Exam 3: Lecture 23 - Anesthetic Complications Flashcards
(40 cards)
When do we automatically associate a death with anesthesia after surgery?
-Death that occurs within 48 hours in small animals, or up to 7 days in horses
In dogs, cats, & rabbits, about ___ % of postoperative deaths occur within 3 hours of the end of anesthesia
50%
In horses, ___% of complications occur in recovery and are neuromuscular or respiratory in nature
92%
What complications can occur days to weeks after anesthesia?
-Decreased renal or hepatic function
What are common complications that can occur during the peri-anesthetic period?
-The 4 H’s!
1. hypoventilation
2. Hypotension
3. Hypothermia
4. Hypoxemia
-CV
-Respiratory
-CNS
-Anesthetic depth
-Temperature regulation
-Dysphoric recovery
-Gastroesophageal Regurgitation (GER) & possible aspiration
What are uncommon side effects that can occur during the peri-anesthetic period?
-Metabolic
-Neuromuscular
-Post-anesthesia cortical blindness
___ is a common CV complication due to drugs, physical status of patient, other causes of vasodilation (e.g. anaphylaxis)
Hypotension (MAP < 60 mmHg or < 90 mmHg on Doppler)
How do we treat the CV complications that can occur during anesthesia?
-Decrease depth, consider fluid therapy, and vasopressor and/or positive inotrope
With hypotension, a severe decrease in ___ leads to decreased perfusion of optic nerve and kidneys
BP
How is hypertension defined?
MAP > 150 mmHg
What are CV complications associated with anesthesia?
-Hypotension
-Hypertension
-Hypovolemia due to hemorrhage
-Cardiac arrest
-Arrhythmias (consider treatment if BP is affected. Look for underlying cause)
How is hypoventilation defined?
-ETCO2 > 55 mmHg
-Most common complication, usually caused by anesthetic drugs and/or excessive anesthetic depth.
-Could be due to pre-existing co-morbidities (always check equipment!)
-Can lead to respiratory acidosis, hypoxemia, and increased intracranial pressure
What is the treatment for hypoventilation?
-Check depth and adjust if appropriate
-Provide IPPV
-Change position of patient if possible
-Check equipment
When would we see hypoxemia in anesthetized patient?
-Unlikely if intubated and on 100% O2, but can quickly become life-threatening
-SpO2 of 95% = PaO2 of 80 mmHg
-SpO2 of 90% = PaO2 of 60 mmHg
-Patient can be hypoxemic and not show cyanosis!
What is the treatment for hypoxemia?
-Check O2 flow rate for adequacy
-Check placement of ETT
-Check anesthesia machine & SpO2 probe
-Give IPPV
-Consider adding PEEP (stert w/ 2.5 cmH2O)
-Assess perfusion and support cardiac output
-Change position to sternal & discontinue anesthesia if no improvement with other interventions
What are the 5 causes of hypoxemia?
- Hypoventilation
- V/Q mismatch
- Decreased FiO2
- Right to left shunt
- Diffusion impairment
When does GER (gastro-esophageal reflux) occur during general anesthesia?
-When gastric contents pass into esophagus
-Can look like clear or brown fluid coming from nose or mouth
Up to ____ % of dogs may experience GER during general anesthesia, but not often noticed
50-60%
Can you see GER in cats?
-Yes, up to 33% incidence reported
What can GER lead to?
-Esophagitis, esophageal stricture formation, or aspiration pneumonia
What are risk factors for GER?
-Pregnancy (later stage)
-Anesthetic drug protocol (e.g. morphine)
-Abdominal & orthopedic sx
-Breed (brachycephalic, large, or deep-chested dogs)
-Expected complication of endoscopy
-Pre-existing conditions (GI disease, megaesophagus, dysphagia, regurgitation)
-Length of preop fasting time & type of food (small meal of canned food 3 hrs prior may reduce incidence of GER)
-Prolonged duration of anesthesia
-Recumbency & changes in body position during anesthesia
-Older dogs
How do we treat GER?
-Be sure ETT cuff has good seal, use pH strip to measure pH - treat if acidic or basic
-Esophagus suctioned & lavaged w/ warm water & bicarb using urinary catheter or double-lumen suction catheter, after regurgitation occurs & before patient recovers
-Sucralfate & H2-receptor antagonist can be considered
-Admin. metoclopramide by bolus & CRI at higher doses than commonly used reduced incidence
-Oral omeprazole 4 hours prior may reduce GER
-Maropitant (Cerenia_ does NOT prevent GER
What are some metabolic complications of anesthesia?
-Hypoglycemia or hyperglycemia (glycemic control important for diabetic patients, monitor BG at reg. intervals & be prepared to treat)
-Acid-base disturbance (resp. acid-base disturbance discussed in blood gas analysis lecture)
-Electrolyte imbalance
Treatment of hyperkalemia should be done
BEFORE anesthesia, even in an emergency case!
