What is Anesthesia?
It is a Greek word which means “without sensation” it is used during surgical procedures.to keep patient relax and sesneles so that the surgical procedure can be performed.
In an ideal anesthesia there is analgesia, temporary paralysis of muscles, and un-consciousness.
Assessment of patient before anesthesia
A. History taking
i) Smoking, chronic cough, drugs or alcohol taking history of allergy from any drug
ii) History of recent therapy with steroids, anti-hypertensive, sedatives, antibiotics, anti-epileptics.
iii) History of diseases like diabetes, cardiac arrest, bronchial asthma, tuberculosis, hepatitis, and Aids.
B. Examination of the patient
i) General examination before anesthesia for example examination of teeth , mouth opening, tremors , jaundice and cyanosis.
ii) Respiratory system evaluation
iii) Airway evaluation
iv) Cardiovascular system examination
v) Spine curvature and structure evaluation
Types of anesthesia:
1. General anesthesia
2. Local anesthesia
3. Topical anesthesia
4. Spinal anesthesia
5. Epidural anesthesia
1. General anesthesia
it is a reversible state of loss of consciousness in which all sensations i.e touch, pain posture and temperature are abolished.
It is used in major surgeries for example thyroidectomy, mastectomy , cardiac surgery, and other major surgeries in which the patient must be unconscious and loss of sensations.
General anesthsesia has 3 main components
a. Analgesia
b. Hypnosis
c. Muscle relaxation
Instruments and equipment used during general anesthesia:
Laryngoscope
Face masks
Endotracheal tube
Orophyrangeal Airways
Laryngeal mask airway (LMA)
Magill’s forceps
Ambu bag
Suction unit
Some anesthetic agents which are used to induced general anesthesia
Gaseous anesthetic agents:
oxygen
Nitrous oxide
Cyclopropane
Intravenous anesthetic agents:
Ketamine
Propofol (most commonly used iv induction agent)
Thiopentone
Fentanyl
Volatile anesthetic agents:
Ether
Trichloroethylene
Halothane
Enflurane
Isoflurane
Sevoflurane
Some muscle relaxants used in general anesthesia:
Depolarizing agents : suxamethonium chloride , suxthonium bromide
Non-depolarizing agents: tubocurarine, pancuronium bromide, vecuronium bromide atracurium
Reversal agents:
Neostigmine with atropine is used as a reversal agent.
Monitoring of the patient with general anesthesia in recovery phase :
Pulse,temp, bp
Breathing
Skin color tongue color
Cardiac monitor
Serum electrolytes
Some complications of general anesthesia
Cardiac arrest
Respiratory failure
Hypoxia
Pneumothorax
Malignant hyperthermia
Anaphylaxis
2. Local anesthesia
The local anesthesia is the type of anesthesia in which the patient is conscious and only that area which has to be treated is blocked by local anesthetic agent which block the transmission of nerve impulse through that part .
It is indicated in the conditions like where general anesthesia is avoided, consciousness of patient is required.
Local anesthesia drugs
Lignocaine /lidocaine /xylocaine
3. Topical anesthesia
In the minor surgeries like in the surgeries of eye ,and in the gastroscopy , laryngoscopy cystoscopy topical anesthseia is used.
Topical anesthesia is available in the form of spray, viscous, ointment gel, etc
4. Spinal anesthesia
In this type of anesthesia an injection of local anesthetic agent is given in the subarachnoid space causing loss of sympathetic tone ,sensation and motor function.
Position for the spinal anesthesia :
Lateral decubitus position with head hips and knees being fully flexed.
Drugs used in spinal anesthesia :
Lignocaine 5%in 6% dextrose
Bupivacaine 0.5% in 5% dextrose
Cinchocaine 0.5% in 6%dextrose
Instruments used for spinal anesthesia
Sponge holder
Lumber puncture needle
syringe
5. Epidural anesthesia
The epidural anesthesia is given at the potential space between the dura anteriorly ligamentum flavum posteriorly which has negative pressure in it .
An epidural catheter is placed in the space and fixed .2% xylocaine with adrenaline or 0.5%bupivacaine is injected in the space.
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