Monitoring and Complications Part 1 Flashcards

1
Q

what do we monitor during anesthesia?

A
  1. anesthetic depths
  2. cardiovascular system: adequate delivery of oxygen to the tissues
  3. respiratory system:
    -adequate oxygenation
    -adequate ventilation
  4. temperature
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2
Q

describe subjective/hand monitoring of anesthetic depth

A
  1. jaw tone: want SOME
    -if have a lot, too light/not very deep
    -if none; potentially too deep
  2. eye position: will change
    -surgical plane is ideally ventromedial
    -staring right at you? could be light and could be deep; if central, nystagmus indicates lighter, esp in large animals
  3. palpebral/corneal reflexes
    -both present: light
    -loss of palpebral: surgical plane
    -loss of corneal: deep, too deep
    (camelids never lose palpebral unless extremely deep)
  4. rectal tone:
    yes or no
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3
Q

describe objective/machine monitoring of anesthetic depth

A
  1. heart rate:
    -tachy: lighter
    brady: deeper
  2. respiratory rate
    -same as HR
  3. blood pressure:
    -hypertension: light
    -hypotension: deep
  4. EEG/BIS (not done clinically)

these categories are highly affected by anesthetic drugs!!!

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4
Q

describe subjective/hand monitoring of cardiovascular system

A
  1. mucous membrane color: assessment of oxygenation and perfusion
    -injected, pink, pale pink, cyanotic
  2. CRT: assess perfusion (should be less than 2 sec)
  3. cardiac auscultation:
    -ID rate, rhythm, murmurs
  4. pulse palpation: assess CV status:
    -strong, weak, thready, not palpable
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5
Q

describe objective/machine monitoring of CV system

A
  1. ECG: visual representation of electrical activity of heart; does NOT tell you if heart contracts
    -used to monitor HR and ID arrhythmias
  2. blood pressure: representative of perfusion pressure to the periphery
    -systolic arterial pressure: peak pressure reached by arterial pulse
    -diastolic arterial pressure: lowest value
    -mean arterial pressure: avg arterial blood pressure throughout pulse wave
    -range of autoregulation: range of blood pressure in which blood flow to organ is autoregulated by body (MAP 60-150mmHg)
    –MAP minimum during anesthesia:
    –SA: 60mmHg
    –LA: 70mmHg
    -hypotension can lead to decreased delivery of oxygen to the tissues and ischemic injury
    -hypertension can lead to over-perfusion, which can cause an increase in intracranial pressure, retinal detachment, hemorrhage, etc.
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6
Q

how to measure blood pressure?

A
  1. invasive: most accurate
    -need an arterial catheter connected to a pressure transducer; provides beat to beat blood pressure measurement
    -disadvantages: technically challenging, potential complications (hematoma, ischemic injury to extremity, infection)
    -best for critical patients in which fluctuations in blood pressure are anticipated
  2. non-invasive: for healthy, non-critical patients
    -oscillometric: cuff on an extremity; machine provides SAP, DAP, MAP
    -doppler + sphymomanometer: cuff on extremity proximal to a doppler crystal; inflate cuff until pulse sound stops then slowly deflate; pressure when pulse sounds return = SAP (not in cats; is closer to MAP); also gives audible pulse of patient

disadvantages of noninvasive:
-less accurate so can really only use as trends (going up or going down, not exact numbers)
-accuracy affected by severe hypotension or hypertension, arrhythmias
-does not provide continuous measurement

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7
Q

describe subjective/hand monitoring of the respiratory system

A
  1. respiratory rate: ventilation
    -counting chest excursions or movement of the bag
  2. respiratory depth: ventilation
    -assessing size of chest excursions or evacuation of the bag
  3. mucus membrane color: oxygenation
    -can be hard if anemic, cannot detect changes in cyanosis
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8
Q

describe objective/machine monitoring of respiratory system

A
  1. pulse oximetry:
    -measures the % of hemoglobin that is saturated with oxygen
    -normal: healthy, awake adult breathing room air: 98-100%
    -uses alternating red and infrared light, commonly placed on tongue or digit: can shave fur on carpus, tarsus, or base of tail and apply a transreflectance (flat) probe
    -sources of error: pigmentation, vasoconstriction, motion, thickness of tissue, anemia, ambient light
    -how trust? if HR matches true pulse, quality of pulse signal, quality of plethysmograph
    -if in doubt, the only way to check is arterial blood gas
  2. capnography
    -a measure of the amount of CO2 in expired gas
    –normal EtCo2 in awake, healthy patient is 35-45mmHg
    -direct assessment of patient ventilatory status
    -indirect assessment of patient cardiac output and metabolic rate
    -some units also measure oxygen and anesthetic gases
    -expired anesthetic gas levels used as a surrogate measure of the amount of inhalant in the brain and can be used to titrate the inhalant anesthetic to effect
    -amount of CO2 expired is inversely related to adequacy of alveolar ventilation

-hypercapnia: hypoventilation
-hypocapnia: hyperventilation

  1. blood gas analysis
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