ANESTHESIA
THE SURGICAL EXPERIENCES
• SEDATION & ANESTHESIA
• Anesthesia
– Greek word anaisthesis, meaning “no sensation”
– a partial or complete loss of sensation, with or without loss of
consciousness as a result of the administration of an anesthetic
agent.
• Analgesia
– lessening of or creating insensibility to pain.
• Anesthetic
– an agent that produces anesthesia; subdivided into general an
regional, according to their actions.
Levels of Sedation & Anesthesia
1. Minimal Sedation
– uses sedatives & anxiolytics that allows the patient to remain
responsive & breath independently.
– Indications are for minor surgeries or as a supplement to local or
regional anesthesia
– Advantages for the patient include anxiety relief, amnesia,
analgesia, comfort & safety
2. Moderate Sedation (Conscious sedation)
– a form of anesthesia that maybe produced intravenously
– A depressed level of consciousness that does not impair the
patient’s ability to maintain a patent airway & to respond
appropriately to physical stimulation & verbal command.
– Goal: a calm tranquil amnesic patient who when sedation is
combined with analgesic agents, is relatively pain free during the
procedure to be able to maintain protective reflexes.
– Can be administered by an anesthesiologist, anesthetist, moderate
sedation is referred to as monitored anesthesia care.
– Midazolam (Versed) or Diazepam (Valium) is used frequently for IV
sedation.
– Patient’s receiving this form of anesthesia is never left alone, and is
closely monitored for respiratory, cardiovascular & CNS depression
(pulse oximetry,
ECG, V/S monitoring)
– Maybe used alone or in the combination with local, regional, or
spinal anesthesia.
3. Deep Sedation
– A drug induced state during which patient cannot be easily
aroused
but can respond purposely after repeated stimulation.
– The difference between deep sedation& anesthesia is that the
anesthetized patient is not arousable. – Deep sedation & anesthesia
are achieved when an anesthetic agent is inhaled or administered
intravenously.
– Inhaled anesthetic agents includes Volatile liquid agents & gases
– Volatile liquid anesthetic produced anesthesia when vapor is
inhaled.
– Gas anesthetics are administered by inhalation & are always
combined with oxygen
– When anesthetic administration is discontinued, the vapor & the
gas is eliminated through the lungs.
4. Anesthesia
– Is a state of narcosis (severe central nervous system depression
produced by pharmacologic agents), analgesia, relaxation, and reflex
loss.
– Patients under general anesthesia are not arousable even to
painful stimuli.
– The loss of the ability to maintain ventilatory function & require
assistance in maintaining a patent airway.
– Cardiovascular function may also be impaired.
General Categories of Anesthesia
I. General Anesthesia
– is the depression of the CNS by administration of drugs or
inhalation agents, resulting in loss of consciousness, sensory
perception and motor function
– Patients are not arousable even with painful stimuli. CP functions
are often impaired.
– Produces total loss of consciousness, analgesia and muscle
relaxation.
Methods of General Anesthesia administration
1. Intravenous
– Agents that produce anesthesia in large doses through sedative-
hypnotic analgesic action.
– Agents are administered as a bolus or continuous drip infusion
directly into the systemic circulation for rapid effects.
– It is used primarily as an induction agent or can use as
maintenance of anesthesia.
– Thiopental (Pentothal Na) agent of choice
– The medication maybe administered for introduction often
used along with inhalation anesthetics but maybe used alone.
– Can also be used to produce moderate sedation.
– Duration of action is brief, and the patient awakens with little
nausea & vomiting
– IV anesthetics are non-explosives, require little equipment & are
easy to administer
– Advantage: Onset of anesthesia is pleasant; preferred by patents
who have experienced various methods.
– Disadvantage: Thiopental: Powerful respiratory depressant
effect.
– Sneezing, coughing & laryngospasm are sometimes noted w/ its
use.
2. Inhalation
- Gases and oxygen are administered into the systemic circulation
through the alveolar membranes of the lungs, with diffusion to the
pulmonary circulation and finally to the brain.
- Halothane (Flouthane), Isoflurane (Forane), Sevoflurane (Ultane),
Enflurane (Ethrane), Desflurane (Suprane)
- Liquid anesthetic maybe administered by mixing the vapors with
oxygen or nitrous oxide-oxygen & then having the patient i nhale the
mixture through tube or a mask, or through a laryngeal mask.
– ET tube can be inserted either through the nose or mouth.
2 types of Inhalation Anesthesia
1. Volatile Agents - liquid that are easily vaporized & produce
anesthesia when inhaled like Ether (Diethyl Ether),
Trichloroethylene, Chloroform, halothane, enflurane,
methoxylflurane, and isoflurane
2. Gaseous Agents
• Nitrous Oxide or laughing gas – a colorless odorless nonexposive
gas that has been referred to as a “carrier of gases.” It is the most
commonly used gas anesthetic. When inhaled, the gas anesthetic
enters the blood though the pulmonary capillaries & act on cerebral
centers to produce loss of consciousness & sedation.
• Ethylene, Cyclopropane
3. Rectal (Pediatrics)
• Metohexital Na, Anectine, Penthotal Na 5-10%
II. Regional Anesthesia
• Referring to a technique that temporary interrupts the
transmission
of nerve impulses to and from a specific area or region.
• Reduce all painful sensations in one region of the body without
inducing unconsciousness.
• Patent is awake & aware of his/her surrounding when regional or
spinal anesthesia is given – unless medication is given to produce
mild sedation or to relieve anxiety
• Nurse must avoid careless conversation, unnecessary noise &
unpleasant odors – may produce a negative view of the surgical
experience
• A quiet environment is therapeutic
• Diagnosis must not be stated aloud if the patient is not to know it
at
all this time.
Methods of Administration for Regional Anesthesia
1. Epidural anesthesia
– Anesthetic injected extradurally to produce anesthesia below level
of diaphragm, used in obstetrics.
– Is achieved by injecting local anesthetic into the spinal canal in the
space
surrounding the dura mater.
– Also blocks the sensory motor & automatic functions but it is
differentiated from the spinal anesthesia by the injection site& the
amount
used
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