Thermoregulation & Post-Op Care

Question 1

What are the 2 major ventilator weaning options?

Answer 1

1. turn off ventilator, rebag and manually give 1-2 breaths per minute
2. leave ventilator on and decrease rate to allow CO2 to build up

Question 2

What are the 2 major cons to mechanical ventilation?

Answer 2

1. decreased cardiac output due to increased pressure occluding vessels
2. increased anesthesia uptake = deeper anesthetic depth

Question 3

How is ventilation monitored?

Answer 3

capnograph ETCO2 levels

Question 4

How does anesthesia cause hypothermia?

Answer 4

anesthesia drugs cause vasoconstriction and the mixing of core and peripheral blood

Question 5

What are the 3 heat transfer mechanisms?

Answer 5

1. RADIATION - transfer of energy between surfaces and the most important mechanism of anesthesia
2. conduction/convection - flow of heat from warmer to cooler surfaces
3. evaporation of liquids from skin or body cavities (open chest or abdomen surgeries)

Question 6

At what temperature is mild hypothermia recognized? What 2 problems is this associated with?

Answer 6

36 C (96.8 F)

1. prolonged recovery
2. bradycardia less responsive to anticholinergic agents

Question 7

At what temperature is moderate-severe hypothermia recognized? What 6 problems is this associated with?

Answer 7

92 F

1. prolonged recovery
2. increased risk of anesthesia agent overdose due to increased potency of inhalants
3. immunosuppression with increased risk of infection
4. shivering in recovery increases O2 demand
5. increased blood viscosity
6. CV effects: arrhythmias, refractory bradycardia, hypotension, arrest

Question 8

In what 4 ways is hypothermia prevented/treated?

Answer 8

1. warming devices - circulating water systems, resistive polymer heating system (HotDog), forced air units, heated surgery tables
2. lower oxygen flow rates
3. airway humidifiers/heaters
4. warm blankets/towels and plastic/bubble wrap

Question 9

What 3 practices should be avoided to prevent burn risk while treating for hypothermia?

Answer 9

1. standard heating pads
2. direct contact with HotDog or heated table, especially for a wet patient
3. direct contact with heated fluid bags or bean bags

Question 10

What are the 3 most common causes of hyperthermia in patients under anesthesia?

Answer 10

1. iatrogenic - turn down/off devices as the patient reaches 99 F, or else they will keep heating up
2. malignant hyperthermia - genetic risk due to exposure to inhaled anesthetics (pigs, Greyhounds)
3. opioids - alters CNS thermoregulation where dogs begin to pant and cats become hyperactive

Question 11

Why are Greyhounds associated with anesthetic hyperthermia?

Answer 11

pre-anesthetic anxiety

Question 12

When do most perioperative deaths occur?

Answer 12

first 3 hours of recovery

• 47-60%

Question 13

What 3 supportive care measures should be used during post-anesthesia recovery?

Answer 13

1. monitoring remaining on until patient is extubated
2. ventilation/oxygenation
3. padding/positioning - sternal, comfortable lateral

Question 14

When should patients be extubated?

Answer 14

when they are swallowing or actively objected to the ET tube

• longer for brachycephalic
• shorter for cats that are prone to biting through and causing the tube to become lodged in the trachea

Question 15

When is pain management given after surgery?

Answer 15

• immediately post-op
• TGH plan

Question 16

What needs to be determined in cases of anxiety, dysphoria, and rough recovery? What is commonly done to avoid/treat this?

Answer 16

is it due to pain?

• sedation
• re-anesthesia

Question 17

What does prolonged recovery lead to?

Answer 17

• hypothermia
• hypoventilation
• hypotension
• hypoxemia
• hypoglycemia
• electrolyte, acid-base disturbances
• neurologic/CNS disease

Question 18

What should be checked if a stable patient is undergoing prolonged recovery (over 45 mins)?

Answer 18

• HR, RR, rhythm, pulse quality, and capillary refill
• anesthetic depth based on jaw tone, palpebral reflex, and response to stimulation
• airway adequately protected
• ensure all inhalant and injectable anesthetics are discontinued
• stimulate the patient by rubbing, tickling ears, and changing recumbency
• use monitors to check hypothermia, hypotension, and hypercarbia
• review anesthetic record
• check for hypoglycemia, anemia, electrolyte or acid-base disorders

Question 19

What should be done if stomach contents move passively into the esophagus/pharynx (regurgitation)? What should be avoided?

Answer 19

• get help to ensure the ETT cuff/seal has no leakage
• check pH of reflux
• clean mouth and pharynx of debris
• suction esophagus and flush until clear
• local bicarbonate instillation of Famotidine and Sucralfate
• keep cuff inflated and patient sternal until strongly swallowing and chewing

pushing a catheter into the stomach, unless significant fluid is present