Managing Anesthetic Complications Flashcards
True or False: accidents are inevitable
True
True or False: risk can be managed
True
True or False: anesthetic risk is independent of procedural risk
False
What is increased perioperative risk associated with?
Smaller patients
Are mortality rates in cats better or worse than for dogs?
Worse. Dogs have an overall mortality rate of 0.17% and cats have a mortality rate of 0.24%
True or False: Compared to dogs or humans, Rabbits and Horses have lower anesthetic risk for elective procedures.
False. Horses have a 2% overall anesthetic risk rate and rabbits have a 1.39%
When do more than half of all dog and cat deaths occur?
During recovery
True or False: Technical solutions and strict procedural guidelines have eliminated accidents.
False, it has decreased, but not eliminated
What are the two types of errors committed in medicine?
Errors of ignorance: mistakes we make because we don’t know enough
Errors of ineptitude: mistakes we make because we don’t make proper use of what we do know
What are the two key elements which make a system vulnerable to accidents?
Complex interactions: Complexity can be due to uncertainty to proliferation or it can be intrinsic
Tight coupling: Where what happens in one part directly and quickly affects another
True or False: Systems exhibiting complex interactions and tight coupling are less likely to have accidents than systems exhibiting linear interactions and loose coupling.
False
What are three proven methods to prevent or reduce accidents?
Teamwork
Checklists
Team discussion before the procedure produces “activation phenomenon”
What is practical drift? Give an example.
Practical drift is the slow, steady uncoupling of local practice from best practice
This occurs when individuals try to meet operational requirements by making small adjustments in recommended procedures
What should be done if an elective OHE has a subnormal temperature prior to induction?
Stop and determine what is going on
True or False: “Bad” drugs/acute drug reactions are a major cause for anesthetic accidents.
False, it is rare for them to be the reason
Which anesthetic agent is MOST associated with intraoperative hypotension?
Inhaled anesthetics
What is the intravascular residence time for isotonic crystalloid solutions like Plasmalyte M or lactate Ringer’s solution?
30 minutes
What is the intravascular residence time for isotonic colloid solutions like Vetastarch or Hetastarch?
24 hours
True or False: Giving > 10 ml/kg/hr of isotonic crystalloid fluids during anesthesia will increase urine production
False, it does not change urine production
What should you do when a patient with previously normal blood volume undergoes cardiac arrest during anesthesia?
Administer a vasopressor
When does hypoventilation occur?
When PaCO2 > 45 mmHg
When does hypoxemia occur?
SpO2 < 85-90%
PaO2 < 60-80 mmHg
When does hypothermia occur?
< 32 deg. C
When does hypotension occur?
MAP < 60 mmHg
Does giving O2 to a hypoventilating animal resolve the hypoventilation?
No
What are clinical signs associated with respiratory difficulty?
Apnea or dyspnea
Increased respiratory rate, depth, or effort
Stridor or sonorous breathing
Cyanosis
Wheezes and crackles
Deformities of head, neck, thorax
Abnormal positioning of head, neck, forelimbs
What is extra-pulmonary respiratory inadequacy?
Conditions that inhibit air movement into and out of the lungs
What is pulmonary respiratory inadequacy?
Conditions that inhibit gas exchange within the lung
What are common causes of extra-pulmonary respiratory inadequacy?
Drug-induced hypoventilation
Upper airway obstruction
Pleural cavity disease
Iatrogenic
What are common causes of pulmonary respiratory inadequacy?
Parenchymal pulmonary disease
Iatrogenic
What are causes of isoflurane-induced hypoventilation?
Increase PaCO2
Iatrogenic, extrapulmonary
What is the treatment for isoflurane-induced hypoventilation?
Improve ventilation
What are causes of propofol-induced hypoventilation?
Increase PaCO2
Iatrogenic, extrapulmonary
What is the treatment for propofol-induced hypoventilation?
Improve ventilation
What is the cause of laryngeal paralysis?
Extrapulmonary
What is the treatment for laryngeal paralysis?
Bypass obstruction to secure open airway, provide O2 as needed
What is the cause of pneumonia?
Decreased PaO2
LowV/Q ratio
Pulmonary
What is the treatment for pneumonia?
Increased FIO2
Describe physiologic stunts
Dynamic
Low V/Q units
Given 100% O2, PaO2 tends to increase
Describe anatomic shunts
Static
Venous admixture
Given 100% O2, PaO2 tends to stay the same
What is accidental hypothermia common with?
Vet anesthesia
What is accidental hyperthermia due to?
Mainly environment
How do animals normally stay warm?
Hypothalamus (central thermoregulatory center)
Shivering thermogenesis/voluntary muscle movement/cutaneous vasomotion
Oronasal countercurrent air/blood heat exchanger present in many species
What is heat loss during anesthesia due to from most common to least?
Radiation (40%)
Convection (30%)
Evaporation (20%)
Respiration (10%)
How does hypothermia affect CO? Hyperthermia?
Decrease
Increase
How does hypothermia affect impulse condition? Hyperthermia?
Decrease
Increase
How does hypothermia affect contractility? Hyperthermia?
+/- or decrease
Increase
How does hypothermia affect HR? Hyperthermia?
Decrease
Increase
How does hypothermia affect PVR? Hyperthermia?
+/- or increase
Decrease
How does hypothermia affect O2 consumption? Hyperthermia?
Decrease
Increase
How does hypothermia affect renal/hepatic function? Hyperthermia?
Decrease
Increase
How does hypothermia affect coagulation? Hyperthermia?
Decrease
Increase
How does hypothermia affect cerebral protection? Hyperthermia?
Increase
Decrease
What happens to MAC for each degree C under 37C?
Decreases 5%
Does the anesthetic requirement for febrile patients increase or decrease?
Increase
How can high IV fluid rate lead to worsened outcomes?
Increase lung water; decrease pulmonary function Increase body weight Coagulation defects Reduced gut motility Reduced tissue oxygenation Increased infection rate Decreased PCV, TP, body temperature
How do you treat hypotension?
Decrease anesthetic depth
Give IV crystalloid bolus
Give colloid
If patient is normovolemic, use a vasopressor
