Sedation & Anesthesia Flashcards
What’s the difference between tranquilization and sedation?
state of reduced consciousness without CNS depression, but with behavioral change —> patient aware of surroundings
state of reduced consciousness with CNS depression —> patient unaware of surroundings
What is shock? How is it associated with anesthesia?
failure of appropriate perfusion or oxygenation for cells of the body
means of calculated/planned/reversible reducing of perfusion, similar to shock
What is considered successful sedation/anesthesia?
optimal/improved function post-anesthesia
- not just waking up
What are the major steps to success for sedation and anesthesia?
- risk identification and drug planning
- optimizing patients pre-anesthesia
- supportive care
- monitoring
- troubleshooting
- prep for emergencies
What 3 things does ASA risk have to do with? What does it have nothing to do with?
- cardiovascular and renal systems
- airway, pulmonary, and pleural systems
- central and peripheral neurologic systems
surgery, age, breed
What is the main difference between ASA 1/2 and ASA 3/4/5?
patients in ASA 1 and 2 are considered low risk and not clinical for their problem
patients in ASA 3, 4, and 5 are considered high-risk and clinical for their problems
What are the 3 major components of a peroperative ASA assessment?
- historical medical facts
- current physical exam, BCS, temperament, pain, body type
- objective diagnostics - bloodwork, imaging, function tests
What premeds are recommended for low-risk (ASA 1 and 2) patients? What local blocks, induction agents, and maintenance are recommended?
mini dose Dex or Ace, an opioid, and an NSAID
+ local block
Ket Val or Propofol
inhalant in 100% O2
What premeds are recommended for high-risk (ASA 3 and 4) patients? What local blocks, induction agents, and maintenance are recommended?
Midaz, opioid, steroid, +/- micro dose Dex
+++++ local block
Ketofol, Alfaxan, Fent/Mid/Ket
less inhalant in 100% O2
What criteria must be optimized to ensure patients are ready for anesthesia?
- neurologic status: cranial nerve function, mentation, ambulation
- temperature: 98-103 F
- pulse rate and rhythm
- respiratory rate and rhythm: 3-40 bpm
- arterial blood pressure: MAP 70-80 mmHg; SAP 100-160 mmHg
- oxygen status: PaO2 > 80% on room air; > 95% on oxygen
- ventilation status: PaCO2 < 50%
- urine output: 1-2 mL/kg/ hr
Why should all tranquilized, sedated, and anesthetized patients be supported?
- loss of homeostasis due to drugs
- main pillar to anesthesia success
- indicator of quality care
- cheap, easy
- in the clients eyes, care is imperative
What do all anesthetized and sedated patients require?
a patent airway, either by intubation or extended head with tongue pulled forward
- objective monitoring (capnograph)
What makes up a patent airway? How is it maintained without an ET tube? With?
nose, nasopharynx, glottis, trachea
sedated or TIA = head and neck extended, tongue pulled forward, no masses or obstructions, monitored with pulse oximeter
fully anesthetized
In what 3 situations is an ET tube recommended for obtaining a patent airway?
- low pulse ox unintubated
- oronasal, facial, or otic surgery
- regurgitation possibility
Do all sedated or anesthetized animals need to be intubated? How does plane of sedation affect this?
NO
deeper plane = fully anesthetized and requires intubation
What are 3 aspects of positioning to obtain a patent airway?
- open mouth
- tongue pulled forward
- neck straightened
What are 3 reasons to provide flow by or mask oxygen to anesthetized or sedated patients?
- hypoxia is inevitable and causes vasoconstriction, shunting of blood, and differential tissue demands
- oxygen is a great carrier for anesthetic gases
- preoxygenation prevents hemoglobin depletion in low CO phases of sedation and anesthesia
In what situations is it recommended to have a tight or loose fitting oxygen mask?
TIGHT = short-nosed, non-panting patients
LOOSE = hyperthermic, brachycephalic, stressed
When is flow by oxygen recommended?
end of rebreathing or non-rebreathing circuits
What does adequate respiration require?
oxygenation and ventilation
(one does not imply the other)
What is ventilation? What happens during hypoventilation?
removal of CO2
buildup of CO2 waste, resulting in increased H+ ions (acidosis), decreased O2, and low perfusion of anesthesia
What are the normal CO2 levels in arterial/venous blood gas of non-intubated patients? ETCO2?
PaCO2 = 25-60 mmHg in cats and dogs
PvCO2 = 30-55 mmHg
tight press mask for 15 seconds = 25-60 mmHg
What are the normal CO2 levels in arterial/venous blood gas of intubated patients? ETCO2?
PaCO2 = 25-40 mmHg, mildly lowing in cats
PvCO2 = mildly lower
ETCO2 = 35-50 mmHg
What are the 4 subtle signs of hypercarbia seen in un-intubated patients?
- tachycardia
- deep plane of anesthesia despite high pulse ox readings
- dampened pulse ox curves
- normothermia to hyperthermia
What should be monitored in intubated patients to assure adequate ventilation? How should the patients plane of anesthesia be maintained?
- arterial and venous blood gases
- capnography
keep patient light enough to respond to CO2 levels —> keep Iso or Sevo minimal necessary for surgery
What is commonly provided to intubated patients to ensure there is adequate ventilation?
intermittent positive pressure ventilation (IPPV), providing an occasional sigh by deflating the breathing bag by hand
What 2 things should be done if ventilation is inadequate in non-intubated patients?
- partially reverse sedation
- intubate and provide IPPV with ambu
What 3 things should be done if ventilation is inadequate in intubated patients?
- maintain adequate plane of anesthesia (avoid deep planes!)
- IPPV - sigh
- mechanical ventilation
Why is IV access important?
- deliver sedatives and anesthesia, especially important in critical and obese patients
- emergency and reversal access
- fluid therapy essential to compensate for low circulation with sedatives and anesthetics (also improves anesthetic plane, oxygenation, and ventilation)
What catheters are used for IV access in sedated and anesthetized patients? Vessels?
smallest bore, since vessels will be needed in the future for chemo or additional surgeries
adequate, peripheral vessels
What are 2 reasons that peripheral IV access is preferred? When is central recommended?
- potential for sepsis
- embolic potential
is massive blood loss is anticipated
What are 5 effects of inappropriate chest pressure during patient transport?
- reduced cardiac output
- reduced oxygenation and ventilation
- lower airway collapse
- increased regurgitation potential
- thoracic vertebral and rib malalignment
What are 4 effects of inappropriate head and neck positioning during patient transport?
- increased intracranial and intraocular pressure
- upper airway obstruction
- ET tube displacement
- cervical vertebral malalignment
_______ is crux of great supportive care and sedation anesthesia success.
monitoring
What 5 things should be monitored during anesthesia?
- anesthetic depth - patient should be insensible to pain
- circulation
- oxygenation
- ventilation
- temperature
What is the difference between non-invasive and invasive monitoring techniques?
NON-INVASIVE = +/- equipment, little risk of complications (no equipment = manual/subjective; equipment = objective)
INVASIVE = greater accuracy and risk of secondary complications
What is considered the best monitor of anesthesia?
TECHS AND DOCTORS - visualization, palpation, auscultation; technology increases ability, quickness, and efficiency
- monitors are only as useful as those who properly use and interpret data
How are heart rate, heart rhythm, stroke volume, and oxygen monitored objectively (equipment)?
HEART RATE = pulse palpation, pulse oximetry, Doppler, stethoscope
HEART RHYTHM = pulse palpation to feel beat variability, ECG
STROKE VOLUME = blood pressure, capnography
OXYGEN = pulse oximetry, blood gas analysis
What are the 3 “firsts” of monitoring?
- only a live animal can be monitored
- get a pulse and respiratory rate pre/post giving a pre-delivery of “shock”, or induction agents
- watch trends!
What 5 subjective monitoring techniques are considered unreliable?
- MM color - difficult with pigmentation or vasoconstriction
- CRT
- pulse pressure - there is a systolic/diastolic difference that makes it NOT related to the mean
- heart beat - commonly altered based on obesity or conformation
- blood loss
What reliable objective monitoring techniques are recommended for heart rate/rhythm, blood pressure, ventilation, and temperature?
ECG, (esophageal) stethoscope, pulse ox
Doppler, oscillometric, sphygmomanometer
ETCO2, Wright’s respirometer (TV), arterial blood gas
electrical probe, thermometer
When is oxygenation more accurately monitored?
without intubation —> O2-Hb dissociation curve
What are 6 major signs of a patient in a good plane of anesthesia?
- jaw tone present
- eyes rolled ventrally (with sclera present)
- iris present
- RR/pulse present, but slow
- pulse ox wave present
- capnograph curve present, but not reduced
What are 6 major signs of a patient in a cardiopulmonary arrest?
- minimal jaw tone
- eyes straight forward
- pupils dilated
- apnea or slow RR/pulse
- pulse ox wave may be present
- capnograph curve absent
CPCR
What are the 7 steps to CPCR?
- turn off inhalant by disconnecting the patient and emptying the circuit
- assess airway by correcting ET tube placement, length and patency
- reattach breathing circuit
- assist respiration - start with one breath to watch chest expansion, then give 10-15 bpm
- pulse palpation - if none present, start chest compressions ar 100/min
- warm the patient
- assure monitors in place (Doppler!)
What 6 reversal drugs are recommended for CPCR? What 2 fluids?
- Atipamezole 0.2 mg/kg
- Naloxone 0.02 mg/kg
- Epinephrine 0.05 mg/kg
- Atropine 0.02 mg/kg
- Lidocaine 2 mg/kg
- Esmolol 0.1 mg/kg
- 20 mL/kg crystalloid
- 3 mL/kg colloid (hetastarch)
What are some anesthesia-associated arrest differentials?
- anesthetic overdose
- baro/volutrauma from APL valve
- airway obstruction
- pnuemothorax
- hypoglycemia
- vagal response
- hyperkalemia
- thromboembolism
- migration of epidural or spinal disease
- ventricular arrhythmia associated with cautery
- increased intracranial pressure
What 5 things does general anesthesia and deep sedation lead to?
- hypothermia
- reduced circulation
- hypoventilation
- hypoglycemia
- depressed autonomic output: hypotension, ileus, decreased renal perfusion, urinary dysfunction
True or false: A sedated (vs. a tranquilized) patient is aware of its surroundings.
FALSE
At What stage should you optimize the patient in order to have a successful outcome to anesthesia?
a. Induction
b. Maintenance
c. Post-anesthesia
d. Pre-anesthesia
D
True or false: Hypotension is the first domino to fall during general anesthesia.
FALSE —> hypoxia
All of the following can be performed (based on AAHA standards and according to Brodbelt 2008, 2009) to increase anesthesia success EXCEPT:
a. Modify a protocol based on the risk
b. Provide solid supportive care (warmth, iv access, adequate oxygenation and ventilation)
c. Monitor patients only if necessary
d. Identify the patient’s risk status
C
What is a major difference between inhalant and injectable anesthesia?
a. Agents are carried by oxygen or similar gas with inhalant anesthesia but not injectable anesthesia
b. Premedication is needed with inhalant anesthesia but not injectable anesthesia
c. Shock is produced with inhalant anesthesia but not injectable anesthesia
d. Patient is unaware of general surroundings with inhalant anesthesia but not injectable anesthesia
A
The chance of a healthy dog dying during or immediately post anesthesia is _____: the same for a cat is______.
a. 0.05%, 0.1%
b. 0.17%, 0.34%
c. 0.05%, 0.05%
d. 0.17%, 0.05%
A
Which monitor constitutes a Poor objective means to measure heart rate?
a. Electrocardiogram
b. Stethoscope
c. Pulse oximetry
d. Doppler crystal
B
You decide to troubleshoot the pulse oximetry reading on this case. What is a first step in your troubleshooting?
a. Turn off vaporizer
b. Warm the patient
c. Check the underbody warming unit
d. Assess airway patency; the ET tube may have become clogged with mucous or even dislodged
D
What of the following are considered reliable monitoring techniques for an intubated patient under general anesthesia?
a. Cranial nerve function testing
b. Pulse pressure
c. Capillary refill test
d. Mucous membrane color
A
True or false: To create a patent airway in a non intubated patient, a technician should open the patient’s mouth, pull the tongue forward, and extend the head and neck.
TRUE
What physiologic variable is NOT needed to calculate cardiac output?
a. Afterload
b. Preload
c. Oxygen delivery
d. Contractility
e. Heart rate
C
An anesthesized 5-year-old FS dachshund has the following cranial nerve function assessment: jaw tone is present with eyes rolled ventrally and palpebral response present. Her vital parameters are: RR and pulse rate are elevated. Pulse Oximetry reads 92% with an adequate signal strength and capnography reads ETC02 of 35mmHg. Is your patient in considered light or dangerously deep?
Light
What is NOT an example of a patent airway?
a. Endotracheal tube correctly inserted
b. Head and neck are flexed
c. No upper airway masses
d. Tongue pulled forward and out
B
As a patient enters stage III general anesthesia (a stage suggesting surgically adequate Cardiocerebropulomany depression) which of the following signs should be present to indicate an adequate depth of anesthesia?
a. Eyeballs should be rotated dorsally and pupils dilated widely
b. Eyeballs should be straight forward and pupils pinpoint
c. Eyeballs should be rotated ventrally and pupils mid dilated
d. Eyeball should be straight forward and pupils dilated widely
C
During anesthesia-related arrest, which of the following events should occur first?
a. The inhalant should be turned up and the system flushed
b. The inhalant should be turned off and the system flushed
c. The patient should be warmed
d. Epinephrine should be administered
B
All of the following can be initial signs of inadequate ventilation of non-intubated patients EXCEPT?
a. “Dampened” pulse ox curves
b. Low body temperature
c. Low heart rate
d. High respiratory rate
C —> would be tachycardic
What is NOT an optimization parameter?
a. Urine output
b. Oxygen status
c. Neurologic status
d. Total protein
D
