anesthesia :
Intubation:
Is the Insertion of a flexible plastic tube into the trachea (windpipe) to maintain an open airway or to serve as a conduit through which to administer certain drugs according to the size of pt. and age.
Intubation is usually performed after administration of general anesthesia.
It can however be performed in the awake patient with local or topical anesthesia, or in an emergency without any anesthesia at all
Intubation is normally facilitated by using a conventional laryngoscope, or bronchoscope
Inhalation gases can be delivered from anesthetic machine through:

19. Face mask inhalation :
Gas is delivered though mask So, the mask should be fit well on the face to prevent leakage of gas.
Laryngeal mask inhalation : Gas is delivered through laryngeal mask which is inserted into the larynx.
Endotracheal tub: Gas inhaled through ET into trachea.

20. Advantages of ET tube:
Ensure patent airway and control of respiration.
Protects lungs from aspiration of blood, vomiting of gastric content.
Helps in minimizing scape of gas into room.

21. Complications of endotracheal tube :
Trauma to teeth , larynx, vocal cord.
pulmonary aspiration of stomach contents
Hypoxia and hypoxemia during intubation or extubation

22. Inhaled anesthetic agents:
The gas is inhaled and circulate into the blood stream by passing across the alveolar membrane to general circulation.
Halothane : ( Fluothane)
Advantages :
Nonflammable
Produce rapid and smooth induction
Useful for pt. with bronchial asthma.

23. Disadvantages:
Depression of cardiovascular system – cause hypotension and Bradycardia.
Potentially toxic to liver.
May cause hypothermia and limited abdominal muscle relaxation.
Note : Halothane is Not recommended to be used in obstetrics because uterine relaxation is not desired.

24. Enflorane : It is similar to halothane.
Advantages :
Rapid induction and recovery.
Muscle relaxant is produced.
Disadvantages :
Depression of BP and respiration.
Contraindication in renal failure.

25. Isoflurane: Advantages: Rapid induction and recovery.
More patent muscle relaxant.
Used for asthmatic pt.
Disadvantages:
Expensive
Respiratory depressant.

26. Nitrous oxide : Advantages: Rapid inhalation and elimination.
Disadvantages :
No muscle relaxant.
Hypoxia develop and should not use alone.
At the end of surgery:
Muscle relaxant should be reversed by using Myostagmine combined with atropine to manage Bradycardia which is caused by Myostagmine drug , and the ET tube should be removed when the pt. is breathing spontaneously and semi or full awake.