Overview of Anesthesia

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Overview of Anesthesia
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The Four Stages of Anesthesia

• Stage I Relaxation

• Biologic Response Amnesia, Analgesia

• Pt Reaction Feels drowsy and dizzy. Exaggerated
  hearing. Decreased sensation of pain.
• May appear inebriated.

• Nsg Actions Close OR doors. Check for proper
  positioning of safety devices. Have suction
  available and working. Keep noise in room at a
  minimum. Provide emotional support for the pt by
  remaining at his side.

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The Four Stages of Anesthesia
Stage II Excitement

• Biologic Response Delirium

• Pt Reaction Irregular breathing. Increased
  muscle tone and involuntary motor activity may
  move all extremities. May vomit, hold breath,
  struggle (pt very susceptible to external stimuli
  such as a loud noise or being touched)

• Nsg Actions Avoid stimulating the patient. Be
  available to protect extremities or to restrain
  the pt. Be available to assist anesthesiologist
  with suctioning.

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The Four Stages of Anesthesia
Stage III Operative or surgical anesthesia

• Biologic Response Partial to complete sensory
  loss. Progression to complete intercostal
  paralysis.

• Pt Reaction Quiet. Regular thoraco-abdominal
  breathing. Jaw relaxed. Auditory and pain
  sensation lost. Moderate to maximum decrease in
  muscle tone. Eyelid reflex is absent.

• Nsg Actions Be available to assist
  anesthesiologist with intubation. Validate with
  anesthesiologist appro. Time for skin scrub and
  positioning of pt. Check position of pts feet
  to ascertain they are not crossed.

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The Four Stages of Anesthesia
Stage IV Danger

• Biologic Response Medullary paralysis and
  respiratory distress.

• Pt Reaction Resp. muscles paralyzed. Pupils
  fixed and dilated. Pulse rapid and thready.
  Respirations cease.

• Nsg Actions Be available to assist in tx. Of
  cardiac or respiratory arrest. Provide emergency
  rug box and defibrillation. Document
  administration of drugs.

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Common Inhalation Agents

• Forane
• Advantage
• lowers resp.,
• good muscle relaxation,
• low incidence of renal or hepatic damage.
• Offers good cardiovascular stability.
• May be given to pts with minimal renal failure.

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Common Inhalation Agents

• Forane
• Disadvantage
• Pungent odor
• Produces more coughing
• expensive

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Common Inhalation Agents

• Halothane
• Advantage
• Rarely irritates the brynx
• Does not increase respiratory secretions

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Common Inhalation Agents

• Halothane
• Disadvantage
• Cases of hepatitis have been reported after
  administration
• Should not be administered to patients with
  abnormal liver fx.

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Common Inhalation Agents

• Ethrane
• Advantage
• Rapid induction
• Rapid recovery with minimal after effects

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Common Inhalation Agents

• Ethrane
• Disadvantage
• Respiration and blood pressure are progressively
  depressed with deepening anesthesia
• Severe renal failure is a contraindication to
  use.
• Seizure activity asso. with use. Not to be
  administered to pt with history of seizures.

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Common Inhalation Agents

• Desflurane
• Advantage
• Allows much faster induction and emergence
• Offers good cardiovascular stability

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Common Inhalation Agents

• Desflurane
• Disadvantage
• Strong odor

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Common Inhalation Agents

• N2O
• Inorganic gas of slight potency,
• supports combustions when combined with oxygen.
  
• Only gas still in use for anesthesia

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Common Inhalation Agents
N2O Advantage rapid uptake and elimination
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Common Inhalation Agents

• N2O
• Disadvantage
• no muscle relaxation,
• possible excitement or laryngospasm,
• hypoxia a hazard

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Common Inhalation Agents
N2O Use because it lacks potency, N2O is
rarely used alone, but as an adjunct to
barbiturates, narcotics, and other drugs.
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Intravenous Anesthetic Agents
Because removal of drug from circulation is
impossible, safety in use is related to
metabolism.
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Intravenous Anesthetic Agents

• Barbituates
• Sodium Pentothal, Brevital
• Important Facts
• Do not produce relief from pain, only marked
  sedation, amnesia, hypnosis.
• Repeated administration has accumulative,
  prolonged effect.
• Extravasation can cause thrombophlebitis, nerve
  injury, tissue necrosis.

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Intravenous Anesthetic Agents

• Diprivan
• Sedative, hypnotic
• Important Facts
• Used for rapid induction and maintenance of
  anesthesia for short periods of time.
• Used for general anesthesia for ambulatory
  surgery patients.

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Intravenous Anesthetic Agents

• High Dose Narcotics
• Following high dose narcotic anesthesia patients
  are
• awake,
• pain free,
• with adequate, though not good ventilation

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Intravenous Anesthetic Agents
High Dose Narcotics Opiods Fentanyl
(Sublimase) 70 times more potent than
Morphine. Sufenta 5 times more potent than
Fentanyl, 625 times more potent than
Morphine. Demerol causes myocardial
depression and tachycardia, 1000 times less
potent than Fentanyl.
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Intravenous Anesthetic Agents

• High Dose Narcotics
• Clinical signs of narcotic toxicity
• Pinpoint pupils
• Depressed respirations
• Reduced consciousness

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Intravenous Anesthetic Agents
High Dose Narcotics Narcotic antagonist given to
reverse narcotic-induced hypoventilation. Narcan
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Intravenous Anesthetic Agents
Nondepolarizing Neuromuscular blockers Act on
enzymes to prevent muscle contraction.
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Intravenous Anesthetic Agents

• Nondepolarizing Neuromuscular blockers
• Curare poison arrows made by South American
  Indians. Caused respiratory paralysis.
• Pavulon 5 times more potent than Curare.
• Norcuron shorter duration of action, more
  potent than Pavulon.
• Tracrium intermediate action about 30 minutes.
  Advantage to liver and renal disease pt because
  metabolizes more quickly.

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Regional Anesthesia
Spinal Anesthesia Agent is injected into the
cerebrospinal fluid (CSF) in the subarachnoid
space using a lumbar interspace in the vertebral
column.
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Regional Anesthesia

• Spinal Anesthesia
• Level of anesthesia depends on
• Position during and immediately after injection
• Cerebrospinal fluid measure
• Site and rate of injection
• Volume, dosage, specific gravity of solution
• Inclusion of vasoconstrictor will prolong effects
• Spinal curvature
• Interspace chosen
• Coughing and straining

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Regional Anesthesia
Epidural Agent is injected into the space between
the ligamenta flava and the dura. Anesthesia is
prolonged while drug is absorbed from CSF into
the blood stream.
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Regional Anesthesia

• Peripheral Block
• Bier Block or Intravenous Regional Block
• Document
• Tourniquet application
• Pressure setting
• Inflation time
• Deflation time
• Surgeon should be notified of tourniquet time
  every 30 min.
• Deflation done intermittent to avoid toxic blood
  level and seizures.

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Regional Anesthesia

• Monitored Anesthesia Care
• Physician administers local anesthesia
• Anesthesia personnel monitor pt
• If nursing personnel monitor pt, must be RN other
  than circulating nurse.
• Abnormalities reported to surgeon.
• Documentation
• monitoring of medications and their dose, route,
  time of administration, effects
• pts LOC should be monitored and recorded.