MAINTAINING%20ANESTHESIA

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MAINTAINING ANESTHESIA
Information is primarily found in ch. 5 of Your
surgery textbook on pgs 139, 140-145, 169-173
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MONITORING

• Involves both _________and __________
• Can be done with or without ___________

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• VITAL SIGNS
• Variables that indicate the response of the
  patients homeostatic mechanisms to anesthesia
  and how well the patient is maintaining
  circulatory and respiratory function during
  anesthesia
• VITAL SIGNS INCLUDE Heart rate, CRT, mucous
  membrane color, pulse strength, blood pressure,
  respiration rate, and temperature

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MONITORING WITHOUT INSTRUMENTATION

• YOUR _________, ________, AND ______ ARE YOUR
  MOST VALUABLE MONITORING TOOLS!
• Machines WILL fail!
• Only rely on machines to provide you with the
  values that you cannot determine on your own
  (______________, _____________, _____________,
  ___________________, ___________________________)

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HEART RATE AND RHYTHM under ANESTHESIA

• DOGS 60-150 bpm
• REPORT if ________ or ______ bpm in lg dogs
• ________ or ______ bpm in sm dogs
• CATS 120-180 bpm
• REPORT if _______ or _______ bpm
• Lower heart rates are commonly observed with
  anesthesia due to the effects of the anesthetic
  agents.
• Anesthetic drugs can also effect the hearts
  rhythm.

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OPTIONS FOR CARDIAC MONITORING

• __________________
• __________________
• _________________________

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ESOPHAGEAL STETHOSCOPE
An esophageal stethoscope is a thin, flexible
tube that is attached to a regular stethoscope.
Lubrication is applied to the end of the tube
which is placed in the oral cavity and down the
esophagus until a heartbeat is heard. This
allows a person to listen to the heart on an
animal that is draped in for a surgical
procedure Always assess heart rate/rhythm along
with pulse strength, CRT, mucous membrane color,
and blood pressure if possible
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CAPILLARY REFILL TIME

• The rate of the return to color for mucous
  membranes after the application of digital
  pressure compresses capillaries and blocks blood
  flow temporarily
• Provides information about __________________
• A normal CRT does not necessarily indicate that
  the patient is normal, however a prolonged CRT
  (longer than 2 seconds) means that tissue
  perfusion is not adequate
• Possibly due to vasoconstriction, hypotension,
  hypothermia, heart failure, shock, or excessive
  anesthetic depth

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MUCOUS MEMBRANE COLOR

• SHOULD BE PINK!
• Look at gingiva most convenient
• If gums are pigmented, look at the conjunctiva,
  or the inner prepuce or vulva
• If pale, there may be blood loss, anemia, or poor
  perfusion
• _______________ purple or blue discoloration.
  EMERGENCY!

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PULSE STRENGTH

• Can be done at the _____________,
  _________________-, _______________________, and
  ________________________________
• Should be strong and match the heart beat
• Weak pulses may indicate hypotension (low blood
  pressure)
• Causes excessive anesthetic depth, excessive
  vasodilation, cardiac insufficiency,
• excessive blood loss

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BLOOD LOSS

• Can cause complications
• such as shock
• One 3x3 gauze
• ______ mL of blood
• The actual amount lost
• may be more due to clotting
• or pooling of blood
• Healthy animal tolerates
• 13mL/kg blood loss
• during surgery

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Intra-abdominal blood clot
Intra-abdominal blood pooling
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RESPIRATION RATE AND DEPTH

• Can be evaluated by watching the _________
  ______________ or ____________________
• Normal values while under
• anesthesia ________ bpm
• ____________________ (volume of air inhaled)
• decreases with the anesthetic depth
• Shallow breaths can cause the
• lung on the down side of the body
• to collapse (atelectasis)

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RESPIRATION RATE AND DEPTH

• Bagging the patient
• Performed when assisted ventilation is necessary
  to _____________________________________ , or to
  _______________________________
• Closing of the pop off valve and gently squeezing
  of the reservoir bag causing the patients chest
  to fill with oxygen/anesthetic gas

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• HYPERVENTILATION and tachypnea
• HYPERVENTILATION Increase in respiratory depth
• (tachypnea increase in respiratory rate)
• Causes of hyperventilation and tachypnea
• Bodys response to increased CO2 in the blood
• Underlying pulmonary disease
• Surgical stimulation
• Decrease in anesthetic depth
• Patient is too light or waking up

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• RESPIRATORY RATE AND DEPTH CONTINUED
• Normal breaths are smooth and regular, not
  gasping or labored
• DO NOT FORGET TO USE YOUR STETHOSCOPE TO EVALUATE
  BREATH SOUNDS!
• Should not hear crackles or wheezes

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THERMOREGULATION

• ______________ is the most common anesthetic
  problem and has many ways to be prevented or
  corrected
• Prevent from the
• moment the animal is induced.
• The greatest decrease is
• within the first 20 minutes.

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• The following can decrease body temperature
• Check the patients temperature at least every
  15-30 minutes if there is not an esophageal or
  rectal probe available to do continous
  monitoring. In between temp measurements, feel
  the animals extremities.

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• Several methods to avoid hypothermia

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Fluid line warmer
Circulating warm water heating pad
Self-warming surgery table
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Bair Huggers
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• ALWAYS PLACE A TOWEL
• OVER HEAT SOURCES
• TO PREVENT BURNS!!!!!!
• Do not place animal directly onto stainless steel
  table or heating pads!
• Also monitor for hyperthermia (especially
  post-operatively) which can happen with some
  anesthetic agents (opiods, ketamine).

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HEATING PAD BURNS
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REFLEXES

• Involuntary response to a stimulus
• Indicate depth of anesthesia, but no info on
  homeostatic mechanisms
• Most commonly used palpebral, pupillary light
  response, swallowing, pedal (withdrawal), ear
  flick, laryngeal

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• _________________ Reflex
• Touch the corner of the eye and the animal
  blinks.
• This reflex is stimulated by tapping the skin at
  the medial or lateral canthus of the eye or by
  running the finger along the eyelashes. This
  reflex is gradually lost as anesthetic depth
  increases.

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• __________________________ Reflex
• Immediate closure of the epiglottis and vocal
  cords when the larynx is touched by any object.
• Stimulation of the larynx will cause the animal
  to swallow. The stimulation may be from outside,
  for example, an attempt to pass an endotracheal
  tube or may be internal for example the presence
  of secretions at the larynx. This is a mechanism
  to prevent accidental aspiration of fluids into
  the lungs.

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• ____________________ Reflex
• Pull a limb gently, pinch the toe and the animal
  will pull back the limb.
• The reflex is obtained by firm pressure of the
  interdigital skin in the dog and cat
  particularly important in animals undergoing
  mask inductions

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• ______________________ Reflex
• Shine a light in the eye and the pupil
  constricts.
• The pupillary responses under anesthesia are
  heavily influenced by pre-medication. Species
  variations exist. There is also variability in
  response to different anesthetics. In general, in
  un-premedicated patients, the pupil is dilated in
  the early excitement phase and then becomes
  progressively constricted as surgical anesthesia
  occurs. With very deep surgical anesthesia the
  pupil begins to dilate again and with entry into
  stage IV, with respiratory and cardiac arrest,
  the pupil is maximally dilated.

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• _________________ Reflex
• Touch the cornea and the animal blinks. Be
  careful not to damage the cornea if this reflex
  is tested.
• This reflex is obtained by gentle palpation of
  the lateral aspect of the cornea. This causes
  reflex closure of the eyelids. This reflex is not
  always reliable in the dog, particularly if the
  eyeball is markedly rotated.

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• _____________________ REFLEX
• Pinnal reflex used in cats.
• Gently touch the hair on the inner surface of
  the ear and watch the pinna twitch.
• Dont test too frequently or the reflex will be
  inaccurately lost.

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