Lecture 23: Anesthetic Complications (Exam 3) Flashcards
1
Q
When do anesthesia related deaths occur
A
- W/in 48 H in small animals
- Up to 7 days in horses
- Dogs, cats, & rabbits - 50% post op occur w/in 3 h of the end of ax
- Horses - 92% of complications occur in recovery & are neuromuscular or respiratory in nature
2
Q
What kind of complications can occur during the peri ax period
A
- Common
- Uncommon
- Complications due to sx or dx procedure
- Human error or px idiosyncratic rxn
3
Q
List the common complications during the peri ax period
A
- Hypoventilation
- Hypotension
- Hypothermia
- Hypoxemia
4
Q
List the uncommon complications that can occur peri ax
A
- Metabolic
- Neuromuscular
- Post ax cortical blindness
5
Q
What are some CV complications
A
- Hypotension - MAP < 60 mmHg
- Hypertension - MAP > 150 mmHg
- Hypovolemia due to hemorrhage
- Cardiac arrest
6
Q
Describe arrhythmias as a CV complication
A
- Consider tx if BP is affected
- Look for underlying cause
7
Q
What is in the decision tree for hypotension
A
- Recognize hypotension
- Check depth of ax & other causes
- Assess HR (determine if anticholinergic warranted)
- Consider IVF bolus up to 2 times (safe to give hourly rate over 15 min)
- Consider colloidal support (can include a transfusion of blood products)
- Discontinue ax as soon as possible
8
Q
What are the two most common respiratory complications
A
- Hypoventilation
- Hypoxemia
9
Q
T/F: Always be prepared @ induction to encounter issues w/ intubation
A
True
10
Q
What is hypoventilation
A
ETCO2 > 55 mmHg
11
Q
What can cause hypoventilation
A
- Anesthetic drugs
- &/or excessive anesthetic depth
- Pre existing co morbidities
- Possible equipment probs
- Decrease in respiratory rate
- Decrease in tidal vol
- Increase in metabolic rate
- Hyperthermia
12
Q
What can hypoventilation lead to
A
- Respiratory acidosis
- Hypooxemia
- Increased intracranial pressure
13
Q
What is the tx for hypoventilation
A
- Check depth & adjust
- Provide IPPV
- Change position of px
- Check equipment
14
Q
Describe hypoxemia
A
- Unlikely if intubated & on 100% O2
- Can quickly become life threatening
- Can be hypoxemic & not show cyanosis
15
Q
SPO2 of 95% = PaO2 of what
A
80 mmHg
16
Q
SPO2 of 90% = PaO2 of what
A
60 mmHg
17
Q
What is the tx of hypoxemia
A
- Check O2 glow rate for adequacy
- Check placement of ETT
- Check ax machine & SpO2 probe
- Give IPPV
- Consider adding PEEP
- Assess perfusion & support cardiac output
- Change position to sternal & discontinue ax if no improvement w/ other interventions
18
Q
What are the causes of hypoxemia
A
- Hypoventilation
- V/Q mismatch
- Decreased FiO2
- Right to left shunt
- Diffusion impairment
19
Q
Slide 19
A
20
Q
Describe malignant hyperthermia
A
- Rare but life threatening phenomena
- May be inherited
- Reported in pigs, dogs (greyhounds), horses, & cats
21
Q
Describe gastro esophageal reflux during gen ax
A
- Occurs when gastric contents pass into the esophagus
- Can be clear or brown fluid coming from the nose or mouth
- 50 to 60% of dogs may experience it
- 33% incidence rate in cats
- Can lead to esophagitis, esophageal stricture formation, or aspiration pneumonia
22
Q
What are risk factors for GER
A
- Late stage preg
- Abdominal & ortho sx
- Expected in endoscopy
- Length of pre op fasting time & type of food
- Recumbency & changes in body position during ax
- Ax drug protocol
- Breed
- Pre existing condition
- Prolonged duration of ax
- Older dogs
23
Q
What is tx for GER
A
- Be sure ETT cuff has a good seal (use pH strip to measure pH)
- Esophagus should be suctioned & lavaged w/ warm water & bicarbonate
- Sucralfate & H2 receptor antagonist
- Admin metoclopramide by bolus @ musch higher doses than commonly used reduces the incidence
- Oral omeprazole to reduce GER
- Maropitant will not prevent GER
24
Q
What are some metabolic complications seen w/ gen ax
A
- Hypoglycemia or hyperglycemia
- A/B disturbance
- Electrolyte imbalance
25
When should hyperkalemia be txed
Before ax
26
What drug doesn't lower K+
Calcium gluconate
27
Which drug promotes the release of insulin & the uptake of K+ into the cells
Dextrose 50%
28
Which drug dilutes the high serum of K+
0.9% NaCl (or another isotonic crystalloid)
29
What drug shift K+ into the cells
Reg insulin
30
What drug alkalinizines the blood by promoting K+ influx intracellularly & is only used in severe hyperkalemia
Sodium bicarbonate
31
Describe myopathy
Caused by ischemic muscle damage due to prolonged compression or inadequate padding &/or prolonged hypotension leading to under perfusion of muscles
32
Describe neuropathy
Caused by stretching, compression, ischemia, metabolic derangement, & surgical resection
33
What are the best tx for myopathy & neuropathy
* Prevention is better by paying attention to adeq padding & positioning of limbs
* Decrease ax
* Promptly treat hypotension
* IVF for diuresis, analgesics, ant inflammatory drugs, sedatives, & vasodilators
* Rehabilitation therapy may be beneficial
34
Describe blindness after ax in cats
* Seen after dental cleanings
* Due to use of mouth gas leading to cerebral ischemia (maxillary artery blood flow compromised)
* Neuro deficit may resolve in some px
* Could also happen due to sever hypotension &/or CPA
35
What are the signs of dysphoria recovery (Rough recovery)
* Vocalization
* Panting
* Restlessness
* Urination/defecation
* Salivation
* Thrashing, agitation, & hyper excitable are sx of emergence delirium
36
Describe dysphoria in recovery
* Seen w/in a short time after extubation
* Distinguish from pain
* Several causes of dysphoria
* Keep safety of px & personnel in mind
* Treat underlying prob & admin drug
37
What are tx for dysphoria in recovery
* Dexmedetomididine is most commonly used
* Acepromazine
* If benzodiazepine is suspected as the cause of dysphoria then consider flumazenil
* If severe consider propofol to reset recovery
* Consider naloxone if opioid induced dysphoria is suspected
38
List examples of preventable complications
* Human error
* Drugs
* Equipment malfunction
39
What causes tracheal tears in cats
* Over inflation of ETT cuff
* Turning the px while connected to breathing system
* Stylet puncture
* Extubation w/ cuff inflated
40
What are clinical sx of tracheal tears in cats
* SubQ emphysema
* Dyspnea
* Respiratory stridor
* Pneumomediastinum +/- pneumothorax
* Blood @ exubation
* may stop eating
* Cough
* Fever
41
What are some other possible complications
* Swollen feet &/or joint pain from being tied too tightly on the sx table
* Corneal ulcers
* Over admin of IVF
* Epidural need or local ax being placed directly in the nerve
42
What can be px reactions
* Anaphylatic & anaphylactoid rxn
* Anaphylactoid doesn't req exposure to antigen & is more common
43
What are pharmacogenetic diffs
Genetic variablilty that determines an indiv response to drugs
44
What are the ax concerns of bracycephalic obstructive airway syndrome (BOAS)
* Smaller ETTS are more challenging for intubation
* Preoxygenate
* Use antiemetics b/c of concern for regurgitation/reflux
* Consider anticholinergics b/c of high vagal tone
* Protect bulging eyes
* Careful drug selection & titration of drug doses
* Injectable steroid for airway inflammation
* Careful monitoring in recovery
